wip

When recv is called in the mirroring client, we noticed an occasional panic when reading the message.

thread 'tokio-runtime-worker' panicked at 'slice index starts at 5 but ends at 0', src/messages.rs:522:18
We are still debugging the reason why this happens but adding a check for slice bounds seems like a good idea. Instead of panicking, this will return an Err to the caller which will close the connection.

.circleci/config.yml

@@ -9,16 +9,43 @@ jobs:
     # Specify the execution environment. You can specify an image from Dockerhub or use one of our Convenience Images from CircleCI's Developer Hub.
     # See: https://circleci.com/docs/2.0/configuration-reference/#docker-machine-macos-windows-executor
     docker:
-      - image: cimg/rust:1.58.1
+      - image: ghcr.io/levkk/pgcat-ci:1.67
         environment:
           RUST_LOG: info
-      - image: cimg/postgres:14.0
-        auth:
-          username: mydockerhub-user
-          password: $DOCKERHUB_PASSWORD
+          LLVM_PROFILE_FILE: /tmp/pgcat-%m-%p.profraw
+          RUSTC_BOOTSTRAP: 1
+          CARGO_INCREMENTAL: 0
+          RUSTFLAGS: "-Zprofile -Ccodegen-units=1 -Copt-level=0 -Clink-dead-code -Coverflow-checks=off -Zpanic_abort_tests -Cpanic=abort -Cinstrument-coverage"
+          RUSTDOCFLAGS: "-Cpanic=abort"
+      - image: postgres:14
+        command: ["postgres", "-p", "5432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
         environment:
           POSTGRES_USER: postgres
           POSTGRES_DB: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_INITDB_ARGS: --auth-local=md5 --auth-host=md5 --auth=md5
+      - image: postgres:14
+        command: ["postgres", "-p", "7432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+        environment:
+          POSTGRES_USER: postgres
+          POSTGRES_DB: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+      - image: postgres:14
+        command: ["postgres", "-p", "8432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+        environment:
+          POSTGRES_USER: postgres
+          POSTGRES_DB: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+      - image: postgres:14
+        command: ["postgres", "-p", "9432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+        environment:
+          POSTGRES_USER: postgres
+          POSTGRES_DB: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+
     # Add steps to the job
     # See: https://circleci.com/docs/2.0/configuration-reference/#steps
     steps:
@@ -29,17 +56,11 @@ jobs:
           name: "Lint"
           command: "cargo fmt --check"
       - run:
-          name: "Install dependencies"
-          command: "sudo apt-get update && sudo apt-get install -y psmisc postgresql-contrib-12 postgresql-client-12 ruby ruby-dev libpq-dev"
-      - run:
-          name: "Build" 
-          command: "cargo build"
-      - run:
-          name: "Test"
-          command: "cargo test"
-      - run:
-          name: "Test end-to-end"
-          command: "bash .circleci/run_tests.sh"
+          name: "Tests"
+          command: "cargo clean && cargo build && cargo test && bash .circleci/run_tests.sh && .circleci/generate_coverage.sh"
+      - store_artifacts:
+          path: /tmp/cov
+          destination: coverage-data
       - save_cache:
           key: cargo-lock-2-{{ checksum "Cargo.lock" }}
           paths:

.circleci/generate_coverage.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+# inspired by https://doc.rust-lang.org/rustc/instrument-coverage.html#tips-for-listing-the-binaries-automatically
+TEST_OBJECTS=$( \
+    for file in $(cargo test --no-run 2>&1 | grep "target/debug/deps/pgcat-[[:alnum:]]\+" -o); \
+    do \
+        printf "%s %s " --object $file; \
+    done \
+)
+
+rust-profdata merge -sparse /tmp/pgcat-*.profraw -o /tmp/pgcat.profdata
+
+bash -c "rust-cov export -ignore-filename-regex='rustc|registry' -Xdemangler=rustfilt -instr-profile=/tmp/pgcat.profdata $TEST_OBJECTS --object ./target/debug/pgcat --format lcov > ./lcov.info"
+
+genhtml lcov.info  --title "PgCat Code Coverage" --css-file ./cov-style.css --no-function-coverage --highlight --ignore-errors source --legend  --output-directory /tmp/cov --prefix $(pwd)

.circleci/pgcat.toml

@@ -5,77 +5,60 @@
 #
 # General pooler settings
 [general]
-
 # What IP to run on, 0.0.0.0 means accessible from everywhere.
 host = "0.0.0.0"
 
 # Port to run on, same as PgBouncer used in this example.
 port = 6432
 
-# How many connections to allocate per server.
-pool_size = 15
+# Whether to enable prometheus exporter or not.
+enable_prometheus_exporter = true
 
-# Pool mode (see PgBouncer docs for more).
-# session: one server connection per connected client
-# transaction: one server connection per client transaction
-pool_mode = "transaction"
+# Port at which prometheus exporter listens on.
+prometheus_exporter_port = 9930
 
 # How long to wait before aborting a server connection (ms).
-connect_timeout = 100
+connect_timeout = 1000
 
-# How much time to give `SELECT 1` health check query to return with a result (ms).
-healthcheck_timeout = 100
+# How much time to give the health check query to return with a result (ms).
+healthcheck_timeout = 1000
+
+# How long to keep connection available for immediate re-use, without running a healthcheck query on it
+healthcheck_delay = 30000
+
+# How much time to give clients during shutdown before forcibly killing client connections (ms).
+shutdown_timeout = 5000
 
 # For how long to ban a server if it fails a health check (seconds).
 ban_time = 60 # Seconds
 
-# Stats will be sent here
-statsd_address = "127.0.0.1:8125"
+# If we should log client connections
+log_client_connections = false
 
-#
-# User to use for authentication against the server.
-[user]
-name = "sharding_user"
-password = "sharding_user"
+# If we should log client disconnections
+log_client_disconnections = false
 
+# Reload config automatically if it changes.
+autoreload = true
 
-#
-# Shards in the cluster
-[shards]
+# TLS
+tls_certificate = ".circleci/server.cert"
+tls_private_key = ".circleci/server.key"
 
-# Shard 0
-[shards.0]
+# Credentials to access the virtual administrative database (pgbouncer or pgcat)
+# Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DATABASES`, etc..
+admin_username = "admin_user"
+admin_password = "admin_pass"
 
-# [ host, port, role ]
-servers = [
-    [ "127.0.0.1", 5432, "primary" ],
-    [ "localhost", 5433, "replica" ],
-    # [ "127.0.1.1", 5432, "replica" ],
-]
-# Database name (e.g. "postgres")
-database = "shard0"
-
-[shards.1]
-# [ host, port, role ]
-servers = [
-    [ "127.0.0.1", 5432, "primary" ],
-    [ "localhost", 5433, "replica" ],
-    # [ "127.0.1.1", 5432, "replica" ],
-]
-database = "shard1"
-
-[shards.2]
-# [ host, port, role ]
-servers = [
-    [ "127.0.0.1", 5432, "primary" ],
-    [ "localhost", 5433, "replica" ],
-    # [ "127.0.1.1", 5432, "replica" ],
-]
-database = "shard2"
-
-
-# Settings for our query routing layer.
-[query_router]
+# pool
+# configs are structured as pool.<pool_name>
+# the pool_name is what clients use as database name when connecting
+# For the example below a client can connect using "postgres://sharding_user:sharding_user@pgcat_host:pgcat_port/sharded_db"
+[pools.sharded_db]
+# Pool mode (see PgBouncer docs for more).
+# session: one server connection per connected client
+# transaction: one server connection per client transaction
+pool_mode = "transaction"
 
 # If the client doesn't specify, route traffic to
 # this role by default.
@@ -85,12 +68,11 @@ database = "shard2"
 # primary: all queries go to the primary unless otherwise specified.
 default_role = "any"
 
-
 # Query parser. If enabled, we'll attempt to parse
 # every incoming query to determine if it's a read or a write.
 # If it's a read query, we'll direct it to a replica. Otherwise, if it's a write,
 # we'll direct it to the primary.
-query_parser_enabled = false
+query_parser_enabled = true
 
 # If the query parser is enabled and this setting is enabled, the primary will be part of the pool of databases used for
 # load balancing of read queries. Otherwise, the primary will only be used for write
@@ -106,3 +88,64 @@ primary_reads_enabled = true
 # sha1: A hashing function based on SHA1
 #
 sharding_function = "pg_bigint_hash"
+
+# Credentials for users that may connect to this cluster
+[pools.sharded_db.users.0]
+username = "sharding_user"
+password = "sharding_user"
+# Maximum number of server connections that can be established for this user
+# The maximum number of connection from a single Pgcat process to any database in the cluster
+# is the sum of pool_size across all users.
+pool_size = 9
+statement_timeout = 0
+
+[pools.sharded_db.users.1]
+username = "other_user"
+password = "other_user"
+pool_size = 21
+statement_timeout = 30000
+
+# Shard 0
+[pools.sharded_db.shards.0]
+# [ host, port, role ]
+servers = [
+    [ "127.0.0.1", 5432, "primary" ],
+    [ "localhost", 5432, "replica" ]
+]
+# Database name (e.g. "postgres")
+database = "shard0"
+
+[pools.sharded_db.shards.1]
+servers = [
+    [ "127.0.0.1", 5432, "primary" ],
+    [ "localhost", 5432, "replica" ],
+]
+database = "shard1"
+
+[pools.sharded_db.shards.2]
+servers = [
+    [ "127.0.0.1", 5432, "primary" ],
+    [ "localhost", 5432, "replica" ],
+]
+database = "shard2"
+
+
+[pools.simple_db]
+pool_mode = "session"
+default_role = "primary"
+query_parser_enabled = true
+primary_reads_enabled = true
+sharding_function = "pg_bigint_hash"
+
+[pools.simple_db.users.0]
+username = "simple_user"
+password = "simple_user"
+pool_size = 5
+statement_timeout = 30000
+
+[pools.simple_db.shards.0]
+servers = [
+    [ "127.0.0.1", 5432, "primary" ],
+    [ "localhost", 5432, "replica" ]
+]
+database = "some_db"

.circleci/run_tests.sh

@@ -3,6 +3,9 @@
 set -e
 set -o xtrace
 
+# non-zero exit code if we provide bad configs
+(! ./target/debug/pgcat "fake_configs"  2>/dev/null)
+
 # Start PgCat with a particular log level
 # for inspection.
 function start_pgcat() {
@@ -12,14 +15,17 @@ function start_pgcat() {
 }
 
 # Setup the database with shards and user
-psql -e -h 127.0.0.1 -p 5432 -U postgres -f tests/sharding/query_routing_setup.sql
+PGPASSWORD=postgres psql -e -h 127.0.0.1 -p 5432 -U postgres -f tests/sharding/query_routing_setup.sql
+PGPASSWORD=postgres psql -e -h 127.0.0.1 -p 7432 -U postgres -f tests/sharding/query_routing_setup.sql
+PGPASSWORD=postgres psql -e -h 127.0.0.1 -p 8432 -U postgres -f tests/sharding/query_routing_setup.sql
+PGPASSWORD=postgres psql -e -h 127.0.0.1 -p 9432 -U postgres -f tests/sharding/query_routing_setup.sql
 
-# Install Toxiproxy to simulate a downed/slow database
-wget -O toxiproxy-2.1.4.deb https://github.com/Shopify/toxiproxy/releases/download/v2.1.4/toxiproxy_2.1.4_amd64.deb
-sudo dpkg -i toxiproxy-2.1.4.deb
+PGPASSWORD=sharding_user pgbench -h 127.0.0.1 -U sharding_user shard0 -i
+PGPASSWORD=sharding_user pgbench -h 127.0.0.1 -U sharding_user shard1 -i
+PGPASSWORD=sharding_user pgbench -h 127.0.0.1 -U sharding_user shard2 -i
 
 # Start Toxiproxy
-toxiproxy-server &
+LOG_LEVEL=error toxiproxy-server &
 sleep 1
 
 # Create a database at port 5433, forward it to Postgres
@@ -27,56 +33,104 @@ toxiproxy-cli create -l 127.0.0.1:5433 -u 127.0.0.1:5432 postgres_replica
 
 start_pgcat "info"
 
+# Check that prometheus is running
+curl --fail localhost:9930/metrics
+
+export PGPASSWORD=sharding_user
+export PGDATABASE=sharded_db
+
 # pgbench test
-pgbench -i -h 127.0.0.1 -p 6432 && \
-    pgbench -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol simple && \
-    pgbench -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol extended
+pgbench -U sharding_user -i -h 127.0.0.1 -p 6432
+pgbench -U sharding_user -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol simple -f tests/pgbench/simple.sql
+pgbench -U sharding_user -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol extended
 
 # COPY TO STDOUT test
-psql -h 127.0.0.1 -p 6432 -c 'COPY (SELECT * FROM pgbench_accounts LIMIT 15) TO STDOUT;' > /dev/null
+psql -U sharding_user -h 127.0.0.1 -p 6432 -c 'COPY (SELECT * FROM pgbench_accounts LIMIT 15) TO STDOUT;' > /dev/null
 
 # Query cancellation test
-(psql -h 127.0.0.1 -p 6432 -c 'SELECT pg_sleep(5)' || true) &
+(psql -U sharding_user -h 127.0.0.1 -p 6432 -c 'SELECT pg_sleep(50)' || true) &
+sleep 1
+killall psql -s SIGINT
+
+# Pause/resume test.
+# Running benches before, during, and after pause/resume.
+pgbench -U sharding_user -t 500 -c 2 -h 127.0.0.1 -p 6432 --protocol extended &
+BENCH_ONE=$!
+PGPASSWORD=admin_pass psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c 'PAUSE sharded_db,sharding_user'
+pgbench -U sharding_user -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol extended &
+BENCH_TWO=$!
+PGPASSWORD=admin_pass psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c 'RESUME sharded_db,sharding_user'
+wait ${BENCH_ONE}
+wait ${BENCH_TWO}
+
+# Reload pool (closing unused server connections)
+PGPASSWORD=admin_pass psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c 'RELOAD'
+
+(psql -U sharding_user -h 127.0.0.1 -p 6432 -c 'SELECT pg_sleep(50)' || true) &
+sleep 1
 killall psql -s SIGINT
 
 # Sharding insert
-psql -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_insert.sql
+psql -U sharding_user -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_insert.sql
 
 # Sharding select
-psql -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_select.sql > /dev/null
+psql -U sharding_user -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_select.sql > /dev/null
 
 # Replica/primary selection & more sharding tests
-psql -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_primary_replica.sql > /dev/null
+psql -U sharding_user -e -h 127.0.0.1 -p 6432 -f tests/sharding/query_routing_test_primary_replica.sql > /dev/null
+
+# Statement timeout tests
+sed -i 's/statement_timeout = 0/statement_timeout = 100/' .circleci/pgcat.toml
+kill -SIGHUP $(pgrep pgcat) # Reload config
+sleep 0.2
+
+# This should timeout
+(! psql -U sharding_user -e -h 127.0.0.1 -p 6432 -c 'select pg_sleep(0.5)')
+
+# Disable statement timeout
+sed -i 's/statement_timeout = 100/statement_timeout = 0/' .circleci/pgcat.toml
+kill -SIGHUP $(pgrep pgcat) # Reload config again
 
 #
-# ActiveRecord tests
+# Integration tests and ActiveRecord tests
 #
-cd tests/ruby && \
-    sudo gem install bundler && \
-    bundle install && \
-    ruby tests.rb && \
+cd tests/ruby
+sudo bundle install
+bundle exec ruby tests.rb --format documentation || exit 1
+bundle exec rspec *_spec.rb --format documentation || exit 1
 cd ../..
 
+#
+# Python tests
+# These tests will start and stop the pgcat server so it will need to be restarted after the tests
+#
+pip3 install -r tests/python/requirements.txt
+python3 tests/python/tests.py || exit 1
+
+start_pgcat "info"
+
 # Admin tests
-psql -e -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW STATS' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'RELOAD' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW CONFIG' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW DATABASES' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW LISTS' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW POOLS' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW VERSION' > /dev/null
-psql -h 127.0.0.1 -p 6432 -d pgbouncer -c "SET client_encoding TO 'utf8'" > /dev/null # will ignore
-(! psql -e -h 127.0.0.1 -p 6432 -d random_db -c 'SHOW STATS' > /dev/null)
+export PGPASSWORD=admin_pass
+psql -U admin_user -e -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW STATS' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c 'RELOAD' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW CONFIG' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW DATABASES' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgcat -c 'SHOW LISTS' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgcat -c 'SHOW POOLS' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgcat -c 'SHOW VERSION' > /dev/null
+psql -U admin_user -h 127.0.0.1 -p 6432 -d pgbouncer -c "SET client_encoding TO 'utf8'" > /dev/null # will ignore
+(! psql -U admin_user -e -h 127.0.0.1 -p 6432 -d random_db -c 'SHOW STATS' > /dev/null)
+export PGPASSWORD=sharding_user
 
 # Start PgCat in debug to demonstrate failover better
-start_pgcat "debug"
+start_pgcat "trace"
 
 # Add latency to the replica at port 5433 slightly above the healthcheck timeout
 toxiproxy-cli toxic add -t latency -a latency=300 postgres_replica
 sleep 1
 
 # Note the failover in the logs
-timeout 5 psql -e -h 127.0.0.1 -p 6432 <<-EOF
+timeout 5 psql -U sharding_user -e -h 127.0.0.1 -p 6432 <<-EOF
 SELECT 1;
 SELECT 1;
 SELECT 1;
@@ -88,13 +142,18 @@ toxiproxy-cli toxic remove --toxicName latency_downstream postgres_replica
 start_pgcat "info"
 
 # Test session mode (and config reload)
-sed -i 's/pool_mode = "transaction"/pool_mode = "session"/' pgcat.toml
+sed -i '0,/simple_db/s/pool_mode = "transaction"/pool_mode = "session"/' .circleci/pgcat.toml
 
 # Reload config test
 kill -SIGHUP $(pgrep pgcat)
 
+# Revert settings after reload. Makes test runs idempotent
+sed -i '0,/simple_db/s/pool_mode = "session"/pool_mode = "transaction"/' .circleci/pgcat.toml
+
+sleep 1
+
 # Prepared statements that will only work in session mode
-pgbench -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol prepared
+pgbench -U sharding_user -h 127.0.0.1 -p 6432 -t 500 -c 2 --protocol prepared
 
 # Attempt clean shut down
 killall pgcat -s SIGINT

.circleci/server.cert

@@ -0,0 +1,21 @@
+-----BEGIN CERTIFICATE-----
+MIIDazCCAlOgAwIBAgIUChIvUGFJGJe5EDch32rchqoxER0wDQYJKoZIhvcNAQEL
+BQAwRTELMAkGA1UEBhMCQVUxEzARBgNVBAgMClNvbWUtU3RhdGUxITAfBgNVBAoM
+GEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDAeFw0yMjA2MjcyMjI2MDZaFw0yMjA3
+MjcyMjI2MDZaMEUxCzAJBgNVBAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEw
+HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwggEiMA0GCSqGSIb3DQEB
+AQUAA4IBDwAwggEKAoIBAQDdTwrBzV1v79faVckFvIn/9V4fypYs4vDi3X+h3wGn
+AjEh6mmizlKCwSwAam07D9Q5zKiXFrzNJqzSioOv5zsOAvObwrnzbtKSwfs3aP5g
+eEh2clHCZYx9p06WszPcgSB5nTz1NeY4XAwvGn3A+SVCLyPMTNwnem48+ONh2F9u
+FHtSuIsEVvTjMlH09O7LjwJlODxy3HNv2JHYM5Hx9tzc+NVYdERPtaVcX8ycw1Eh
+9hgGSgfaNM52/JfRMIDhENrsn0S1omRUtcJe72loreiwrECUOLAnAfp9Xqc+rMPP
+aLA6ElzmYef1+ZEC0p6isCHPhxY5ESVhKYhE9nQvksjnAgMBAAGjUzBRMB0GA1Ud
+DgQWBBQLDtzexqjx7xPtUZuZB/angU9oSDAfBgNVHSMEGDAWgBQLDtzexqjx7xPt
+UZuZB/angU9oSDAPBgNVHRMBAf8EBTADAQH/MA0GCSqGSIb3DQEBCwUAA4IBAQC/
+mxY/a/WeLENVj2Gg9EUH0CKzfqeTey1mb6YfPGxzrD7oq1m0Vn2MmTbjZrJgh/Ob
+QckO3ElF4kC9+6XP+iDPmabGpjeLgllBboT5l2aqnD1syMrf61WPLzgRzRfplYGy
+cjBQDDKPu8Lu0QRMWU28tHYN0bMxJoCuXysGGX5WsuFnKCA6f/V+nycJJXxJH3eB
+eLjTueD9/RE3OXhi6m8A29Q1E9AE5EF4uRxYXrr91BmYnk4aFvSmBxhUEzE12eSN
+lHB/uSc0+Dp+UVmVr6wW8AQfd16UBA0BUf3kSW3aSvirYPYH0rXiOOpEJgOwOMnR
+f5+XAbN1Y+3OsFz/ZmP9
+-----END CERTIFICATE-----

.circleci/server.key

@@ -0,0 +1,28 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQDdTwrBzV1v79fa
+VckFvIn/9V4fypYs4vDi3X+h3wGnAjEh6mmizlKCwSwAam07D9Q5zKiXFrzNJqzS
+ioOv5zsOAvObwrnzbtKSwfs3aP5geEh2clHCZYx9p06WszPcgSB5nTz1NeY4XAwv
+Gn3A+SVCLyPMTNwnem48+ONh2F9uFHtSuIsEVvTjMlH09O7LjwJlODxy3HNv2JHY
+M5Hx9tzc+NVYdERPtaVcX8ycw1Eh9hgGSgfaNM52/JfRMIDhENrsn0S1omRUtcJe
+72loreiwrECUOLAnAfp9Xqc+rMPPaLA6ElzmYef1+ZEC0p6isCHPhxY5ESVhKYhE
+9nQvksjnAgMBAAECggEAbnvddO9frFhivJ+DIhgEFQKcIOb0nigV9kx6QYehvYy8
+lp/+aMb0Lk7d9r8rFQdL/icMK5GwZALg2KNKJvEbbF1Q3PwT9VHoUlgBYKJMDEFA
+e9GKu7ASuVBjTZzdUUItwkkbe5eS/aQGeSWSjlpTnX0HNCFS72qRymK+scRhsAQf
+ZoHyZHDslkvPR3Pos+sndWBYCDHag5/KoPhsMt1+5S9NQcOUHx9Ac0gLHjau3N+P
+0FhODHFFGnnpyQvLvj6u3ZOR34ladMgoBglE0O3vPFhckn92EK4teeTWOsUMotiz
+qM3QIJTOJjtiY6VDGY93bIa4pFvt7Zi4vIerenKt0QKBgQD/UMFqfevTAMrk10AC
+bOa4+cM07ORY4ZwVj5ILhZn+8crDEEtBsUyuEU2FTINtnoEq1yGc/IXpsyS1BHjL
+L1xSml5LN3jInbi8z5XQfY5Sj3VOMtwY6yD20jcdeDC44rz3nStXdkcMWxbTMapx
+iOPsap5ciUKOMS7LyMidPEG/LQKBgQDd5vHgrLN0FBIIm+vZg6MEm4QyobstVp4l
+7V/GZsdL+M8AQv1Rx+5wSUSWKomOIv5lglis7f6g0c9O7Qkr78/wzoyoKC2RRqPp
+I90GjY2Iv22N4GIkRrDAgMZbkTitzIB6tbXEVeLAOh3frFJ8IwauRCOiXIjrZdJ4
+FvV86+nU4wKBgQDdWTP2kWkMrBk7QOp7r9Jv+AmnLuHhtOdPQgOJ/bA++X2ik9PL
+Bl3GY7XjpSwks1CkxZKcucmXjPp7/X6EGXFfI/owF82dkDADca0e7lufdERtIWb0
+K5WOpz2lTPhgsiLGQfq7fw2lxqsJOnvcpqOD6gOVkmKjSDyb7F0RBJazmQKBgQDD
+a8PQTcesjpBjLI3EfX1vbVY7ENu6zfFxDV+vZoxVh8UlQdm90AlYse3JIaUKnB7W
+Xrihcucv0hZ0N6RAIW5LcFvHK7sVmdR4WbEpODhRGeTtcZJ8yBSZM898jKQRy2vK
+pYRyaADNsWDlvujVkjMr/a40KrIaPQ3h3LZNUaYYaQKBgQD1x8A5S5SiE1cN1vFr
+aACkmA2WqEDKKhUsUigJdwW6WB/B9kWlIlz/iV1H9uwBXtSIYG4VqCSTAvh0z4gX
+Qu2SrdPm5PYnKzpdynpz78OnGdflD1RKWFGHItR6GN6tj/VmulO6mlFvT4jzBQ7j
++Hf8m2TcD4U3ksz3xw+YOD+cmA==
+-----END RSA PRIVATE KEY-----

.dockerignore

@@ -2,3 +2,5 @@ target/
 tests/
 tracing/
 .circleci/
+.git/
+dev/

.github/dependabot.yml

@@ -0,0 +1,12 @@
+version: 2
+updates:
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "daily"
+      time: "04:00" # UTC
+    labels:
+      - "dependencies"
+    commit-message:
+      prefix: "chore(deps)"
+    open-pull-requests-limit: 10

.github/workflows/build-and-push.yaml

@@ -0,0 +1,54 @@
+name: Build and Push
+
+on: push
+
+env:
+  registry: ghcr.io
+  image-name: ${{ github.repository }}
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Determine tags
+        id: metadata
+        uses: docker/metadata-action@v4
+        with:
+          images: ${{ env.registry }}/${{ env.image-name }}
+          tags: |
+            type=sha,prefix=,format=long
+            type=schedule
+            type=ref,event=branch
+            type=ref,event=pr
+            type=raw,value=latest,enable={{ is_default_branch }}
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v2.1.0
+        with:
+          registry: ${{ env.registry }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push ${{ env.image-name }}
+        uses: docker/build-push-action@v3
+        with:
+          push: true
+          tags: ${{ steps.metadata.outputs.tags }}
+          labels: ${{ steps.metadata.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true

.github/workflows/publish-ci-docker-image.yml

@@ -0,0 +1,20 @@
+name: publish-ci-docker-image
+on:
+  push:
+    branches: [ main ]
+jobs:
+  publish-ci-docker-image:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build CI Docker image
+        run: |
+          docker build . -f Dockerfile.ci --tag ghcr.io/levkk/pgcat-ci:latest
+          docker run ghcr.io/levkk/pgcat-ci:latest
+          docker push ghcr.io/levkk/pgcat-ci:latest

.gitignore

@@ -1,5 +1,12 @@
+.idea
 /target
 *.deb
-.idea/*
-tests/ruby/.bundle/*
-tests/ruby/vendor/*
+.vscode
+*.profraw
+cov/
+lcov.info
+
+# Dev
+dev/.bash_history
+dev/cache
+!dev/cache/.keepme

CONFIG.md

@@ -0,0 +1,340 @@
+# PgCat Configurations 
+## `general` Section
+
+### host
+```
+path: general.host
+default: "0.0.0.0"
+```
+
+What IP to run on, 0.0.0.0 means accessible from everywhere.
+
+### port
+```
+path: general.port
+default: 6432
+```
+
+Port to run on, same as PgBouncer used in this example.
+
+### enable_prometheus_exporter
+```
+path: general.enable_prometheus_exporter
+default: true
+```
+
+Whether to enable prometheus exporter or not.
+
+### prometheus_exporter_port
+```
+path: general.prometheus_exporter_port
+default: 9930
+```
+
+Port at which prometheus exporter listens on.
+
+### connect_timeout
+```
+path: general.connect_timeout
+default: 5000 # milliseconds
+```
+
+How long to wait before aborting a server connection (ms).
+
+### idle_timeout
+```
+path: general.idle_timeout
+default: 30000 # milliseconds
+```
+
+How long an idle connection with a server is left open (ms).
+
+### healthcheck_timeout
+```
+path: general.healthcheck_timeout
+default: 1000 # milliseconds
+```
+
+How much time to give the health check query to return with a result (ms).
+
+### healthcheck_delay
+```
+path: general.healthcheck_delay
+default: 30000 # milliseconds
+```
+
+How long to keep connection available for immediate re-use, without running a healthcheck query on it
+
+### shutdown_timeout
+```
+path: general.shutdown_timeout
+default: 60000 # milliseconds
+```
+
+How much time to give clients during shutdown before forcibly killing client connections (ms).
+
+### ban_time
+```
+path: general.ban_time
+default: 60 # seconds
+```
+
+How long to ban a server if it fails a health check (seconds).
+
+### log_client_connections
+```
+path: general.log_client_connections
+default: false
+```
+
+If we should log client connections
+
+### log_client_disconnections
+```
+path: general.log_client_disconnections
+default: false
+```
+
+If we should log client disconnections
+
+### autoreload
+```
+path: general.autoreload
+default: false
+```
+
+When set to true, PgCat reloads configs if it detects a change in the config file.
+
+### worker_threads
+```
+path: general.worker_threads
+default: 5
+```
+
+Number of worker threads the Runtime will use (4 by default).
+
+### tcp_keepalives_idle
+```
+path: general.tcp_keepalives_idle
+default: 5
+```
+
+Number of seconds of connection idleness to wait before sending a keepalive packet to the server.
+
+### tcp_keepalives_count
+```
+path: general.tcp_keepalives_count
+default: 5
+```
+
+Number of unacknowledged keepalive packets allowed before giving up and closing the connection.
+
+### tcp_keepalives_interval
+```
+path: general.tcp_keepalives_interval
+default: 5
+```
+
+Number of seconds between keepalive packets.
+
+### tls_certificate
+```
+path: general.tls_certificate
+default: <UNSET>
+example: "server.cert"
+```
+
+Path to TLS Certficate file to use for TLS connections
+
+### tls_private_key
+```
+path: general.tls_private_key
+default: <UNSET>
+example: "server.key"
+```
+
+Path to TLS private key file to use for TLS connections
+
+### admin_username
+```
+path: general.admin_username
+default: "admin_user"
+```
+
+User name to access the virtual administrative database (pgbouncer or pgcat)
+Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DATABASES`, etc..
+
+### admin_password
+```
+path: general.admin_password
+default: "admin_pass"
+```
+
+Password to access the virtual administrative database
+
+## `pools.<pool_name>` Section
+
+### pool_mode
+```
+path: pools.<pool_name>.pool_mode
+default: "transaction"
+```
+
+Pool mode (see PgBouncer docs for more).
+`session` one server connection per connected client
+`transaction` one server connection per client transaction
+
+### load_balancing_mode
+```
+path: pools.<pool_name>.load_balancing_mode
+default: "random"
+```
+
+Load balancing mode
+`random` selects the server at random
+`loc` selects the server with the least outstanding busy conncetions
+
+### default_role
+```
+path: pools.<pool_name>.default_role
+default: "any"
+```
+
+If the client doesn't specify, PgCat routes traffic to this role by default.
+`any` round-robin between primary and replicas,
+`replica` round-robin between replicas only without touching the primary,
+`primary` all queries go to the primary unless otherwise specified.
+
+### query_parser_enabled (experimental)
+```
+path: pools.<pool_name>.query_parser_enabled
+default: true
+```
+
+If Query Parser is enabled, we'll attempt to parse
+every incoming query to determine if it's a read or a write.
+If it's a read query, we'll direct it to a replica. Otherwise, if it's a write,
+we'll direct it to the primary.
+
+### primary_reads_enabled
+```
+path: pools.<pool_name>.primary_reads_enabled
+default: true
+```
+
+If the query parser is enabled and this setting is enabled, the primary will be part of the pool of databases used for
+load balancing of read queries. Otherwise, the primary will only be used for write
+queries. The primary can always be explicitly selected with our custom protocol.
+
+### sharding_key_regex (experimental)
+```
+path: pools.<pool_name>.sharding_key_regex
+default: <UNSET>
+example: '/\* sharding_key: (\d+) \*/'
+```
+
+Allow sharding commands to be passed as statement comments instead of
+separate commands. If these are unset this functionality is disabled.
+
+### sharding_function
+```
+path: pools.<pool_name>.sharding_function
+default: "pg_bigint_hash"
+```
+
+So what if you wanted to implement a different hashing function,
+or you've already built one and you want this pooler to use it?
+Current options:
+`pg_bigint_hash`: PARTITION BY HASH (Postgres hashing function)
+`sha1`: A hashing function based on SHA1
+
+### automatic_sharding_key (experimental)
+```
+path: pools.<pool_name>.automatic_sharding_key
+default: <UNSET>
+example: "data.id"
+```
+
+Automatically parse this from queries and route queries to the right shard!
+
+### idle_timeout
+```
+path: pools.<pool_name>.idle_timeout
+default: 40000
+```
+
+Idle timeout can be overwritten in the pool
+
+### connect_timeout
+```
+path: pools.<pool_name>.connect_timeout
+default: 3000
+```
+
+Connect timeout can be overwritten in the pool
+
+## `pools.<pool_name>.users.<user_index>` Section
+
+### username
+```
+path: pools.<pool_name>.users.<user_index>.username
+default: "sharding_user"
+```
+
+Postgresql username
+
+### password
+```
+path: pools.<pool_name>.users.<user_index>.password
+default: "sharding_user"
+```
+
+Postgresql password
+
+### pool_size
+```
+path: pools.<pool_name>.users.<user_index>.pool_size
+default: 9
+```
+
+Maximum number of server connections that can be established for this user
+The maximum number of connection from a single Pgcat process to any database in the cluster
+is the sum of pool_size across all users.
+
+### statement_timeout
+```
+path: pools.<pool_name>.users.<user_index>.statement_timeout
+default: 0
+```
+
+Maximum query duration. Dangerous, but protects against DBs that died in a non-obvious way.
+0 means it is disabled.
+
+## `pools.<pool_name>.shards.<shard_index>` Section
+
+### servers
+```
+path: pools.<pool_name>.shards.<shard_index>.servers
+default: [["127.0.0.1", 5432, "primary"], ["localhost", 5432, "replica"]]
+```
+
+Array of servers in the shard, each server entry is an array of `[host, port, role]`
+
+### mirrors (experimental)
+```
+path: pools.<pool_name>.shards.<shard_index>.mirrors
+default: <UNSET>
+example: [["1.2.3.4", 5432, 0], ["1.2.3.4", 5432, 1]]
+```
+
+Array of mirrors for the shard, each mirror entry is an array of `[host, port, index of server in servers array]`
+Traffic hitting the server identified by the index will be sent to the mirror.
+
+### database
+```
+path: pools.<pool_name>.shards.<shard_index>.database
+default: "shard0"
+```
+
+Database name (e.g. "postgres")
+

CONTRIBUTING.md

@@ -10,10 +10,4 @@ Happy hacking!
 
 ## TODOs
 
-A non-exhaustive list of things that would be useful to implement:
-
-#### Client authentication
-MD5 is probably sufficient, but maybe others too.
-
-#### Admin
-Admin database for stats collection and pooler administration. PgBouncer gives us a nice example on how to do that, specifically how to implement `RowDescription` and `DataRow` messages, [example here](https://github.com/pgbouncer/pgbouncer/blob/4f9ced8e63d317a6ff45c8b0efa876b32161f6db/src/admin.c#L813).
+See [Issues]([url](https://github.com/levkk/pgcat/issues)).

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pgcat"
-version = "0.1.0"
+version = "0.6.0-alpha1"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -9,21 +9,34 @@ edition = "2021"
 tokio = { version = "1", features = ["full"] }
 bytes = "1"
 md-5 = "0.10"
-bb8 = "0.7"
+bb8 = "0.8.0"
 async-trait = "0.1"
 rand = "0.8"
 chrono = "0.4"
 sha-1 = "0.10"
-toml = "0.5"
+toml = "0.7"
 serde = "1"
 serde_derive = "1"
-serde_json = "1"
 regex = "1"
 num_cpus = "1"
 once_cell = "1"
-statsd = "0.15"
-sqlparser = "0.14"
+sqlparser = "0.32.0"
 log = "0.4"
 arc-swap = "1"
-env_logger = "0.9"
-parking_lot = "0.11"
+env_logger = "0.10"
+parking_lot = "0.12.1"
+hmac = "0.12"
+sha2 = "0.10"
+base64 = "0.21"
+stringprep = "0.1"
+tokio-rustls = "0.23"
+rustls-pemfile = "1"
+hyper = { version = "0.14", features = ["full"] }
+phf = { version = "0.11.1", features = ["macros"] }
+exitcode = "1.1.2"
+futures = "0.3"
+socket2 = { version = "0.4.7", features = ["all"] }
+nix = "0.26.2"
+
+[target.'cfg(not(target_env = "msvc"))'.dependencies]
+jemallocator = "0.5.0"

Dockerfile

@@ -1,11 +1,11 @@
-FROM rust:1.58-slim-buster AS builder
+FROM rust:1 AS builder
 COPY . /app
 WORKDIR /app
 RUN cargo build --release
 
-FROM debian:buster-slim
+FROM debian:bullseye-slim
 COPY --from=builder /app/target/release/pgcat /usr/bin/pgcat
 COPY --from=builder /app/pgcat.toml /etc/pgcat/pgcat.toml
 WORKDIR /etc/pgcat
 ENV RUST_LOG=info
-ENTRYPOINT ["/usr/bin/pgcat"]
+CMD ["pgcat"]

Dockerfile.ci

@@ -0,0 +1,12 @@
+FROM cimg/rust:1.67.1
+RUN sudo apt-get update && \
+	sudo apt-get install -y \
+		psmisc postgresql-contrib-14 postgresql-client-14 libpq-dev \
+		ruby ruby-dev python3 python3-pip \
+		lcov llvm-11 iproute2 && \
+	sudo apt-get upgrade curl && \
+	cargo install cargo-binutils rustfilt && \
+	rustup component add llvm-tools-preview && \
+ 	pip3 install psycopg2 && sudo gem install bundler && \
+	wget -O /tmp/toxiproxy-2.4.0.deb https://github.com/Shopify/toxiproxy/releases/download/v2.4.0/toxiproxy_2.4.0_linux_$(dpkg --print-architecture).deb && \
+	sudo dpkg -i /tmp/toxiproxy-2.4.0.deb

README.md

@@ -1,57 +1,45 @@
-# PgCat
+##### PgCat: PostgreSQL at petabyte scale
 
 [![CircleCI](https://circleci.com/gh/levkk/pgcat/tree/main.svg?style=svg)](https://circleci.com/gh/levkk/pgcat/tree/main)
+<a href="https://discord.gg/DmyJP3qJ7U" target="_blank">
+    <img src="https://img.shields.io/discord/1013868243036930099" alt="Join our Discord!" />
+</a>
 
-![PgCat](./pgcat3.png)
+PostgreSQL pooler (like PgBouncer) with sharding, load balancing and failover support.
 
-Meow. PgBouncer rewritten in Rust, with sharding, load balancing and failover support.
-
-**Alpha**: looking for alpha testers, see [#35](https://github.com/levkk/pgcat/issues/35).
+**Beta**: looking for beta testers, see [#35](https://github.com/levkk/pgcat/issues/35).
 
 ## Features
-| **Feature**                    | **Status**            | **Comments**                                                                                                                                          |
-|--------------------------------|-----------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|
-| Transaction pooling            | :white_check_mark:    | Identical to PgBouncer.                                                                                                                               |
-| Session pooling                | :white_check_mark:    | Identical to PgBouncer.                                                                                                                               |
-| `COPY` support                 | :white_check_mark:    | Both `COPY TO` and `COPY FROM` are supported.                                                                                                         |
-| Query cancellation             | :white_check_mark:    | Supported both in transaction and session pooling modes.                                                                                              |
-| Load balancing of read queries | :white_check_mark:    | Using round-robin between replicas. Primary is included when `primary_reads_enabled` is enabled (default).                                            |
-| Sharding                       | :white_check_mark:    | Transactions are sharded using `SET SHARD TO` and `SET SHARDING KEY TO` syntax extensions; see examples below.                                        |
-| Failover                       | :white_check_mark:    | Replicas are tested with a health check. If a health check fails, remaining replicas are attempted; see below for algorithm description and examples. |
-| Statistics reporting           | :white_check_mark:    | Statistics similar to PgBouncers are reported via StatsD.                                                                                             |
-| Live configuration reloading   | :construction_worker: | Reload config with a `SIGHUP` to the process, e.g. `kill -s SIGHUP $(pgrep pgcat)`. Not all settings can be reloaded without a restart.               |
-| Client authentication          | :x: :wrench:          | On the roadmap; currently all clients are allowed to connect and one user is used to connect to Postgres.                                             |
+| **Feature**                    | **Status**                  | **Comments**                                                                                                                                          |
+|--------------------------------|-----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Transaction pooling            | :white_check_mark:          | Identical to PgBouncer.                                                                                                                               |
+| Session pooling                | :white_check_mark:          | Identical to PgBouncer.                                                                                                                               |
+| `COPY` support                 | :white_check_mark:          | Both `COPY TO` and `COPY FROM` are supported.                                                                                                         |
+| Query cancellation             | :white_check_mark:          | Supported both in transaction and session pooling modes.                                                                                              |
+| Load balancing of read queries | :white_check_mark:          | Using random between replicas. Primary is included when `primary_reads_enabled` is enabled (default).                                            |
+| Sharding                       | :white_check_mark:          | Transactions are sharded using `SET SHARD TO` and `SET SHARDING KEY TO` syntax extensions; see examples below.                                        |
+| Failover                       | :white_check_mark:          | Replicas are tested with a health check. If a health check fails, remaining replicas are attempted; see below for algorithm description and examples. |
+| Statistics                     | :white_check_mark:          | Statistics available in the admin database (`pgcat` and `pgbouncer`) with `SHOW STATS`, `SHOW POOLS` and others.                                      |
+| Live configuration reloading   | :white_check_mark:          | Reload supported settings with a `SIGHUP` to the process, e.g. `kill -s SIGHUP $(pgrep pgcat)` or `RELOAD` query issued to the admin database.        |
+| Client authentication          | :white_check_mark: :wrench: | MD5 password authentication is supported, SCRAM is on the roadmap; one user is used to connect to Postgres with both SCRAM and MD5 supported.         |
+| Admin database                 | :white_check_mark:          | The admin database, similar to PgBouncer's, allows to query for statistics and reload the configuration.                                              |
 
 ## Deployment
 
-See `Dockerfile` for example deployment using Docker. The pooler is configured to spawn 4 workers so 4 CPUs are recommended for optimal performance.
-That setting can be adjusted to spawn as many (or as little) workers as needed.
+See `Dockerfile` for example deployment using Docker. The pooler is configured to spawn 4 workers so 4 CPUs are recommended for optimal performance. That setting can be adjusted to spawn as many (or as little) workers as needed.
+
+For quick local example, use the Docker Compose environment provided:
+
+```bash
+docker-compose up
+
+# In a new terminal:
+PGPASSWORD=postgres psql -h 127.0.0.1 -p 6432 -U postgres -c 'SELECT 1'
+```
 
 ### Config
 
-| **Name**                | **Description**                                                                                                                            | **Examples**                     |
-|-------------------------|--------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------|
-| **`general`**           |                                                                                                                                            |                                  |
-| `host`                  | The pooler will run on this host, 0.0.0.0 means accessible from everywhere.                                                                | `0.0.0.0`                        |
-| `port`                  | The pooler will run on this port.                                                                                                          | `6432`                           |
-| `pool_size`             | Maximum allowed server connections per pool. Pools are separated for each user/shard/server role. The connections are allocated as needed. | `15`                             |
-| `pool_mode`             | The pool mode to use, i.e. `session` or `transaction`.                                                                                     | `transaction`                    |
-| `connect_timeout`       | Maximum time to establish a connection to a server (milliseconds). If reached, the server is banned and the next target is attempted.      | `5000`                           |
-| `healthcheck_timeout`   | Maximum time to pass a health check (`SELECT 1`, milliseconds). If reached, the server is banned and the next target is attempted.         | `1000`                           |
-| `ban_time`              | Ban time for a server (seconds). It won't be allowed to serve transactions until the ban expires; failover targets will be used instead.   | `60`                             |
-| `statsd_address`        | StatsD host and port. Statistics will be sent there every 15 seconds.                                                                      | `127.0.0.1:8125`                 |
-|                         |                                                                                                                                            |                                  |
-| **`user`**              |                                                                                                                                            |                                  |
-| `name`                  | The user name.                                                                                                                             | `sharding_user`                  |
-| `password`              | The user password in plaintext.                                                                                                            | `hunter2`                        |
-|                         |                                                                                                                                            |                                  |
-| **`shards`**            | Shards are numerically numbered starting from 0; the order in the config is preserved by the pooler to route queries accordingly.          | `[shards.0]`                     |
-| `servers`               | List of servers to connect to and their roles. A server is: `[host, port, role]`, where `role` is either `primary` or `replica`.           | `["127.0.0.1", 5432, "primary"]` |
-| `database`              | The name of the database to connect to. This is the same on all servers that are part of one shard.                                        |                                  |
-| **`query_router`**      |                                                                                                                                            |                                  |
-| `default_role`          | Traffic is routed to this role by default (round-robin), unless the client specifies otherwise. Default is `any`, for any role available.  | `any`, `primary`, `replica`      |
-| `query_parser_enabled`  | Enable the query parser which will inspect incoming queries and route them to a primary or replicas.                                       | `false`                          |
-| `primary_reads_enabled` | Enable this to allow read queries on the primary; otherwise read queries are routed to the replicas.                                       | `true`                           |
+See [Configurations page](https://github.com/levkk/pgcat/blob/main/CONFIG.md)
 
 ## Local development
 
@@ -73,6 +61,14 @@ pgbench -t 1000 -p 6432 -h 127.0.0.1 --protocol extended
 
 See [sharding README](./tests/sharding/README.md) for sharding logic testing.
 
+Run `cargo test` to run Rust tests.
+
+Run the following commands to run Integration tests locally.
+```
+cd tests/docker/
+docker compose up --exit-code-from main # This will also produce coverage report under ./cov/
+```
+
 | **Feature**           | **Tested in CI**   | **Tested manually** | **Comments**                                                                                                             |
 |-----------------------|--------------------|---------------------|--------------------------------------------------------------------------------------------------------------------------|
 | Transaction pooling   | :white_check_mark: | :white_check_mark:  | Used by default for all tests.                                                                                           |
@@ -82,9 +78,20 @@ See [sharding README](./tests/sharding/README.md) for sharding logic testing.
 | Load balancing        | :white_check_mark: | :white_check_mark:  | We could test this by emitting statistics for each replica and compare them.                                             |
 | Failover              | :white_check_mark: | :white_check_mark:  | Misconfigure a replica in `pgcat.toml` and watch it forward queries to spares. CI testing is using Toxiproxy.            |
 | Sharding              | :white_check_mark: | :white_check_mark:  | See `tests/sharding` and `tests/ruby` for an Rails/ActiveRecord example.                                                 |
-| Statistics reporting  | :x:                | :white_check_mark:  | Run `nc -l -u 8125` and watch the stats come in every 15 seconds.                                                        |
+| Statistics            | :white_check_mark: | :white_check_mark:  | Query the admin database with `psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW STATS'`.                                  |
 | Live config reloading | :white_check_mark: | :white_check_mark:  | Run `kill -s SIGHUP $(pgrep pgcat)` and watch the config reload.                                                         |
 
+### Dev
+
+Also, you can open a 'dev' environment where you can debug tests easier by running the following command:
+
+```
+./dev/script/console
+```
+
+This will open a terminal in an environment similar to that used in tests. In there you can compile, run tests, do some debugging with the test environment, etc. Objects
+compiled inside the contaner (and bundled gems) will be placed in `dev/cache` so they don't interfere with what you have in your host.
+
 ## Usage
 
 ### Session mode
@@ -98,7 +105,7 @@ In transaction mode, a client talks to one server for the duration of a single t
 This mode is enabled by default.
 
 ### Load balancing of read queries
-All queries are load balanced against the configured servers using the round-robin algorithm. The most straight forward configuration example would be to put this pooler in front of several replicas and let it load balance all queries.
+All queries are load balanced against the configured servers using the random algorithm. The most straight forward configuration example would be to put this pooler in front of several replicas and let it load balance all queries.
 
 If the configuration includes a primary and replicas, the queries can be separated with the built-in query parser. The query parser will interpret the query and route all `SELECT` queries to a replica, while all other queries including explicit transactions will be routed to the primary.
 
@@ -137,18 +144,18 @@ Failover behavior can get pretty interesting (read complex) when multiple config
 
 | **Query**                 | **`SET SERVER ROLE TO`** | **`query_parser_enabled`** | **`primary_reads_enabled`** | **Target state** | **Outcome**                                                                                                                                                          |
 |---------------------------|--------------------------|----------------------------|-----------------------------|------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| Read query, i.e. `SELECT` | unset (any)              | false                      | false                       | up               | Query is routed to the first instance in the round-robin loop.                                                                                                       |
-| Read query                | unset (any)              | true                       | false                       | up               | Query is routed to the first replica instance in the round-robin loop.                                                                                               |
-| Read query                | unset (any)              | true                       | true                        | up               | Query is routed to the first instance in the round-robin loop.                                                                                                       |
-| Read query                | replica                  | false                      | false                       | up               | Query is routed to the first replica instance in the round-robin loop.                                                                                               |
+| Read query, i.e. `SELECT` | unset (any)              | false                      | false                       | up               | Query is routed to the first instance in the random loop.                                                                                                       |
+| Read query                | unset (any)              | true                       | false                       | up               | Query is routed to the first replica instance in the random loop.                                                                                               |
+| Read query                | unset (any)              | true                       | true                        | up               | Query is routed to the first instance in the random loop.                                                                                                       |
+| Read query                | replica                  | false                      | false                       | up               | Query is routed to the first replica instance in the random loop.                                                                                               |
 | Read query                | primary                  | false                      | false                       | up               | Query is routed to the primary.                                                                                                                                      |
-| Read query                | unset (any)              | false                      | false                       | down             | First instance is banned for reads. Next target in the round-robin loop is attempted.                                                                                |
-| Read query                | unset (any)              | true                       | false                       | down             | First replica instance is banned. Next replica instance is attempted in the round-robin loop.                                                                        |
-| Read query                | unset (any)              | true                       | true                        | down             | First instance (even if primary) is banned for reads. Next instance is attempted in the round-robin loop.                                                            |
-| Read query                | replica                  | false                      | false                       | down             | First replica instance is banned. Next replica instance is attempted in the round-robin loop.                                                                        |
+| Read query                | unset (any)              | false                      | false                       | down             | First instance is banned for reads. Next target in the random loop is attempted.                                                                                |
+| Read query                | unset (any)              | true                       | false                       | down             | First replica instance is banned. Next replica instance is attempted in the random loop.                                                                        |
+| Read query                | unset (any)              | true                       | true                        | down             | First instance (even if primary) is banned for reads. Next instance is attempted in the random loop.                                                            |
+| Read query                | replica                  | false                      | false                       | down             | First replica instance is banned. Next replica instance is attempted in the random loop.                                                                        |
 | Read query                | primary                  | false                      | false                       | down             | The query is attempted against the primary and fails. The client receives an error.                                                                                  |
 |                           |                          |                            |                             |                  |                                                                                                                                                                      |
-| Write query e.g. `INSERT` | unset (any)              | false                      | false                       | up               | The query is attempted against the first available instance in the round-robin loop. If the instance is a replica, the query fails and the client receives an error. |
+| Write query e.g. `INSERT` | unset (any)              | false                      | false                       | up               | The query is attempted against the first available instance in the random loop. If the instance is a replica, the query fails and the client receives an error. |
 | Write query               | unset (any)              | true                       | false                       | up               | The query is routed to the primary.                                                                                                                                  |
 | Write query               | unset (any)              | true                       | true                        | up               | The query is routed to the primary.                                                                                                                                  |
 | Write query               | primary                  | false                      | false                       | up               | The query is routed to the primary.                                                                                                                                  |
@@ -164,7 +171,7 @@ We use the `PARTITION BY HASH` hashing function, the same as used by Postgres fo
 To route queries to a particular shard, we use this custom SQL syntax:
 
 ```sql
--- To talk to a shard explicitely
+-- To talk to a shard explicitly
 SET SHARD TO '1';
 
 -- To let the pooler choose based on a value
@@ -225,11 +232,15 @@ SELECT * FROM users WHERE email = 'test@example.com'; -- shard setting lasts unt
 
 ### Statistics reporting
 
-Stats are reported using StatsD every 15 seconds. The address is configurable with `statsd_address`, the default is `127.0.0.1:8125`. The stats are very similar to what Pgbouncer reports and the names are kept to be comparable.
+The stats are very similar to what Pgbouncer reports and the names are kept to be comparable. They are accessible by querying the admin database `pgcat`, and `pgbouncer` for compatibility.
+
+```
+psql -h 127.0.0.1 -p 6432 -d pgbouncer -c 'SHOW DATABASES'
+```
 
 ### Live configuration reloading
 
-The config can be reloaded by sending a `kill -s SIGHUP` to the process. Not all settings are currently supported by live reload:
+The config can be reloaded by sending a `kill -s SIGHUP` to the process or by querying `RELOAD` to the admin database. Not all settings are currently supported by live reload:
 
 | **Config**              | **Requires restart** |
 |-------------------------|----------------------|
@@ -238,8 +249,9 @@ The config can be reloaded by sending a `kill -s SIGHUP` to the process. Not all
 | `pool_mode`             | no                   |
 | `connect_timeout`       | yes                  |
 | `healthcheck_timeout`   | no                   |
+| `shutdown_timeout`      | no                   |
+| `healthcheck_delay`     | no                   |
 | `ban_time`              | no                   |
-| `statsd_address`        | yes                  |
 | `user`                  | yes                  |
 | `shards`                | yes                  |
 | `default_role`          | no                   |
@@ -428,7 +440,7 @@ Always good to have a base line.
 
 ```
 $ pgbench -t 1000 -c 16 -j 2 -p 5432 -h 127.0.0.1 -S --protocol extended shard0
-Password: 
+Password:
 starting vacuum...end.
 transaction type: <builtin: select only>
 scaling factor: 1
@@ -442,7 +454,7 @@ tps = 139443.955722 (including connections establishing)
 tps = 142314.859075 (excluding connections establishing)
 
 $ pgbench -t 1000 -c 32 -j 2 -p 5432 -h 127.0.0.1 -S --protocol extended shard0
-Password: 
+Password:
 starting vacuum...end.
 transaction type: <builtin: select only>
 scaling factor: 1
@@ -456,7 +468,7 @@ tps = 150644.840891 (including connections establishing)
 tps = 152218.499430 (excluding connections establishing)
 
 $ pgbench -t 1000 -c 64 -j 2 -p 5432 -h 127.0.0.1 -S --protocol extended shard0
-Password: 
+Password:
 starting vacuum...end.
 transaction type: <builtin: select only>
 scaling factor: 1
@@ -470,7 +482,7 @@ tps = 152517.663404 (including connections establishing)
 tps = 153319.188482 (excluding connections establishing)
 
 $ pgbench -t 1000 -c 128 -j 2 -p 5432 -h 127.0.0.1 -S --protocol extended shard0
-Password: 
+Password:
 starting vacuum...end.
 transaction type: <builtin: select only>
 scaling factor: 1

cov-style.css

@@ -0,0 +1,158 @@
+/*
+ * Copyright 2021 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+body {
+	background-color: #f2f2f2;
+	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
+		"Noto Sans", Ubuntu, Cantarell, "Helvetica Neue", sans-serif,
+		"Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol",
+		"Noto Color Emoji";
+}
+
+.sourceHeading, .source, .coverFn,
+.testName, .testPer, .testNum,
+.coverLegendCovLo, .headerCovTableEntryLo, .coverPerLo, .coverNumLo,
+.coverLegendCovMed, .headerCovTableEntryMed, .coverPerMed, .coverNumMed,
+.coverLegendCovHi, .headerCovTableEntryHi, .coverPerHi, .coverNumHi,
+.coverFile {
+	font-family: "Menlo", "DejaVu Sans Mono", "Liberation Mono",
+		"Consolas", "Ubuntu Mono", "Courier New", "andale mono",
+		"lucida console", monospace;
+}
+
+pre {
+	font-size: 0.7875rem;
+}
+
+.headerCovTableEntry, .testPer, .testNum, .testName,
+.coverLegendCovLo, .headerCovTableEntryLo, .coverPerLo, .coverNumLo,
+.coverLegendCovMed, .headerCovTableEntryMed, .coverPerMed, .coverNumMed,
+.coverLegendCovHi, .headerCovTableEntryHi, .coverPerHi, .coverNumHi {
+	text-align: right;
+	white-space: nowrap;
+}
+
+.coverPerLo, .coverPerMed, .coverPerHi, .testPer {
+/*	font-weight: bold;*/
+}
+
+.coverNumLo, .coverNumMed, .coverNumHi, .testNum {
+	font-style: italic;
+	font-size: 90%;
+	padding-left: 1em;
+}
+
+.title {
+	font-size: 200%;
+}
+
+.tableHead {
+	text-align: center;
+	font-weight: bold;
+	background-color: #bfbfbf;
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+
+.coverFile, .coverBar, .coverFn {
+	background-color: #d9d9d9;
+}
+
+.headerCovTableHead {
+	font-weight: bold;
+	text-align: right;
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+	background-color: #d9d9d9;
+}
+
+.coverFnLo,
+.coverLegendCovLo, .headerCovTableEntryLo, .coverPerLo, .coverNumLo {
+	background-color: #f2dada;
+}
+
+.coverFnHi,
+.coverLegendCovMed, .headerCovTableEntryMed, .coverPerMed, .coverNumMed {
+	background-color: #add9ad;
+}
+
+.coverLegendCovHi, .headerCovTableEntryHi, .coverPerHi, .coverNumHi {
+	background-color: #59b359;
+}
+
+.coverBarOutline {
+	border-style: solid;
+	border-width: 1px;
+	border-color: black;
+	padding: 0px;
+}
+
+.coverFnLo, .coverFnHi {
+	text-align: right;
+}
+
+.lineNum {
+	background-color: #d9d9d9;
+}
+
+.coverLegendCov, .lineCov, .branchCov {
+	background-image: url('data:image/png;base64,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');
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+	background-position: left top;
+	background-color: #c6ffb8;
+}
+
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+	background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAgAAAABCAIAAABsYngUAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAB3RJTUUH5QMUCiMidNgp2gAAABl0RVh0Q29tbWVudABDcmVhdGVkIHdpdGggR0lNUFeBDhcAAAAPSURBVAjXY/wZIcWADQAAIa4BbZaExr0AAAAASUVORK5CYII=');
+	background-repeat: repeat-y;
+	background-position: left top;
+	background-color: #ffcfbb;
+}
+
+.coverLegendCov, .coverLegendNoCov {
+	padding: 0em 1em 0em 1em;
+}
+
+.headerItem, .headerValue, .headerValueLeg {
+	white-space: nowrap;
+}
+
+.headerItem {
+	text-align: right;
+	font-weight: bold;
+}
+
+.ruler {
+	background-color: #d9d9d9;
+}
+
+.detail {
+	font-size: 80%;
+}
+
+.versionInfo {
+	font-size: 80%;
+	text-align: right;
+}
+

dev/Dockerfile

@@ -0,0 +1,33 @@
+FROM rust:bullseye
+
+# Dependencies
+RUN apt-get update -y \
+    && apt-get install -y \
+    llvm-11 psmisc postgresql-contrib postgresql-client \
+    ruby ruby-dev libpq-dev python3 python3-pip lcov curl sudo iproute2 \
+    strace ngrep iproute2 dnsutils lsof net-tools telnet
+
+# Rust
+RUN cargo install cargo-binutils rustfilt
+RUN rustup component add llvm-tools-preview
+
+# Ruby
+RUN sudo gem install bundler
+
+# Toxyproxy
+RUN wget -O toxiproxy-2.4.0.deb https://github.com/Shopify/toxiproxy/releases/download/v2.4.0/toxiproxy_2.4.0_linux_$(dpkg --print-architecture).deb && \
+    sudo dpkg -i toxiproxy-2.4.0.deb
+
+# Config
+ENV APP_ROOT=/app
+ARG APP_USER=pgcat
+COPY dev_bashrc /etc/bash.bashrc
+
+RUN useradd -m -o -u 999 ${APP_USER} || exit 0 && mkdir ${APP_ROOT} && chown ${APP_USER} ${APP_ROOT}
+RUN adduser ${APP_USER} sudo \
+    && echo "${APP_USER} ALL=NOPASSWD: ALL" > /etc/sudoers.d/${APP_USER} \
+    && chmod ugo+s /usr/sbin/usermod /usr/sbin/groupmod
+ENV HOME=${APP_ROOT}
+WORKDIR ${APP_ROOT}
+
+ENTRYPOINT ["/bin/bash"]

dev/dev_bashrc

@@ -0,0 +1,120 @@
+# ~/.bashrc: executed by bash(1) for non-login shells.
+# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
+# for examples
+
+# FIX USER NEEDED SO WE CAN SHARE UID BETWEEN HOST AND DEV ENV
+usermod -o -u $(id -u) pgcat 
+groupmod -o -g $(id -g) pgcat 
+
+# We fix the setuid in those commands as we now have sudo
+sudo chmod ugo-s /usr/sbin/usermod /usr/sbin/groupmod 
+
+# Environment customization
+export DEV_ROOT="${APP_ROOT}/dev"
+export HISTFILE="${DEV_ROOT}/.bash_history"
+export CARGO_TARGET_DIR="${DEV_ROOT}/cache/target"
+export CARGO_HOME="${DEV_ROOT}/cache/target/.cargo"
+export BUNDLE_PATH="${DEV_ROOT}/cache/bundle"
+
+# Regular bashrc
+# If not running interactively, don't do anything
+case $- in
+  *i*) ;;
+  *) return;;
+esac
+
+# don't put duplicate lines or lines starting with space in the history.
+# See bash(1) for more options
+HISTCONTROL=ignoreboth
+
+# append to the history file, don't overwrite it
+shopt -s histappend
+
+# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
+HISTSIZE=1000
+HISTFILESIZE=2000
+
+# check the window size after each command and, if necessary,
+# update the values of LINES and COLUMNS.
+shopt -s checkwinsize
+
+# If set, the pattern "**" used in a pathname expansion context will
+# match all files and zero or more directories and subdirectories.
+#shopt -s globstar
+
+# make less more friendly for non-text input files, see lesspipe(1)
+[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"
+
+# set variable identifying the chroot you work in (used in the prompt below)
+if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
+  debian_chroot=$(cat /etc/debian_chroot)
+fi
+
+# set a fancy prompt (non-color, unless we know we "want" color)
+case "$TERM" in
+  xterm-color|*-256color) color_prompt=yes;;
+esac
+
+# uncomment for a colored prompt, if the terminal has the capability; turned
+# off by default to not distract the user: the focus in a terminal window
+# should be on the output of commands, not on the prompt
+#force_color_prompt=yes
+
+if [ -n "$force_color_prompt" ]; then
+  if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
+    # We have color support; assume it's compliant with Ecma-48
+    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
+    # a case would tend to support setf rather than setaf.)
+    color_prompt=yes
+  else
+    color_prompt=
+  fi
+fi
+
+PS1='\[\e]0;pgcat@dev-container\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]pgcat\[\033[00m\]@\[\033[01;32m\]dev-container\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\[\033[01;31m\]$(git branch &>/dev/null; if [ $? -eq 0 ]; then echo " ($(git branch | grep ^* |sed s/\*\ //))"; fi)\[\033[00m\]\$ '
+
+unset color_prompt force_color_prompt
+
+# enable color support of ls and also add handy aliases
+if [ -x /usr/bin/dircolors ]; then
+  test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
+  alias ls='ls --color=auto'
+  #alias dir='dir --color=auto'
+  #alias vdir='vdir --color=auto'
+
+  alias grep='grep --color=auto'
+  alias fgrep='fgrep --color=auto'
+  alias egrep='egrep --color=auto'
+fi
+
+# colored GCC warnings and errors
+#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'
+
+# some more ls aliases
+alias ll='ls -alF'
+alias la='ls -A'
+alias l='ls -CF'
+
+# Add an "alert" alias for long running commands.  Use like so:
+#   sleep 10; alert
+alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'
+
+# Alias definitions.
+# You may want to put all your additions into a separate file like
+# ~/.bash_aliases, instead of adding them here directly.
+# See /usr/share/doc/bash-doc/examples in the bash-doc package.
+
+if [ -f ~/.bash_aliases ]; then
+  . ~/.bash_aliases
+fi
+
+# enable programmable completion features (you don't need to enable
+# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
+# sources /etc/bash.bashrc).
+if ! shopt -oq posix; then
+  if [ -f /usr/share/bash-completion/bash_completion ]; then
+    . /usr/share/bash-completion/bash_completion
+  elif [ -f /etc/bash_completion ]; then
+    . /etc/bash_completion
+  fi
+fi

dev/docker-compose.yaml

@@ -0,0 +1,84 @@
+version: "3"
+
+x-common-definition-pg:
+  &common-definition-pg
+  image: postgres:14
+  network_mode: "service:main"
+  healthcheck:
+    test: [ "CMD-SHELL", "pg_isready -U postgres -d postgres" ]
+    interval: 5s
+    timeout: 5s
+    retries: 5
+  volumes:
+    - type: bind
+      source: ../tests/sharding/query_routing_setup.sql
+      target: /docker-entrypoint-initdb.d/query_routing_setup.sql
+    - type: bind
+      source: ../tests/sharding/partition_hash_test_setup.sql
+      target: /docker-entrypoint-initdb.d/partition_hash_test_setup.sql
+
+x-common-env-pg:
+  &common-env-pg
+  POSTGRES_USER: postgres
+  POSTGRES_DB: postgres
+  POSTGRES_PASSWORD: postgres
+
+services:
+  main:
+    image: kubernetes/pause
+
+  pg1:
+    <<: *common-definition-pg
+    environment:
+      <<: *common-env-pg
+      POSTGRES_INITDB_ARGS: --auth-local=md5 --auth-host=md5 --auth=md5
+      PGPORT: 5432
+    command: ["postgres", "-p", "5432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+
+  pg2:
+    <<: *common-definition-pg
+    environment:
+      <<: *common-env-pg
+      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+      PGPORT: 7432
+    command: ["postgres", "-p", "7432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+  pg3:
+    <<: *common-definition-pg
+    environment:
+      <<: *common-env-pg
+      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+      PGPORT: 8432
+    command: ["postgres", "-p", "8432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+  pg4:
+    <<: *common-definition-pg
+    environment:
+      <<: *common-env-pg
+      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+      PGPORT: 9432
+    command: ["postgres", "-p", "9432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+
+  toxiproxy:
+    build: .
+    network_mode: "service:main"
+    container_name: toxiproxy
+    environment:
+      LOG_LEVEL: info
+    entrypoint: toxiproxy-server
+    depends_on:
+      - pg1
+      - pg2
+      - pg3
+      - pg4
+
+  pgcat-shell:
+    stdin_open: true
+    user: "${HOST_UID}:${HOST_GID}"
+    build: .
+    network_mode: "service:main"
+    depends_on:
+      - toxiproxy
+    volumes:
+      - ../:/app/
+    entrypoint:
+      - /bin/bash
+      - -i

dev/script/console

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+export HOST_UID="$(id -u)"
+export HOST_GID="$(id -g)"
+
+if [[ "${1}" == "down" ]]; then
+	docker-compose -f "${DIR}/../docker-compose.yaml" down
+	exit 0
+else
+	docker-compose -f "${DIR}/../docker-compose.yaml" run --rm pgcat-shell
+fi

docker-compose.yml

@@ -0,0 +1,17 @@
+version: "3"
+services:
+  postgres:
+    image: postgres:14
+    environment:
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_HOST_AUTH_METHOD: md5
+  pgcat:
+    build: .
+    command:
+      - "pgcat"
+      - "/etc/pgcat/pgcat.toml"
+    volumes:
+      - "${PWD}/examples/docker/pgcat.toml:/etc/pgcat/pgcat.toml"
+    ports:
+      - "6432:6432"
+      - "9930:9930"

examples/docker/pgcat.toml

@@ -0,0 +1,126 @@
+#
+# PgCat config example.
+#
+
+#
+# General pooler settings
+[general]
+# What IP to run on, 0.0.0.0 means accessible from everywhere.
+host = "0.0.0.0"
+
+# Port to run on, same as PgBouncer used in this example.
+port = 6432
+
+# Whether to enable prometheus exporter or not.
+enable_prometheus_exporter = true
+
+# Port at which prometheus exporter listens on.
+prometheus_exporter_port = 9930
+
+# How long to wait before aborting a server connection (ms).
+connect_timeout = 5000
+
+# How much time to give `SELECT 1` health check query to return with a result (ms).
+healthcheck_timeout = 1000
+
+# How long to keep connection available for immediate re-use, without running a healthcheck query on it
+healthcheck_delay = 30000
+
+# How much time to give clients during shutdown before forcibly killing client connections (ms).
+shutdown_timeout = 60000
+
+# For how long to ban a server if it fails a health check (seconds).
+ban_time = 60 # seconds
+
+# If we should log client connections
+log_client_connections = false
+
+# If we should log client disconnections
+log_client_disconnections = false
+
+# Reload config automatically if it changes.
+autoreload = false
+
+# TLS
+# tls_certificate = "server.cert"
+# tls_private_key = "server.key"
+
+# Credentials to access the virtual administrative database (pgbouncer or pgcat)
+# Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DATABASES`, etc..
+admin_username = "postgres"
+admin_password = "postgres"
+
+# pool
+# configs are structured as pool.<pool_name>
+# the pool_name is what clients use as database name when connecting
+# For the example below a client can connect using "postgres://sharding_user:sharding_user@pgcat_host:pgcat_port/sharded"
+[pools.postgres]
+# Pool mode (see PgBouncer docs for more).
+# session: one server connection per connected client
+# transaction: one server connection per client transaction
+pool_mode = "transaction"
+
+# If the client doesn't specify, route traffic to
+# this role by default.
+#
+# any: round-robin between primary and replicas,
+# replica: round-robin between replicas only without touching the primary,
+# primary: all queries go to the primary unless otherwise specified.
+default_role = "any"
+
+# Query parser. If enabled, we'll attempt to parse
+# every incoming query to determine if it's a read or a write.
+# If it's a read query, we'll direct it to a replica. Otherwise, if it's a write,
+# we'll direct it to the primary.
+query_parser_enabled = true
+
+# If the query parser is enabled and this setting is enabled, the primary will be part of the pool of databases used for
+# load balancing of read queries. Otherwise, the primary will only be used for write
+# queries. The primary can always be explicitely selected with our custom protocol.
+primary_reads_enabled = true
+
+# So what if you wanted to implement a different hashing function,
+# or you've already built one and you want this pooler to use it?
+#
+# Current options:
+#
+# pg_bigint_hash: PARTITION BY HASH (Postgres hashing function)
+# sha1: A hashing function based on SHA1
+#
+sharding_function = "pg_bigint_hash"
+
+# Credentials for users that may connect to this cluster
+[pools.postgres.users.0]
+username = "postgres"
+password = "postgres"
+# Maximum number of server connections that can be established for this user
+# The maximum number of connection from a single Pgcat process to any database in the cluster
+# is the sum of pool_size across all users.
+pool_size = 9
+
+# Maximum query duration. Dangerous, but protects against DBs that died in a non-obvious way.
+statement_timeout = 0
+
+# Shard 0
+[pools.postgres.shards.0]
+# [ host, port, role ]
+servers = [
+    [ "postgres", 5432, "primary" ],
+    [ "postgres", 5432, "replica" ]
+]
+# Database name (e.g. "postgres")
+database = "postgres"
+
+[pools.postgres.shards.1]
+servers = [
+    [ "postgres", 5432, "primary" ],
+    [ "postgres", 5432, "replica" ],
+]
+database = "postgres"
+
+[pools.postgres.shards.2]
+servers = [
+    [ "postgres", 5432, "primary" ],
+    [ "postgres", 5432, "replica" ],
+]
+database = "postgres"

pgcat.toml

@@ -5,104 +5,181 @@
 #
 # General pooler settings
 [general]
-
 # What IP to run on, 0.0.0.0 means accessible from everywhere.
 host = "0.0.0.0"
 
 # Port to run on, same as PgBouncer used in this example.
 port = 6432
 
-# How many connections to allocate per server.
-pool_size = 15
+# Whether to enable prometheus exporter or not.
+enable_prometheus_exporter = true
 
-# Pool mode (see PgBouncer docs for more).
-# session: one server connection per connected client
-# transaction: one server connection per client transaction
-pool_mode = "transaction"
+# Port at which prometheus exporter listens on.
+prometheus_exporter_port = 9930
 
 # How long to wait before aborting a server connection (ms).
-connect_timeout = 5000
+connect_timeout = 5000 # milliseconds
 
-# How much time to give `SELECT 1` health check query to return with a result (ms).
-healthcheck_timeout = 1000
+# How long an idle connection with a server is left open (ms).
+idle_timeout = 30000 # milliseconds
 
-# For how long to ban a server if it fails a health check (seconds).
-ban_time = 60 # Seconds
+# How much time to give the health check query to return with a result (ms).
+healthcheck_timeout = 1000 # milliseconds
 
-# Stats will be sent here
-statsd_address = "127.0.0.1:8125"
+# How long to keep connection available for immediate re-use, without running a healthcheck query on it
+healthcheck_delay = 30000 # milliseconds
 
-#
-# User to use for authentication against the server.
-[user]
-name = "sharding_user"
-password = "sharding_user"
+# How much time to give clients during shutdown before forcibly killing client connections (ms).
+shutdown_timeout = 60000 # milliseconds
 
+# How long to ban a server if it fails a health check (seconds).
+ban_time = 60 # seconds
 
-#
-# Shards in the cluster
-[shards]
+# If we should log client connections
+log_client_connections = false
 
-# Shard 0
-[shards.0]
+# If we should log client disconnections
+log_client_disconnections = false
 
-# [ host, port, role ]
-servers = [
-    ["127.0.0.1", 5432, "primary"],
-    ["localhost", 5432, "replica"],
-    # [ "127.0.1.1", 5432, "replica" ],
-]
-# Database name (e.g. "postgres")
-database = "shard0"
+# When set to true, PgCat reloads configs if it detects a change in the config file.
+autoreload = false
 
-[shards.1]
-# [ host, port, role ]
-servers = [
-    ["127.0.0.1", 5432, "primary"],
-    ["localhost", 5432, "replica"],
-    # [ "127.0.1.1", 5432, "replica" ],
-]
-database = "shard1"
+# Number of worker threads the Runtime will use (4 by default).
+worker_threads = 5
 
-[shards.2]
-# [ host, port, role ]
-servers = [
-    ["127.0.0.1", 5432, "primary"],
-    ["localhost", 5432, "replica"],
-    # [ "127.0.1.1", 5432, "replica" ],
-]
-database = "shard2"
+# Number of seconds of connection idleness to wait before sending a keepalive packet to the server.
+tcp_keepalives_idle = 5
+# Number of unacknowledged keepalive packets allowed before giving up and closing the connection.
+tcp_keepalives_count = 5
+# Number of seconds between keepalive packets.
+tcp_keepalives_interval = 5
 
+# Path to TLS Certficate file to use for TLS connections
+# tls_certificate = "server.cert"
+# Path to TLS private key file to use for TLS connections
+# tls_private_key = "server.key"
 
-# Settings for our query routing layer.
-[query_router]
+# User name to access the virtual administrative database (pgbouncer or pgcat)
+# Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DATABASES`, etc..
+admin_username = "admin_user"
+# Password to access the virtual administrative database
+admin_password = "admin_pass"
 
-# If the client doesn't specify, route traffic to
-# this role by default.
-#
-# any: round-robin between primary and replicas,
-# replica: round-robin between replicas only without touching the primary,
-# primary: all queries go to the primary unless otherwise specified.
+# pool configs are structured as pool.<pool_name>
+# the pool_name is what clients use as database name when connecting.
+# For a pool named `sharded_db`, clients access that pool using connection string like
+# `postgres://sharding_user:sharding_user@pgcat_host:pgcat_port/sharded_db`
+[pools.sharded_db]
+# Pool mode (see PgBouncer docs for more).
+# `session` one server connection per connected client
+# `transaction` one server connection per client transaction
+pool_mode = "transaction"
+
+# Load balancing mode
+# `random` selects the server at random
+# `loc` selects the server with the least outstanding busy conncetions
+load_balancing_mode = "random"
+
+# If the client doesn't specify, PgCat routes traffic to this role by default.
+# `any` round-robin between primary and replicas,
+# `replica` round-robin between replicas only without touching the primary,
+# `primary` all queries go to the primary unless otherwise specified.
 default_role = "any"
 
-
-# Query parser. If enabled, we'll attempt to parse
+# If Query Parser is enabled, we'll attempt to parse
 # every incoming query to determine if it's a read or a write.
 # If it's a read query, we'll direct it to a replica. Otherwise, if it's a write,
 # we'll direct it to the primary.
-query_parser_enabled = false
+query_parser_enabled = true
 
 # If the query parser is enabled and this setting is enabled, the primary will be part of the pool of databases used for
 # load balancing of read queries. Otherwise, the primary will only be used for write
-# queries. The primary can always be explicitely selected with our custom protocol.
+# queries. The primary can always be explicitly selected with our custom protocol.
 primary_reads_enabled = true
 
+# Allow sharding commands to be passed as statement comments instead of
+# separate commands. If these are unset this functionality is disabled.
+# sharding_key_regex = '/\* sharding_key: (\d+) \*/'
+# shard_id_regex = '/\* shard_id: (\d+) \*/'
+# regex_search_limit = 1000 # only look at the first 1000 characters of SQL statements
+
 # So what if you wanted to implement a different hashing function,
 # or you've already built one and you want this pooler to use it?
-#
 # Current options:
-#
-# pg_bigint_hash: PARTITION BY HASH (Postgres hashing function)
-# sha1: A hashing function based on SHA1
-#
+# `pg_bigint_hash`: PARTITION BY HASH (Postgres hashing function)
+# `sha1`: A hashing function based on SHA1
 sharding_function = "pg_bigint_hash"
+
+# Automatically parse this from queries and route queries to the right shard!
+# automatic_sharding_key = "data.id"
+
+# Idle timeout can be overwritten in the pool
+idle_timeout = 40000
+
+# Connect timeout can be overwritten in the pool
+connect_timeout = 3000
+
+# User configs are structured as pool.<pool_name>.users.<user_index>
+# This secion holds the credentials for users that may connect to this cluster
+[pools.sharded_db.users.0]
+# Postgresql username
+username = "sharding_user"
+# Postgresql password
+password = "sharding_user"
+# Maximum number of server connections that can be established for this user
+# The maximum number of connection from a single Pgcat process to any database in the cluster
+# is the sum of pool_size across all users.
+pool_size = 9
+
+# Maximum query duration. Dangerous, but protects against DBs that died in a non-obvious way.
+# 0 means it is disabled.
+statement_timeout = 0
+
+[pools.sharded_db.users.1]
+username = "other_user"
+password = "other_user"
+pool_size = 21
+statement_timeout = 15000
+
+# Shard configs are structured as pool.<pool_name>.shards.<shard_id>
+# Each shard config contains a list of servers that make up the shard
+# and the database name to use.
+[pools.sharded_db.shards.0]
+# Array of servers in the shard, each server entry is an array of `[host, port, role]`
+servers = [["127.0.0.1", 5432, "primary"], ["localhost", 5432, "replica"]]
+
+# Array of mirrors for the shard, each mirror entry is an array of `[host, port, index of server in servers array]`
+# Traffic hitting the server identified by the index will be sent to the mirror.
+# mirrors = [["1.2.3.4", 5432, 0], ["1.2.3.4", 5432, 1]]
+
+# Database name (e.g. "postgres")
+database = "shard0"
+
+[pools.sharded_db.shards.1]
+servers = [["127.0.0.1", 5432, "primary"], ["localhost", 5432, "replica"]]
+database = "shard1"
+
+[pools.sharded_db.shards.2]
+servers = [["127.0.0.1", 5432, "primary" ], ["localhost", 5432, "replica" ]]
+database = "shard2"
+
+
+[pools.simple_db]
+pool_mode = "session"
+default_role = "primary"
+query_parser_enabled = true
+primary_reads_enabled = true
+sharding_function = "pg_bigint_hash"
+
+[pools.simple_db.users.0]
+username = "simple_user"
+password = "simple_user"
+pool_size = 5
+statement_timeout = 0
+
+[pools.simple_db.shards.0]
+servers = [
+    [ "127.0.0.1", 5432, "primary" ],
+    [ "localhost", 5432, "replica" ]
+]
+database = "some_db"

src/admin.rs

@@ -1,87 +1,174 @@
+use crate::pool::BanReason;
+/// Admin database.
 use bytes::{Buf, BufMut, BytesMut};
-use log::{info, trace};
-use tokio::net::tcp::OwnedWriteHalf;
-
+use log::{error, info, trace};
+use nix::sys::signal::{self, Signal};
+use nix::unistd::Pid;
 use std::collections::HashMap;
+use std::time::{SystemTime, UNIX_EPOCH};
+use tokio::time::Instant;
 
-use crate::config::{get_config, parse};
+use crate::config::{get_config, reload_config, VERSION};
 use crate::errors::Error;
 use crate::messages::*;
-use crate::pool::ConnectionPool;
-use crate::stats::get_stats;
+use crate::pool::{get_all_pools, get_pool};
+use crate::stats::{
+    get_address_stats, get_client_stats, get_pool_stats, get_server_stats, ClientState, ServerState,
+};
+use crate::ClientServerMap;
 
-/// Handle admin client
-pub async fn handle_admin(
-    stream: &mut OwnedWriteHalf,
+pub fn generate_server_info_for_admin() -> BytesMut {
+    let mut server_info = BytesMut::new();
+
+    server_info.put(server_parameter_message("application_name", ""));
+    server_info.put(server_parameter_message("client_encoding", "UTF8"));
+    server_info.put(server_parameter_message("server_encoding", "UTF8"));
+    server_info.put(server_parameter_message("server_version", VERSION));
+    server_info.put(server_parameter_message("DateStyle", "ISO, MDY"));
+
+    server_info
+}
+
+/// Handle admin client.
+pub async fn handle_admin<T>(
+    stream: &mut T,
     mut query: BytesMut,
-    pool: ConnectionPool,
-) -> Result<(), Error> {
+    client_server_map: ClientServerMap,
+) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let code = query.get_u8() as char;
 
     if code != 'Q' {
-        return Err(Error::ProtocolSyncError);
+        return Err(Error::ProtocolSyncError(format!(
+            "Invalid code, expected 'Q' but got '{}'",
+            code
+        )));
     }
 
     let len = query.get_i32() as usize;
-    let query = String::from_utf8_lossy(&query[..len - 5])
-        .to_string()
-        .to_ascii_uppercase();
+    let query = String::from_utf8_lossy(&query[..len - 5]).to_string();
 
     trace!("Admin query: {}", query);
 
-    if query.starts_with("SHOW STATS") {
-        trace!("SHOW STATS");
-        show_stats(stream).await
-    } else if query.starts_with("RELOAD") {
-        trace!("RELOAD");
-        reload(stream).await
-    } else if query.starts_with("SHOW CONFIG") {
-        trace!("SHOW CONFIG");
-        show_config(stream).await
-    } else if query.starts_with("SHOW DATABASES") {
-        trace!("SHOW DATABASES");
-        show_databases(stream, &pool).await
-    } else if query.starts_with("SHOW POOLS") {
-        trace!("SHOW POOLS");
-        show_pools(stream, &pool).await
-    } else if query.starts_with("SHOW LISTS") {
-        trace!("SHOW LISTS");
-        show_lists(stream, &pool).await
-    } else if query.starts_with("SHOW VERSION") {
-        trace!("SHOW VERSION");
-        show_version(stream).await
-    } else if query.starts_with("SET ") {
-        trace!("SET");
-        ignore_set(stream).await
-    } else {
-        error_response(stream, "Unsupported query against the admin database").await
+    let query_parts: Vec<&str> = query.trim_end_matches(';').split_whitespace().collect();
+
+    match query_parts[0].to_ascii_uppercase().as_str() {
+        "BAN" => {
+            trace!("BAN");
+            ban(stream, query_parts).await
+        }
+        "UNBAN" => {
+            trace!("UNBAN");
+            unban(stream, query_parts).await
+        }
+        "RELOAD" => {
+            trace!("RELOAD");
+            reload(stream, client_server_map).await
+        }
+        "SET" => {
+            trace!("SET");
+            ignore_set(stream).await
+        }
+        "PAUSE" => {
+            trace!("PAUSE");
+            pause(stream, query_parts[1]).await
+        }
+        "RESUME" => {
+            trace!("RESUME");
+            resume(stream, query_parts[1]).await
+        }
+        "SHUTDOWN" => {
+            trace!("SHUTDOWN");
+            shutdown(stream).await
+        }
+        "SHOW" => match query_parts[1].to_ascii_uppercase().as_str() {
+            "BANS" => {
+                trace!("SHOW BANS");
+                show_bans(stream).await
+            }
+            "CONFIG" => {
+                trace!("SHOW CONFIG");
+                show_config(stream).await
+            }
+            "DATABASES" => {
+                trace!("SHOW DATABASES");
+                show_databases(stream).await
+            }
+            "LISTS" => {
+                trace!("SHOW LISTS");
+                show_lists(stream).await
+            }
+            "POOLS" => {
+                trace!("SHOW POOLS");
+                show_pools(stream).await
+            }
+            "CLIENTS" => {
+                trace!("SHOW CLIENTS");
+                show_clients(stream).await
+            }
+            "SERVERS" => {
+                trace!("SHOW SERVERS");
+                show_servers(stream).await
+            }
+            "STATS" => {
+                trace!("SHOW STATS");
+                show_stats(stream).await
+            }
+            "VERSION" => {
+                trace!("SHOW VERSION");
+                show_version(stream).await
+            }
+            "USERS" => {
+                trace!("SHOW USERS");
+                show_users(stream).await
+            }
+            _ => error_response(stream, "Unsupported SHOW query against the admin database").await,
+        },
+        _ => error_response(stream, "Unsupported query against the admin database").await,
     }
 }
 
-/// SHOW LISTS
-async fn show_lists(stream: &mut OwnedWriteHalf, pool: &ConnectionPool) -> Result<(), Error> {
-    let stats = get_stats();
+/// Column-oriented statistics.
+async fn show_lists<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let client_stats = get_client_stats();
+    let server_stats = get_server_stats();
 
     let columns = vec![("list", DataType::Text), ("items", DataType::Int4)];
 
+    let mut users = 1;
+    let mut databases = 1;
+    for (_, pool) in get_all_pools() {
+        databases += pool.databases();
+        users += 1; // One user per pool
+    }
     let mut res = BytesMut::new();
     res.put(row_description(&columns));
     res.put(data_row(&vec![
         "databases".to_string(),
-        (pool.databases() + 1).to_string(), // see comment below
+        databases.to_string(),
     ]));
-    res.put(data_row(&vec!["users".to_string(), "1".to_string()]));
-    res.put(data_row(&vec![
-        "pools".to_string(),
-        (pool.databases() + 1).to_string(), // +1 for the pgbouncer admin db pool which isn't real
-    ])); // but admin tools that work with pgbouncer want this
+    res.put(data_row(&vec!["users".to_string(), users.to_string()]));
+    res.put(data_row(&vec!["pools".to_string(), databases.to_string()]));
     res.put(data_row(&vec![
         "free_clients".to_string(),
-        stats["cl_idle"].to_string(),
+        client_stats
+            .keys()
+            .filter(|client_id| client_stats.get(client_id).unwrap().state == ClientState::Idle)
+            .count()
+            .to_string(),
     ]));
     res.put(data_row(&vec![
         "used_clients".to_string(),
-        stats["cl_active"].to_string(),
+        client_stats
+            .keys()
+            .filter(|client_id| client_stats.get(client_id).unwrap().state == ClientState::Active)
+            .count()
+            .to_string(),
     ]));
     res.put(data_row(&vec![
         "login_clients".to_string(),
@@ -89,11 +176,19 @@ async fn show_lists(stream: &mut OwnedWriteHalf, pool: &ConnectionPool) -> Resul
     ]));
     res.put(data_row(&vec![
         "free_servers".to_string(),
-        stats["sv_idle"].to_string(),
+        server_stats
+            .keys()
+            .filter(|server_id| server_stats.get(server_id).unwrap().state == ServerState::Idle)
+            .count()
+            .to_string(),
     ]));
     res.put(data_row(&vec![
         "used_servers".to_string(),
-        stats["sv_active"].to_string(),
+        server_stats
+            .keys()
+            .filter(|server_id| server_stats.get(server_id).unwrap().state == ServerState::Active)
+            .count()
+            .to_string(),
     ]));
     res.put(data_row(&vec!["dns_names".to_string(), "0".to_string()]));
     res.put(data_row(&vec!["dns_zones".to_string(), "0".to_string()]));
@@ -106,35 +201,39 @@ async fn show_lists(stream: &mut OwnedWriteHalf, pool: &ConnectionPool) -> Resul
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }
 
-/// SHOW VERSION
-async fn show_version(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
+/// Show PgCat version.
+async fn show_version<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let mut res = BytesMut::new();
 
     res.put(row_description(&vec![("version", DataType::Text)]));
-    res.put(data_row(&vec!["PgCat 0.1.0".to_string()]));
+    res.put(data_row(&vec![format!("PgCat {}", VERSION)]));
     res.put(command_complete("SHOW"));
 
     res.put_u8(b'Z');
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }
 
-/// SHOW POOLS
-async fn show_pools(stream: &mut OwnedWriteHalf, _pool: &ConnectionPool) -> Result<(), Error> {
-    let stats = get_stats();
-    let config = {
-        let guard = get_config();
-        &*guard.clone()
-    };
+/// Show utilization of connection pools for each shard and replicas.
+async fn show_pools<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let all_pool_stats = get_pool_stats();
 
     let columns = vec![
         ("database", DataType::Text),
         ("user", DataType::Text),
+        ("pool_mode", DataType::Text),
+        ("cl_idle", DataType::Numeric),
         ("cl_active", DataType::Numeric),
         ("cl_waiting", DataType::Numeric),
         ("cl_cancel_req", DataType::Numeric),
@@ -145,37 +244,50 @@ async fn show_pools(stream: &mut OwnedWriteHalf, _pool: &ConnectionPool) -> Resu
         ("sv_login", DataType::Numeric),
         ("maxwait", DataType::Numeric),
         ("maxwait_us", DataType::Numeric),
-        ("pool_mode", DataType::Text),
     ];
 
     let mut res = BytesMut::new();
     res.put(row_description(&columns));
+    for (user_pool, pool) in get_all_pools() {
+        let def = HashMap::default();
+        let pool_stats = all_pool_stats
+            .get(&(user_pool.db.clone(), user_pool.user.clone()))
+            .unwrap_or(&def);
 
-    let mut row = vec![String::from("all"), config.user.name.clone()];
-
-    for column in &columns[2..columns.len() - 1] {
-        let value = stats.get(column.0).unwrap_or(&0).to_string();
-        row.push(value);
+        let pool_config = &pool.settings;
+        let mut row = vec![
+            user_pool.db.clone(),
+            user_pool.user.clone(),
+            pool_config.pool_mode.to_string(),
+        ];
+        for column in &columns[3..columns.len()] {
+            let value = match column.0 {
+                "maxwait" => (pool_stats.get("maxwait_us").unwrap_or(&0) / 1_000_000).to_string(),
+                "maxwait_us" => {
+                    (pool_stats.get("maxwait_us").unwrap_or(&0) % 1_000_000).to_string()
+                }
+                _other_values => pool_stats.get(column.0).unwrap_or(&0).to_string(),
+            };
+            row.push(value);
+        }
+        res.put(data_row(&row));
     }
 
-    row.push(config.general.pool_mode.to_string());
-
-    res.put(data_row(&row));
     res.put(command_complete("SHOW"));
 
+    // ReadyForQuery
     res.put_u8(b'Z');
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }
 
-/// SHOW DATABASES
-async fn show_databases(stream: &mut OwnedWriteHalf, pool: &ConnectionPool) -> Result<(), Error> {
-    let guard = get_config();
-    let config = &*guard.clone();
-    drop(guard);
-
+/// Show shards and replicas.
+async fn show_databases<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     // Columns
     let columns = vec![
         ("name", DataType::Text),
@@ -195,34 +307,44 @@ async fn show_databases(stream: &mut OwnedWriteHalf, pool: &ConnectionPool) -> R
 
     let mut res = BytesMut::new();
 
-    // RowDescription
     res.put(row_description(&columns));
 
-    for shard in 0..pool.shards() {
-        let database_name = &config.shards[&shard.to_string()].database;
+    for (_, pool) in get_all_pools() {
+        let pool_config = pool.settings.clone();
+        for shard in 0..pool.shards() {
+            let database_name = &pool.address(shard, 0).database;
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                let pool_state = pool.pool_state(shard, server);
+                let banned = pool.is_banned(address);
+                let paused = pool.paused();
 
-        for server in 0..pool.servers(shard) {
-            let address = pool.address(shard, server);
-            let pool_state = pool.pool_state(shard, server);
-
-            res.put(data_row(&vec![
-                address.name(),                       // name
-                address.host.to_string(),             // host
-                address.port.to_string(),             // port
-                database_name.to_string(),            // database
-                config.user.name.to_string(),         // force_user
-                config.general.pool_size.to_string(), // pool_size
-                "0".to_string(),                      // min_pool_size
-                "0".to_string(),                      // reserve_pool
-                config.general.pool_mode.to_string(), // pool_mode
-                config.general.pool_size.to_string(), // max_connections
-                pool_state.connections.to_string(),   // current_connections
-                "0".to_string(),                      // paused
-                "0".to_string(),                      // disabled
-            ]));
+                res.put(data_row(&vec![
+                    address.name(),                         // name
+                    address.host.to_string(),               // host
+                    address.port.to_string(),               // port
+                    database_name.to_string(),              // database
+                    pool_config.user.username.to_string(),  // force_user
+                    pool_config.user.pool_size.to_string(), // pool_size
+                    "0".to_string(),                        // min_pool_size
+                    "0".to_string(),                        // reserve_pool
+                    pool_config.pool_mode.to_string(),      // pool_mode
+                    pool_config.user.pool_size.to_string(), // max_connections
+                    pool_state.connections.to_string(),     // current_connections
+                    match paused {
+                        // paused
+                        true => "1".to_string(),
+                        false => "0".to_string(),
+                    },
+                    match banned {
+                        // disabled
+                        true => "1".to_string(),
+                        false => "0".to_string(),
+                    },
+                ]));
+            }
         }
     }
-
     res.put(command_complete("SHOW"));
 
     // ReadyForQuery
@@ -230,31 +352,188 @@ async fn show_databases(stream: &mut OwnedWriteHalf, pool: &ConnectionPool) -> R
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }
 
 /// Ignore any SET commands the client sends.
 /// This is common initialization done by ORMs.
-async fn ignore_set(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
+async fn ignore_set<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     custom_protocol_response_ok(stream, "SET").await
 }
 
-/// RELOAD
-async fn reload(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
+/// Bans a host from being used
+async fn ban<T>(stream: &mut T, tokens: Vec<&str>) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let host = match tokens.get(1) {
+        Some(host) => host,
+        None => return error_response(stream, "usage: BAN hostname duration_seconds").await,
+    };
+
+    let duration_seconds = match tokens.get(2) {
+        Some(duration_seconds) => match duration_seconds.parse::<i64>() {
+            Ok(duration_seconds) => duration_seconds,
+            Err(_) => {
+                return error_response(stream, "duration_seconds must be an integer").await;
+            }
+        },
+        None => return error_response(stream, "usage: BAN hostname duration_seconds").await,
+    };
+
+    if duration_seconds <= 0 {
+        return error_response(stream, "duration_seconds must be >= 0").await;
+    }
+
+    let columns = vec![
+        ("db", DataType::Text),
+        ("user", DataType::Text),
+        ("role", DataType::Text),
+        ("host", DataType::Text),
+    ];
+    let mut res = BytesMut::new();
+    res.put(row_description(&columns));
+
+    for (id, pool) in get_all_pools().iter() {
+        for address in pool.get_addresses_from_host(host) {
+            if !pool.is_banned(&address) {
+                pool.ban(&address, BanReason::AdminBan(duration_seconds), -1);
+                res.put(data_row(&vec![
+                    id.db.clone(),
+                    id.user.clone(),
+                    address.role.to_string(),
+                    address.host,
+                ]));
+            }
+        }
+    }
+
+    res.put(command_complete("BAN"));
+
+    // ReadyForQuery
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Clear a host for use
+async fn unban<T>(stream: &mut T, tokens: Vec<&str>) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let host = match tokens.get(1) {
+        Some(host) => host,
+        None => return error_response(stream, "UNBAN command requires a hostname to unban").await,
+    };
+
+    let columns = vec![
+        ("db", DataType::Text),
+        ("user", DataType::Text),
+        ("role", DataType::Text),
+        ("host", DataType::Text),
+    ];
+    let mut res = BytesMut::new();
+    res.put(row_description(&columns));
+
+    for (id, pool) in get_all_pools().iter() {
+        for address in pool.get_addresses_from_host(host) {
+            if pool.is_banned(&address) {
+                pool.unban(&address);
+                res.put(data_row(&vec![
+                    id.db.clone(),
+                    id.user.clone(),
+                    address.role.to_string(),
+                    address.host,
+                ]));
+            }
+        }
+    }
+
+    res.put(command_complete("UNBAN"));
+
+    // ReadyForQuery
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Shows all the bans
+async fn show_bans<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let columns = vec![
+        ("db", DataType::Text),
+        ("user", DataType::Text),
+        ("role", DataType::Text),
+        ("host", DataType::Text),
+        ("reason", DataType::Text),
+        ("ban_time", DataType::Text),
+        ("ban_duration_seconds", DataType::Text),
+        ("ban_remaining_seconds", DataType::Text),
+    ];
+    let mut res = BytesMut::new();
+    res.put(row_description(&columns));
+
+    // The block should be pretty quick so we cache the time outside
+    let now = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("Time went backwards")
+        .as_secs() as i64;
+
+    for (id, pool) in get_all_pools().iter() {
+        for (address, (ban_reason, ban_time)) in pool.get_bans().iter() {
+            let ban_duration = match ban_reason {
+                BanReason::AdminBan(duration) => *duration,
+                _ => pool.settings.ban_time,
+            };
+            let remaining = ban_duration - (now - ban_time.timestamp());
+            if remaining <= 0 {
+                continue;
+            }
+            res.put(data_row(&vec![
+                id.db.clone(),
+                id.user.clone(),
+                address.role.to_string(),
+                address.host.clone(),
+                format!("{:?}", ban_reason),
+                ban_time.to_string(),
+                ban_duration.to_string(),
+                remaining.to_string(),
+            ]));
+        }
+    }
+
+    res.put(command_complete("SHOW BANS"));
+
+    // ReadyForQuery
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Reload the configuration file without restarting the process.
+async fn reload<T>(stream: &mut T, client_server_map: ClientServerMap) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     info!("Reloading config");
 
-    let config = get_config();
-    let path = config.path.clone().unwrap();
+    reload_config(client_server_map).await?;
 
-    parse(&path).await?;
-
-    let config = get_config();
-
-    config.show();
+    get_config().show();
 
     let mut res = BytesMut::new();
 
-    // CommandComplete
     res.put(command_complete("RELOAD"));
 
     // ReadyForQuery
@@ -262,16 +541,18 @@ async fn reload(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }
 
-async fn show_config(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
-    let guard = get_config();
-    let config = &*guard.clone();
+/// Shows current configuration.
+async fn show_config<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let config = &get_config();
     let config: HashMap<String, String> = config.into();
-    drop(guard);
 
-    // Configs that cannot be changed dynamically.
+    // Configs that cannot be changed without restarting.
     let immutables = ["host", "port", "connect_timeout"];
 
     // Columns
@@ -301,17 +582,23 @@ async fn show_config(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
 
     res.put(command_complete("SHOW"));
 
+    // ReadyForQuery
     res.put_u8(b'Z');
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }
 
-/// SHOW STATS
-async fn show_stats(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
+/// Show shard and replicas statistics.
+async fn show_stats<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let columns = vec![
+        ("instance", DataType::Text),
         ("database", DataType::Text),
+        ("user", DataType::Text),
         ("total_xact_count", DataType::Numeric),
         ("total_query_count", DataType::Numeric),
         ("total_received", DataType::Numeric),
@@ -319,33 +606,301 @@ async fn show_stats(stream: &mut OwnedWriteHalf) -> Result<(), Error> {
         ("total_xact_time", DataType::Numeric),
         ("total_query_time", DataType::Numeric),
         ("total_wait_time", DataType::Numeric),
+        ("total_errors", DataType::Numeric),
         ("avg_xact_count", DataType::Numeric),
         ("avg_query_count", DataType::Numeric),
         ("avg_recv", DataType::Numeric),
         ("avg_sent", DataType::Numeric),
+        ("avg_errors", DataType::Numeric),
         ("avg_xact_time", DataType::Numeric),
         ("avg_query_time", DataType::Numeric),
         ("avg_wait_time", DataType::Numeric),
     ];
 
-    let stats = get_stats();
+    let all_stats = get_address_stats();
     let mut res = BytesMut::new();
     res.put(row_description(&columns));
 
-    let mut row = vec![
-        String::from("all"), // TODO: per-database stats,
-    ];
+    for (user_pool, pool) in get_all_pools() {
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                let stats = match all_stats.get(&address.id) {
+                    Some(stats) => stats.clone(),
+                    None => HashMap::new(),
+                };
 
-    for column in &columns[1..] {
-        row.push(stats.get(column.0).unwrap_or(&0).to_string());
+                let mut row = vec![address.name(), user_pool.db.clone(), user_pool.user.clone()];
+                for column in &columns[3..] {
+                    row.push(stats.get(column.0).unwrap_or(&0).to_string());
+                }
+
+                res.put(data_row(&row));
+            }
+        }
+    }
+
+    res.put(command_complete("SHOW"));
+
+    // ReadyForQuery
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Show currently connected clients
+async fn show_clients<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let columns = vec![
+        ("client_id", DataType::Text),
+        ("database", DataType::Text),
+        ("user", DataType::Text),
+        ("application_name", DataType::Text),
+        ("state", DataType::Text),
+        ("transaction_count", DataType::Numeric),
+        ("query_count", DataType::Numeric),
+        ("error_count", DataType::Numeric),
+        ("age_seconds", DataType::Numeric),
+    ];
+
+    let new_map = get_client_stats();
+    let mut res = BytesMut::new();
+    res.put(row_description(&columns));
+
+    for (_, client) in new_map {
+        let row = vec![
+            format!("{:#010X}", client.client_id),
+            client.pool_name,
+            client.username,
+            client.application_name.clone(),
+            client.state.to_string(),
+            client.transaction_count.to_string(),
+            client.query_count.to_string(),
+            client.error_count.to_string(),
+            Instant::now()
+                .duration_since(client.connect_time)
+                .as_secs()
+                .to_string(),
+        ];
+
+        res.put(data_row(&row));
+    }
+
+    res.put(command_complete("SHOW"));
+
+    // ReadyForQuery
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Show currently connected servers
+async fn show_servers<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let columns = vec![
+        ("server_id", DataType::Text),
+        ("database_name", DataType::Text),
+        ("user", DataType::Text),
+        ("address_id", DataType::Text),
+        ("application_name", DataType::Text),
+        ("state", DataType::Text),
+        ("transaction_count", DataType::Numeric),
+        ("query_count", DataType::Numeric),
+        ("bytes_sent", DataType::Numeric),
+        ("bytes_received", DataType::Numeric),
+        ("age_seconds", DataType::Numeric),
+    ];
+
+    let new_map = get_server_stats();
+    let mut res = BytesMut::new();
+    res.put(row_description(&columns));
+
+    for (_, server) in new_map {
+        let row = vec![
+            format!("{:#010X}", server.server_id),
+            server.pool_name,
+            server.username,
+            server.address_name,
+            server.application_name,
+            server.state.to_string(),
+            server.transaction_count.to_string(),
+            server.query_count.to_string(),
+            server.bytes_sent.to_string(),
+            server.bytes_received.to_string(),
+            Instant::now()
+                .duration_since(server.connect_time)
+                .as_secs()
+                .to_string(),
+        ];
+
+        res.put(data_row(&row));
+    }
+
+    res.put(command_complete("SHOW"));
+
+    // ReadyForQuery
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Pause a pool. It won't pass any more queries to the backends.
+async fn pause<T>(stream: &mut T, query: &str) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let parts: Vec<&str> = query.split(",").map(|part| part.trim()).collect();
+
+    if parts.len() != 2 {
+        error_response(
+            stream,
+            "PAUSE requires a database and a user, e.g. PAUSE my_db,my_user",
+        )
+        .await
+    } else {
+        let database = parts[0];
+        let user = parts[1];
+
+        match get_pool(database, user) {
+            Some(pool) => {
+                pool.pause();
+
+                let mut res = BytesMut::new();
+
+                res.put(command_complete(&format!("PAUSE {},{}", database, user)));
+
+                // ReadyForQuery
+                res.put_u8(b'Z');
+                res.put_i32(5);
+                res.put_u8(b'I');
+
+                write_all_half(stream, &res).await
+            }
+
+            None => {
+                error_response(
+                    stream,
+                    &format!(
+                        "No pool configured for database: {}, user: {}",
+                        database, user
+                    ),
+                )
+                .await
+            }
+        }
+    }
+}
+
+/// Resume a pool. Queries are allowed again.
+async fn resume<T>(stream: &mut T, query: &str) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let parts: Vec<&str> = query.split(",").map(|part| part.trim()).collect();
+
+    if parts.len() != 2 {
+        error_response(
+            stream,
+            "RESUME requires a database and a user, e.g. RESUME my_db,my_user",
+        )
+        .await
+    } else {
+        let database = parts[0];
+        let user = parts[1];
+
+        match get_pool(database, user) {
+            Some(pool) => {
+                pool.resume();
+
+                let mut res = BytesMut::new();
+
+                res.put(command_complete(&format!("RESUME {},{}", database, user)));
+
+                // ReadyForQuery
+                res.put_u8(b'Z');
+                res.put_i32(5);
+                res.put_u8(b'I');
+
+                write_all_half(stream, &res).await
+            }
+
+            None => {
+                error_response(
+                    stream,
+                    &format!(
+                        "No pool configured for database: {}, user: {}",
+                        database, user
+                    ),
+                )
+                .await
+            }
+        }
+    }
+}
+
+/// Send response packets for shutdown.
+async fn shutdown<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let mut res = BytesMut::new();
+
+    res.put(row_description(&vec![("success", DataType::Text)]));
+
+    let mut shutdown_success = "t";
+
+    let pid = std::process::id();
+    if signal::kill(Pid::from_raw(pid.try_into().unwrap()), Signal::SIGINT).is_err() {
+        error!("Unable to send SIGINT to PID: {}", pid);
+        shutdown_success = "f";
+    }
+
+    res.put(data_row(&vec![shutdown_success.to_string()]));
+
+    res.put(command_complete("SHUTDOWN"));
+
+    res.put_u8(b'Z');
+    res.put_i32(5);
+    res.put_u8(b'I');
+
+    write_all_half(stream, &res).await
+}
+
+/// Show Users.
+async fn show_users<T>(stream: &mut T) -> Result<(), Error>
+where
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let mut res = BytesMut::new();
+
+    res.put(row_description(&vec![
+        ("name", DataType::Text),
+        ("pool_mode", DataType::Text),
+    ]));
+
+    for (user_pool, pool) in get_all_pools() {
+        let pool_config = &pool.settings;
+        res.put(data_row(&vec![
+            user_pool.user.clone(),
+            pool_config.pool_mode.to_string(),
+        ]));
     }
 
-    res.put(data_row(&row));
     res.put(command_complete("SHOW"));
 
     res.put_u8(b'Z');
     res.put_i32(5);
     res.put_u8(b'I');
 
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await
 }

src/constants.rs

@@ -1,7 +1,6 @@
 /// Various protocol constants, as defined in
-/// https://www.postgresql.org/docs/12/protocol-message-formats.html
+/// <https://www.postgresql.org/docs/12/protocol-message-formats.html>
 /// and elsewhere in the source code.
-/// Also other constants we use elsewhere.
 
 // Used in the StartupMessage to indicate regular handshake.
 pub const PROTOCOL_VERSION_NUMBER: i32 = 196608;
@@ -15,6 +14,13 @@ pub const CANCEL_REQUEST_CODE: i32 = 80877102;
 // AuthenticationMD5Password
 pub const MD5_ENCRYPTED_PASSWORD: i32 = 5;
 
+// SASL
+pub const SASL: i32 = 10;
+pub const SASL_CONTINUE: i32 = 11;
+pub const SASL_FINAL: i32 = 12;
+pub const SCRAM_SHA_256: &str = "SCRAM-SHA-256";
+pub const NONCE_LENGTH: usize = 24;
+
 // AuthenticationOk
 pub const AUTHENTICATION_SUCCESSFUL: i32 = 0;
 

src/errors.rs

@@ -1,14 +1,18 @@
+/// Errors.
+
+/// Various errors.
 #[derive(Debug, PartialEq)]
 pub enum Error {
-    SocketError,
-    // ClientDisconnected,
+    SocketError(String),
     ClientBadStartup,
-    ProtocolSyncError,
+    ProtocolSyncError(String),
+    BadQuery(String),
     ServerError,
-    // ServerTimeout,
-    // DirtyServer,
     BadConfig,
-    BadUserList,
     AllServersDown,
-    AuthenticationError
+    ClientError(String),
+    TlsError,
+    StatementTimeout,
+    ShuttingDown,
+    ParseBytesError(String),
 }

src/lib.rs

@@ -0,0 +1,34 @@
+pub mod config;
+pub mod constants;
+pub mod errors;
+pub mod messages;
+pub mod mirrors;
+pub mod multi_logger;
+pub mod pool;
+pub mod scram;
+pub mod server;
+pub mod sharding;
+pub mod stats;
+pub mod tls;
+
+/// Format chrono::Duration to be more human-friendly.
+///
+/// # Arguments
+///
+/// * `duration` - A duration of time
+pub fn format_duration(duration: &chrono::Duration) -> String {
+    let milliseconds = format!("{:0>3}", duration.num_milliseconds() % 1000);
+
+    let seconds = format!("{:0>2}", duration.num_seconds() % 60);
+
+    let minutes = format!("{:0>2}", duration.num_minutes() % 60);
+
+    let hours = format!("{:0>2}", duration.num_hours() % 24);
+
+    let days = duration.num_days().to_string();
+
+    format!(
+        "{}d {}:{}:{}.{}",
+        days, hours, minutes, seconds, milliseconds
+    )
+}

src/main.rs

@@ -1,4 +1,4 @@
-// Copyright (c) 2022 Lev Kokotov <lev@levthe.dev>
+// Copyright (c) 2022 Lev Kokotov <hi@levthe.dev>
 
 // Permission is hereby granted, free of charge, to any person obtaining
 // a copy of this software and associated documentation files (the
@@ -24,58 +24,72 @@ extern crate async_trait;
 extern crate bb8;
 extern crate bytes;
 extern crate env_logger;
+extern crate exitcode;
 extern crate log;
 extern crate md5;
 extern crate num_cpus;
 extern crate once_cell;
+extern crate rustls_pemfile;
 extern crate serde;
 extern crate serde_derive;
 extern crate sqlparser;
-extern crate statsd;
 extern crate tokio;
+extern crate tokio_rustls;
 extern crate toml;
 
-use log::{error, info};
+#[cfg(not(target_env = "msvc"))]
+use jemallocator::Jemalloc;
+
+#[cfg(not(target_env = "msvc"))]
+#[global_allocator]
+static GLOBAL: Jemalloc = Jemalloc;
+
+use log::{debug, error, info, warn};
 use parking_lot::Mutex;
+use pgcat::format_duration;
 use tokio::net::TcpListener;
-use tokio::{
-    signal,
-    signal::unix::{signal as unix_signal, SignalKind},
-    sync::mpsc,
-};
+#[cfg(not(windows))]
+use tokio::signal::unix::{signal as unix_signal, SignalKind};
+#[cfg(windows)]
+use tokio::signal::windows as win_signal;
+use tokio::{runtime::Builder, sync::mpsc};
 
 use std::collections::HashMap;
+use std::net::SocketAddr;
+use std::str::FromStr;
 use std::sync::Arc;
+use tokio::sync::broadcast;
 
 mod admin;
 mod client;
 mod config;
-mod userlist;
 mod constants;
 mod errors;
 mod messages;
+mod mirrors;
+mod multi_logger;
 mod pool;
+mod prometheus;
 mod query_router;
+mod scram;
 mod server;
 mod sharding;
 mod stats;
+mod tls;
 
-// Support for query cancellation: this maps our process_ids and
-// secret keys to the backend's.
-use config::get_config;
-use pool::{ClientServerMap, ConnectionPool};
-use stats::{Collector, Reporter};
+use crate::config::{get_config, reload_config, VERSION};
+use crate::pool::{ClientServerMap, ConnectionPool};
+use crate::prometheus::start_metric_server;
+use crate::stats::{Collector, Reporter, REPORTER};
 
-/// Main!
-#[tokio::main(worker_threads = 4)]
-async fn main() {
-    env_logger::init();
-    info!("Welcome to PgCat! Meow.");
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    multi_logger::MultiLogger::init().unwrap();
+
+    info!("Welcome to PgCat! Meow. (Version {})", VERSION);
 
-    // Prepare regexes
     if !query_router::QueryRouter::setup() {
         error!("Could not setup query router");
-        return;
+        std::process::exit(exitcode::CONFIG);
     }
 
     let args = std::env::args().collect::<Vec<String>>();
@@ -86,178 +100,249 @@ async fn main() {
         String::from("pgcat.toml")
     };
 
-    // Prepare the config
-    match config::parse(&config_file).await {
-        Ok(_) => (),
-        Err(err) => {
-            error!("Config parse error: {:?}", err);
-            return;
-        }
-    };
+    // Create a transient runtime for loading the config for the first time.
+    {
+        let runtime = Builder::new_multi_thread().worker_threads(1).build()?;
 
-    // Prepare user list
-    match userlist::parse("userlist.json").await {
-        Ok(_) => (),
-        Err(err) => {
-            error!("Userlist parse error: {:?}", err);
-            return;
-        }
-    };
+        runtime.block_on(async {
+            match config::parse(&config_file).await {
+                Ok(_) => (),
+                Err(err) => {
+                    error!("Config parse error: {:?}", err);
+                    std::process::exit(exitcode::CONFIG);
+                }
+            };
+        });
+    }
 
     let config = get_config();
 
-    let addr = format!("{}:{}", config.general.host, config.general.port);
-    let listener = match TcpListener::bind(&addr).await {
-        Ok(sock) => sock,
-        Err(err) => {
-            error!("Listener socket error: {:?}", err);
-            return;
-        }
-    };
+    // Create the runtime now we know required worker_threads.
+    let runtime = Builder::new_multi_thread()
+        .worker_threads(config.general.worker_threads)
+        .enable_all()
+        .build()?;
 
-    info!("Running on {}", addr);
-    config.show();
+    runtime.block_on(async move {
 
-    // Tracks which client is connected to which server for query cancellation.
-    let client_server_map: ClientServerMap = Arc::new(Mutex::new(HashMap::new()));
+        if let Some(true) = config.general.enable_prometheus_exporter {
+            let http_addr_str = format!(
+                "{}:{}",
+                config.general.host, config.general.prometheus_exporter_port
+            );
 
-    // Collect statistics and send them to StatsD
-    let (tx, rx) = mpsc::channel(100);
-    let collector_tx = tx.clone();
-    tokio::task::spawn(async move {
-        let mut stats_collector = Collector::new(rx, collector_tx);
-        stats_collector.collect().await;
-    });
-
-    let mut pool =
-        ConnectionPool::from_config(client_server_map.clone(), Reporter::new(tx.clone())).await;
-
-    let server_info = match pool.validate().await {
-        Ok(info) => info,
-        Err(err) => {
-            error!("Could not validate connection pool: {:?}", err);
-            return;
-        }
-    };
-
-    info!("Waiting for clients");
-
-    // Main app runs here.
-    tokio::task::spawn(async move {
-        loop {
-            let pool = pool.clone();
-            let client_server_map = client_server_map.clone();
-            let server_info = server_info.clone();
-            let reporter = Reporter::new(tx.clone());
-
-            let (socket, addr) = match listener.accept().await {
-                Ok((socket, addr)) => (socket, addr),
+            let http_addr = match SocketAddr::from_str(&http_addr_str) {
+                Ok(addr) => addr,
                 Err(err) => {
-                    error!("{:?}", err);
-                    continue;
+                    error!("Invalid http address: {}", err);
+                    std::process::exit(exitcode::CONFIG);
                 }
             };
 
-            // Client goes to another thread, bye.
             tokio::task::spawn(async move {
-                let start = chrono::offset::Utc::now().naive_utc();
-                match client::Client::startup(socket, client_server_map, server_info, reporter)
-                    .await
-                {
-                    Ok(mut client) => {
-                        info!("Client {:?} connected", addr);
-                        match client.handle(pool).await {
+                start_metric_server(http_addr).await;
+            });
+        }
+
+        let addr = format!("{}:{}", config.general.host, config.general.port);
+
+        let listener = match TcpListener::bind(&addr).await {
+            Ok(sock) => sock,
+            Err(err) => {
+                error!("Listener socket error: {:?}", err);
+                std::process::exit(exitcode::CONFIG);
+            }
+        };
+
+        info!("Running on {}", addr);
+
+        config.show();
+
+        // Tracks which client is connected to which server for query cancellation.
+        let client_server_map: ClientServerMap = Arc::new(Mutex::new(HashMap::new()));
+
+        // Statistics reporting.
+        let (stats_tx, stats_rx) = mpsc::channel(500_000);
+        REPORTER.store(Arc::new(Reporter::new(stats_tx.clone())));
+
+        // Connection pool that allows to query all shards and replicas.
+        match ConnectionPool::from_config(client_server_map.clone()).await {
+            Ok(_) => (),
+            Err(err) => {
+                error!("Pool error: {:?}", err);
+                std::process::exit(exitcode::CONFIG);
+            }
+        };
+
+        tokio::task::spawn(async move {
+            let mut stats_collector = Collector::new(stats_rx, stats_tx.clone());
+            stats_collector.collect().await;
+        });
+
+        info!("Config autoreloader: {}", config.general.autoreload);
+
+        let mut autoreload_interval = tokio::time::interval(tokio::time::Duration::from_millis(15_000));
+        let autoreload_client_server_map = client_server_map.clone();
+
+        tokio::task::spawn(async move {
+            loop {
+                autoreload_interval.tick().await;
+                if config.general.autoreload {
+                    info!("Automatically reloading config");
+
+                    if let Ok(changed) = reload_config(autoreload_client_server_map.clone()).await {
+                        if changed {
+                            get_config().show()
+                        }
+                    };
+                }
+            }
+        });
+
+        #[cfg(windows)]
+        let mut term_signal = win_signal::ctrl_close().unwrap();
+        #[cfg(windows)]
+        let mut interrupt_signal = win_signal::ctrl_c().unwrap();
+        #[cfg(windows)]
+        let mut sighup_signal = win_signal::ctrl_shutdown().unwrap();
+
+        #[cfg(not(windows))]
+        let mut term_signal = unix_signal(SignalKind::terminate()).unwrap();
+        #[cfg(not(windows))]
+        let mut interrupt_signal = unix_signal(SignalKind::interrupt()).unwrap();
+        #[cfg(not(windows))]
+        let mut sighup_signal = unix_signal(SignalKind::hangup()).unwrap();
+        let (shutdown_tx, _) = broadcast::channel::<()>(1);
+        let (drain_tx, mut drain_rx) = mpsc::channel::<i32>(2048);
+        let (exit_tx, mut exit_rx) = mpsc::channel::<()>(1);
+        let mut admin_only = false;
+        let mut total_clients = 0;
+
+        info!("Waiting for clients");
+
+        loop {
+            tokio::select! {
+                // Reload config:
+                // kill -SIGHUP $(pgrep pgcat)
+                _ = sighup_signal.recv() => {
+                    info!("Reloading config");
+
+                    _ = reload_config(client_server_map.clone()).await;
+
+                    get_config().show();
+                },
+
+                // Initiate graceful shutdown sequence on sig int
+                _ = interrupt_signal.recv() => {
+                    info!("Got SIGINT");
+
+                    // Don't want this to happen more than once
+                    if admin_only {
+                        continue;
+                    }
+
+                    admin_only = true;
+
+                    // Broadcast that client tasks need to finish
+                    let _ = shutdown_tx.send(());
+                    let exit_tx = exit_tx.clone();
+                    let _ = drain_tx.send(0).await;
+
+                    tokio::task::spawn(async move {
+                        let mut interval = tokio::time::interval(tokio::time::Duration::from_millis(config.general.shutdown_timeout));
+
+                        // First tick fires immediately.
+                        interval.tick().await;
+
+                        // Second one in the interval time.
+                        interval.tick().await;
+
+                        // We're done waiting.
+                        error!("Graceful shutdown timed out. {} active clients being closed", total_clients);
+
+                        let _ = exit_tx.send(()).await;
+                    });
+                },
+
+                _ = term_signal.recv() => {
+                    info!("Got SIGTERM, closing with {} clients active", total_clients);
+                    break;
+                },
+
+                new_client = listener.accept() => {
+                    let (socket, addr) = match new_client {
+                        Ok((socket, addr)) => (socket, addr),
+                        Err(err) => {
+                            error!("{:?}", err);
+                            continue;
+                        }
+                    };
+
+                    let shutdown_rx = shutdown_tx.subscribe();
+                    let drain_tx = drain_tx.clone();
+                    let client_server_map = client_server_map.clone();
+
+                    let tls_certificate = config.general.tls_certificate.clone();
+
+                    tokio::task::spawn(async move {
+                        let start = chrono::offset::Utc::now().naive_utc();
+
+                        match client::client_entrypoint(
+                            socket,
+                            client_server_map,
+                            shutdown_rx,
+                            drain_tx,
+                            admin_only,
+                            tls_certificate.clone(),
+                            config.general.log_client_connections,
+                        )
+                        .await
+                        {
                             Ok(()) => {
                                 let duration = chrono::offset::Utc::now().naive_utc() - start;
 
-                                info!(
-                                    "Client {:?} disconnected, session duration: {}",
-                                    addr,
-                                    format_duration(&duration)
-                                );
+                                if config.general.log_client_disconnections {
+                                    info!(
+                                        "Client {:?} disconnected, session duration: {}",
+                                        addr,
+                                        format_duration(&duration)
+                                    );
+                                } else {
+                                    debug!(
+                                        "Client {:?} disconnected, session duration: {}",
+                                        addr,
+                                        format_duration(&duration)
+                                    );
+                                }
                             }
 
                             Err(err) => {
-                                error!("Client disconnected with error: {:?}", err);
-                                client.release();
+                                match err {
+                                    errors::Error::ClientBadStartup => debug!("Client disconnected with error {:?}", err),
+                                    _ => warn!("Client disconnected with error {:?}", err),
+                                }
+
                             }
-                        }
-                    }
-
-                    Err(err) => {
-                        error!("Client failed to login: {:?}", err);
-                    }
-                };
-            });
-        }
-    });
-
-    // Reload config
-    // kill -SIGHUP $(pgrep pgcat)
-    tokio::task::spawn(async move {
-        let mut stream = unix_signal(SignalKind::hangup()).unwrap();
-
-        loop {
-            stream.recv().await;
-            info!("Reloading config");
-            match config::parse("pgcat.toml").await {
-                Ok(_) => {
-                    get_config().show();
+                        };
+                    });
                 }
-                Err(err) => {
-                    error!("{:?}", err);
-                    return;
+
+                _ = exit_rx.recv() => {
+                    break;
                 }
-            };
+
+                client_ping = drain_rx.recv() => {
+                    let client_ping = client_ping.unwrap();
+                    total_clients += client_ping;
+
+                    if total_clients == 0 && admin_only {
+                        let _ = exit_tx.send(()).await;
+                    }
+                }
+            }
         }
+
+    info!("Shutting down...");
     });
-
-    // Setup shut down sequence
-    match signal::ctrl_c().await {
-        Ok(()) => {
-            info!("Shutting down...");
-        }
-
-        Err(err) => {
-            error!("Unable to listen for shutdown signal: {}", err);
-        }
-    };
-}
-
-/// Format chrono::Duration to be more human-friendly.
-///
-/// # Arguments
-///
-/// * `duration` - A duration of time
-fn format_duration(duration: &chrono::Duration) -> String {
-    let seconds = {
-        let seconds = duration.num_seconds() % 60;
-        if seconds < 10 {
-            format!("0{}", seconds)
-        } else {
-            format!("{}", seconds)
-        }
-    };
-
-    let minutes = {
-        let minutes = duration.num_minutes() % 60;
-        if minutes < 10 {
-            format!("0{}", minutes)
-        } else {
-            format!("{}", minutes)
-        }
-    };
-
-    let hours = {
-        let hours = duration.num_hours() % 24;
-        if hours < 10 {
-            format!("0{}", hours)
-        } else {
-            format!("{}", hours)
-        }
-    };
-
-    let days = duration.num_days().to_string();
-
-    format!("{}d {}:{}:{}", days, hours, minutes, seconds)
+    Ok(())
 }

src/messages.rs

@@ -1,23 +1,18 @@
 /// Helper functions to send one-off protocol messages
 /// and handle TcpStream (TCP socket).
-
-
 use bytes::{Buf, BufMut, BytesMut};
+use log::error;
 use md5::{Digest, Md5};
-use tokio::io::{AsyncReadExt, AsyncWriteExt, BufReader};
-use tokio::net::{
-    tcp::{OwnedReadHalf, OwnedWriteHalf},
-    TcpStream,
-};
-use log::{error};
+use socket2::{SockRef, TcpKeepalive};
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpStream;
 
+use crate::config::get_config;
 use crate::errors::Error;
 use std::collections::HashMap;
-
-use rand::Rng;
-
-use crate::userlist::get_user_list;
-
+use std::io::{BufRead, Cursor};
+use std::mem;
+use std::time::Duration;
 
 /// Postgres data type mappings
 /// used in RowDescription ('T') message.
@@ -37,122 +32,59 @@ impl From<&DataType> for i32 {
     }
 }
 
-/**
-1. Generate salt (4 bytes of random data)
-md5(concat(md5(concat(password, username)), random-salt)))
-2. Send md5 auth request
-3. recieve PasswordMessage with salt.
-4. refactor md5_password function to be reusable
-5. check username hash combo against file
-6. AuthenticationOk or ErrorResponse
- **/
-pub async fn start_auth(stream: &mut TcpStream, user_name: &String) -> Result<(), Error> {
-    let mut rng = rand::thread_rng();
-
-    //Generate random 4 byte salt
-    let salt = rng.gen::<u32>();
-
-    // Send AuthenticationMD5Password request
-    send_md5_request(stream, salt).await?;
-
-    let code = match stream.read_u8().await {
-        Ok(code) => code as char,
-        Err(_) => return Err(Error::AuthenticationError),
-    };
-
-    match code {
-        // Password response
-        'p' => {
-            fetch_password_and_authenticate(stream, &user_name, &salt).await?;
-            Ok(auth_ok(stream).await?)
-        }
-        _ => {
-            error!("Unknown code: {}", code);
-            return Err(Error::AuthenticationError);
-        }
-    }
-}
-
-pub async fn send_md5_request(stream: &mut TcpStream, salt: u32) -> Result<(), Error> {
-    let mut authentication_md5password = BytesMut::with_capacity(12);
-    authentication_md5password.put_u8(b'R');
-    authentication_md5password.put_i32(12);
-    authentication_md5password.put_i32(5);
-    authentication_md5password.put_u32(salt);
-
-    // Send AuthenticationMD5Password request
-    Ok(write_all(stream, authentication_md5password).await?)
-}
-
-pub async fn fetch_password_and_authenticate(stream: &mut TcpStream, user_name: &String, salt: &u32) -> Result<(), Error> {
-    /**
-    1. How do I store the lists of users and paswords? clear text or hash?? wtf
-    2. Add auth to tests
-    **/
-
-    let len = match stream.read_i32().await {
-        Ok(len) => len,
-        Err(_) => return Err(Error::AuthenticationError),
-    };
-
-    // Read whatever is left.
-    let mut password_hash = vec![0u8; len as usize - 4];
-
-    match stream.read_exact(&mut password_hash).await {
-        Ok(_) => (),
-        Err(_) => return Err(Error::AuthenticationError),
-    };
-
-    let user_list = get_user_list();
-    let mut password: String = String::new();
-    match user_list.get(&user_name) {
-        Some(&p) => password = p,
-        None => return Err(Error::AuthenticationError),
-    }
-
-    let mut md5 = Md5::new();
-
-    //    concat('md5', md5(concat(md5(concat(password, username)), random-salt)))
-    // First pass
-    md5.update(&password.as_bytes());
-    md5.update(&user_name.as_bytes());
-    let output = md5.finalize_reset();
-    // Second pass
-    md5.update(format!("{:x}", output));
-    md5.update(salt.to_be_bytes().to_vec());
-
-
-    let password_string: String = String::from_utf8(password_hash).expect("Could not get password hash");
-    match format!("md5{:x}", md5.finalize()) == password_string {
-        true => Ok(()),
-        _ => Err(Error::AuthenticationError)
-    }
-}
-
 /// Tell the client that authentication handshake completed successfully.
-pub async fn auth_ok(stream: &mut TcpStream) -> Result<(), Error> {
+pub async fn auth_ok<S>(stream: &mut S) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let mut auth_ok = BytesMut::with_capacity(9);
 
     auth_ok.put_u8(b'R');
     auth_ok.put_i32(8);
     auth_ok.put_i32(0);
 
-    Ok(write_all(stream, auth_ok).await?)
+    write_all(stream, auth_ok).await
+}
+
+/// Generate md5 password challenge.
+pub async fn md5_challenge<S>(stream: &mut S) -> Result<[u8; 4], Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    // let mut rng = rand::thread_rng();
+    let salt: [u8; 4] = [
+        rand::random(),
+        rand::random(),
+        rand::random(),
+        rand::random(),
+    ];
+
+    let mut res = BytesMut::new();
+    res.put_u8(b'R');
+    res.put_i32(12);
+    res.put_i32(5); // MD5
+    res.put_slice(&salt[..]);
+
+    write_all(stream, res).await?;
+    Ok(salt)
 }
 
 /// Give the client the process_id and secret we generated
 /// used in query cancellation.
-pub async fn backend_key_data(
-    stream: &mut TcpStream,
+pub async fn backend_key_data<S>(
+    stream: &mut S,
     backend_id: i32,
     secret_key: i32,
-) -> Result<(), Error> {
+) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let mut key_data = BytesMut::from(&b"K"[..]);
     key_data.put_i32(12);
     key_data.put_i32(backend_id);
     key_data.put_i32(secret_key);
 
-    Ok(write_all(stream, key_data).await?)
+    write_all(stream, key_data).await
 }
 
 /// Construct a `Q`: Query message.
@@ -161,20 +93,25 @@ pub fn simple_query(query: &str) -> BytesMut {
     let query = format!("{}\0", query);
 
     res.put_i32(query.len() as i32 + 4);
-    res.put_slice(&query.as_bytes());
+    res.put_slice(query.as_bytes());
 
     res
 }
 
 /// Tell the client we're ready for another query.
-pub async fn ready_for_query(stream: &mut TcpStream) -> Result<(), Error> {
-    let mut bytes = BytesMut::with_capacity(5);
+pub async fn ready_for_query<S>(stream: &mut S) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let mut bytes = BytesMut::with_capacity(
+        mem::size_of::<u8>() + mem::size_of::<i32>() + mem::size_of::<u8>(),
+    );
 
     bytes.put_u8(b'Z');
     bytes.put_i32(5);
     bytes.put_u8(b'I'); // Idle
 
-    Ok(write_all(stream, bytes).await?)
+    write_all(stream, bytes).await
 }
 
 /// Send the startup packet the server. We're pretending we're a Pg client.
@@ -186,12 +123,12 @@ pub async fn startup(stream: &mut TcpStream, user: &str, database: &str) -> Resu
 
     // User
     bytes.put(&b"user\0"[..]);
-    bytes.put_slice(&user.as_bytes());
+    bytes.put_slice(user.as_bytes());
     bytes.put_u8(0);
 
     // Database
     bytes.put(&b"database\0"[..]);
-    bytes.put_slice(&database.as_bytes());
+    bytes.put_slice(database.as_bytes());
     bytes.put_u8(0);
     bytes.put_u8(0); // Null terminator
 
@@ -204,7 +141,12 @@ pub async fn startup(stream: &mut TcpStream, user: &str, database: &str) -> Resu
 
     match stream.write_all(&startup).await {
         Ok(_) => Ok(()),
-        Err(_) => return Err(Error::SocketError),
+        Err(err) => {
+            return Err(Error::SocketError(format!(
+                "Error writing startup to server socket - Error: {:?}",
+                err
+            )))
+        }
     }
 }
 
@@ -223,7 +165,7 @@ pub fn parse_params(mut bytes: BytesMut) -> Result<HashMap<String, String>, Erro
             c = bytes.get_u8();
         }
 
-        if tmp.len() > 0 {
+        if !tmp.is_empty() {
             buf.push(tmp.clone());
             tmp.clear();
         }
@@ -260,14 +202,8 @@ pub fn parse_startup(bytes: BytesMut) -> Result<HashMap<String, String>, Error>
     Ok(result)
 }
 
-/// Send password challenge response to the server.
-/// This is the MD5 challenge.
-pub async fn md5_password(
-    stream: &mut TcpStream,
-    user: &str,
-    password: &str,
-    salt: &[u8],
-) -> Result<(), Error> {
+/// Create md5 password hash given a salt.
+pub fn md5_hash_password(user: &str, password: &str, salt: &[u8]) -> Vec<u8> {
     let mut md5 = Md5::new();
 
     // First pass
@@ -286,22 +222,38 @@ pub async fn md5_password(
         .collect::<Vec<u8>>();
     password.push(0);
 
+    password
+}
+
+/// Send password challenge response to the server.
+/// This is the MD5 challenge.
+pub async fn md5_password<S>(
+    stream: &mut S,
+    user: &str,
+    password: &str,
+    salt: &[u8],
+) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let password = md5_hash_password(user, password, salt);
+
     let mut message = BytesMut::with_capacity(password.len() as usize + 5);
 
     message.put_u8(b'p');
     message.put_i32(password.len() as i32 + 4);
     message.put_slice(&password[..]);
 
-    Ok(write_all(stream, message).await?)
+    write_all(stream, message).await
 }
 
 /// Implements a response to our custom `SET SHARDING KEY`
 /// and `SET SERVER ROLE` commands.
 /// This tells the client we're ready for the next query.
-pub async fn custom_protocol_response_ok(
-    stream: &mut OwnedWriteHalf,
-    message: &str,
-) -> Result<(), Error> {
+pub async fn custom_protocol_response_ok<S>(stream: &mut S, message: &str) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let mut res = BytesMut::with_capacity(25);
 
     let set_complete = BytesMut::from(&format!("{}\0", message)[..]);
@@ -312,18 +264,28 @@ pub async fn custom_protocol_response_ok(
     res.put_i32(len);
     res.put_slice(&set_complete[..]);
 
-    // ReadyForQuery (idle)
-    res.put_u8(b'Z');
-    res.put_i32(5);
-    res.put_u8(b'I');
-
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await?;
+    ready_for_query(stream).await
 }
 
 /// Send a custom error message to the client.
 /// Tell the client we are ready for the next query and no rollback is necessary.
-/// Docs on error codes: https://www.postgresql.org/docs/12/errcodes-appendix.html
-pub async fn error_response(stream: &mut OwnedWriteHalf, message: &str) -> Result<(), Error> {
+/// Docs on error codes: <https://www.postgresql.org/docs/12/errcodes-appendix.html>.
+pub async fn error_response<S>(stream: &mut S, message: &str) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    error_response_terminal(stream, message).await?;
+    ready_for_query(stream).await
+}
+
+/// Send a custom error message to the client.
+/// Tell the client we are ready for the next query and no rollback is necessary.
+/// Docs on error codes: <https://www.postgresql.org/docs/12/errcodes-appendix.html>.
+pub async fn error_response_terminal<S>(stream: &mut S, message: &str) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let mut error = BytesMut::new();
 
     // Error level
@@ -340,36 +302,62 @@ pub async fn error_response(stream: &mut OwnedWriteHalf, message: &str) -> Resul
 
     // The short error message.
     error.put_u8(b'M');
-    error.put_slice(&format!("{}\0", message).as_bytes());
+    error.put_slice(format!("{}\0", message).as_bytes());
 
     // No more fields follow.
     error.put_u8(0);
 
-    // Ready for query, no rollback needed (I = idle).
-    let mut ready_for_query = BytesMut::new();
+    // Compose the two message reply.
+    let mut res = BytesMut::with_capacity(error.len() + 5);
 
-    ready_for_query.put_u8(b'Z');
-    ready_for_query.put_i32(5);
-    ready_for_query.put_u8(b'I');
+    res.put_u8(b'E');
+    res.put_i32(error.len() as i32 + 4);
+    res.put(error);
+
+    write_all_half(stream, &res).await
+}
+
+pub async fn wrong_password<S>(stream: &mut S, user: &str) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    let mut error = BytesMut::new();
+
+    // Error level
+    error.put_u8(b'S');
+    error.put_slice(&b"FATAL\0"[..]);
+
+    // Error level (non-translatable)
+    error.put_u8(b'V');
+    error.put_slice(&b"FATAL\0"[..]);
+
+    // Error code: not sure how much this matters.
+    error.put_u8(b'C');
+    error.put_slice(&b"28P01\0"[..]); // system_error, see Appendix A.
+
+    // The short error message.
+    error.put_u8(b'M');
+    error.put_slice(format!("password authentication failed for user \"{}\"\0", user).as_bytes());
+
+    // No more fields follow.
+    error.put_u8(0);
 
     // Compose the two message reply.
-    let mut res = BytesMut::with_capacity(error.len() + ready_for_query.len() + 5);
+    let mut res = BytesMut::new();
 
     res.put_u8(b'E');
     res.put_i32(error.len() as i32 + 4);
 
     res.put(error);
-    res.put(ready_for_query);
 
-    Ok(write_all_half(stream, res).await?)
+    write_all(stream, res).await
 }
 
 /// Respond to a SHOW SHARD command.
-pub async fn show_response(
-    stream: &mut OwnedWriteHalf,
-    name: &str,
-    value: &str,
-) -> Result<(), Error> {
+pub async fn show_response<S>(stream: &mut S, name: &str, value: &str) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     // A SELECT response consists of:
     // 1. RowDescription
     // 2. One or more DataRow
@@ -388,12 +376,8 @@ pub async fn show_response(
     // CommandComplete
     res.put(command_complete("SELECT 1"));
 
-    // ReadyForQuery
-    res.put_u8(b'Z');
-    res.put_i32(5);
-    res.put_u8(b'I');
-
-    write_all_half(stream, res).await
+    write_all_half(stream, &res).await?;
+    ready_for_query(stream).await
 }
 
 pub fn row_description(columns: &Vec<(&str, DataType)>) -> BytesMut {
@@ -405,7 +389,7 @@ pub fn row_description(columns: &Vec<(&str, DataType)>) -> BytesMut {
 
     for (name, data_type) in columns {
         // Column name
-        row_desc.put_slice(&format!("{}\0", name).as_bytes());
+        row_desc.put_slice(format!("{}\0", name).as_bytes());
 
         // Doesn't belong to any table
         row_desc.put_i32(0);
@@ -439,6 +423,7 @@ pub fn row_description(columns: &Vec<(&str, DataType)>) -> BytesMut {
     res
 }
 
+/// Create a DataRow message.
 pub fn data_row(row: &Vec<String>) -> BytesMut {
     let mut res = BytesMut::new();
     let mut data_row = BytesMut::new();
@@ -448,7 +433,7 @@ pub fn data_row(row: &Vec<String>) -> BytesMut {
     for column in row {
         let column = column.as_bytes();
         data_row.put_i32(column.len() as i32);
-        data_row.put_slice(&column);
+        data_row.put_slice(column);
     }
 
     res.put_u8(b'D');
@@ -458,6 +443,7 @@ pub fn data_row(row: &Vec<String>) -> BytesMut {
     res
 }
 
+/// Create a CommandComplete message.
 pub fn command_complete(command: &str) -> BytesMut {
     let cmd = BytesMut::from(format!("{}\0", command).as_bytes());
     let mut res = BytesMut::new();
@@ -468,45 +454,142 @@ pub fn command_complete(command: &str) -> BytesMut {
 }
 
 /// Write all data in the buffer to the TcpStream.
-pub async fn write_all(stream: &mut TcpStream, buf: BytesMut) -> Result<(), Error> {
+pub async fn write_all<S>(stream: &mut S, buf: BytesMut) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     match stream.write_all(&buf).await {
         Ok(_) => Ok(()),
-        Err(_) => return Err(Error::SocketError),
+        Err(err) => {
+            return Err(Error::SocketError(format!(
+                "Error writing to socket - Error: {:?}",
+                err
+            )))
+        }
     }
 }
 
 /// Write all the data in the buffer to the TcpStream, write owned half (see mpsc).
-pub async fn write_all_half(stream: &mut OwnedWriteHalf, buf: BytesMut) -> Result<(), Error> {
-    match stream.write_all(&buf).await {
+pub async fn write_all_half<S>(stream: &mut S, buf: &BytesMut) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    match stream.write_all(buf).await {
         Ok(_) => Ok(()),
-        Err(_) => return Err(Error::SocketError),
+        Err(err) => {
+            return Err(Error::SocketError(format!(
+                "Error writing to socket - Error: {:?}",
+                err
+            )))
+        }
     }
 }
 
 /// Read a complete message from the socket.
-pub async fn read_message(stream: &mut BufReader<OwnedReadHalf>) -> Result<BytesMut, Error> {
+pub async fn read_message<S>(stream: &mut S) -> Result<BytesMut, Error>
+where
+    S: tokio::io::AsyncRead + std::marker::Unpin,
+{
     let code = match stream.read_u8().await {
         Ok(code) => code,
-        Err(_) => return Err(Error::SocketError),
+        Err(err) => {
+            return Err(Error::SocketError(format!(
+                "Error reading message code from socket - Error {:?}",
+                err
+            )))
+        }
     };
 
     let len = match stream.read_i32().await {
         Ok(len) => len,
-        Err(_) => return Err(Error::SocketError),
-    };
-
-    let mut buf = vec![0u8; len as usize - 4];
-
-    match stream.read_exact(&mut buf).await {
-        Ok(_) => (),
-        Err(_) => return Err(Error::SocketError),
+        Err(err) => {
+            return Err(Error::SocketError(format!(
+                "Error reading message len from socket - Code: {:?}, Error: {:?}",
+                code, err
+            )))
+        }
     };
 
     let mut bytes = BytesMut::with_capacity(len as usize + 1);
 
     bytes.put_u8(code);
     bytes.put_i32(len);
-    bytes.put_slice(&buf);
+
+    bytes.resize(bytes.len() + len as usize - mem::size_of::<i32>(), b'0');
+
+    let slice_start = mem::size_of::<u8>() + mem::size_of::<i32>();
+    let slice_end = slice_start + len as usize - mem::size_of::<i32>();
+
+    // Avoids a panic
+    if slice_end < slice_start {
+        return Err(Error::SocketError(format!(
+            "Error reading message from socket - Code: {:?} - Length {:?}, Error: {:?}",
+            code, len, "Unexpected length value for message"
+        )));
+    }
+
+    match stream.read_exact(&mut bytes[slice_start..slice_end]).await {
+        Ok(_) => (),
+        Err(err) => {
+            return Err(Error::SocketError(format!(
+                "Error reading message from socket - Code: {:?}, Error: {:?}",
+                code, err
+            )))
+        }
+    };
 
     Ok(bytes)
 }
+
+pub fn server_parameter_message(key: &str, value: &str) -> BytesMut {
+    let mut server_info = BytesMut::new();
+
+    let null_byte_size = 1;
+    let len: usize =
+        mem::size_of::<i32>() + key.len() + null_byte_size + value.len() + null_byte_size;
+
+    server_info.put_slice("S".as_bytes());
+    server_info.put_i32(len.try_into().unwrap());
+    server_info.put_slice(key.as_bytes());
+    server_info.put_bytes(0, 1);
+    server_info.put_slice(value.as_bytes());
+    server_info.put_bytes(0, 1);
+
+    server_info
+}
+
+pub fn configure_socket(stream: &TcpStream) {
+    let sock_ref = SockRef::from(stream);
+    let conf = get_config();
+
+    match sock_ref.set_keepalive(true) {
+        Ok(_) => {
+            match sock_ref.set_tcp_keepalive(
+                &TcpKeepalive::new()
+                    .with_interval(Duration::from_secs(conf.general.tcp_keepalives_interval))
+                    .with_retries(conf.general.tcp_keepalives_count)
+                    .with_time(Duration::from_secs(conf.general.tcp_keepalives_idle)),
+            ) {
+                Ok(_) => (),
+                Err(err) => error!("Could not configure socket: {}", err),
+            }
+        }
+        Err(err) => error!("Could not configure socket: {}", err),
+    }
+}
+
+pub trait BytesMutReader {
+    fn read_string(&mut self) -> Result<String, Error>;
+}
+
+impl BytesMutReader for Cursor<&BytesMut> {
+    /// Should only be used when reading strings from the message protocol.
+    /// Can be used to read multiple strings from the same message which are separated by the null byte
+    fn read_string(&mut self) -> Result<String, Error> {
+        let mut buf = vec![];
+        match self.read_until(b'\0', &mut buf) {
+            Ok(_) => Ok(String::from_utf8_lossy(&buf[..buf.len() - 1]).to_string()),
+            Err(err) => return Err(Error::ParseBytesError(err.to_string())),
+        }
+    }
+}

src/mirrors.rs

@@ -0,0 +1,179 @@
+/// A mirrored PostgreSQL client.
+/// Packets arrive to us through a channel from the main client and we send them to the server.
+use bb8::Pool;
+use bytes::{Bytes, BytesMut};
+
+use crate::config::{get_config, Address, Role, User};
+use crate::pool::{ClientServerMap, ServerPool};
+use crate::stats::get_reporter;
+use log::{error, info, trace, warn};
+use tokio::sync::mpsc::{channel, Receiver, Sender};
+
+pub struct MirroredClient {
+    address: Address,
+    user: User,
+    database: String,
+    bytes_rx: Receiver<Bytes>,
+    disconnect_rx: Receiver<()>,
+}
+
+impl MirroredClient {
+    async fn create_pool(&self) -> Pool<ServerPool> {
+        let config = get_config();
+        let default = std::time::Duration::from_millis(10_000).as_millis() as u64;
+        let (connection_timeout, idle_timeout) = match config.pools.get(&self.address.pool_name) {
+            Some(cfg) => (
+                cfg.connect_timeout.unwrap_or(default),
+                cfg.idle_timeout.unwrap_or(default),
+            ),
+            None => (default, default),
+        };
+
+        let manager = ServerPool::new(
+            self.address.clone(),
+            self.user.clone(),
+            self.database.as_str(),
+            ClientServerMap::default(),
+            get_reporter(),
+        );
+
+        Pool::builder()
+            .max_size(1)
+            .connection_timeout(std::time::Duration::from_millis(connection_timeout))
+            .idle_timeout(Some(std::time::Duration::from_millis(idle_timeout)))
+            .test_on_check_out(false)
+            .build(manager)
+            .await
+            .unwrap()
+    }
+
+    pub fn start(mut self) {
+        tokio::spawn(async move {
+            let pool = self.create_pool().await;
+            let address = self.address.clone();
+            loop {
+                let mut server = match pool.get().await {
+                    Ok(server) => server,
+                    Err(err) => {
+                        error!(
+                            "Failed to get connection from pool, Discarding message {:?}, {:?}",
+                            err,
+                            address.clone()
+                        );
+                        continue;
+                    }
+                };
+
+                tokio::select! {
+                    // Exit channel events
+                    _ = self.disconnect_rx.recv() => {
+                        info!("Got mirror exit signal, exiting {:?}", address.clone());
+                        break;
+                    }
+
+                    // Incoming data from server (we read to clear the socket buffer and discard the data)
+                    recv_result = server.recv() => {
+                        match recv_result {
+                            Ok(message) => trace!("Received from mirror: {} {:?}", String::from_utf8_lossy(&message[..]), address.clone()),
+                            Err(err) => {
+                                server.mark_bad();
+                                error!("Failed to receive from mirror {:?} {:?}", err, address.clone());
+                            }
+                        }
+                    }
+
+                    // Messages to send to the server
+                    message = self.bytes_rx.recv() => {
+                        match message {
+                            Some(bytes) => {
+                                match server.send(&BytesMut::from(&bytes[..])).await {
+                                    Ok(_) => trace!("Sent to mirror: {} {:?}", String::from_utf8_lossy(&bytes[..]), address.clone()),
+                                    Err(err) => {
+                                        server.mark_bad();
+                                        error!("Failed to send to mirror, Discarding message {:?}, {:?}", err, address.clone())
+                                    }
+                                }
+                            }
+                            None => {
+                                info!("Mirror channel closed, exiting {:?}", address.clone());
+                                break;
+                            },
+                        }
+                    }
+                }
+            }
+        });
+    }
+}
+pub struct MirroringManager {
+    pub byte_senders: Vec<Sender<Bytes>>,
+    pub disconnect_senders: Vec<Sender<()>>,
+}
+impl MirroringManager {
+    pub fn from_addresses(
+        user: User,
+        database: String,
+        addresses: Vec<Address>,
+    ) -> MirroringManager {
+        let mut byte_senders: Vec<Sender<Bytes>> = vec![];
+        let mut exit_senders: Vec<Sender<()>> = vec![];
+
+        addresses.iter().for_each(|mirror| {
+            let (bytes_tx, bytes_rx) = channel::<Bytes>(10);
+            let (exit_tx, exit_rx) = channel::<()>(1);
+            let mut addr = mirror.clone();
+            addr.role = Role::Mirror;
+            let client = MirroredClient {
+                user: user.clone(),
+                database: database.to_owned(),
+                address: addr,
+                bytes_rx,
+                disconnect_rx: exit_rx,
+            };
+            exit_senders.push(exit_tx.clone());
+            byte_senders.push(bytes_tx.clone());
+            client.start();
+        });
+
+        Self {
+            byte_senders: byte_senders,
+            disconnect_senders: exit_senders,
+        }
+    }
+
+    pub fn send(self: &mut Self, bytes: &BytesMut) {
+        // We want to avoid performing an allocation if we won't be able to send the message
+        // There is a possibility of a race here where we check the capacity and then the channel is
+        // closed or the capacity is reduced to 0, but mirroring is best effort anyway
+        if self
+            .byte_senders
+            .iter()
+            .all(|sender| sender.capacity() == 0 || sender.is_closed())
+        {
+            return;
+        }
+        let immutable_bytes = bytes.clone().freeze();
+        self.byte_senders.iter_mut().for_each(|sender| {
+            match sender.try_send(immutable_bytes.clone()) {
+                Ok(_) => {}
+                Err(err) => {
+                    warn!("Failed to send bytes to a mirror channel {}", err);
+                }
+            }
+        });
+    }
+
+    pub fn disconnect(self: &mut Self) {
+        self.disconnect_senders
+            .iter_mut()
+            .for_each(|sender| match sender.try_send(()) {
+                Ok(_) => {}
+                Err(err) => {
+                    warn!(
+                        "Failed to send disconnect signal to a mirror channel {}",
+                        err
+                    );
+                }
+            });
+    }
+}

src/multi_logger.rs

@@ -0,0 +1,80 @@
+use log::{Level, Log, Metadata, Record, SetLoggerError};
+
+// This is a special kind of logger that allows sending logs to different
+// targets depending on the log level.
+//
+// By default, if nothing is set, it acts as a regular env_log logger,
+// it sends everything to standard error.
+//
+// If the Env variable `STDOUT_LOG` is defined, it will be used for
+// configuring the standard out logger.
+//
+// The behavior is:
+//   - If it is an error, the message is written to standard error.
+//   - If it is not, and it matches the log level of the standard output logger (`STDOUT_LOG` env var), it will be send to standard output.
+//   - If the above is not true, it is sent to the stderr logger that will log it or not depending on the value
+//     of the RUST_LOG env var.
+//
+// So to summarize, if no `STDOUT_LOG` env var is present, the logger is the default logger. If `STDOUT_LOG` is set, everything
+// but errors, that matches the log level set in the `STDOUT_LOG` env var is sent to stdout. You can have also some esoteric configuration
+// where you set `RUST_LOG=debug` and `STDOUT_LOG=info`, in here, erros will go to stderr, warns and infos to stdout and debugs to stderr.
+//
+pub struct MultiLogger {
+    stderr_logger: env_logger::Logger,
+    stdout_logger: env_logger::Logger,
+}
+
+impl MultiLogger {
+    fn new() -> Self {
+        let stderr_logger = env_logger::builder().format_timestamp_micros().build();
+        let stdout_logger = env_logger::Builder::from_env("STDOUT_LOG")
+            .format_timestamp_micros()
+            .target(env_logger::Target::Stdout)
+            .build();
+
+        Self {
+            stderr_logger,
+            stdout_logger,
+        }
+    }
+
+    pub fn init() -> Result<(), SetLoggerError> {
+        let logger = Self::new();
+
+        log::set_max_level(logger.stderr_logger.filter());
+        log::set_boxed_logger(Box::new(logger))
+    }
+}
+
+impl Log for MultiLogger {
+    fn enabled(&self, metadata: &Metadata) -> bool {
+        self.stderr_logger.enabled(metadata) && self.stdout_logger.enabled(metadata)
+    }
+
+    fn log(&self, record: &Record) {
+        if record.level() == Level::Error {
+            self.stderr_logger.log(record);
+        } else {
+            if self.stdout_logger.matches(record) {
+                self.stdout_logger.log(record);
+            } else {
+                self.stderr_logger.log(record);
+            }
+        }
+    }
+
+    fn flush(&self) {
+        self.stderr_logger.flush();
+        self.stdout_logger.flush();
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_init() {
+        MultiLogger::init().unwrap();
+    }
+}

src/prometheus.rs

@@ -0,0 +1,376 @@
+use hyper::service::{make_service_fn, service_fn};
+use hyper::{Body, Method, Request, Response, Server, StatusCode};
+use log::{error, info, warn};
+use phf::phf_map;
+use std::collections::HashMap;
+use std::fmt;
+use std::net::SocketAddr;
+
+use crate::config::Address;
+use crate::pool::get_all_pools;
+use crate::stats::{get_address_stats, get_pool_stats, get_server_stats, ServerInformation};
+
+struct MetricHelpType {
+    help: &'static str,
+    ty: &'static str,
+}
+
+// reference for metric types: https://prometheus.io/docs/concepts/metric_types/
+// counters only increase
+// gauges can arbitrarily increase or decrease
+static METRIC_HELP_AND_TYPES_LOOKUP: phf::Map<&'static str, MetricHelpType> = phf_map! {
+    "stats_total_query_count" => MetricHelpType {
+        help: "Number of queries sent by all clients",
+        ty: "counter",
+    },
+    "stats_total_query_time" => MetricHelpType {
+        help: "Total amount of time for queries to execute",
+        ty: "counter",
+    },
+    "stats_total_received" => MetricHelpType {
+        help: "Number of bytes received from the server",
+        ty: "counter",
+    },
+    "stats_total_sent" => MetricHelpType {
+        help: "Number of bytes sent to the server",
+        ty: "counter",
+    },
+    "stats_total_xact_count" => MetricHelpType {
+        help: "Total number of transactions started by the client",
+        ty: "counter",
+    },
+    "stats_total_xact_time" => MetricHelpType {
+        help: "Total amount of time for all transactions to execute",
+        ty: "counter",
+    },
+    "stats_total_wait_time" => MetricHelpType {
+        help: "Total time client waited for a server connection",
+        ty: "counter",
+    },
+    "stats_avg_query_count" => MetricHelpType {
+        help: "Average of total_query_count every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_query_time" => MetricHelpType {
+        help: "Average time taken for queries to execute every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_recv" => MetricHelpType {
+        help: "Average of total_received bytes every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_sent" => MetricHelpType {
+        help: "Average of total_sent bytes every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_errors" => MetricHelpType {
+        help: "Average number of errors every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_xact_count" => MetricHelpType {
+        help: "Average of total_xact_count every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_xact_time" => MetricHelpType {
+        help: "Average of total_xact_time every 15 seconds",
+        ty: "gauge",
+    },
+    "stats_avg_wait_time" => MetricHelpType {
+        help: "Average of total_wait_time every 15 seconds",
+        ty: "gauge",
+    },
+    "pools_maxwait_us" => MetricHelpType {
+        help: "The time a client waited for a server connection in microseconds",
+        ty: "gauge",
+    },
+    "pools_maxwait" => MetricHelpType {
+        help: "The time a client waited for a server connection in seconds",
+        ty: "gauge",
+    },
+    "pools_cl_waiting" => MetricHelpType {
+        help: "How many clients are waiting for a connection from the pool",
+        ty: "gauge",
+    },
+    "pools_cl_active" => MetricHelpType {
+        help: "How many clients are actively communicating with a server",
+        ty: "gauge",
+    },
+    "pools_cl_idle" => MetricHelpType {
+        help: "How many clients are idle",
+        ty: "gauge",
+    },
+    "pools_sv_idle" => MetricHelpType {
+        help: "How many server connections are idle",
+        ty: "gauge",
+    },
+    "pools_sv_active" => MetricHelpType {
+        help: "How many server connections are actively communicating with a client",
+        ty: "gauge",
+    },
+    "pools_sv_login" => MetricHelpType {
+        help: "How many server connections are currently being created",
+        ty: "gauge",
+    },
+    "pools_sv_tested" => MetricHelpType {
+        help: "How many server connections are currently waiting on a health check to succeed",
+        ty: "gauge",
+    },
+    "servers_bytes_received" => MetricHelpType {
+        help: "Volume in bytes of network traffic received by server",
+        ty: "gauge",
+    },
+    "servers_bytes_sent" => MetricHelpType {
+        help: "Volume in bytes of network traffic sent by server",
+        ty: "gauge",
+    },
+    "servers_transaction_count" => MetricHelpType {
+        help: "Number of transactions executed by server",
+        ty: "gauge",
+    },
+    "servers_query_count" => MetricHelpType {
+        help: "Number of queries executed by server",
+        ty: "gauge",
+    },
+    "servers_error_count" => MetricHelpType {
+        help: "Number of errors",
+        ty: "gauge",
+    },
+    "databases_pool_size" => MetricHelpType {
+        help: "Maximum number of server connections",
+        ty: "gauge",
+    },
+    "databases_current_connections" => MetricHelpType {
+        help: "Current number of connections for this database",
+        ty: "gauge",
+    },
+};
+
+struct PrometheusMetric<Value: fmt::Display> {
+    name: String,
+    help: String,
+    ty: String,
+    labels: HashMap<&'static str, String>,
+    value: Value,
+}
+
+impl<Value: fmt::Display> fmt::Display for PrometheusMetric<Value> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let formatted_labels = self
+            .labels
+            .iter()
+            .map(|(key, value)| format!("{}=\"{}\"", key, value))
+            .collect::<Vec<_>>()
+            .join(",");
+        write!(
+            f,
+            "# HELP {name} {help}\n# TYPE {name} {ty}\n{name}{{{formatted_labels}}} {value}\n",
+            name = format_args!("pgcat_{}", self.name),
+            help = self.help,
+            ty = self.ty,
+            formatted_labels = formatted_labels,
+            value = self.value
+        )
+    }
+}
+
+impl<Value: fmt::Display> PrometheusMetric<Value> {
+    fn from_name<V: fmt::Display>(
+        name: &str,
+        value: V,
+        labels: HashMap<&'static str, String>,
+    ) -> Option<PrometheusMetric<V>> {
+        METRIC_HELP_AND_TYPES_LOOKUP
+            .get(name)
+            .map(|metric| PrometheusMetric::<V> {
+                name: name.to_owned(),
+                help: metric.help.to_owned(),
+                ty: metric.ty.to_owned(),
+                value,
+                labels,
+            })
+    }
+
+    fn from_database_info(
+        address: &Address,
+        name: &str,
+        value: u32,
+    ) -> Option<PrometheusMetric<u32>> {
+        let mut labels = HashMap::new();
+        labels.insert("host", address.host.clone());
+        labels.insert("shard", address.shard.to_string());
+        labels.insert("role", address.role.to_string());
+        labels.insert("pool", address.pool_name.clone());
+        labels.insert("database", address.database.to_string());
+
+        Self::from_name(&format!("databases_{}", name), value, labels)
+    }
+
+    fn from_server_info(
+        address: &Address,
+        name: &str,
+        value: u64,
+    ) -> Option<PrometheusMetric<u64>> {
+        let mut labels = HashMap::new();
+        labels.insert("host", address.host.clone());
+        labels.insert("shard", address.shard.to_string());
+        labels.insert("role", address.role.to_string());
+        labels.insert("pool", address.pool_name.clone());
+        labels.insert("database", address.database.to_string());
+
+        Self::from_name(&format!("servers_{}", name), value, labels)
+    }
+
+    fn from_address(address: &Address, name: &str, value: i64) -> Option<PrometheusMetric<i64>> {
+        let mut labels = HashMap::new();
+        labels.insert("host", address.host.clone());
+        labels.insert("shard", address.shard.to_string());
+        labels.insert("pool", address.pool_name.clone());
+        labels.insert("role", address.role.to_string());
+        labels.insert("database", address.database.to_string());
+
+        Self::from_name(&format!("stats_{}", name), value, labels)
+    }
+
+    fn from_pool(pool: &(String, String), name: &str, value: i64) -> Option<PrometheusMetric<i64>> {
+        let mut labels = HashMap::new();
+        labels.insert("pool", pool.0.clone());
+        labels.insert("user", pool.1.clone());
+
+        Self::from_name(&format!("pools_{}", name), value, labels)
+    }
+}
+
+async fn prometheus_stats(request: Request<Body>) -> Result<Response<Body>, hyper::http::Error> {
+    match (request.method(), request.uri().path()) {
+        (&Method::GET, "/metrics") => {
+            let mut lines = Vec::new();
+            push_address_stats(&mut lines);
+            push_pool_stats(&mut lines);
+            push_server_stats(&mut lines);
+            push_database_stats(&mut lines);
+
+            Response::builder()
+                .header("content-type", "text/plain; version=0.0.4")
+                .body(lines.join("\n").into())
+        }
+        _ => Response::builder()
+            .status(StatusCode::NOT_FOUND)
+            .body("".into()),
+    }
+}
+
+// Adds metrics shown in a SHOW STATS admin command.
+fn push_address_stats(lines: &mut Vec<String>) {
+    let address_stats: HashMap<usize, HashMap<String, i64>> = get_address_stats();
+    for (_, pool) in get_all_pools() {
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                if let Some(address_stats) = address_stats.get(&address.id) {
+                    for (key, value) in address_stats.iter() {
+                        if let Some(prometheus_metric) =
+                            PrometheusMetric::<i64>::from_address(address, key, *value)
+                        {
+                            lines.push(prometheus_metric.to_string());
+                        } else {
+                            warn!("Metric {} not implemented for {}", key, address.name());
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+// Adds relevant metrics shown in a SHOW POOLS admin command.
+fn push_pool_stats(lines: &mut Vec<String>) {
+    let pool_stats = get_pool_stats();
+    for (pool, stats) in pool_stats.iter() {
+        for (name, value) in stats.iter() {
+            if let Some(prometheus_metric) = PrometheusMetric::<i64>::from_pool(pool, name, *value)
+            {
+                lines.push(prometheus_metric.to_string());
+            } else {
+                warn!(
+                    "Metric {} not implemented for ({},{})",
+                    name, pool.0, pool.1
+                );
+            }
+        }
+    }
+}
+
+// Adds relevant metrics shown in a SHOW DATABASES admin command.
+fn push_database_stats(lines: &mut Vec<String>) {
+    for (_, pool) in get_all_pools() {
+        let pool_config = pool.settings.clone();
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                let pool_state = pool.pool_state(shard, server);
+
+                let metrics = vec![
+                    ("pool_size", pool_config.user.pool_size),
+                    ("current_connections", pool_state.connections),
+                ];
+                for (key, value) in metrics {
+                    if let Some(prometheus_metric) =
+                        PrometheusMetric::<u32>::from_database_info(address, key, value)
+                    {
+                        lines.push(prometheus_metric.to_string());
+                    } else {
+                        warn!("Metric {} not implemented for {}", key, address.name());
+                    }
+                }
+            }
+        }
+    }
+}
+
+// Adds relevant metrics shown in a SHOW SERVERS admin command.
+fn push_server_stats(lines: &mut Vec<String>) {
+    let server_stats = get_server_stats();
+    let mut server_stats_by_addresses = HashMap::<String, ServerInformation>::new();
+    for (_, info) in server_stats {
+        server_stats_by_addresses.insert(info.address_name.clone(), info);
+    }
+
+    for (_, pool) in get_all_pools() {
+        for shard in 0..pool.shards() {
+            for server in 0..pool.servers(shard) {
+                let address = pool.address(shard, server);
+                if let Some(server_info) = server_stats_by_addresses.get(&address.name()) {
+                    let metrics = [
+                        ("bytes_received", server_info.bytes_received),
+                        ("bytes_sent", server_info.bytes_sent),
+                        ("transaction_count", server_info.transaction_count),
+                        ("query_count", server_info.query_count),
+                        ("error_count", server_info.error_count),
+                    ];
+                    for (key, value) in metrics {
+                        if let Some(prometheus_metric) =
+                            PrometheusMetric::<u64>::from_server_info(address, key, value)
+                        {
+                            lines.push(prometheus_metric.to_string());
+                        } else {
+                            warn!("Metric {} not implemented for {}", key, address.name());
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+pub async fn start_metric_server(http_addr: SocketAddr) {
+    let http_service_factory =
+        make_service_fn(|_conn| async { Ok::<_, hyper::Error>(service_fn(prometheus_stats)) });
+    let server = Server::bind(&http_addr).serve(http_service_factory);
+    info!(
+        "Exposing prometheus metrics on http://{}/metrics.",
+        http_addr
+    );
+    if let Err(e) = server.await {
+        error!("Failed to run HTTP server: {}.", e);
+    }
+}

src/scram.rs

@@ -0,0 +1,325 @@
+// SCRAM-SHA-256 authentication. Heavily inspired by
+// https://github.com/sfackler/rust-postgres/
+// SASL implementation.
+
+use base64::{engine::general_purpose, Engine as _};
+use bytes::BytesMut;
+use hmac::{Hmac, Mac};
+use rand::{self, Rng};
+use sha2::digest::FixedOutput;
+use sha2::{Digest, Sha256};
+
+use std::fmt::Write;
+
+use crate::constants::*;
+use crate::errors::Error;
+
+/// Normalize a password string. Postgres
+/// passwords don't have to be UTF-8.
+fn normalize(pass: &[u8]) -> Vec<u8> {
+    let pass = match std::str::from_utf8(pass) {
+        Ok(pass) => pass,
+        Err(_) => return pass.to_vec(),
+    };
+
+    match stringprep::saslprep(pass) {
+        Ok(pass) => pass.into_owned().into_bytes(),
+        Err(_) => pass.as_bytes().to_vec(),
+    }
+}
+
+/// Keep the SASL state through the exchange.
+/// It takes 3 messages to complete the authentication.
+pub struct ScramSha256 {
+    password: String,
+    salted_password: [u8; 32],
+    auth_message: String,
+    message: BytesMut,
+    nonce: String,
+}
+
+impl ScramSha256 {
+    /// Create the Scram state from a password. It'll automatically
+    /// generate a nonce.
+    pub fn new(password: &str) -> ScramSha256 {
+        let mut rng = rand::thread_rng();
+        let nonce = (0..NONCE_LENGTH)
+            .map(|_| {
+                let mut v = rng.gen_range(0x21u8..0x7e);
+                if v == 0x2c {
+                    v = 0x7e
+                }
+                v as char
+            })
+            .collect::<String>();
+
+        Self::from_nonce(password, &nonce)
+    }
+
+    /// Used for testing.
+    pub fn from_nonce(password: &str, nonce: &str) -> ScramSha256 {
+        let message = BytesMut::from(format!("{}n=,r={}", "n,,", nonce).as_bytes());
+
+        ScramSha256 {
+            password: password.to_string(),
+            nonce: String::from(nonce),
+            message,
+            salted_password: [0u8; 32],
+            auth_message: String::new(),
+        }
+    }
+
+    /// Get the current state of the SASL authentication.
+    pub fn message(&mut self) -> BytesMut {
+        self.message.clone()
+    }
+
+    /// Update the state with message received from server.
+    pub fn update(&mut self, message: &BytesMut) -> Result<BytesMut, Error> {
+        let server_message = Message::parse(message)?;
+
+        if !server_message.nonce.starts_with(&self.nonce) {
+            return Err(Error::ProtocolSyncError(format!("SCRAM")));
+        }
+
+        let salt = match general_purpose::STANDARD.decode(&server_message.salt) {
+            Ok(salt) => salt,
+            Err(_) => return Err(Error::ProtocolSyncError(format!("SCRAM"))),
+        };
+
+        let salted_password = Self::hi(
+            &normalize(self.password.as_bytes()),
+            &salt,
+            server_message.iterations,
+        );
+
+        // Save for verification of final server message.
+        self.salted_password = salted_password;
+
+        let mut hmac = match Hmac::<Sha256>::new_from_slice(&salted_password) {
+            Ok(hmac) => hmac,
+            Err(_) => return Err(Error::ServerError),
+        };
+
+        hmac.update(b"Client Key");
+
+        let client_key = hmac.finalize().into_bytes();
+
+        let mut hash = Sha256::default();
+        hash.update(client_key.as_slice());
+
+        let stored_key = hash.finalize_fixed();
+        let mut cbind_input = vec![];
+        cbind_input.extend("n,,".as_bytes());
+
+        let cbind_input = general_purpose::STANDARD.encode(&cbind_input);
+
+        self.message.clear();
+
+        // Start writing the client reply.
+        match write!(
+            &mut self.message,
+            "c={},r={}",
+            cbind_input, server_message.nonce
+        ) {
+            Ok(_) => (),
+            Err(_) => return Err(Error::ServerError),
+        };
+
+        let auth_message = format!(
+            "n=,r={},{},{}",
+            self.nonce,
+            String::from_utf8_lossy(&message[..]),
+            String::from_utf8_lossy(&self.message[..])
+        );
+
+        let mut hmac = match Hmac::<Sha256>::new_from_slice(&stored_key) {
+            Ok(hmac) => hmac,
+            Err(_) => return Err(Error::ServerError),
+        };
+        hmac.update(auth_message.as_bytes());
+
+        // Save the auth message for server final message verification.
+        self.auth_message = auth_message;
+
+        let client_signature = hmac.finalize().into_bytes();
+
+        // Sign the client proof.
+        let mut client_proof = client_key;
+        for (proof, signature) in client_proof.iter_mut().zip(client_signature) {
+            *proof ^= signature;
+        }
+
+        match write!(
+            &mut self.message,
+            ",p={}",
+            general_purpose::STANDARD.encode(&*client_proof)
+        ) {
+            Ok(_) => (),
+            Err(_) => return Err(Error::ServerError),
+        };
+
+        Ok(self.message.clone())
+    }
+
+    /// Verify final server message.
+    pub fn finish(&mut self, message: &BytesMut) -> Result<(), Error> {
+        let final_message = FinalMessage::parse(message)?;
+
+        let verifier = match general_purpose::STANDARD.decode(&final_message.value) {
+            Ok(verifier) => verifier,
+            Err(_) => return Err(Error::ProtocolSyncError(format!("SCRAM"))),
+        };
+
+        let mut hmac = match Hmac::<Sha256>::new_from_slice(&self.salted_password) {
+            Ok(hmac) => hmac,
+            Err(_) => return Err(Error::ServerError),
+        };
+        hmac.update(b"Server Key");
+        let server_key = hmac.finalize().into_bytes();
+
+        let mut hmac = match Hmac::<Sha256>::new_from_slice(&server_key) {
+            Ok(hmac) => hmac,
+            Err(_) => return Err(Error::ServerError),
+        };
+        hmac.update(self.auth_message.as_bytes());
+
+        match hmac.verify_slice(&verifier) {
+            Ok(_) => Ok(()),
+            Err(_) => Err(Error::ServerError),
+        }
+    }
+
+    /// Hash the password with the salt i-times.
+    fn hi(str: &[u8], salt: &[u8], i: u32) -> [u8; 32] {
+        let mut hmac =
+            Hmac::<Sha256>::new_from_slice(str).expect("HMAC is able to accept all key sizes");
+        hmac.update(salt);
+        hmac.update(&[0, 0, 0, 1]);
+        let mut prev = hmac.finalize().into_bytes();
+
+        let mut hi = prev;
+
+        for _ in 1..i {
+            let mut hmac = Hmac::<Sha256>::new_from_slice(str).expect("already checked above");
+            hmac.update(&prev);
+            prev = hmac.finalize().into_bytes();
+
+            for (hi, prev) in hi.iter_mut().zip(prev) {
+                *hi ^= prev;
+            }
+        }
+
+        hi.into()
+    }
+}
+
+/// Parse the server challenge.
+struct Message {
+    nonce: String,
+    salt: String,
+    iterations: u32,
+}
+
+impl Message {
+    /// Parse the server SASL challenge.
+    fn parse(message: &BytesMut) -> Result<Message, Error> {
+        let parts = String::from_utf8_lossy(&message[..])
+            .split(',')
+            .map(|s| s.to_string())
+            .collect::<Vec<String>>();
+
+        if parts.len() != 3 {
+            return Err(Error::ProtocolSyncError(format!("SCRAM")));
+        }
+
+        let nonce = str::replace(&parts[0], "r=", "");
+        let salt = str::replace(&parts[1], "s=", "");
+        let iterations = match str::replace(&parts[2], "i=", "").parse::<u32>() {
+            Ok(iterations) => iterations,
+            Err(_) => return Err(Error::ProtocolSyncError(format!("SCRAM"))),
+        };
+
+        Ok(Message {
+            nonce,
+            salt,
+            iterations,
+        })
+    }
+}
+
+/// Parse server final validation message.
+struct FinalMessage {
+    value: String,
+}
+
+impl FinalMessage {
+    /// Parse the server final validation message.
+    pub fn parse(message: &BytesMut) -> Result<FinalMessage, Error> {
+        if !message.starts_with(b"v=") || message.len() < 4 {
+            return Err(Error::ProtocolSyncError(format!("SCRAM")));
+        }
+
+        Ok(FinalMessage {
+            value: String::from_utf8_lossy(&message[2..]).to_string(),
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn parse_server_first_message() {
+        let message = BytesMut::from(
+            "r=fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j,s=QSXCR+Q6sek8bf92,i=4096".as_bytes(),
+        );
+        let message = Message::parse(&message).unwrap();
+        assert_eq!(message.nonce, "fyko+d2lbbFgONRv9qkxdawL3rfcNHYJY1ZVvWVs7j");
+        assert_eq!(message.salt, "QSXCR+Q6sek8bf92");
+        assert_eq!(message.iterations, 4096);
+    }
+
+    #[test]
+    fn parse_server_last_message() {
+        let f = FinalMessage::parse(&BytesMut::from(
+            "v=U+ppxD5XUKtradnv8e2MkeupiA8FU87Sg8CXzXHDAzw".as_bytes(),
+        ))
+        .unwrap();
+        assert_eq!(
+            f.value,
+            "U+ppxD5XUKtradnv8e2MkeupiA8FU87Sg8CXzXHDAzw".to_string()
+        );
+    }
+
+    // recorded auth exchange from psql
+    #[test]
+    fn exchange() {
+        let password = "foobar";
+        let nonce = "9IZ2O01zb9IgiIZ1WJ/zgpJB";
+
+        let client_first = "n,,n=,r=9IZ2O01zb9IgiIZ1WJ/zgpJB";
+        let server_first =
+            "r=9IZ2O01zb9IgiIZ1WJ/zgpJBjx/oIRLs02gGSHcw1KEty3eY,s=fs3IXBy7U7+IvVjZ,i\
+             =4096";
+        let client_final =
+            "c=biws,r=9IZ2O01zb9IgiIZ1WJ/zgpJBjx/oIRLs02gGSHcw1KEty3eY,p=AmNKosjJzS3\
+             1NTlQYNs5BTeQjdHdk7lOflDo5re2an8=";
+        let server_final = "v=U+ppxD5XUKtradnv8e2MkeupiA8FU87Sg8CXzXHDAzw=";
+
+        let mut scram = ScramSha256::from_nonce(password, nonce);
+
+        let message = scram.message();
+        assert_eq!(std::str::from_utf8(&message).unwrap(), client_first);
+
+        let result = scram
+            .update(&BytesMut::from(server_first.as_bytes()))
+            .unwrap();
+        assert_eq!(std::str::from_utf8(&result).unwrap(), client_final);
+
+        scram
+            .finish(&BytesMut::from(server_final.as_bytes()))
+            .unwrap();
+    }
+}

src/server.rs

@@ -1,7 +1,9 @@
+/// Implementation of the PostgreSQL server (database) protocol.
+/// Here we are pretending to the a Postgres client.
 use bytes::{Buf, BufMut, BytesMut};
-///! Implementation of the PostgreSQL server (database) protocol.
-///! Here we are pretending to the a Postgres client.
-use log::{debug, error, info, trace};
+use log::{debug, error, info, trace, warn};
+use std::io::Read;
+use std::time::SystemTime;
 use tokio::io::{AsyncReadExt, BufReader};
 use tokio::net::{
     tcp::{OwnedReadHalf, OwnedWriteHalf},
@@ -12,54 +14,70 @@ use crate::config::{Address, User};
 use crate::constants::*;
 use crate::errors::Error;
 use crate::messages::*;
+use crate::mirrors::MirroringManager;
+use crate::pool::ClientServerMap;
+use crate::scram::ScramSha256;
 use crate::stats::Reporter;
-use crate::ClientServerMap;
 
 /// Server state.
 pub struct Server {
-    // Server host, e.g. localhost,
-    // port, e.g. 5432, and role, e.g. primary or replica.
+    server_id: i32,
+
+    /// Server host, e.g. localhost,
+    /// port, e.g. 5432, and role, e.g. primary or replica.
     address: Address,
 
-    // Buffered read socket.
+    /// Buffered read socket.
     read: BufReader<OwnedReadHalf>,
 
-    // Unbuffered write socket (our client code buffers).
+    /// Unbuffered write socket (our client code buffers).
     write: OwnedWriteHalf,
 
-    // Our server response buffer. We buffer data before we give it to the client.
+    /// Our server response buffer. We buffer data before we give it to the client.
     buffer: BytesMut,
 
-    // Server information the server sent us over on startup.
+    /// Server information the server sent us over on startup.
     server_info: BytesMut,
 
-    // Backend id and secret key used for query cancellation.
+    /// Backend id and secret key used for query cancellation.
     process_id: i32,
     secret_key: i32,
 
-    // Is the server inside a transaction or idle.
+    /// Is the server inside a transaction or idle.
     in_transaction: bool,
 
-    // Is there more data for the client to read.
+    /// Is there more data for the client to read.
     data_available: bool,
 
-    // Is the server broken? We'll remote it from the pool if so.
+    /// Is the server broken? We'll remote it from the pool if so.
     bad: bool,
 
-    // Mapping of clients and servers used for query cancellation.
+    /// If server connection requires a DISCARD ALL before checkin
+    needs_cleanup: bool,
+
+    /// Mapping of clients and servers used for query cancellation.
     client_server_map: ClientServerMap,
 
-    // Server connected at.
+    /// Server connected at.
     connected_at: chrono::naive::NaiveDateTime,
 
-    // Reports various metrics, e.g. data sent & received.
+    /// Reports various metrics, e.g. data sent & received.
     stats: Reporter,
+
+    /// Application name using the server at the moment.
+    application_name: String,
+
+    // Last time that a successful server send or response happened
+    last_activity: SystemTime,
+
+    mirror_manager: Option<MirroringManager>,
 }
 
 impl Server {
     /// Pretend to be the Postgres client and connect to the server given host, port and credentials.
     /// Perform the authentication and return the server in a ready for query state.
     pub async fn startup(
+        server_id: i32,
         address: &Address,
         user: &User,
         database: &str,
@@ -67,18 +85,22 @@ impl Server {
         stats: Reporter,
     ) -> Result<Server, Error> {
         let mut stream =
-            match TcpStream::connect(&format!("{}:{}", &address.host, &address.port)).await {
+            match TcpStream::connect(&format!("{}:{}", &address.host, address.port)).await {
                 Ok(stream) => stream,
                 Err(err) => {
                     error!("Could not connect to server: {}", err);
-                    return Err(Error::SocketError);
+                    return Err(Error::SocketError(format!(
+                        "Could not connect to server: {}",
+                        err
+                    )));
                 }
             };
+        configure_socket(&stream);
 
         trace!("Sending StartupMessage");
 
-        // Send the startup packet telling the server we're a normal Postgres client.
-        startup(&mut stream, &user.name, database).await?;
+        // StartupMessage
+        startup(&mut stream, &user.username, database).await?;
 
         let mut server_info = BytesMut::new();
         let mut process_id: i32 = 0;
@@ -86,15 +108,17 @@ impl Server {
 
         // We'll be handling multiple packets, but they will all be structured the same.
         // We'll loop here until this exchange is complete.
+        let mut scram = ScramSha256::new(&user.password);
+
         loop {
             let code = match stream.read_u8().await {
                 Ok(code) => code as char,
-                Err(_) => return Err(Error::SocketError),
+                Err(_) => return Err(Error::SocketError(format!("Error reading message code on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
             };
 
             let len = match stream.read_i32().await {
                 Ok(len) => len,
-                Err(_) => return Err(Error::SocketError),
+                Err(_) => return Err(Error::SocketError(format!("Error reading message len on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
             };
 
             trace!("Message: {}", code);
@@ -105,7 +129,7 @@ impl Server {
                     // Determine which kind of authentication is required, if any.
                     let auth_code = match stream.read_i32().await {
                         Ok(auth_code) => auth_code,
-                        Err(_) => return Err(Error::SocketError),
+                        Err(_) => return Err(Error::SocketError(format!("Error reading auth code on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                     };
 
                     trace!("Auth: {}", auth_code);
@@ -118,15 +142,100 @@ impl Server {
 
                             match stream.read_exact(&mut salt).await {
                                 Ok(_) => (),
-                                Err(_) => return Err(Error::SocketError),
+                                Err(_) => return Err(Error::SocketError(format!("Error reading salt on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                             };
 
-                            md5_password(&mut stream, &user.name, &user.password, &salt[..])
+                            md5_password(&mut stream, &user.username, &user.password, &salt[..])
                                 .await?;
                         }
 
                         AUTHENTICATION_SUCCESSFUL => (),
 
+                        SASL => {
+                            debug!("Starting SASL authentication");
+                            let sasl_len = (len - 8) as usize;
+                            let mut sasl_auth = vec![0u8; sasl_len];
+
+                            match stream.read_exact(&mut sasl_auth).await {
+                                Ok(_) => (),
+                                Err(_) => return Err(Error::SocketError(format!("Error reading sasl message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                            };
+
+                            let sasl_type = String::from_utf8_lossy(&sasl_auth[..sasl_len - 2]);
+
+                            if sasl_type == SCRAM_SHA_256 {
+                                debug!("Using {}", SCRAM_SHA_256);
+
+                                // Generate client message.
+                                let sasl_response = scram.message();
+
+                                // SASLInitialResponse (F)
+                                let mut res = BytesMut::new();
+                                res.put_u8(b'p');
+
+                                // length + String length + length + length of sasl response
+                                res.put_i32(
+                                    4 // i32 size
+                                        + SCRAM_SHA_256.len() as i32 // length of SASL version string,
+                                        + 1 // Null terminator for the SASL version string,
+                                        + 4 // i32 size
+                                        + sasl_response.len() as i32, // length of SASL response
+                                );
+
+                                res.put_slice(format!("{}\0", SCRAM_SHA_256).as_bytes());
+                                res.put_i32(sasl_response.len() as i32);
+                                res.put(sasl_response);
+
+                                write_all(&mut stream, res).await?;
+                            } else {
+                                error!("Unsupported SCRAM version: {}", sasl_type);
+                                return Err(Error::ServerError);
+                            }
+                        }
+
+                        SASL_CONTINUE => {
+                            trace!("Continuing SASL");
+
+                            let mut sasl_data = vec![0u8; (len - 8) as usize];
+
+                            match stream.read_exact(&mut sasl_data).await {
+                                Ok(_) => (),
+                                Err(_) => return Err(Error::SocketError(format!("Error reading sasl cont message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                            };
+
+                            let msg = BytesMut::from(&sasl_data[..]);
+                            let sasl_response = scram.update(&msg)?;
+
+                            // SASLResponse
+                            let mut res = BytesMut::new();
+                            res.put_u8(b'p');
+                            res.put_i32(4 + sasl_response.len() as i32);
+                            res.put(sasl_response);
+
+                            write_all(&mut stream, res).await?;
+                        }
+
+                        SASL_FINAL => {
+                            trace!("Final SASL");
+
+                            let mut sasl_final = vec![0u8; len as usize - 8];
+                            match stream.read_exact(&mut sasl_final).await {
+                                Ok(_) => (),
+                                Err(_) => return Err(Error::SocketError(format!("Error reading sasl final message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                            };
+
+                            match scram.finish(&BytesMut::from(&sasl_final[..])) {
+                                Ok(_) => {
+                                    debug!("SASL authentication successful");
+                                }
+
+                                Err(err) => {
+                                    debug!("SASL authentication failed");
+                                    return Err(err);
+                                }
+                            };
+                        }
+
                         _ => {
                             error!("Unsupported authentication mechanism: {}", auth_code);
                             return Err(Error::ServerError);
@@ -138,7 +247,7 @@ impl Server {
                 'E' => {
                     let error_code = match stream.read_u8().await {
                         Ok(error_code) => error_code,
-                        Err(_) => return Err(Error::SocketError),
+                        Err(_) => return Err(Error::SocketError(format!("Error reading error code message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                     };
 
                     trace!("Error: {}", error_code);
@@ -154,7 +263,7 @@ impl Server {
 
                             match stream.read_exact(&mut error).await {
                                 Ok(_) => (),
-                                Err(_) => return Err(Error::SocketError),
+                                Err(_) => return Err(Error::SocketError(format!("Error reading error message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                             };
 
                             // TODO: the error message contains multiple fields; we can decode them and
@@ -173,7 +282,7 @@ impl Server {
 
                     match stream.read_exact(&mut param).await {
                         Ok(_) => (),
-                        Err(_) => return Err(Error::SocketError),
+                        Err(_) => return Err(Error::SocketError(format!("Error reading parameter status message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                     };
 
                     // Save the parameter so we can pass it to the client later.
@@ -187,15 +296,15 @@ impl Server {
                 // BackendKeyData
                 'K' => {
                     // The frontend must save these values if it wishes to be able to issue CancelRequest messages later.
-                    // See: https://www.postgresql.org/docs/12/protocol-message-formats.html
+                    // See: <https://www.postgresql.org/docs/12/protocol-message-formats.html>.
                     process_id = match stream.read_i32().await {
                         Ok(id) => id,
-                        Err(_) => return Err(Error::SocketError),
+                        Err(_) => return Err(Error::SocketError(format!("Error reading process id message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                     };
 
                     secret_key = match stream.read_i32().await {
                         Ok(id) => id,
-                        Err(_) => return Err(Error::SocketError),
+                        Err(_) => return Err(Error::SocketError(format!("Error reading secret key message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                     };
                 }
 
@@ -205,35 +314,52 @@ impl Server {
 
                     match stream.read_exact(&mut idle).await {
                         Ok(_) => (),
-                        Err(_) => return Err(Error::SocketError),
+                        Err(_) => return Err(Error::SocketError(format!("Error reading transaction status message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
                     };
 
-                    // This is the last step in the client-server connection setup,
-                    // and indicates the server is ready for to query it.
                     let (read, write) = stream.into_split();
 
-                    return Ok(Server {
+                    let mut server = Server {
                         address: address.clone(),
                         read: BufReader::new(read),
-                        write: write,
+                        write,
                         buffer: BytesMut::with_capacity(8196),
-                        server_info: server_info,
-                        process_id: process_id,
-                        secret_key: secret_key,
+                        server_info,
+                        server_id,
+                        process_id,
+                        secret_key,
                         in_transaction: false,
                         data_available: false,
                         bad: false,
-                        client_server_map: client_server_map,
+                        needs_cleanup: false,
+                        client_server_map,
                         connected_at: chrono::offset::Utc::now().naive_utc(),
-                        stats: stats,
-                    });
+                        stats,
+                        application_name: String::new(),
+                        last_activity: SystemTime::now(),
+                        mirror_manager: match address.mirrors.len() {
+                            0 => None,
+                            _ => Some(MirroringManager::from_addresses(
+                                user.clone(),
+                                database.to_owned(),
+                                address.mirrors.clone(),
+                            )),
+                        },
+                    };
+
+                    server.set_name("pgcat").await?;
+
+                    return Ok(server);
                 }
 
                 // We have an unexpected message from the server during this exchange.
                 // Means we implemented the protocol wrong or we're not talking to a Postgres server.
                 _ => {
                     error!("Unknown code: {}", code);
-                    return Err(Error::ProtocolSyncError);
+                    return Err(Error::ProtocolSyncError(format!(
+                        "Unknown server code: {}",
+                        code
+                    )));
                 }
             };
         }
@@ -243,7 +369,7 @@ impl Server {
     /// Uses a separate connection that's not part of the connection pool.
     pub async fn cancel(
         host: &str,
-        port: &str,
+        port: u16,
         process_id: i32,
         secret_key: i32,
     ) -> Result<(), Error> {
@@ -251,9 +377,10 @@ impl Server {
             Ok(stream) => stream,
             Err(err) => {
                 error!("Could not connect to server: {}", err);
-                return Err(Error::SocketError);
+                return Err(Error::SocketError(format!("Error reading cancel message")));
             }
         };
+        configure_socket(&stream);
 
         debug!("Sending CancelRequest");
 
@@ -263,15 +390,20 @@ impl Server {
         bytes.put_i32(process_id);
         bytes.put_i32(secret_key);
 
-        Ok(write_all(&mut stream, bytes).await?)
+        write_all(&mut stream, bytes).await
     }
 
     /// Send messages to the server from the client.
-    pub async fn send(&mut self, messages: BytesMut) -> Result<(), Error> {
-        self.stats.data_sent(messages.len());
+    pub async fn send(&mut self, messages: &BytesMut) -> Result<(), Error> {
+        self.mirror_send(messages);
+        self.stats.data_sent(messages.len(), self.server_id);
 
         match write_all_half(&mut self.write, messages).await {
-            Ok(_) => Ok(()),
+            Ok(_) => {
+                // Successfully sent to server
+                self.last_activity = SystemTime::now();
+                Ok(())
+            }
             Err(err) => {
                 error!("Terminating server because of: {:?}", err);
                 self.bad = true;
@@ -318,7 +450,7 @@ impl Server {
                             self.in_transaction = false;
                         }
 
-                        // Some error occured, the transaction was rolled back.
+                        // Some error occurred, the transaction was rolled back.
                         'E' => {
                             self.in_transaction = true;
                         }
@@ -326,7 +458,10 @@ impl Server {
                         // Something totally unexpected, this is not a Postgres server we know.
                         _ => {
                             self.bad = true;
-                            return Err(Error::ProtocolSyncError);
+                            return Err(Error::ProtocolSyncError(format!(
+                                "Unknown transaction state: {}",
+                                transaction_state
+                            )));
                         }
                     };
 
@@ -336,13 +471,45 @@ impl Server {
                     break;
                 }
 
+                // CommandComplete
+                'C' => {
+                    let mut command_tag = String::new();
+                    match message.reader().read_to_string(&mut command_tag) {
+                        Ok(_) => {
+                            // Non-exhaustive list of commands that are likely to change session variables/resources
+                            // which can leak between clients. This is a best effort to block bad clients
+                            // from poisoning a transaction-mode pool by setting inappropriate session variables
+                            match command_tag.as_str() {
+                                "SET\0" => {
+                                    // We don't detect set statements in transactions
+                                    // No great way to differentiate between set and set local
+                                    // As a result, we will miss cases when set statements are used in transactions
+                                    // This will reduce amount of discard statements sent
+                                    if !self.in_transaction {
+                                        debug!("Server connection marked for clean up");
+                                        self.needs_cleanup = true;
+                                    }
+                                }
+                                "PREPARE\0" => {
+                                    debug!("Server connection marked for clean up");
+                                    self.needs_cleanup = true;
+                                }
+                                _ => (),
+                            }
+                        }
+
+                        Err(err) => {
+                            warn!("Encountered an error while parsing CommandTag {}", err);
+                        }
+                    }
+                }
+
                 // DataRow
                 'D' => {
                     // More data is available after this message, this is not the end of the reply.
                     self.data_available = true;
 
-                    // Don't flush yet, the more we buffer, the faster this goes...
-                    // up to a limit of course.
+                    // Don't flush yet, the more we buffer, the faster this goes...up to a limit.
                     if self.buffer.len() >= 8196 {
                         break;
                     }
@@ -357,9 +524,13 @@ impl Server {
                     break;
                 }
 
-                // CopyData: we are not buffering this one because there will be many more
-                // and we don't know how big this packet could be, best not to take a risk.
-                'd' => break,
+                // CopyData
+                'd' => {
+                    // Don't flush yet, buffer until we reach limit
+                    if self.buffer.len() >= 8196 {
+                        break;
+                    }
+                }
 
                 // CopyDone
                 // Buffer until ReadyForQuery shows up, so don't exit the loop yet.
@@ -374,11 +545,14 @@ impl Server {
         let bytes = self.buffer.clone();
 
         // Keep track of how much data we got from the server for stats.
-        self.stats.data_received(bytes.len());
+        self.stats.data_received(bytes.len(), self.server_id);
 
         // Clear the buffer for next query.
         self.buffer.clear();
 
+        // Successfully received data from server
+        self.last_activity = SystemTime::now();
+
         // Pass the data back to the client.
         Ok(bytes)
     }
@@ -386,6 +560,7 @@ impl Server {
     /// If the server is still inside a transaction.
     /// If the client disconnects while the server is in a transaction, we will clean it up.
     pub fn in_transaction(&self) -> bool {
+        debug!("Server in transaction: {}", self.in_transaction);
         self.in_transaction
     }
 
@@ -409,7 +584,7 @@ impl Server {
 
     /// Indicate that this server connection cannot be re-used and must be discarded.
     pub fn mark_bad(&mut self) {
-        error!("Server marked bad");
+        error!("Server {:?} marked bad", self.address);
         self.bad = true;
     }
 
@@ -422,7 +597,7 @@ impl Server {
                 self.process_id,
                 self.secret_key,
                 self.address.host.clone(),
-                self.address.port.clone(),
+                self.address.port,
             ),
         );
     }
@@ -433,7 +608,7 @@ impl Server {
     pub async fn query(&mut self, query: &str) -> Result<(), Error> {
         let query = simple_query(query);
 
-        self.send(query).await?;
+        self.send(&query).await?;
 
         loop {
             let _ = self.recv().await?;
@@ -446,12 +621,48 @@ impl Server {
         Ok(())
     }
 
+    /// Perform any necessary cleanup before putting the server
+    /// connection back in the pool
+    pub async fn checkin_cleanup(&mut self) -> Result<(), Error> {
+        // Client disconnected with an open transaction on the server connection.
+        // Pgbouncer behavior is to close the server connection but that can cause
+        // server connection thrashing if clients repeatedly do this.
+        // Instead, we ROLLBACK that transaction before putting the connection back in the pool
+        if self.in_transaction() {
+            warn!("Server returned while still in transaction, rolling back transaction");
+            self.query("ROLLBACK").await?;
+        }
+
+        // Client disconnected but it performed session-altering operations such as
+        // SET statement_timeout to 1 or create a prepared statement. We clear that
+        // to avoid leaking state between clients. For performance reasons we only
+        // send `DISCARD ALL` if we think the session is altered instead of just sending
+        // it before each checkin.
+        if self.needs_cleanup {
+            warn!("Server returned with session state altered, discarding state");
+            self.query("DISCARD ALL").await?;
+            self.needs_cleanup = false;
+        }
+
+        Ok(())
+    }
+
     /// A shorthand for `SET application_name = $1`.
-    #[allow(dead_code)]
     pub async fn set_name(&mut self, name: &str) -> Result<(), Error> {
-        Ok(self
-            .query(&format!("SET application_name = '{}'", name))
-            .await?)
+        if self.application_name != name {
+            self.application_name = name.to_string();
+            // We don't want `SET application_name` to mark the server connection
+            // as needing cleanup
+            let needs_cleanup_before = self.needs_cleanup;
+
+            let result = Ok(self
+                .query(&format!("SET application_name = '{}'", name))
+                .await?);
+            self.needs_cleanup = needs_cleanup_before;
+            result
+        } else {
+            Ok(())
+        }
     }
 
     /// Get the servers address.
@@ -460,8 +671,34 @@ impl Server {
         self.address.clone()
     }
 
-    pub fn process_id(&self) -> i32 {
-        self.process_id
+    /// Get the server connection identifier
+    /// Used to uniquely identify connection in statistics
+    pub fn server_id(&self) -> i32 {
+        self.server_id
+    }
+
+    // Get server's latest response timestamp
+    pub fn last_activity(&self) -> SystemTime {
+        self.last_activity
+    }
+
+    // Marks a connection as needing DISCARD ALL at checkin
+    pub fn mark_dirty(&mut self) {
+        self.needs_cleanup = true;
+    }
+
+    pub fn mirror_send(&mut self, bytes: &BytesMut) {
+        match self.mirror_manager.as_mut() {
+            Some(manager) => manager.send(bytes),
+            None => (),
+        }
+    }
+
+    pub fn mirror_disconnect(&mut self) {
+        match self.mirror_manager.as_mut() {
+            Some(manager) => manager.disconnect(),
+            None => (),
+        }
     }
 }
 
@@ -470,7 +707,8 @@ impl Drop for Server {
     /// the socket is in non-blocking mode, so it may not be ready
     /// for a write.
     fn drop(&mut self) {
-        self.stats.server_disconnecting(self.process_id());
+        self.mirror_disconnect();
+        self.stats.server_disconnecting(self.server_id);
 
         let mut bytes = BytesMut::with_capacity(4);
         bytes.put_u8(b'X');
@@ -478,16 +716,18 @@ impl Drop for Server {
 
         match self.write.try_write(&bytes) {
             Ok(_) => (),
-            Err(_) => (),
+            Err(_) => debug!("Dirty shutdown"),
         };
 
+        // Should not matter.
         self.bad = true;
 
         let now = chrono::offset::Utc::now().naive_utc();
         let duration = now - self.connected_at;
 
         info!(
-            "Server connection closed, session duration: {}",
+            "Server connection closed {:?}, session duration: {}",
+            self.address,
             crate::format_duration(&duration)
         );
     }

src/sharding.rs

@@ -1,20 +1,39 @@
+use serde_derive::{Deserialize, Serialize};
+/// Implements various sharding functions.
 use sha1::{Digest, Sha1};
 
-// https://github.com/postgres/postgres/blob/27b77ecf9f4d5be211900eda54d8155ada50d696/src/include/catalog/partition.h#L20
+/// See: <https://github.com/postgres/postgres/blob/27b77ecf9f4d5be211900eda54d8155ada50d696/src/include/catalog/partition.h#L20>.
 const PARTITION_HASH_SEED: u64 = 0x7A5B22367996DCFD;
 
-#[derive(Debug, PartialEq, Copy, Clone)]
+/// The sharding functions we support.
+#[derive(Debug, PartialEq, Copy, Clone, Serialize, Deserialize, Hash, std::cmp::Eq)]
 pub enum ShardingFunction {
+    #[serde(alias = "pg_bigint_hash", alias = "PgBigintHash")]
     PgBigintHash,
+    #[serde(alias = "sha1", alias = "Sha1")]
     Sha1,
 }
 
+impl ToString for ShardingFunction {
+    fn to_string(&self) -> String {
+        match *self {
+            ShardingFunction::PgBigintHash => "pg_bigint_hash".to_string(),
+            ShardingFunction::Sha1 => "sha1".to_string(),
+        }
+    }
+}
+
+/// The sharder.
 pub struct Sharder {
+    /// Number of shards in the cluster.
     shards: usize,
+
+    /// The sharding function in use.
     sharding_function: ShardingFunction,
 }
 
 impl Sharder {
+    /// Create new instance of the sharder.
     pub fn new(shards: usize, sharding_function: ShardingFunction) -> Sharder {
         Sharder {
             shards,
@@ -22,6 +41,7 @@ impl Sharder {
         }
     }
 
+    /// Compute the shard given sharding key.
     pub fn shard(&self, key: i64) -> usize {
         match self.sharding_function {
             ShardingFunction::PgBigintHash => self.pg_bigint_hash(key),
@@ -31,7 +51,7 @@ impl Sharder {
 
     /// Hash function used by Postgres to determine which partition
     /// to put the row in when using HASH(column) partitioning.
-    /// Source: https://github.com/postgres/postgres/blob/27b77ecf9f4d5be211900eda54d8155ada50d696/src/common/hashfn.c#L631
+    /// Source: <https://github.com/postgres/postgres/blob/27b77ecf9f4d5be211900eda54d8155ada50d696/src/common/hashfn.c#L631>.
     /// Supports only 1 bigint at the moment, but we can add more later.
     fn pg_bigint_hash(&self, key: i64) -> usize {
         let mut lohalf = key as u32;
@@ -113,14 +133,15 @@ impl Sharder {
     #[inline]
     fn combine(mut a: u64, b: u64) -> u64 {
         a ^= b
-            .wrapping_add(0x49a0f4dd15e5a8e3 as u64)
+            .wrapping_add(0x49a0f4dd15e5a8e3_u64)
             .wrapping_add(a << 54)
             .wrapping_add(a >> 7);
         a
     }
 
+    #[inline]
     fn pg_u32_hash(k: u32) -> u64 {
-        let mut a: u32 = 0x9e3779b9 as u32 + std::mem::size_of::<u32>() as u32 + 3923095 as u32;
+        let mut a: u32 = 0x9e3779b9_u32 + std::mem::size_of::<u32>() as u32 + 3923095_u32;
         let mut b = a;
         let c = a;
 

src/tls.rs

@@ -0,0 +1,66 @@
+// Stream wrapper.
+
+use rustls_pemfile::{certs, read_one, Item};
+use std::iter;
+use std::path::Path;
+use std::sync::Arc;
+use tokio_rustls::rustls::{self, Certificate, PrivateKey};
+use tokio_rustls::TlsAcceptor;
+
+use crate::config::get_config;
+use crate::errors::Error;
+
+// TLS
+pub fn load_certs(path: &Path) -> std::io::Result<Vec<Certificate>> {
+    certs(&mut std::io::BufReader::new(std::fs::File::open(path)?))
+        .map_err(|_| std::io::Error::new(std::io::ErrorKind::InvalidInput, "invalid cert"))
+        .map(|mut certs| certs.drain(..).map(Certificate).collect())
+}
+
+pub fn load_keys(path: &Path) -> std::io::Result<Vec<PrivateKey>> {
+    let mut rd = std::io::BufReader::new(std::fs::File::open(path)?);
+
+    iter::from_fn(|| read_one(&mut rd).transpose())
+        .filter_map(|item| match item {
+            Err(err) => Some(Err(err)),
+            Ok(Item::RSAKey(key)) => Some(Ok(PrivateKey(key))),
+            Ok(Item::ECKey(key)) => Some(Ok(PrivateKey(key))),
+            Ok(Item::PKCS8Key(key)) => Some(Ok(PrivateKey(key))),
+            _ => None,
+        })
+        .collect()
+}
+
+pub struct Tls {
+    pub acceptor: TlsAcceptor,
+}
+
+impl Tls {
+    pub fn new() -> Result<Self, Error> {
+        let config = get_config();
+
+        let certs = match load_certs(Path::new(&config.general.tls_certificate.unwrap())) {
+            Ok(certs) => certs,
+            Err(_) => return Err(Error::TlsError),
+        };
+
+        let mut keys = match load_keys(Path::new(&config.general.tls_private_key.unwrap())) {
+            Ok(keys) => keys,
+            Err(_) => return Err(Error::TlsError),
+        };
+
+        let config = match rustls::ServerConfig::builder()
+            .with_safe_defaults()
+            .with_no_client_auth()
+            .with_single_cert(certs, keys.remove(0))
+            .map_err(|err| std::io::Error::new(std::io::ErrorKind::InvalidInput, err))
+        {
+            Ok(c) => c,
+            Err(_) => return Err(Error::TlsError),
+        };
+
+        Ok(Tls {
+            acceptor: TlsAcceptor::from(Arc::new(config)),
+        })
+    }
+}

src/userlist.json

@@ -1,4 +0,0 @@
-{
-  "sven": "clear_text_password",
-  "sharding_user": "sharding_user"
-}

src/userlist.rs

@@ -1,57 +0,0 @@
-use arc_swap::{ArcSwap, Guard};
-use log::{error};
-use once_cell::sync::Lazy;
-use tokio::fs::File;
-use tokio::io::AsyncReadExt;
-
-use std::collections::{HashMap};
-use std::sync::Arc;
-
-use crate::errors::Error;
-
-pub type UserList = HashMap<String, String>;
-static USER_LIST: Lazy<ArcSwap<UserList>> = Lazy::new(|| ArcSwap::from_pointee(HashMap::new()));
-
-pub fn get_user_list() -> Guard<Arc<UserList>> {
-    USER_LIST.load()
-}
-
-/// Parse the user list.
-pub async fn parse(path: &str) -> Result<(), Error> {
-    let mut contents = String::new();
-    let mut file = match File::open(path).await {
-        Ok(file) => file,
-        Err(err) => {
-            error!("Could not open '{}': {}", path, err.to_string());
-            return Err(Error::BadConfig);
-        }
-    };
-
-    match file.read_to_string(&mut contents).await {
-        Ok(_) => (),
-        Err(err) => {
-            error!("Could not read config file: {}", err.to_string());
-            return Err(Error::BadConfig);
-        }
-    };
-
-    let map: HashMap<String, String> = serde_json::from_str(&contents).expect("JSON was not well-formatted");
-
-
-
-    USER_LIST.store(Arc::new(map.clone()));
-
-    Ok(())
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[tokio::test]
-    async fn test_config() {
-        parse("userlist.json").await.unwrap();
-        assert_eq!(get_user_list()["sven"], "clear_text_password");
-        assert_eq!(get_user_list()["sharding_user"], "sharding_user");
-    }
-}

tests/docker/Dockerfile

@@ -0,0 +1,8 @@
+FROM rust:bullseye
+
+RUN apt-get update && apt-get install llvm-11 psmisc postgresql-contrib postgresql-client ruby ruby-dev libpq-dev python3 python3-pip lcov curl sudo iproute2 -y
+RUN cargo install cargo-binutils rustfilt
+RUN rustup component add llvm-tools-preview
+RUN sudo gem install bundler
+RUN wget -O toxiproxy-2.4.0.deb https://github.com/Shopify/toxiproxy/releases/download/v2.4.0/toxiproxy_2.4.0_linux_$(dpkg --print-architecture).deb && \
+	sudo dpkg -i toxiproxy-2.4.0.deb

tests/docker/docker-compose.yml

@@ -0,0 +1,44 @@
+version: "3"
+services:
+  pg1:
+    image: postgres:14
+    network_mode: "service:main"
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_INITDB_ARGS: --auth-local=md5 --auth-host=md5 --auth=md5
+    command: ["postgres", "-p", "5432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+  pg2:
+    image: postgres:14
+    network_mode: "service:main"
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+    command: ["postgres", "-p", "7432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+  pg3:
+    image: postgres:14
+    network_mode: "service:main"
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+    command: ["postgres", "-p", "8432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+  pg4:
+    image: postgres:14
+    network_mode: "service:main"
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256 --auth=scram-sha-256
+    command: ["postgres", "-p", "9432", "-c", "shared_preload_libraries=pg_stat_statements", "-c", "pg_stat_statements.track=all", "-c", "pg_stat_statements.max=100000"]
+  main:
+    build: .
+    command: ["bash", "/app/tests/docker/run.sh"]
+    volumes:
+      - ../../:/app/
+      - /app/target/

tests/docker/run.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+rm -rf /app/target/ || true
+rm /app/*.profraw || true
+rm /app/pgcat.profdata || true
+rm -rf /app/cov || true
+
+export LLVM_PROFILE_FILE="/app/pgcat-%m-%p.profraw"
+export RUSTC_BOOTSTRAP=1
+export CARGO_INCREMENTAL=0
+export RUSTFLAGS="-Zprofile -Ccodegen-units=1 -Copt-level=0 -Clink-dead-code -Coverflow-checks=off -Zpanic_abort_tests -Cpanic=abort -Cinstrument-coverage"
+export RUSTDOCFLAGS="-Cpanic=abort"
+
+cd /app/
+cargo clean
+cargo build
+cargo test --tests
+
+bash .circleci/run_tests.sh
+
+TEST_OBJECTS=$( \
+    for file in $(cargo test --no-run 2>&1 | grep "target/debug/deps/pgcat-[[:alnum:]]\+" -o); \
+    do \
+        printf "%s %s " --object $file; \
+    done \
+)
+
+echo "Generating coverage report"
+
+rust-profdata merge -sparse /app/pgcat-*.profraw -o /app/pgcat.profdata
+
+bash -c "rust-cov export -ignore-filename-regex='rustc|registry' -Xdemangler=rustfilt -instr-profile=/app/pgcat.profdata $TEST_OBJECTS --object ./target/debug/pgcat --format lcov > ./lcov.info"
+
+genhtml lcov.info --title "PgCat Code Coverage" --css-file ./cov-style.css --highlight --no-function-coverage --ignore-errors source --legend  --output-directory cov --prefix $(pwd)
+
+rm /app/*.profraw
+rm /app/pgcat.profdata

tests/pgbench/simple.sql

@@ -0,0 +1,39 @@
+
+-- \setrandom aid 1 :naccounts
+\set aid random(1, 100000)
+-- \setrandom bid 1 :nbranches
+\set bid random(1, 100000)
+-- \setrandom tid 1 :ntellers
+\set tid random(1, 100000)
+-- \setrandom delta -5000 5000
+\set delta random(-5000,5000)
+
+\set shard random(0, 2)
+
+SET SHARD TO :shard;
+
+SET SERVER ROLE TO 'auto';
+
+BEGIN;
+
+UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;
+
+SELECT abalance FROM pgbench_accounts WHERE aid = :aid;
+
+UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;
+
+UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;
+
+INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);
+
+END;
+
+SET SHARDING KEY TO :aid;
+
+-- Read load balancing
+SELECT abalance FROM pgbench_accounts WHERE aid = :aid;
+
+SET SERVER ROLE TO 'replica';
+
+-- Read load balancing
+SELECT abalance FROM pgbench_accounts WHERE aid = :aid;

tests/python/requirements.txt

@@ -1 +1,2 @@
 psycopg2==2.9.3
+psutil==5.9.1

tests/python/tests.py

@@ -1,11 +1,318 @@
+from typing import Tuple
 import psycopg2
+import psutil
+import os
+import signal
+import time
 
-conn = psycopg2.connect("postgres://random:password@127.0.0.1:6432/db")
-cur = conn.cursor()
+SHUTDOWN_TIMEOUT = 5
 
-cur.execute("SELECT 1");
-res = cur.fetchall()
+PGCAT_HOST = "127.0.0.1"
+PGCAT_PORT = "6432"
 
-print(res)
 
-# conn.commit()
+def pgcat_start():
+    pg_cat_send_signal(signal.SIGTERM)
+    os.system("./target/debug/pgcat .circleci/pgcat.toml &")
+    time.sleep(2)
+
+
+def pg_cat_send_signal(signal: signal.Signals):
+    try:
+        for proc in psutil.process_iter(["pid", "name"]):
+            if "pgcat" == proc.name():
+                os.kill(proc.pid, signal)
+    except Exception as e:
+        # The process can be gone when we send this signal
+        print(e)
+
+    if signal == signal.SIGTERM:
+        # Returns 0 if pgcat process exists
+        time.sleep(2)
+        if not os.system('pgrep pgcat'):
+            raise Exception("pgcat not closed after SIGTERM")
+
+
+def connect_db(
+    autocommit: bool = True,
+    admin: bool = False,
+) -> Tuple[psycopg2.extensions.connection, psycopg2.extensions.cursor]:
+
+    if admin:
+        user = "admin_user"
+        password = "admin_pass"
+        db = "pgcat"
+    else:
+        user = "sharding_user"
+        password = "sharding_user"
+        db = "sharded_db"
+
+    conn = psycopg2.connect(
+        f"postgres://{user}:{password}@{PGCAT_HOST}:{PGCAT_PORT}/{db}?application_name=testing_pgcat",
+        connect_timeout=2,
+    )
+    conn.autocommit = autocommit
+    cur = conn.cursor()
+
+    return (conn, cur)
+
+
+def cleanup_conn(conn: psycopg2.extensions.connection, cur: psycopg2.extensions.cursor):
+    cur.close()
+    conn.close()
+
+
+def test_normal_db_access():
+    conn, cur = connect_db(autocommit=False)
+    cur.execute("SELECT 1")
+    res = cur.fetchall()
+    print(res)
+    cleanup_conn(conn, cur)
+
+
+def test_admin_db_access():
+    conn, cur = connect_db(admin=True)
+
+    cur.execute("SHOW POOLS")
+    res = cur.fetchall()
+    print(res)
+    cleanup_conn(conn, cur)
+
+
+def test_shutdown_logic():
+
+    # - - - - - - - - - - - - - - - - - -
+    # NO ACTIVE QUERIES SIGINT HANDLING
+
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and send query (not in transaction)
+    conn, cur = connect_db()
+
+    cur.execute("BEGIN;")
+    cur.execute("SELECT 1;")
+    cur.execute("COMMIT;")
+
+    # Send sigint to pgcat
+    pg_cat_send_signal(signal.SIGINT)
+    time.sleep(1)
+
+    # Check that any new queries fail after sigint since server should close with no active transactions
+    try:
+        cur.execute("SELECT 1;")
+    except psycopg2.OperationalError as e:
+        pass
+    else:
+        # Fail if query execution succeeded
+        raise Exception("Server not closed after sigint")
+
+    cleanup_conn(conn, cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # NO ACTIVE QUERIES ADMIN SHUTDOWN COMMAND
+
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction
+    conn, cur = connect_db()
+    admin_conn, admin_cur = connect_db(admin=True)
+
+    cur.execute("BEGIN;")
+    cur.execute("SELECT 1;")
+    cur.execute("COMMIT;")
+
+    # Send SHUTDOWN command pgcat while not in transaction
+    admin_cur.execute("SHUTDOWN;")
+    time.sleep(1)
+
+    # Check that any new queries fail after SHUTDOWN command since server should close with no active transactions
+    try:
+        cur.execute("SELECT 1;")
+    except psycopg2.OperationalError as e:
+        pass
+    else:
+        # Fail if query execution succeeded
+        raise Exception("Server not closed after sigint")
+
+    cleanup_conn(conn, cur)
+    cleanup_conn(admin_conn, admin_cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # HANDLE TRANSACTION WITH SIGINT
+
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction
+    conn, cur = connect_db()
+
+    cur.execute("BEGIN;")
+    cur.execute("SELECT 1;")
+
+    # Send sigint to pgcat while still in transaction
+    pg_cat_send_signal(signal.SIGINT)
+    time.sleep(1)
+
+    # Check that any new queries succeed after sigint since server should still allow transaction to complete
+    try:
+        cur.execute("SELECT 1;")
+    except psycopg2.OperationalError as e:
+        # Fail if query fails since server closed
+        raise Exception("Server closed while in transaction", e.pgerror)
+
+    cleanup_conn(conn, cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # HANDLE TRANSACTION WITH ADMIN SHUTDOWN COMMAND
+
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction
+    conn, cur = connect_db()
+    admin_conn, admin_cur = connect_db(admin=True)
+
+    cur.execute("BEGIN;")
+    cur.execute("SELECT 1;")
+
+    # Send SHUTDOWN command pgcat while still in transaction
+    admin_cur.execute("SHUTDOWN;")
+    if admin_cur.fetchall()[0][0] != "t":
+        raise Exception("PgCat unable to send signal")
+    time.sleep(1)
+
+    # Check that any new queries succeed after SHUTDOWN command since server should still allow transaction to complete
+    try:
+        cur.execute("SELECT 1;")
+    except psycopg2.OperationalError as e:
+        # Fail if query fails since server closed
+        raise Exception("Server closed while in transaction", e.pgerror)
+
+    cleanup_conn(conn, cur)
+    cleanup_conn(admin_conn, admin_cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # NO NEW NON-ADMIN CONNECTIONS DURING SHUTDOWN
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction
+    transaction_conn, transaction_cur = connect_db()
+
+    transaction_cur.execute("BEGIN;")
+    transaction_cur.execute("SELECT 1;")
+
+    # Send sigint to pgcat while still in transaction
+    pg_cat_send_signal(signal.SIGINT)
+    time.sleep(1)
+
+    start = time.perf_counter()
+    try:
+        conn, cur = connect_db()
+        cur.execute("SELECT 1;")
+        cleanup_conn(conn, cur)
+    except psycopg2.OperationalError as e:
+        time_taken = time.perf_counter() - start
+        if time_taken > 0.1:
+            raise Exception(
+                "Failed to reject connection within 0.1 seconds, got", time_taken, "seconds")
+        pass
+    else:
+        raise Exception("Able connect to database during shutdown")
+
+    cleanup_conn(transaction_conn, transaction_cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # ALLOW NEW ADMIN CONNECTIONS DURING SHUTDOWN
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction
+    transaction_conn, transaction_cur = connect_db()
+
+    transaction_cur.execute("BEGIN;")
+    transaction_cur.execute("SELECT 1;")
+
+    # Send sigint to pgcat while still in transaction
+    pg_cat_send_signal(signal.SIGINT)
+    time.sleep(1)
+
+    try:
+        conn, cur = connect_db(admin=True)
+        cur.execute("SHOW DATABASES;")
+        cleanup_conn(conn, cur)
+    except psycopg2.OperationalError as e:
+        raise Exception(e)
+
+    cleanup_conn(transaction_conn, transaction_cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # ADMIN CONNECTIONS CONTINUING TO WORK AFTER SHUTDOWN
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction
+    transaction_conn, transaction_cur = connect_db()
+    transaction_cur.execute("BEGIN;")
+    transaction_cur.execute("SELECT 1;")
+
+    admin_conn, admin_cur = connect_db(admin=True)
+    admin_cur.execute("SHOW DATABASES;")
+
+    # Send sigint to pgcat while still in transaction
+    pg_cat_send_signal(signal.SIGINT)
+    time.sleep(1)
+
+    try:
+        admin_cur.execute("SHOW DATABASES;")
+    except psycopg2.OperationalError as e:
+        raise Exception("Could not execute admin command:", e)
+
+    cleanup_conn(transaction_conn, transaction_cur)
+    cleanup_conn(admin_conn, admin_cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+    # HANDLE SHUTDOWN TIMEOUT WITH SIGINT
+
+    # Start pgcat
+    pgcat_start()
+
+    # Create client connection and begin transaction, which should prevent server shutdown unless shutdown timeout is reached
+    conn, cur = connect_db()
+
+    cur.execute("BEGIN;")
+    cur.execute("SELECT 1;")
+
+    # Send sigint to pgcat while still in transaction
+    pg_cat_send_signal(signal.SIGINT)
+
+    # pgcat shutdown timeout is set to SHUTDOWN_TIMEOUT seconds, so we sleep for SHUTDOWN_TIMEOUT + 1 seconds
+    time.sleep(SHUTDOWN_TIMEOUT + 1)
+
+    # Check that any new queries succeed after sigint since server should still allow transaction to complete
+    try:
+        cur.execute("SELECT 1;")
+    except psycopg2.OperationalError as e:
+        pass
+    else:
+        # Fail if query execution succeeded
+        raise Exception("Server not closed after sigint and expected timeout")
+
+    cleanup_conn(conn, cur)
+    pg_cat_send_signal(signal.SIGTERM)
+
+    # - - - - - - - - - - - - - - - - - -
+
+
+test_normal_db_access()
+test_admin_db_access()
+test_shutdown_logic()

tests/ruby/.ruby-version

@@ -1 +1,2 @@
-2.7.1
+3.0.0
+

tests/ruby/Gemfile

@@ -1,4 +1,8 @@
 source "https://rubygems.org"
 
 gem "pg"
+gem "toml"
+gem "rspec"
+gem "rubocop"
+gem "toxiproxy"
 gem "activerecord"

tests/ruby/Gemfile.lock

@@ -1,30 +1,74 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activemodel (7.0.2.2)
-      activesupport (= 7.0.2.2)
-    activerecord (7.0.2.2)
-      activemodel (= 7.0.2.2)
-      activesupport (= 7.0.2.2)
-    activesupport (7.0.2.2)
+    activemodel (7.0.4.1)
+      activesupport (= 7.0.4.1)
+    activerecord (7.0.4.1)
+      activemodel (= 7.0.4.1)
+      activesupport (= 7.0.4.1)
+    activesupport (7.0.4.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
       tzinfo (~> 2.0)
-    concurrent-ruby (1.1.9)
-    i18n (1.10.0)
+    ast (2.4.2)
+    concurrent-ruby (1.1.10)
+    diff-lcs (1.5.0)
+    i18n (1.12.0)
       concurrent-ruby (~> 1.0)
-    minitest (5.15.0)
+    minitest (5.17.0)
+    parallel (1.22.1)
+    parser (3.1.2.0)
+      ast (~> 2.4.1)
+    parslet (2.0.0)
     pg (1.3.2)
-    tzinfo (2.0.4)
+    rainbow (3.1.1)
+    regexp_parser (2.3.1)
+    rexml (3.2.5)
+    rspec (3.11.0)
+      rspec-core (~> 3.11.0)
+      rspec-expectations (~> 3.11.0)
+      rspec-mocks (~> 3.11.0)
+    rspec-core (3.11.0)
+      rspec-support (~> 3.11.0)
+    rspec-expectations (3.11.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.11.0)
+    rspec-mocks (3.11.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.11.0)
+    rspec-support (3.11.0)
+    rubocop (1.29.0)
+      parallel (~> 1.10)
+      parser (>= 3.1.0.0)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8, < 3.0)
+      rexml (>= 3.2.5, < 4.0)
+      rubocop-ast (>= 1.17.0, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 3.0)
+    rubocop-ast (1.17.0)
+      parser (>= 3.1.1.0)
+    ruby-progressbar (1.11.0)
+    toml (0.3.0)
+      parslet (>= 1.8.0, < 3.0.0)
+    toxiproxy (2.0.1)
+    tzinfo (2.0.5)
       concurrent-ruby (~> 1.0)
+    unicode-display_width (2.1.0)
 
 PLATFORMS
+  aarch64-linux
+  arm64-darwin-21
   x86_64-linux
 
 DEPENDENCIES
   activerecord
   pg
+  rspec
+  rubocop
+  toml
+  toxiproxy
 
 BUNDLED WITH
-   2.3.7
+   2.3.21

tests/ruby/admin_spec.rb

@@ -0,0 +1,369 @@
+# frozen_string_literal: true
+require 'uri'
+require_relative 'spec_helper'
+
+describe "Admin" do
+  let(:processes) { Helpers::Pgcat.single_instance_setup("sharded_db", 10) }
+  let(:pgcat_conn_str) { processes.pgcat.connection_string("sharded_db", "sharding_user") }
+
+  after do
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  describe "SHOW STATS" do
+    context "clients connect and make one query" do
+      it "updates *_query_time and *_wait_time" do
+        connection = PG::connect("#{pgcat_conn_str}?application_name=one_query")
+        connection.async_exec("SELECT pg_sleep(0.25)")
+        connection.async_exec("SELECT pg_sleep(0.25)")
+        connection.async_exec("SELECT pg_sleep(0.25)")
+        connection.close
+
+        # wait for averages to be calculated, we shouldn't do this too often
+        sleep(15.5)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW STATS")[0]
+        admin_conn.close
+        expect(results["total_query_time"].to_i).to be_within(200).of(750)
+        expect(results["avg_query_time"].to_i).to_not eq(0)
+
+        expect(results["total_wait_time"].to_i).to_not eq(0)
+        expect(results["avg_wait_time"].to_i).to_not eq(0)
+      end
+    end
+  end
+
+  describe "SHOW POOLS" do
+    context "bad credentials" do
+      it "does not change any stats" do
+        bad_passsword_url = URI(pgcat_conn_str)
+        bad_passsword_url.password = "wrong"
+        expect { PG::connect("#{bad_passsword_url.to_s}?application_name=bad_password") }.to raise_error(PG::ConnectionBad)
+
+        sleep(1)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_idle cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+
+        expect(results["sv_idle"]).to eq("1")
+      end
+    end
+
+    context "bad database name" do
+      it "does not change any stats" do
+        bad_db_url = URI(pgcat_conn_str)
+        bad_db_url.path = "/wrong_db"
+        expect { PG::connect("#{bad_db_url.to_s}?application_name=bad_db") }.to raise_error(PG::ConnectionBad)
+
+        sleep(1)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_idle cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+
+        expect(results["sv_idle"]).to eq("1")
+      end
+    end
+
+    context "client connects but issues no queries" do
+      it "only affects cl_idle stats" do
+        connections = Array.new(20) { PG::connect(pgcat_conn_str) }
+        sleep(1)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["cl_idle"]).to eq("20")
+        expect(results["sv_idle"]).to eq("1")
+
+        connections.map(&:close)
+        sleep(1.1)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_active cl_idle cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["sv_idle"]).to eq("1")
+      end
+    end
+
+    context "clients connect and make one query" do
+      it "only affects cl_idle, sv_idle stats" do
+        connections = Array.new(5) { PG::connect("#{pgcat_conn_str}?application_name=one_query") }
+        connections.each do |c|
+          Thread.new { c.async_exec("SELECT pg_sleep(2.5)") }
+        end
+
+        sleep(1.1)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_idle cl_waiting cl_cancel_req sv_idle sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["cl_active"]).to eq("5")
+        expect(results["sv_active"]).to eq("5")
+
+        sleep(3)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["cl_idle"]).to eq("5")
+        expect(results["sv_idle"]).to eq("5")
+
+        connections.map(&:close)
+        sleep(1)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_idle cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["sv_idle"]).to eq("5")
+      end
+    end
+
+    context "client connects and opens a transaction and closes connection uncleanly" do
+      it "produces correct statistics" do
+        connections = Array.new(5) { PG::connect("#{pgcat_conn_str}?application_name=one_query") }
+        connections.each do |c|
+          Thread.new do
+            c.async_exec("BEGIN")
+            c.async_exec("SELECT pg_sleep(0.01)")
+            c.close
+          end
+        end
+
+        sleep(1.1)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_idle cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["sv_idle"]).to eq("5")
+      end
+    end
+
+    context "client fail to checkout connection from the pool" do
+      it "counts clients as idle" do
+        new_configs = processes.pgcat.current_config
+        new_configs["general"]["connect_timeout"] = 500
+        new_configs["general"]["ban_time"] = 1
+        new_configs["general"]["shutdown_timeout"] = 1
+        new_configs["pools"]["sharded_db"]["users"]["0"]["pool_size"] = 1
+        processes.pgcat.update_config(new_configs)
+        processes.pgcat.reload_config
+
+        threads = []
+        connections = Array.new(5) { PG::connect("#{pgcat_conn_str}?application_name=one_query") }
+        connections.each do |c|
+          threads << Thread.new { c.async_exec("SELECT pg_sleep(1)") rescue PG::SystemError }
+        end
+
+        sleep(2)
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["cl_idle"]).to eq("5")
+        expect(results["sv_idle"]).to eq("1")
+
+        threads.map(&:join)
+        connections.map(&:close)
+      end
+    end
+
+    context "clients overwhelm server pools" do
+      let(:processes) { Helpers::Pgcat.single_instance_setup("sharded_db", 2) }
+
+      it "cl_waiting is updated to show it" do
+        threads = []
+        connections = Array.new(4) { PG::connect("#{pgcat_conn_str}?application_name=one_query") }
+        connections.each do |c|
+          threads << Thread.new { c.async_exec("SELECT pg_sleep(1.5)") }
+        end
+
+        sleep(1.1) # Allow time for stats to update
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_idle cl_cancel_req sv_idle sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+
+        expect(results["cl_waiting"]).to eq("2")
+        expect(results["cl_active"]).to eq("2")
+        expect(results["sv_active"]).to eq("2")
+
+        sleep(2.5) # Allow time for stats to update
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        %w[cl_active cl_waiting cl_cancel_req sv_active sv_used sv_tested sv_login maxwait].each do |s|
+          raise StandardError, "Field #{s} was expected to be 0 but found to be #{results[s]}" if results[s] != "0"
+        end
+        expect(results["cl_idle"]).to eq("4")
+        expect(results["sv_idle"]).to eq("2")
+
+        threads.map(&:join)
+        connections.map(&:close)
+      end
+
+      it "show correct max_wait" do
+        threads = []
+        connections = Array.new(4) { PG::connect("#{pgcat_conn_str}?application_name=one_query") }
+        connections.each do |c|
+          threads << Thread.new { c.async_exec("SELECT pg_sleep(1.5)") }
+        end
+
+        sleep(2.5) # Allow time for stats to update
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+
+        expect(results["maxwait"]).to eq("1")
+        expect(results["maxwait_us"].to_i).to be_within(200_000).of(500_000)
+
+        sleep(4.5) # Allow time for stats to update
+        results = admin_conn.async_exec("SHOW POOLS")[0]
+        expect(results["maxwait"]).to eq("0")
+
+        threads.map(&:join)
+        connections.map(&:close)
+      end
+    end
+  end
+
+  describe "SHOW CLIENTS" do
+    it "reports correct number and application names" do
+      conn_str = processes.pgcat.connection_string("sharded_db", "sharding_user")
+      connections = Array.new(20) { |i| PG::connect("#{conn_str}?application_name=app#{i % 5}") }
+
+      admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+      sleep(1) # Wait for stats to be updated
+
+      results = admin_conn.async_exec("SHOW CLIENTS")
+      expect(results.count).to eq(21) # count admin clients
+      expect(results.select { |c| c["application_name"] == "app3" ||  c["application_name"] == "app4" }.count).to eq(8)
+      expect(results.select { |c| c["database"] == "pgcat" }.count).to eq(1)
+
+      connections[0..5].map(&:close)
+      sleep(1) # Wait for stats to be updated
+      results = admin_conn.async_exec("SHOW CLIENTS")
+      expect(results.count).to eq(15)
+
+      connections[6..].map(&:close)
+      sleep(1) # Wait for stats to be updated
+      expect(admin_conn.async_exec("SHOW CLIENTS").count).to eq(1)
+      admin_conn.close
+    end
+
+    it "reports correct number of queries and transactions" do
+      conn_str = processes.pgcat.connection_string("sharded_db", "sharding_user")
+
+      connections = Array.new(2) { |i| PG::connect("#{conn_str}?application_name=app#{i}") }
+      connections.each do |c|
+        c.async_exec("SELECT 1")
+        c.async_exec("SELECT 2")
+        c.async_exec("SELECT 3")
+        c.async_exec("BEGIN")
+        c.async_exec("SELECT 4")
+        c.async_exec("SELECT 5")
+        c.async_exec("COMMIT")
+      end
+
+      admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+      sleep(1) # Wait for stats to be updated
+
+      results = admin_conn.async_exec("SHOW CLIENTS")
+      expect(results.count).to eq(3)
+      normal_client_results = results.reject { |r| r["database"] == "pgcat" }
+      expect(normal_client_results[0]["transaction_count"]).to eq("4")
+      expect(normal_client_results[1]["transaction_count"]).to eq("4")
+      expect(normal_client_results[0]["query_count"]).to eq("7")
+      expect(normal_client_results[1]["query_count"]).to eq("7")
+
+      admin_conn.close
+      connections.map(&:close)
+    end
+  end
+
+  describe "Manual Banning" do
+    let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 10) }
+    before do
+      new_configs = processes.pgcat.current_config
+      # Prevent immediate unbanning when we ban localhost
+      new_configs["pools"]["sharded_db"]["shards"]["0"]["servers"][0][0] = "127.0.0.1"
+      new_configs["pools"]["sharded_db"]["shards"]["0"]["servers"][1][0] = "127.0.0.1"
+      processes.pgcat.update_config(new_configs)
+      processes.pgcat.reload_config
+    end
+
+    describe "BAN/UNBAN and SHOW BANS" do
+      it "bans/unbans hosts" do
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+
+        # Returns a list of the banned addresses
+        results = admin_conn.async_exec("BAN localhost 10").to_a
+        expect(results.count).to eq(2)
+        expect(results.map{ |r| r["host"] }.uniq).to eq(["localhost"])
+
+        # Subsequent calls should yield no results
+        results = admin_conn.async_exec("BAN localhost 10").to_a
+        expect(results.count).to eq(0)
+
+        results = admin_conn.async_exec("SHOW BANS").to_a
+        expect(results.count).to eq(2)
+        expect(results.map{ |r| r["host"] }.uniq).to eq(["localhost"])
+
+        # Returns a list of the unbanned addresses
+        results = admin_conn.async_exec("UNBAN localhost").to_a
+        expect(results.count).to eq(2)
+        expect(results.map{ |r| r["host"] }.uniq).to eq(["localhost"])
+
+        # Subsequent calls should yield no results
+        results = admin_conn.async_exec("UNBAN localhost").to_a
+        expect(results.count).to eq(0)
+
+        results = admin_conn.async_exec("SHOW BANS").to_a
+        expect(results.count).to eq(0)
+      end
+
+      it "honors ban duration" do
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+
+        # Returns a list of the banned addresses
+        results = admin_conn.async_exec("BAN localhost 1").to_a
+        expect(results.count).to eq(2)
+        expect(results.map{ |r| r["host"] }.uniq).to eq(["localhost"])
+
+        sleep(2)
+
+        # After 2 seconds the ban should be lifted
+        results = admin_conn.async_exec("SHOW BANS").to_a
+        expect(results.count).to eq(0)
+      end
+
+      it "can handle bad input" do
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+
+        expect { admin_conn.async_exec("BAN").to_a }.to raise_error(PG::SystemError)
+        expect { admin_conn.async_exec("BAN a").to_a }.to raise_error(PG::SystemError)
+        expect { admin_conn.async_exec("BAN a a").to_a }.to raise_error(PG::SystemError)
+        expect { admin_conn.async_exec("BAN a -5").to_a }.to raise_error(PG::SystemError)
+        expect { admin_conn.async_exec("BAN a 0").to_a }.to raise_error(PG::SystemError)
+        expect { admin_conn.async_exec("BAN a a a").to_a }.to raise_error(PG::SystemError)
+        expect { admin_conn.async_exec("UNBAN").to_a }.to raise_error(PG::SystemError)
+      end
+    end
+  end
+
+  describe "SHOW users" do
+    it "returns the right users" do
+      admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+      results = admin_conn.async_exec("SHOW USERS")[0]
+      admin_conn.close
+      expect(results["name"]).to eq("sharding_user")
+      expect(results["pool_mode"]).to eq("transaction")
+    end
+  end
+end

tests/ruby/helpers/pg_instance.rb

@@ -0,0 +1,94 @@
+require 'pg'
+require 'toxiproxy'
+
+class PgInstance
+  attr_reader :port
+  attr_reader :username
+  attr_reader :password
+  attr_reader :database_name
+
+  def initialize(port, username, password, database_name)
+    @original_port = port
+    @toxiproxy_port = 10000 + port.to_i
+    @port = @toxiproxy_port
+
+    @username = username
+    @password = password
+    @database_name = database_name
+    @toxiproxy_name = "database_#{@original_port}"
+    Toxiproxy.populate([{
+      name: @toxiproxy_name,
+      listen: "0.0.0.0:#{@toxiproxy_port}",
+      upstream: "localhost:#{@original_port}",
+    }])
+
+    # Toxiproxy server will outlive our PgInstance objects
+    # so we want to destroy our proxies before exiting
+    # Ruby finalizer is ideal for doing this
+    ObjectSpace.define_finalizer(@toxiproxy_name, proc { Toxiproxy[@toxiproxy_name].destroy })
+  end
+
+  def with_connection
+    conn = PG.connect("postgres://#{@username}:#{@password}@localhost:#{port}/#{database_name}")
+    yield conn
+  ensure
+    conn&.close
+  end
+
+  def reset
+    reset_toxics
+    reset_stats
+    drop_connections
+    sleep 0.1
+  end
+
+  def toxiproxy
+    Toxiproxy[@toxiproxy_name]
+  end
+
+  def take_down
+    if block_given?
+      Toxiproxy[@toxiproxy_name].toxic(:limit_data, bytes: 5).apply { yield }
+    else
+      Toxiproxy[@toxiproxy_name].toxic(:limit_data, bytes: 5).toxics.each(&:save)
+    end
+  end
+
+  def add_latency(latency)
+    if block_given?
+      Toxiproxy[@toxiproxy_name].toxic(:latency, latency: latency).apply { yield }
+    else
+      Toxiproxy[@toxiproxy_name].toxic(:latency, latency: latency).toxics.each(&:save)
+    end
+  end
+
+  def delete_proxy
+    Toxiproxy[@toxiproxy_name].delete
+  end
+
+  def reset_toxics
+    Toxiproxy[@toxiproxy_name].toxics.each(&:destroy)
+    sleep 0.1
+  end
+
+  def reset_stats
+    with_connection { |c| c.async_exec("SELECT pg_stat_statements_reset()") }
+  end
+
+  def drop_connections
+    username = with_connection { |c| c.async_exec("SELECT current_user")[0]["current_user"] }
+    with_connection { |c| c.async_exec("SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE pid <> pg_backend_pid() AND usename='#{username}'") }
+  end
+
+  def count_connections
+    with_connection { |c| c.async_exec("SELECT COUNT(*) as count FROM pg_stat_activity")[0]["count"].to_i }
+  end
+
+  def count_query(query)
+    with_connection { |c| c.async_exec("SELECT SUM(calls) FROM pg_stat_statements WHERE query = '#{query}'")[0]["sum"].to_i }
+  end
+
+  def count_select_1_plus_2
+    with_connection { |c| c.async_exec("SELECT SUM(calls) FROM pg_stat_statements WHERE query = 'SELECT $1 + $2'")[0]["sum"].to_i }
+  end
+end

tests/ruby/helpers/pgcat_helper.rb

@@ -0,0 +1,148 @@
+require 'json'
+require 'ostruct'
+require_relative 'pgcat_process'
+require_relative 'pg_instance'
+
+module Helpers
+  module Pgcat
+    def self.three_shard_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random", log_level="info")
+      user = {
+        "password" => "sharding_user",
+        "pool_size" => pool_size,
+        "statement_timeout" => 0,
+        "username" => "sharding_user"
+      }
+
+      pgcat    = PgcatProcess.new(log_level)
+      primary0 = PgInstance.new(5432, user["username"], user["password"], "shard0")
+      primary1 = PgInstance.new(7432, user["username"], user["password"], "shard1")
+      primary2 = PgInstance.new(8432, user["username"], user["password"], "shard2")
+
+      pgcat_cfg = pgcat.current_config
+      pgcat_cfg["pools"] = {
+        "#{pool_name}" => {
+          "default_role" => "any",
+          "pool_mode" => pool_mode,
+          "load_balancing_mode" => lb_mode,
+          "primary_reads_enabled" => true,
+          "query_parser_enabled" => true,
+          "automatic_sharding_key" => "data.id",
+          "sharding_function" => "pg_bigint_hash",
+          "shards" => {
+            "0" => { "database" => "shard0", "servers" => [["localhost", primary0.port.to_s, "primary"]] },
+            "1" => { "database" => "shard1", "servers" => [["localhost", primary1.port.to_s, "primary"]] },
+            "2" => { "database" => "shard2", "servers" => [["localhost", primary2.port.to_s, "primary"]] },
+          },
+          "users" => { "0" => user }
+        }
+      }
+      pgcat.update_config(pgcat_cfg)
+
+      pgcat.start
+      pgcat.wait_until_ready
+
+      OpenStruct.new.tap do |struct|
+        struct.pgcat = pgcat
+        struct.shards = [primary0, primary1, primary2]
+        struct.all_databases = [primary0, primary1, primary2]
+      end
+    end
+
+    def self.single_instance_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random", log_level="trace")
+      user = {
+        "password" => "sharding_user",
+        "pool_size" => pool_size,
+        "statement_timeout" => 0,
+        "username" => "sharding_user"
+      }
+
+      pgcat = PgcatProcess.new(log_level)
+      pgcat_cfg = pgcat.current_config
+
+      primary  = PgInstance.new(5432, user["username"], user["password"], "shard0")
+
+      # Main proxy configs
+      pgcat_cfg["pools"] = {
+        "#{pool_name}" => {
+          "default_role" => "primary",
+          "pool_mode" => pool_mode,
+          "load_balancing_mode" => lb_mode,
+          "primary_reads_enabled" => false,
+          "query_parser_enabled" => false,
+          "sharding_function" => "pg_bigint_hash",
+          "shards" => {
+            "0" => {
+              "database" => "shard0",
+              "servers" => [
+                ["localhost", primary.port.to_s, "primary"]
+              ]
+            },
+          },
+          "users" => { "0" => user }
+        }
+      }
+      pgcat_cfg["general"]["port"] = pgcat.port
+      pgcat.update_config(pgcat_cfg)
+      pgcat.start
+      pgcat.wait_until_ready
+
+      OpenStruct.new.tap do |struct|
+        struct.pgcat = pgcat
+        struct.primary = primary
+        struct.all_databases = [primary]
+      end
+    end
+
+    def self.single_shard_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random", log_level="info")
+      user = {
+        "password" => "sharding_user",
+        "pool_size" => pool_size,
+        "statement_timeout" => 0,
+        "username" => "sharding_user"
+      }
+
+      pgcat = PgcatProcess.new(log_level)
+      pgcat_cfg = pgcat.current_config
+
+      primary  = PgInstance.new(5432, user["username"], user["password"], "shard0")
+      replica0 = PgInstance.new(7432, user["username"], user["password"], "shard0")
+      replica1 = PgInstance.new(8432, user["username"], user["password"], "shard0")
+      replica2 = PgInstance.new(9432, user["username"], user["password"], "shard0")
+
+      # Main proxy configs
+      pgcat_cfg["pools"] = {
+        "#{pool_name}" => {
+          "default_role" => "any",
+          "pool_mode" => pool_mode,
+          "load_balancing_mode" => lb_mode,
+          "primary_reads_enabled" => false,
+          "query_parser_enabled" => false,
+          "sharding_function" => "pg_bigint_hash",
+          "shards" => {
+            "0" => {
+              "database" => "shard0",
+              "servers" => [
+                ["localhost", primary.port.to_s, "primary"],
+                ["localhost", replica0.port.to_s, "replica"],
+                ["localhost", replica1.port.to_s, "replica"],
+                ["localhost", replica2.port.to_s, "replica"]
+              ]
+            },
+          },
+          "users" => { "0" => user }
+        }
+      }
+      pgcat_cfg["general"]["port"] = pgcat.port
+      pgcat.update_config(pgcat_cfg)
+      pgcat.start
+      pgcat.wait_until_ready
+
+      OpenStruct.new.tap do |struct|
+        struct.pgcat = pgcat
+        struct.primary = primary
+        struct.replicas = [replica0, replica1, replica2]
+        struct.all_databases = [primary, replica0, replica1, replica2]
+      end
+    end
+  end
+end

tests/ruby/helpers/pgcat_process.rb

@@ -0,0 +1,131 @@
+require 'pg'
+require 'toml'
+require 'fileutils'
+require 'securerandom'
+
+class PgcatProcess
+  attr_reader :port
+  attr_reader :pid
+
+  def self.finalize(pid, log_filename, config_filename)
+    if pid
+      Process.kill("TERM", pid)
+      Process.wait(pid)
+    end
+
+    File.delete(config_filename) if File.exist?(config_filename)
+    File.delete(log_filename) if File.exist?(log_filename)
+  end
+
+  def initialize(log_level)
+    @env = {"RUST_LOG" => log_level}
+    @port = rand(20000..32760)
+    @log_level = log_level
+    @log_filename = "/tmp/pgcat_log_#{SecureRandom.urlsafe_base64}.log"
+    @config_filename = "/tmp/pgcat_cfg_#{SecureRandom.urlsafe_base64}.toml"
+
+    command_path = if ENV['CARGO_TARGET_DIR'] then
+                     "#{ENV['CARGO_TARGET_DIR']}/debug/pgcat"
+                   else
+                     '../../target/debug/pgcat'
+                   end
+
+    @command = "#{command_path} #{@config_filename}"
+
+    FileUtils.cp("../../pgcat.toml", @config_filename)
+    cfg = current_config
+    cfg["general"]["port"] = @port.to_i
+    cfg["general"]["enable_prometheus_exporter"] = false
+
+    update_config(cfg)
+  end
+
+  def logs
+    File.read(@log_filename)
+  end
+
+  def update_config(config_hash)
+    @original_config = current_config
+    output_to_write = TOML::Generator.new(config_hash).body
+    output_to_write = output_to_write.gsub(/,\s*["|'](\d+)["|']\s*,/, ',\1,')
+    output_to_write = output_to_write.gsub(/,\s*["|'](\d+)["|']\s*\]/, ',\1]')
+    File.write(@config_filename, output_to_write)
+  end
+
+  def current_config
+    loadable_string = File.read(@config_filename)
+    loadable_string = loadable_string.gsub(/,\s*(\d+)\s*,/,  ', "\1",')
+    loadable_string = loadable_string.gsub(/,\s*(\d+)\s*\]/, ', "\1"]')
+    TOML.load(loadable_string)
+  end
+
+  def reload_config
+    `kill -s HUP #{@pid}`
+    sleep 0.5
+  end
+
+  def start
+    raise StandardError, "Process is already started" unless @pid.nil?
+    @pid = Process.spawn(@env, @command, err: @log_filename, out: @log_filename)
+    ObjectSpace.define_finalizer(@log_filename, proc { PgcatProcess.finalize(@pid, @log_filename, @config_filename) })
+
+    return self
+  end
+
+  def wait_until_ready
+    exc = nil
+    10.times do
+      PG::connect(example_connection_string).close
+
+      return self
+    rescue => e
+      exc = e
+      sleep(0.5)
+    end
+    puts exc
+    raise StandardError, "Process #{@pid} never became ready. Logs #{logs}"
+  end
+
+  def stop
+    return unless @pid
+
+    Process.kill("TERM", @pid)
+    Process.wait(@pid)
+    @pid = nil
+  end
+
+  def shutdown
+    stop
+    File.delete(@config_filename) if File.exist?(@config_filename)
+    File.delete(@log_filename) if File.exist?(@log_filename)
+  end
+
+  def admin_connection_string
+    cfg = current_config
+    username = cfg["general"]["admin_username"]
+    password = cfg["general"]["admin_password"]
+
+    "postgresql://#{username}:#{password}@0.0.0.0:#{@port}/pgcat"
+  end
+
+  def connection_string(pool_name, username)
+    cfg = current_config
+
+    user_idx, user_obj = cfg["pools"][pool_name]["users"].detect { |k, user| user["username"] == username }
+    password = user_obj["password"]
+
+    "postgresql://#{username}:#{password}@0.0.0.0:#{@port}/#{pool_name}"
+  end
+
+  def example_connection_string
+    cfg = current_config
+    first_pool_name = cfg["pools"].keys[0]
+
+    db_name = first_pool_name
+
+    username = cfg["pools"][first_pool_name]["users"]["0"]["username"]
+    password = cfg["pools"][first_pool_name]["users"]["0"]["password"]
+
+    "postgresql://#{username}:#{password}@0.0.0.0:#{@port}/#{db_name}?application_name=example_app"
+  end
+end

tests/ruby/load_balancing_spec.rb

@@ -0,0 +1,164 @@
+# frozen_string_literal: true
+require_relative 'spec_helper'
+
+describe "Random Load Balancing" do
+  let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 5) }
+  after do
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  context "under regular circumstances" do
+    it "balances query volume between all instances" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+
+      query_count = QUERY_COUNT
+      expected_share = query_count / processes.all_databases.count
+      failed_count = 0
+
+      query_count.times do
+        conn.async_exec("SELECT 1 + 2")
+      rescue
+        failed_count += 1
+      end
+
+      expect(failed_count).to eq(0)
+      processes.all_databases.map(&:count_select_1_plus_2).each do |instance_share|
+        expect(instance_share).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+      end
+    end
+  end
+
+  context "when some replicas are down" do
+    it "balances query volume between working instances" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      expected_share = QUERY_COUNT / (processes.all_databases.count - 2)
+      failed_count = 0
+
+      processes[:replicas][0].take_down do
+        processes[:replicas][1].take_down do
+          QUERY_COUNT.times do
+            conn.async_exec("SELECT 1 + 2")
+          rescue
+            conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+            failed_count += 1
+          end
+        end
+      end
+
+      processes.all_databases.each do |instance|
+        queries_routed = instance.count_select_1_plus_2
+        if processes.replicas[0..1].include?(instance)
+          expect(queries_routed).to eq(0)
+        else
+          expect(queries_routed).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+        end
+      end
+    end
+  end
+end
+
+describe "Least Outstanding Queries Load Balancing" do
+  let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 1, "transaction", "loc") }
+  after do
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  context "under homogenous load" do
+    it "balances query volume between all instances" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+
+      query_count = QUERY_COUNT
+      expected_share = query_count / processes.all_databases.count
+      failed_count = 0
+
+      query_count.times do
+        conn.async_exec("SELECT 1 + 2")
+      rescue
+        failed_count += 1
+      end
+
+      expect(failed_count).to eq(0)
+      processes.all_databases.map(&:count_select_1_plus_2).each do |instance_share|
+        expect(instance_share).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+      end
+    end
+  end
+
+  context "under heterogeneous load" do
+    xit "balances query volume between all instances based on how busy they are" do
+      slow_query_count = 2
+      threads = Array.new(slow_query_count) do
+        Thread.new do
+          conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("BEGIN")
+        end
+      end
+
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+
+      query_count = QUERY_COUNT
+      expected_share = query_count / (processes.all_databases.count - slow_query_count)
+      failed_count = 0
+
+      query_count.times do
+        conn.async_exec("SELECT 1 + 2")
+      rescue
+        failed_count += 1
+      end
+
+      expect(failed_count).to eq(0)
+      # Under LOQ, we expect replicas running the slow pg_sleep
+      # to get no selects
+      expect(
+        processes.
+          all_databases.
+          map(&:count_select_1_plus_2).
+          count { |instance_share| instance_share == 0 }
+      ).to eq(slow_query_count)
+
+      # We also expect the quick queries to be spread across
+      # the idle servers only
+      processes.
+        all_databases.
+        map(&:count_select_1_plus_2).
+        reject { |instance_share| instance_share == 0 }.
+        each do |instance_share|
+          expect(instance_share).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+      end
+
+      threads.map(&:join)
+    end
+  end
+
+  context "when some replicas are down" do
+    it "balances query volume between working instances" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      expected_share = QUERY_COUNT / (processes.all_databases.count - 2)
+      failed_count = 0
+
+      processes[:replicas][0].take_down do
+        processes[:replicas][1].take_down do
+          QUERY_COUNT.times do
+            conn.async_exec("SELECT 1 + 2")
+          rescue
+            conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+            failed_count += 1
+          end
+        end
+      end
+
+      expect(failed_count).to be <= 2
+      processes.all_databases.each do |instance|
+        queries_routed = instance.count_select_1_plus_2
+        if processes.replicas[0..1].include?(instance)
+          expect(queries_routed).to eq(0)
+        else
+          expect(queries_routed).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+        end
+      end
+    end
+  end
+end
+

tests/ruby/mirrors_spec.rb

@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+require 'uri'
+require_relative 'spec_helper'
+
+describe "Query Mirroing" do
+  let(:processes) { Helpers::Pgcat.single_instance_setup("sharded_db", 10) }
+  let(:mirror_pg) { PgInstance.new(8432, "sharding_user", "sharding_user", "shard2")}
+  let(:pgcat_conn_str) { processes.pgcat.connection_string("sharded_db", "sharding_user") }
+  let(:mirror_host) { "localhost" }
+
+  before do
+    new_configs = processes.pgcat.current_config
+    new_configs["pools"]["sharded_db"]["shards"]["0"]["mirrors"] = [
+      [mirror_host, mirror_pg.port.to_s, "0"],
+      [mirror_host, mirror_pg.port.to_s, "0"],
+      [mirror_host, mirror_pg.port.to_s, "0"],
+    ]
+    processes.pgcat.update_config(new_configs)
+    processes.pgcat.reload_config
+  end
+
+  after do
+    processes.all_databases.map(&:reset)
+    mirror_pg.reset
+    processes.pgcat.shutdown
+  end
+
+  it "can mirror a query" do
+    conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+    runs = 15
+    runs.times { conn.async_exec("SELECT 1 + 2") }
+    sleep 0.5
+    expect(processes.all_databases.first.count_select_1_plus_2).to eq(runs)
+    expect(mirror_pg.count_select_1_plus_2).to eq(runs * 3)
+  end
+
+  context "when main server connection is closed" do
+    it "closes the mirror connection" do
+      baseline_count = processes.all_databases.first.count_connections
+      5.times do |i|
+        # Force pool cycling to detect zombie mirror connections
+        new_configs = processes.pgcat.current_config
+        new_configs["pools"]["sharded_db"]["idle_timeout"] = 5000 + i
+        new_configs["pools"]["sharded_db"]["shards"]["0"]["mirrors"] = [
+          [mirror_host, mirror_pg.port.to_s, "0"],
+          [mirror_host, mirror_pg.port.to_s, "0"],
+          [mirror_host, mirror_pg.port.to_s, "0"],
+        ]
+        processes.pgcat.update_config(new_configs)
+        processes.pgcat.reload_config
+      end
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      conn.async_exec("SELECT 1 + 2")
+      sleep 0.5
+      # Expect same number of connection even after pool cycling
+      expect(processes.all_databases.first.count_connections).to be < baseline_count + 2
+    end
+  end
+
+  xcontext "when mirror server goes down temporarily" do
+    it "continues to transmit queries after recovery" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      mirror_pg.take_down do
+        conn.async_exec("SELECT 1 + 2")
+        sleep 0.1
+      end
+      10.times { conn.async_exec("SELECT 1 + 2") }
+      sleep 1
+      expect(mirror_pg.count_select_1_plus_2).to be >= 2
+    end
+  end
+
+  context "when a mirror is down" do
+    let(:mirror_host) { "badhost" }
+
+    it "does not fail to send the main query" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      # No Errors here
+      conn.async_exec("SELECT 1 + 2")
+      expect(processes.all_databases.first.count_select_1_plus_2).to eq(1)
+    end
+
+    it "does not fail to send the main query (even after thousands of mirror attempts)" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      # No Errors here
+      1000.times { conn.async_exec("SELECT 1 + 2") }
+      expect(processes.all_databases.first.count_select_1_plus_2).to eq(1000)
+    end
+  end
+end

tests/ruby/misc_spec.rb

@@ -0,0 +1,312 @@
+# frozen_string_literal: true
+require_relative 'spec_helper'
+
+describe "Miscellaneous" do
+  let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 5) }
+  after do
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  context "when adding then removing instance using RELOAD" do
+    it "works correctly" do
+      admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+
+      current_configs = processes.pgcat.current_config
+      correct_count = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].count
+      expect(admin_conn.async_exec("SHOW DATABASES").count).to eq(correct_count)
+
+      extra_replica = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].last.clone
+      extra_replica[0] = "127.0.0.1"
+      current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"] << extra_replica
+
+      processes.pgcat.update_config(current_configs) # with replica added
+      processes.pgcat.reload_config
+      correct_count = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].count
+      expect(admin_conn.async_exec("SHOW DATABASES").count).to eq(correct_count)
+
+      current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].pop
+
+      processes.pgcat.update_config(current_configs) # with replica removed again
+      processes.pgcat.reload_config
+      correct_count = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].count
+      expect(admin_conn.async_exec("SHOW DATABASES").count).to eq(correct_count)
+    end
+  end
+
+  context "when removing then adding instance back using RELOAD" do
+    it "works correctly" do
+      admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+
+      current_configs = processes.pgcat.current_config
+      correct_count = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].count
+      expect(admin_conn.async_exec("SHOW DATABASES").count).to eq(correct_count)
+
+      removed_replica = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].pop
+      processes.pgcat.update_config(current_configs) # with replica removed
+      processes.pgcat.reload_config
+      correct_count = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].count
+      expect(admin_conn.async_exec("SHOW DATABASES").count).to eq(correct_count)
+
+      current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"] << removed_replica
+
+      processes.pgcat.update_config(current_configs) # with replica added again
+      processes.pgcat.reload_config
+      correct_count = current_configs["pools"]["sharded_db"]["shards"]["0"]["servers"].count
+      expect(admin_conn.async_exec("SHOW DATABASES").count).to eq(correct_count)
+    end
+  end
+
+  describe "TCP Keepalives" do
+    # Ideally, we should block TCP traffic to the database using
+    # iptables to mimic passive (connection is dropped without a RST packet)
+    # but we cannot do this in CircleCI because iptables requires NET_ADMIN
+    # capability that we cannot enable in CircleCI
+    # Toxiproxy won't work either because it does not block keepalives
+    # so our best bet is to query the OS keepalive params set on the socket
+
+    context "default settings" do
+      it "applies default keepalive settings" do
+        # We query ss command to verify that we have correct keepalive values set
+        # we can only verify the keepalives_idle parameter but that's good enough
+        # example output
+        #Recv-Q Send-Q Local Address:Port  Peer Address:Port Process
+        #0      0          127.0.0.1:60526    127.0.0.1:18432 timer:(keepalive,1min59sec,0)
+        #0      0          127.0.0.1:60664    127.0.0.1:19432 timer:(keepalive,4.123ms,0)
+
+        port_search_criteria = processes.all_databases.map { |d| "dport = :#{d.port}"}.join(" or ")
+        results = `ss -t4 state established -o -at '( #{port_search_criteria}  )'`.lines
+        results.shift
+        results.each { |line| expect(line).to match(/timer:\(keepalive,.*ms,0\)/) }
+      end
+    end
+
+    context "changed settings" do
+      it "applies keepalive settings from config" do
+        new_configs = processes.pgcat.current_config
+
+        new_configs["general"]["tcp_keepalives_idle"] = 120
+        new_configs["general"]["tcp_keepalives_count"] = 1
+        new_configs["general"]["tcp_keepalives_interval"] = 1
+        processes.pgcat.update_config(new_configs)
+        # We need to kill the old process that was using the default configs
+        processes.pgcat.stop
+        processes.pgcat.start
+        processes.pgcat.wait_until_ready
+
+        port_search_criteria = processes.all_databases.map { |d| "dport = :#{d.port}"}.join(" or ")
+        results = `ss -t4 state established -o -at '( #{port_search_criteria}  )'`.lines
+        results.shift
+        results.each { |line| expect(line).to include("timer:(keepalive,1min") }
+      end
+    end
+  end
+
+  describe "Extended Protocol handling" do
+    it "does not send packets that client does not expect during extended protocol sequence" do
+      new_configs = processes.pgcat.current_config
+
+      new_configs["general"]["connect_timeout"] = 500
+      new_configs["general"]["ban_time"] = 1
+      new_configs["general"]["shutdown_timeout"] = 1
+      new_configs["pools"]["sharded_db"]["users"]["0"]["pool_size"] = 1
+
+      processes.pgcat.update_config(new_configs)
+      processes.pgcat.reload_config
+
+      25.times do
+        Thread.new do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SELECT pg_sleep(5)") rescue PG::SystemError
+        ensure
+          conn&.close
+        end
+      end
+
+      sleep(0.5)
+      conn_under_test = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      stdout, stderr = with_captured_stdout_stderr do
+        15.times do |i|
+          conn_under_test.async_exec("SELECT 1") rescue PG::SystemError
+          conn_under_test.exec_params("SELECT #{i} + $1", [i]) rescue PG::SystemError
+          sleep 1
+        end
+      end
+
+      raise StandardError, "Libpq got unexpected messages while idle" if stderr.include?("arrived from server while idle")
+    end
+  end
+
+  describe "Pool recycling after config reload" do
+    let(:processes) { Helpers::Pgcat.three_shard_setup("sharded_db", 5) }
+
+    it "should update pools for new clients and clients that are no longer in transaction" do
+      server_conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      server_conn.async_exec("BEGIN")
+
+      # No config change yet, client should set old configs
+      current_datebase_from_pg = server_conn.async_exec("SELECT current_database();")[0]["current_database"]
+      expect(current_datebase_from_pg).to eq('shard0')
+
+      # Swap shards
+      new_config = processes.pgcat.current_config
+      shard0 = new_config["pools"]["sharded_db"]["shards"]["0"]
+      shard1 = new_config["pools"]["sharded_db"]["shards"]["1"]
+      new_config["pools"]["sharded_db"]["shards"]["0"] = shard1
+      new_config["pools"]["sharded_db"]["shards"]["1"] = shard0
+
+      # Reload config
+      processes.pgcat.update_config(new_config)
+      processes.pgcat.reload_config
+      sleep 0.5
+
+      # Config changed but transaction is in progress, client should set old configs
+      current_datebase_from_pg = server_conn.async_exec("SELECT current_database();")[0]["current_database"]
+      expect(current_datebase_from_pg).to eq('shard0')
+      server_conn.async_exec("COMMIT")
+
+      # Transaction finished, client should get new configs
+      current_datebase_from_pg = server_conn.async_exec("SELECT current_database();")[0]["current_database"]
+      expect(current_datebase_from_pg).to eq('shard1')
+
+      # New connection should get new configs
+      server_conn.close()
+      server_conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      current_datebase_from_pg = server_conn.async_exec("SELECT current_database();")[0]["current_database"]
+      expect(current_datebase_from_pg).to eq('shard1')
+    end
+  end
+
+  describe "Clients closing connection in the middle of transaction" do
+    it "sends a rollback to the server" do
+      conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      conn.async_exec("SET SERVER ROLE to 'primary'")
+      conn.async_exec("BEGIN")
+      conn.close
+
+      expect(processes.primary.count_query("ROLLBACK")).to eq(1)
+    end
+  end
+
+  describe "Server version reporting" do
+    it "reports correct version for normal and admin databases" do
+      server_conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      expect(server_conn.server_version).not_to eq(0)
+      server_conn.close
+
+      admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+      expect(admin_conn.server_version).not_to eq(0)
+      admin_conn.close
+    end
+  end
+
+  describe "State clearance" do
+    context "session mode" do
+      let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 5, "session") }
+
+      it "Clears state before connection checkin" do
+        # Both modes of operation should not raise
+        # ERROR:  prepared statement "prepared_q" already exists
+        15.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("PREPARE prepared_q (int) AS SELECT $1")
+          conn.close
+        end
+
+        conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+        initial_value = conn.async_exec("SHOW statement_timeout")[0]["statement_timeout"]
+        conn.async_exec("SET statement_timeout to 1000")
+        current_value = conn.async_exec("SHOW statement_timeout")[0]["statement_timeout"]
+        expect(conn.async_exec("SHOW statement_timeout")[0]["statement_timeout"]).to eq("1s")
+        conn.close
+      end
+
+      it "Does not send DISCARD ALL unless necessary" do
+        10.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SET SERVER ROLE to 'primary'")
+          conn.async_exec("SELECT 1")
+          conn.close
+        end
+
+        expect(processes.primary.count_query("DISCARD ALL")).to eq(0)
+
+        10.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SET SERVER ROLE to 'primary'")
+          conn.async_exec("SELECT 1")
+          conn.async_exec("SET statement_timeout to 5000")
+          conn.close
+        end
+
+        expect(processes.primary.count_query("DISCARD ALL")).to eq(10)
+      end
+    end
+
+    context "transaction mode" do
+      let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 5, "transaction") }
+      it "Clears state before connection checkin" do
+        # Both modes of operation should not raise
+        # ERROR:  prepared statement "prepared_q" already exists
+        15.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("PREPARE prepared_q (int) AS SELECT $1")
+          conn.close
+        end
+
+        15.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.prepare("prepared_q", "SELECT $1")
+          conn.close
+        end
+      end
+
+      it "Does not send DISCARD ALL unless necessary" do
+        10.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SET SERVER ROLE to 'primary'")
+          conn.async_exec("SELECT 1")
+          conn.exec_params("SELECT $1", [1])
+          conn.close
+        end
+
+        expect(processes.primary.count_query("DISCARD ALL")).to eq(0)
+
+        10.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SET SERVER ROLE to 'primary'")
+          conn.async_exec("SELECT 1")
+          conn.async_exec("SET statement_timeout to 5000")
+          conn.close
+        end
+
+        expect(processes.primary.count_query("DISCARD ALL")).to eq(10)
+      end
+    end
+
+    context "transaction mode with transactions" do
+      let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 5, "transaction") }
+      it "Does not clear set statement state when declared in a transaction" do
+        10.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SET SERVER ROLE to 'primary'")
+          conn.async_exec("BEGIN")
+          conn.async_exec("SET statement_timeout to 1000")
+          conn.async_exec("COMMIT")
+          conn.close
+        end
+        expect(processes.primary.count_query("DISCARD ALL")).to eq(0)
+
+        10.times do
+          conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+          conn.async_exec("SET SERVER ROLE to 'primary'")
+          conn.async_exec("BEGIN")
+          conn.async_exec("SET LOCAL statement_timeout to 1000")
+          conn.async_exec("COMMIT")
+          conn.close
+        end
+        expect(processes.primary.count_query("DISCARD ALL")).to eq(0)
+      end
+    end
+  end
+end

tests/ruby/routing_spec.rb

@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+require_relative 'spec_helper'
+
+
+describe "Routing" do
+  let(:processes) { Helpers::Pgcat.single_shard_setup("sharded_db", 5) }
+  after do
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  describe "SET ROLE" do
+    context "primary" do
+      it "routes queries only to primary" do
+        conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+        conn.async_exec("SET SERVER ROLE to 'primary'")
+
+        query_count = 30
+        failed_count = 0
+
+        query_count.times do
+          conn.async_exec("SELECT 1 + 2")
+        rescue
+          failed_count += 1
+        end
+
+        expect(failed_count).to eq(0)
+        processes.replicas.map(&:count_select_1_plus_2).each do |instance_share|
+          expect(instance_share).to eq(0)
+        end
+
+        expect(processes.primary.count_select_1_plus_2).to eq(query_count)
+      end
+    end
+    context "replica" do
+      it "routes queries only to replicas" do
+        conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+        conn.async_exec("SET SERVER ROLE to 'replica'")
+
+        expected_share = QUERY_COUNT / processes.replicas.count
+        failed_count = 0
+
+        QUERY_COUNT.times do
+          conn.async_exec("SELECT 1 + 2")
+        rescue
+          failed_count += 1
+        end
+
+        expect(failed_count).to eq(0)
+
+        processes.replicas.map(&:count_select_1_plus_2).each do |instance_share|
+          expect(instance_share).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+        end
+
+        expect(processes.primary.count_select_1_plus_2).to eq(0)
+      end
+    end
+
+    context "any" do
+      it "routes queries to all instances" do
+        conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+        conn.async_exec("SET SERVER ROLE to 'any'")
+
+        expected_share = QUERY_COUNT / processes.all_databases.count
+        failed_count = 0
+
+        QUERY_COUNT.times do
+          conn.async_exec("SELECT 1 + 2")
+        rescue
+          failed_count += 1
+        end
+
+        expect(failed_count).to eq(0)
+
+        processes.all_databases.map(&:count_select_1_plus_2).each do |instance_share|
+          expect(instance_share).to be_within(expected_share * MARGIN_OF_ERROR).of(expected_share)
+        end
+      end
+    end
+  end
+end

tests/ruby/sharding_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+require_relative 'spec_helper'
+
+
+describe "Sharding" do
+  let(:processes) { Helpers::Pgcat.three_shard_setup("sharded_db", 5) }
+
+  before do
+    conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+
+    # Setup the sharding data
+    3.times do |i|
+      conn.exec("SET SHARD TO '#{i}'")
+      conn.exec("DELETE FROM data WHERE id > 0")
+    end
+
+    18.times do |i|
+      i = i + 1
+      conn.exec("SET SHARDING KEY TO '#{i}'")
+      conn.exec("INSERT INTO data (id, value) VALUES (#{i}, 'value_#{i}')")
+    end
+  end
+
+  after do
+
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  describe "automatic routing of extended procotol" do
+    it "can do it" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      conn.exec("SET SERVER ROLE TO 'auto'")
+
+      18.times do |i|
+        result = conn.exec_params("SELECT * FROM data WHERE id = $1", [i + 1])
+        expect(result.ntuples).to eq(1)
+      end
+    end
+
+    it "can do it with multiple parameters" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      conn.exec("SET SERVER ROLE TO 'auto'")
+
+      18.times do |i|
+        result = conn.exec_params("SELECT * FROM data WHERE id = $1 AND id = $2", [i + 1, i + 1])
+        expect(result.ntuples).to eq(1)
+      end
+    end
+  end
+end

tests/ruby/spec_helper.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require 'pg'
+require_relative 'helpers/pgcat_helper'
+
+QUERY_COUNT = 300
+MARGIN_OF_ERROR = 0.35
+
+def with_captured_stdout_stderr
+  sout = STDOUT.clone
+  serr = STDERR.clone
+  STDOUT.reopen("/tmp/out.txt", "w+")
+  STDERR.reopen("/tmp/err.txt", "w+")
+  STDOUT.sync = true
+  STDERR.sync = true
+  yield
+  return File.read('/tmp/out.txt'), File.read('/tmp/err.txt')
+ensure
+  STDOUT.reopen(sout)
+  STDERR.reopen(serr)
+end

tests/ruby/tests.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
-
+require 'pg'
 require 'active_record'
 
 # Uncomment these two to see all queries.
@@ -12,7 +12,8 @@ ActiveRecord::Base.establish_connection(
   port: 6432,
   username: 'sharding_user',
   password: 'sharding_user',
-  database: 'rails_dev',
+  database: 'sharded_db',
+  application_name: 'testing_pgcat',
   prepared_statements: false, # Transaction mode
   advisory_locks: false # Same
 )

tests/sharding/query_routing_setup.sql

@@ -1,11 +1,12 @@
-
 DROP DATABASE IF EXISTS shard0;
 DROP DATABASE IF EXISTS shard1;
 DROP DATABASE IF EXISTS shard2;
+DROP DATABASE IF EXISTS some_db;
 
 CREATE DATABASE shard0;
 CREATE DATABASE shard1;
 CREATE DATABASE shard2;
+CREATE DATABASE some_db;
 
 \c shard0
 
@@ -41,21 +42,63 @@ CREATE TABLE data (
 
 CREATE TABLE data_shard_2 PARTITION OF data FOR VALUES WITH (MODULUS 3, REMAINDER 2);
 
-DROP ROLE IF EXISTS sharding_user;
-CREATE ROLE sharding_user ENCRYPTED PASSWORD 'sharding_user' LOGIN;
 
-GRANT CONNECT ON DATABASE shard0 TO sharding_user;
-GRANT CONNECT ON DATABASE shard1 TO sharding_user;
-GRANT CONNECT ON DATABASE shard2 TO sharding_user;
+\c some_db
+
+DROP TABLE IF EXISTS data CASCADE;
+
+CREATE TABLE data (
+    id BIGINT,
+    value VARCHAR
+);
+
+DROP ROLE IF EXISTS sharding_user;
+DROP ROLE IF EXISTS other_user;
+DROP ROLE IF EXISTS simple_user;
+CREATE ROLE sharding_user ENCRYPTED PASSWORD 'sharding_user' LOGIN;
+CREATE ROLE other_user ENCRYPTED PASSWORD 'other_user' LOGIN;
+CREATE ROLE simple_user ENCRYPTED PASSWORD 'simple_user' LOGIN;
+
+GRANT CONNECT ON DATABASE shard0  TO sharding_user;
+GRANT CONNECT ON DATABASE shard1  TO sharding_user;
+GRANT CONNECT ON DATABASE shard2  TO sharding_user;
+
+GRANT CONNECT ON DATABASE shard0  TO other_user;
+GRANT CONNECT ON DATABASE shard1  TO other_user;
+GRANT CONNECT ON DATABASE shard2  TO other_user;
+
+GRANT CONNECT ON DATABASE some_db TO simple_user;
 
 \c shard0
+CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO sharding_user;
 GRANT ALL ON SCHEMA public TO sharding_user;
 GRANT ALL ON TABLE data TO sharding_user;
+GRANT ALL ON SCHEMA public TO other_user;
+GRANT ALL ON TABLE data TO other_user;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO other_user;
 
 \c shard1
+CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO sharding_user;
 GRANT ALL ON SCHEMA public TO sharding_user;
 GRANT ALL ON TABLE data TO sharding_user;
+GRANT ALL ON SCHEMA public TO other_user;
+GRANT ALL ON TABLE data TO other_user;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO other_user;
+
 
 \c shard2
+CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO sharding_user;
 GRANT ALL ON SCHEMA public TO sharding_user;
 GRANT ALL ON TABLE data TO sharding_user;
+GRANT ALL ON SCHEMA public TO other_user;
+GRANT ALL ON TABLE data TO other_user;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO other_user;
+
+\c some_db
+CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
+GRANT EXECUTE ON FUNCTION pg_stat_statements_reset TO simple_user;
+GRANT ALL ON SCHEMA public TO simple_user;
+GRANT ALL ON TABLE data TO simple_user;

tests/sharding/query_routing_test_primary_replica.sql

@@ -151,3 +151,12 @@ SELECT 1;
 set server role to 'replica';
 SeT SeRver Role TO 'PrImARY';
 select 1;
+
+SET PRIMARY READS TO 'on';
+SELECT 1;
+
+SET PRIMARY READS TO 'off';
+SELECT 1;
+
+SET PRIMARY READS TO 'default';
+SELECT 1;

utilities/generate_config_docs.py

@@ -0,0 +1,92 @@
+import re
+import tomli
+
+class DocGenerator:
+    def __init__(self, filename):
+        self.doc = []
+        self.current_section = ""
+        self.current_comment = []
+        self.current_field_name = ""
+        self.current_field_value = []
+        self.current_field_unset = False
+        self.filename = filename
+
+    def write(self):
+        with open("../CONFIG.md", "w") as text_file:
+            text_file.write("# PgCat Configurations \n")
+            for entry in self.doc:
+                if entry["name"] == "__section__":
+                    text_file.write("## `" + entry["section"] + "` Section" + "\n")
+                    text_file.write("\n")
+                    continue
+                text_file.write("### " + entry["name"]+ "\n")
+                text_file.write("```"+ "\n")
+                text_file.write("path: " + entry["fqdn"]+ "\n")
+                text_file.write("default: " + entry["defaults"].strip()+ "\n")
+                if entry["example"] is not None:
+                    text_file.write("example: " + entry["example"].strip()+ "\n")
+                text_file.write("```"+ "\n")
+                text_file.write("\n")
+                text_file.write(entry["comment"]+ "\n")
+                text_file.write("\n")
+
+    def save_entry(self):
+        if len(self.current_field_name) == 0:
+            return
+        if len(self.current_comment) == 0:
+            return
+        self.current_section = self.current_section.replace("sharded_db", "<pool_name>")
+        self.current_section = self.current_section.replace("simple_db", "<pool_name>")
+        self.current_section = self.current_section.replace("users.0", "users.<user_index>")
+        self.current_section = self.current_section.replace("users.1", "users.<user_index>")
+        self.current_section = self.current_section.replace("shards.0", "shards.<shard_index>")
+        self.current_section = self.current_section.replace("shards.1", "shards.<shard_index>")
+        self.doc.append(
+            {
+                "name": self.current_field_name,
+                "fqdn": self.current_section + "." + self.current_field_name,
+                "section": self.current_section,
+                "comment": "\n".join(self.current_comment),
+                "defaults": self.current_field_value if not self.current_field_unset else "<UNSET>",
+                "example": self.current_field_value  if self.current_field_unset  else None
+            }
+        )
+        self.current_comment = []
+        self.current_field_name = ""
+        self.current_field_value = []
+    def parse(self):
+        with open("../pgcat.toml", "r") as f:
+            for line in f.readlines():
+                line = line.strip()
+                if len(line) == 0:
+                    self.save_entry()
+
+                if line.startswith("["):
+                    self.current_section = line[1:-1]
+                    self.current_field_name = "__section__"
+                    self.current_field_unset = False
+                    self.save_entry()
+
+                elif line.startswith("#"):
+                    results = re.search("^#\s*([A-Za-z0-9_]+)\s*=(.+)$", line)
+                    if results is not None:
+                        self.current_field_name = results.group(1)
+                        self.current_field_value = results.group(2)
+                        self.current_field_unset = True
+                        self.save_entry()
+                    else:
+                        self.current_comment.append(line[1:].strip())
+                else:
+                    results = re.search("^\s*([A-Za-z0-9_]+)\s*=(.+)$", line)
+                    if results is None:
+                        continue
+                    self.current_field_name = results.group(1)
+                    self.current_field_value = results.group(2)
+                    self.current_field_unset = False
+                    self.save_entry()
+        self.save_entry()
+        return self
+
+
+DocGenerator("../pgcat.toml").parse().write()
+