chore(deps): bump socket2 from 0.4.7 to 0.5.3

Bumps [socket2](https://github.com/rust-lang/socket2) from 0.4.7 to 0.5.3.
- [Release notes](https://github.com/rust-lang/socket2/releases)
- [Changelog](https://github.com/rust-lang/socket2/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rust-lang/socket2/commits)

---
updated-dependencies:
- dependency-name: socket2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.circleci/pgcat.toml

@@ -39,7 +39,7 @@ log_client_connections = false
 log_client_disconnections = false
 
 # Reload config automatically if it changes.
-autoreload = true
+autoreload = 15000
 
 # TLS
 tls_certificate = ".circleci/server.cert"

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.rs]
+indent_style = space
+indent_size = 4
+max_line_length = 120
+
+[*.toml]
+indent_style = space
+indent_size = 2

CONFIG.md

@@ -49,6 +49,14 @@ default: 30000 # milliseconds
 
 How long an idle connection with a server is left open (ms).
 
+### server_lifetime
+```
+path: general.server_lifetime
+default: 86400000 # 24 hours
+```
+
+Max connection lifetime before it's closed, even if actively used.
+
 ### idle_client_in_transaction_timeout
 ```
 path: general.idle_client_in_transaction_timeout
@@ -108,7 +116,7 @@ If we should log client disconnections
 ### autoreload
 ```
 path: general.autoreload
-default: false
+default: 15000
 ```
 
 When set to true, PgCat reloads configs if it detects a change in the config file.
@@ -152,7 +160,7 @@ default: <UNSET>
 example: "server.cert"
 ```
 
-Path to TLS Certficate file to use for TLS connections
+Path to TLS Certificate file to use for TLS connections
 
 ### tls_private_key
 ```
@@ -175,40 +183,26 @@ Connecting to that database allows running commands like `SHOW POOLS`, `SHOW DAT
 ### admin_password
 ```
 path: general.admin_password
-default: <UNSET>
+default: "admin_pass"
 ```
 
 Password to access the virtual administrative database
 
-### auth_query (experimental)
+### dns_cache_enabled
 ```
-path: general.auth_query
-default: <UNSET>
+path: general.dns_cache_enabled
+default: false
 ```
+When enabled, ip resolutions for server connections specified using hostnames will be cached
+and checked for changes every `dns_max_ttl` seconds. If a change in the host resolution is found
+old ip connections are closed (gracefully) and new connections will start using new ip.
 
-Query to be sent to servers to obtain the hash used for md5 authentication. The connection will be
-established using the database configured in the pool. This parameter is inherited by every pool
-and can be redefined in pool configuration.
-
-### auth_query_user (experimental)
+### dns_max_ttl
 ```
-path: general.auth_query_user
-default: <UNSET>
+path: general.dns_max_ttl
+default: 30
 ```
-
-User to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
-specified in `auth_query_user`. The connection will be established using the database configured in the pool.
-This parameter is inherited by every pool and can be redefined in pool configuration.
-
-### auth_query_password (experimental)
-```
-path: general.auth_query_password
-default: <UNSET>
-```
-
-Password to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
-specified in `auth_query_user`. The connection will be established using the database configured in the pool.
-This parameter is inherited by every pool and can be redefined in pool configuration.
+Specifies how often (in seconds) cached ip addresses for servers are rechecked (see `dns_cache_enabled`).
 
 ## `pools.<pool_name>` Section
 
@@ -243,7 +237,7 @@ If the client doesn't specify, PgCat routes traffic to this role by default.
 `replica` round-robin between replicas only without touching the primary,
 `primary` all queries go to the primary unless otherwise specified.
 
-### query_parser_enabled (experimental)
+### query_parser_enabled
 ```
 path: pools.<pool_name>.query_parser_enabled
 default: true
@@ -264,7 +258,7 @@ If the query parser is enabled and this setting is enabled, the primary will be
 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)
+### sharding_key_regex
 ```
 path: pools.<pool_name>.sharding_key_regex
 default: <UNSET>
@@ -286,7 +280,40 @@ Current options:
 `pg_bigint_hash`: PARTITION BY HASH (Postgres hashing function)
 `sha1`: A hashing function based on SHA1
 
-### automatic_sharding_key (experimental)
+### auth_query
+```
+path: pools.<pool_name>.auth_query
+default: <UNSET>
+example: "SELECT $1"
+```
+
+Query to be sent to servers to obtain the hash used for md5 authentication. The connection will be
+established using the database configured in the pool. This parameter is inherited by every pool
+and can be redefined in pool configuration.
+
+### auth_query_user
+```
+path: pools.<pool_name>.auth_query_user
+default: <UNSET>
+example: "sharding_user"
+```
+
+User to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
+specified in `auth_query_user`. The connection will be established using the database configured in the pool.
+This parameter is inherited by every pool and can be redefined in pool configuration.
+
+### auth_query_password
+```
+path: pools.<pool_name>.auth_query_password
+default: <UNSET>
+example: "sharding_user"
+```
+
+Password to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
+specified in `auth_query_user`. The connection will be established using the database configured in the pool.
+This parameter is inherited by every pool and can be redefined in pool configuration.
+
+### automatic_sharding_key
 ```
 path: pools.<pool_name>.automatic_sharding_key
 default: <UNSET>
@@ -311,30 +338,6 @@ default: 3000
 
 Connect timeout can be overwritten in the pool
 
-### auth_query (experimental)
-```
-path: general.auth_query
-default: <UNSET>
-```
-
-Auth query can be overwritten in the pool
-
-### auth_query_user (experimental)
-```
-path: general.auth_query_user
-default: <UNSET>
-```
-
-Auth query user can be overwritten in the pool
-
-### auth_query_password (experimental)
-```
-path: general.auth_query_password
-default: <UNSET>
-```
-
-Auth query password can be overwritten in the pool
-
 ## `pools.<pool_name>.users.<user_index>` Section
 
 ### username
@@ -343,7 +346,8 @@ path: pools.<pool_name>.users.<user_index>.username
 default: "sharding_user"
 ```
 
-Postgresql username
+PostgreSQL username used to authenticate the user and connect to the server
+if `server_username` is not set.
 
 ### password
 ```
@@ -351,7 +355,26 @@ path: pools.<pool_name>.users.<user_index>.password
 default: "sharding_user"
 ```
 
-Postgresql password
+PostgreSQL password used to authenticate the user and connect to the server
+if `server_password` is not set.
+
+### server_username
+```
+path: pools.<pool_name>.users.<user_index>.server_username
+default: <UNSET>
+example: "another_user"
+```
+
+PostgreSQL username used to connect to the server.
+
+### server_password
+```
+path: pools.<pool_name>.users.<user_index>.server_password
+default: <UNSET>
+example: "another_password"
+```
+
+PostgreSQL password used to connect to the server.
 
 ### pool_size
 ```
@@ -382,7 +405,7 @@ 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)
+### mirrors
 ```
 path: pools.<pool_name>.shards.<shard_index>.mirrors
 default: <UNSET>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "pgcat"
-version = "1.0.0"
+version = "1.0.2-alpha3"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -14,12 +14,12 @@ rand = "0.8"
 chrono = "0.4"
 sha-1 = "0.10"
 toml = "0.7"
-serde = "1"
+serde = { version = "1", features = ["derive"] }
 serde_derive = "1"
 regex = "1"
 num_cpus = "1"
 once_cell = "1"
-sqlparser = "0.32.0"
+sqlparser = {version = "0.33", features = ["visitor"] }
 log = "0.4"
 arc-swap = "1"
 env_logger = "0.10"
@@ -28,17 +28,25 @@ hmac = "0.12"
 sha2 = "0.10"
 base64 = "0.21"
 stringprep = "0.1"
-tokio-rustls = "0.23"
+tokio-rustls = "0.24"
 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"] }
+socket2 = { version = "0.5.3", features = ["all"] }
 nix = "0.26.2"
 atomic_enum = "0.2.0"
-postgres-protocol = "0.6.4"
+postgres-protocol = "0.6.5"
 fallible-iterator = "0.2"
+pin-project = "1"
+webpki-roots = "0.23"
+rustls = { version = "0.21", features = ["dangerous_configuration"] }
+trust-dns-resolver = "0.22.0"
+tokio-test = "0.4.2"
+serde_json = "1"
+itertools = "0.10"
 
 [target.'cfg(not(target_env = "msvc"))'.dependencies]
 jemallocator = "0.5.0"
+

README.md

@@ -18,25 +18,56 @@ PostgreSQL pooler and proxy (like PgBouncer) with support for sharding, load bal
 | Failover | **Stable** | Queries are automatically rerouted around broken replicas, validated by regular health checks. |
 | Admin database statistics | **Stable** | Pooler statistics and administration via the `pgbouncer` and `pgcat` databases. |
 | Prometheus statistics | **Stable** | Statistics are reported via a HTTP endpoint for Prometheus. |
-| Client TLS | **Stable** | Clients can connect to the pooler using TLS/SSL. |
+| SSL/TLS | **Stable** | Clients can connect to the pooler using TLS. Pooler can connect to Postgres servers using TLS. |
 | Client/Server authentication | **Stable** | Clients can connect using MD5 authentication, supported by `libpq` and all Postgres client drivers. PgCat can connect to Postgres using MD5 and SCRAM-SHA-256. |
 | Live configuration reloading | **Stable** | Identical to PgBouncer; all settings can be reloaded dynamically (except `host` and `port`). |
+| Auth passthrough | **Stable** | MD5 password authentication can be configured to use an `auth_query` so no cleartext passwords are needed in the config file.|
 | Sharding using extended SQL syntax | **Experimental** | Clients can dynamically configure the pooler to route queries to specific shards. |
 | Sharding using comments parsing/Regex | **Experimental** | Clients can include shard information (sharding key, shard ID) in the query comments. |
 | Automatic sharding | **Experimental** | PgCat can parse queries, detect sharding keys automatically, and route queries to the correct shard. |
 | Mirroring | **Experimental** | Mirror queries between multiple databases in order to test servers with realistic production traffic. |
-| Auth passthrough | **Experimental** | MD5 password authentication can be configured to use an `auth_query` so no cleartext passwords are needed in the config file. |
-| Password rotation | **Experimental** | Allows to rotate passwords without downtime or using third-party tools to manage Postgres authentication. |
 
 
 ## Status
 
-PgCat is stable and used in production to serve hundreds of thousands of queries per second. Some features remain experimental and are being actively developed. They are optional and can be enabled through configuration.
+PgCat is stable and used in production to serve hundreds of thousands of queries per second.
 
-| | |
-|-|-|
-|<a href="https://tech.instacart.com/adopting-pgcat-a-nextgen-postgres-proxy-3cf284e68c2f"><img src="./images/instacart.webp" height="70" width="auto"></a>|<a href="https://postgresml.org/blog/scaling-postgresml-to-one-million-requests-per-second"><img src="./images/postgresml.webp" height="70" width="auto"></a>|
-| [Instacart](https://tech.instacart.com/adopting-pgcat-a-nextgen-postgres-proxy-3cf284e68c2f) | [PostgresML](https://postgresml.org/blog/scaling-postgresml-to-one-million-requests-per-second) |
+<table>
+  <tr>
+    <td>
+      <a href="https://tech.instacart.com/adopting-pgcat-a-nextgen-postgres-proxy-3cf284e68c2f">
+        <img src="./images/instacart.webp" height="70" width="auto">
+      </a>
+    </td>
+    <td>
+      <a href="https://postgresml.org/blog/scaling-postgresml-to-one-million-requests-per-second">
+        <img src="./images/postgresml.webp" height="70" width="auto">
+      </a>
+    </td>
+    <td>
+      <a href="https://onesignal.com">
+        <img src="./images/one_signal.webp" height="70" width="auto">
+      </a>
+    </td>
+  </tr>
+  <tr>
+    <td>
+      <a href="https://tech.instacart.com/adopting-pgcat-a-nextgen-postgres-proxy-3cf284e68c2f">
+        Instacart
+      </a>
+    </td>
+    <td>
+      <a href="https://postgresml.org/blog/scaling-postgresml-to-one-million-requests-per-second">
+        PostgresML
+      </a>
+    </td>
+    <td>
+      OneSignal
+    </td>
+  </tr>
+</table>
+
+Some features remain experimental and are being actively developed. They are optional and can be enabled through configuration.
 
 ## Deployment
 
@@ -100,7 +131,7 @@ You can open a Docker development environment where you can debug tests easier.
 ./dev/script/console
 ```
 
-This will open a terminal in an environment similar to that used in tests. In there, you can compile the pooler, 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 on your machine.
+This will open a terminal in an environment similar to that used in tests. In there, you can compile the pooler, run tests, do some debugging with the test environment, etc. Objects compiled inside the container (and bundled gems) will be placed in `dev/cache` so they don't interfere with what you have on your machine.
 
 ## Usage
 
@@ -245,12 +276,6 @@ The config can be reloaded by sending a `kill -s SIGHUP` to the process or by qu
 
 Mirroring allows to route queries to multiple databases at the same time. This is useful for prewarning replicas before placing them into the active configuration, or for testing different versions of Postgres with live traffic.
 
-### Password rotation
-
-Password rotation allows to specify multiple passwords for a user, so they can connect to PgCat with multiple credentials. This allows distributed applications to change their configuration (connection strings) gradually and for PgCat to monitor their progression in admin statistics. Once the new secret is deployed everywhere, the old one can be removed from PgCat.
-
-This also decouples server passwords from client passwords, allowing to change one without necessarily changing the other.
-
 ## License
 
 PgCat is free and open source, released under the MIT license.

dev/docker-compose.yaml

@@ -25,7 +25,7 @@ x-common-env-pg:
 
 services:
   main:
-    image: kubernetes/pause
+    image: gcr.io/google_containers/pause:3.2
     ports:
       - 6432
 

examples/docker/pgcat.toml

@@ -38,9 +38,6 @@ 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"
@@ -76,7 +73,7 @@ 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
 
 # So what if you wanted to implement a different hashing function,

pgcat.minimal.toml

@@ -0,0 +1,22 @@
+# This is an example of the most basic config
+# that will mimic what PgBouncer does in transaction mode with one server.
+
+[general]
+
+host = "0.0.0.0"
+port = 6433
+admin_username = "pgcat"
+admin_password = "pgcat"
+
+[pools.pgml.users.0]
+username = "postgres"
+password = "postgres"
+pool_size = 10
+min_pool_size = 1
+pool_mode = "transaction"
+
+[pools.pgml.shards.0]
+servers = [
+  ["127.0.0.1", 28815, "primary"]
+]
+database = "postgres"

pgcat.toml

@@ -23,6 +23,9 @@ connect_timeout = 5000 # milliseconds
 # How long an idle connection with a server is left open (ms).
 idle_timeout = 30000 # milliseconds
 
+# Max connection lifetime before it's closed, even if actively used.
+server_lifetime = 86400000 # 24 hours
+
 # How long a client is allowed to be idle while in a transaction (ms).
 idle_client_in_transaction_timeout = 0 # milliseconds
 
@@ -45,7 +48,7 @@ log_client_connections = false
 log_client_disconnections = false
 
 # When set to true, PgCat reloads configs if it detects a change in the config file.
-autoreload = false
+autoreload = 15000
 
 # Number of worker threads the Runtime will use (4 by default).
 worker_threads = 5
@@ -57,17 +60,75 @@ tcp_keepalives_count = 5
 # Number of seconds between keepalive packets.
 tcp_keepalives_interval = 5
 
-# Path to TLS Certficate file to use for TLS connections
+# Path to TLS Certificate file to use for TLS connections
 # tls_certificate = ".circleci/server.cert"
 # Path to TLS private key file to use for TLS connections
 # tls_private_key = ".circleci/server.key"
 
+# Enable/disable server TLS
+server_tls = false
+
+# Verify server certificate is completely authentic.
+verify_server_certificate = false
+
 # 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"
 
+# Default plugins that are configured on all pools.
+[plugins]
+
+# Prewarmer plugin that runs queries on server startup, before giving the connection
+# to the client.
+[plugins.prewarmer]
+enabled = false
+queries = [
+  "SELECT pg_prewarm('pgbench_accounts')",
+]
+
+# Log all queries to stdout.
+[plugins.query_logger]
+enabled = false
+
+# Block access to tables that Postgres does not allow us to control.
+[plugins.table_access]
+enabled = false
+tables = [
+  "pg_user",
+  "pg_roles",
+  "pg_database",
+]
+
+# Intercept user queries and give a fake reply.
+[plugins.intercept]
+enabled = true
+
+[plugins.intercept.queries.0]
+
+query = "select current_database() as a, current_schemas(false) as b"
+schema = [
+  ["a", "text"],
+  ["b", "text"],
+]
+result = [
+  ["${DATABASE}", "{public}"],
+]
+
+[plugins.intercept.queries.1]
+
+query = "select current_database(), current_schema(), current_user"
+schema = [
+  ["current_database", "text"],
+  ["current_schema", "text"],
+  ["current_user", "text"],
+]
+result = [
+  ["${DATABASE}", "public", "${USER}"],
+]
+
+
 # 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
@@ -113,6 +174,21 @@ primary_reads_enabled = true
 # `sha1`: A hashing function based on SHA1
 sharding_function = "pg_bigint_hash"
 
+# Query to be sent to servers to obtain the hash used for md5 authentication. The connection will be
+# established using the database configured in the pool. This parameter is inherited by every pool
+# and can be redefined in pool configuration.
+# auth_query = "SELECT $1"
+
+# User to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
+# specified in `auth_query_user`. The connection will be established using the database configured in the pool.
+# This parameter is inherited by every pool and can be redefined in pool configuration.
+# auth_query_user = "sharding_user"
+
+# Password to be used for connecting to servers to obtain the hash used for md5 authentication by sending the query
+# specified in `auth_query_user`. The connection will be established using the database configured in the pool.
+# This parameter is inherited by every pool and can be redefined in pool configuration.
+# auth_query_password = "sharding_user"
+
 # Automatically parse this from queries and route queries to the right shard!
 # automatic_sharding_key = "data.id"
 
@@ -122,26 +198,86 @@ idle_timeout = 40000
 # Connect timeout can be overwritten in the pool
 connect_timeout = 3000
 
-# auth_query = "SELECT * FROM public.user_lookup('$1')"
-# auth_query_user = "postgres"
-# auth_query_password = "postgres"
+# When enabled, ip resolutions for server connections specified using hostnames will be cached
+# and checked for changes every `dns_max_ttl` seconds. If a change in the host resolution is found
+# old ip connections are closed (gracefully) and new connections will start using new ip.
+# dns_cache_enabled = false
+
+# Specifies how often (in seconds) cached ip addresses for servers are rechecked (see `dns_cache_enabled`).
+# dns_max_ttl = 30
+
+# Plugins can be configured on a pool-per-pool basis. This overrides the global plugins setting,
+# so all plugins have to be configured here again.
+[pool.sharded_db.plugins]
+
+[pools.sharded_db.plugins.prewarmer]
+enabled = true
+queries = [
+  "SELECT pg_prewarm('pgbench_accounts')",
+]
+
+[pools.sharded_db.plugins.query_logger]
+enabled = false
+
+[pools.sharded_db.plugins.table_access]
+enabled = false
+tables = [
+  "pg_user",
+  "pg_roles",
+  "pg_database",
+]
+
+[pools.sharded_db.plugins.intercept]
+enabled = true
+
+[pools.sharded_db.plugins.intercept.queries.0]
+
+query = "select current_database() as a, current_schemas(false) as b"
+schema = [
+  ["a", "text"],
+  ["b", "text"],
+]
+result = [
+  ["${DATABASE}", "{public}"],
+]
+
+[pools.sharded_db.plugins.intercept.queries.1]
+
+query = "select current_database(), current_schema(), current_user"
+schema = [
+  ["current_database", "text"],
+  ["current_schema", "text"],
+  ["current_user", "text"],
+]
+result = [
+  ["${DATABASE}", "public", "${USER}"],
+]
 
 # User configs are structured as pool.<pool_name>.users.<user_index>
-# This secion holds the credentials for users that may connect to this cluster
+# This section holds the credentials for users that may connect to this cluster
 [pools.sharded_db.users.0]
-# Postgresql username
+# PostgreSQL username used to authenticate the user and connect to the server
+# if `server_username` is not set.
 username = "sharding_user"
-# Postgresql password
+
+# PostgreSQL password used to authenticate the user and connect to the server
+# if `server_password` is not set.
 password = "sharding_user"
 
-# # Passwords the client can use to connect. Useful for password rotations.
-# secrets = [ "secret_one", "secret_two" ]
+pool_mode = "session"
+
+# PostgreSQL username used to connect to the server.
+# server_username = "another_user"
+
+# PostgreSQL password used to connect to the server.
+# server_password = "another_password"
 
 # 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
@@ -186,6 +322,8 @@ sharding_function = "pg_bigint_hash"
 username = "simple_user"
 password = "simple_user"
 pool_size = 5
+min_pool_size = 3
+server_lifetime = 60000
 statement_timeout = 0
 
 [pools.simple_db.shards.0]

src/admin.rs

@@ -12,9 +12,9 @@ use tokio::time::Instant;
 use crate::config::{get_config, reload_config, VERSION};
 use crate::errors::Error;
 use crate::messages::*;
+use crate::pool::ClientServerMap;
 use crate::pool::{get_all_pools, get_pool};
 use crate::stats::{get_client_stats, get_pool_stats, get_server_stats, ClientState, ServerState};
-use crate::ClientServerMap;
 
 pub fn generate_server_info_for_admin() -> BytesMut {
     let mut server_info = BytesMut::new();
@@ -259,7 +259,6 @@ where
     let columns = vec![
         ("database", DataType::Text),
         ("user", DataType::Text),
-        ("secret", DataType::Text),
         ("pool_mode", DataType::Text),
         ("cl_idle", DataType::Numeric),
         ("cl_active", DataType::Numeric),
@@ -277,11 +276,10 @@ where
     let mut res = BytesMut::new();
     res.put(row_description(&columns));
 
-    for (_, pool_stats) in all_pool_stats {
+    for ((_user_pool, _pool), pool_stats) in all_pool_stats {
         let mut row = vec![
             pool_stats.database(),
             pool_stats.user(),
-            pool_stats.redacted_secret(),
             pool_stats.pool_mode().to_string(),
         ];
         pool_stats.populate_row(&mut row);
@@ -782,7 +780,7 @@ where
         let database = parts[0];
         let user = parts[1];
 
-        match get_pool(database, user, None) {
+        match get_pool(database, user) {
             Some(pool) => {
                 pool.pause();
 
@@ -829,7 +827,7 @@ where
         let database = parts[0];
         let user = parts[1];
 
-        match get_pool(database, user, None) {
+        match get_pool(database, user) {
             Some(pool) => {
                 pool.resume();
 
@@ -897,20 +895,13 @@ where
     res.put(row_description(&vec![
         ("name", DataType::Text),
         ("pool_mode", DataType::Text),
-        ("secret", DataType::Text),
     ]));
 
     for (user_pool, pool) in get_all_pools() {
         let pool_config = &pool.settings;
-        let redacted_secret = match user_pool.secret {
-            Some(secret) => format!("****{}", &secret[secret.len() - 4..]),
-            None => "<no secret>".to_string(),
-        };
-
         res.put(data_row(&vec![
             user_pool.user.clone(),
             pool_config.pool_mode.to_string(),
-            redacted_secret,
         ]));
     }
 

src/auth.rs

@@ -1,452 +0,0 @@
-//! Module implementing various client authentication mechanisms.
-//!
-//! Currently supported: plain (via TLS), md5 (via TLS and plain text connection).
-
-use crate::errors::Error;
-use crate::tokio::io::AsyncReadExt;
-use crate::{
-    auth_passthrough::AuthPassthrough,
-    config::get_config,
-    messages::{
-        error_response, md5_hash_password, md5_hash_second_pass, write_all, wrong_password,
-    },
-    pool::{get_pool, ConnectionPool},
-};
-use bytes::{BufMut, BytesMut};
-use log::debug;
-
-async fn refetch_auth_hash<S>(
-    pool: &ConnectionPool,
-    stream: &mut S,
-    username: &str,
-    pool_name: &str,
-) -> Result<String, Error>
-where
-    S: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
-{
-    let config = get_config();
-
-    debug!("Fetching auth hash");
-
-    if config.is_auth_query_configured() {
-        let address = pool.address(0, 0);
-        if let Some(apt) = AuthPassthrough::from_pool_settings(&pool.settings) {
-            let hash = apt.fetch_hash(address).await?;
-
-            debug!("Auth query succeeded");
-
-            return Ok(hash);
-        }
-    } else {
-        debug!("Auth query not configured on pool");
-    }
-
-    error_response(
-        stream,
-        &format!(
-            "No password set and auth passthrough failed for database: {}, user: {}",
-            pool_name, username
-        ),
-    )
-    .await?;
-
-    Err(Error::ClientError(format!(
-        "Could not obtain hash for {{ username: {:?}, database: {:?} }}. Auth passthrough not enabled.",
-        pool_name, username
-    )))
-}
-
-/// Read 'p' message from client.
-async fn response<R>(stream: &mut R) -> Result<Vec<u8>, Error>
-where
-    R: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send,
-{
-    let code = match stream.read_u8().await {
-        Ok(code) => code,
-        Err(_) => {
-            return Err(Error::SocketError(
-                "Error reading password code from client".to_string(),
-            ))
-        }
-    };
-
-    if code as char != 'p' {
-        return Err(Error::SocketError(format!("Expected p, got {}", code)));
-    }
-
-    let len = match stream.read_i32().await {
-        Ok(len) => len,
-        Err(_) => {
-            return Err(Error::SocketError(
-                "Error reading password length from client".to_string(),
-            ))
-        }
-    };
-
-    let mut response = vec![0; (len - 4) as usize];
-
-    // Too short to be a password (null-terminated)
-    if response.len() < 2 {
-        return Err(Error::ClientError(format!("Password response too short")));
-    }
-
-    match stream.read_exact(&mut response).await {
-        Ok(_) => (),
-        Err(_) => {
-            return Err(Error::SocketError(
-                "Error reading password from client".to_string(),
-            ))
-        }
-    };
-
-    Ok(response.to_vec())
-}
-
-/// Make sure the pool we authenticated to has at least one server connection
-/// that can serve our request.
-async fn validate_pool<W>(
-    stream: &mut W,
-    mut pool: ConnectionPool,
-    username: &str,
-    pool_name: &str,
-) -> Result<(), Error>
-where
-    W: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
-{
-    if !pool.validated() {
-        match pool.validate().await {
-            Ok(_) => Ok(()),
-            Err(err) => {
-                error_response(
-                    stream,
-                    &format!("Pool down for database: {}, user: {}", pool_name, username,),
-                )
-                .await?;
-
-                Err(Error::ClientError(format!("Pool down: {:?}", err)))
-            }
-        }
-    } else {
-        Ok(())
-    }
-}
-
-/// Clear text authentication.
-///
-/// The client will send the password in plain text over the wire.
-/// To protect against obvious security issues, this is only used over TLS.
-///
-/// Clear text authentication is used to support zero-downtime password rotation.
-/// It allows the client to use multiple passwords when talking to the PgCat
-/// while the password is being rotated across multiple app instances.
-pub struct ClearText {
-    username: String,
-    pool_name: String,
-    application_name: String,
-}
-
-impl ClearText {
-    /// Create a new ClearText authentication mechanism.
-    pub fn new(username: &str, pool_name: &str, application_name: &str) -> ClearText {
-        ClearText {
-            username: username.to_string(),
-            pool_name: pool_name.to_string(),
-            application_name: application_name.to_string(),
-        }
-    }
-
-    /// Issue 'R' clear text challenge to client.
-    pub async fn challenge<W>(&self, stream: &mut W) -> Result<(), Error>
-    where
-        W: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
-    {
-        debug!("Sending plain challenge");
-
-        let mut msg = BytesMut::new();
-        msg.put_u8(b'R');
-        msg.put_i32(8);
-        msg.put_i32(3); // Clear text
-
-        write_all(stream, msg).await
-    }
-
-    /// Authenticate client with server password or secret.
-    pub async fn authenticate<R, W>(
-        &self,
-        read: &mut R,
-        write: &mut W,
-    ) -> Result<Option<String>, Error>
-    where
-        R: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send,
-        W: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
-    {
-        let response = response(read).await?;
-
-        let secret = String::from_utf8_lossy(&response[0..response.len() - 1]).to_string();
-
-        match get_pool(&self.pool_name, &self.username, Some(secret.clone())) {
-            None => match get_pool(&self.pool_name, &self.username, None) {
-                Some(pool) => {
-                    match pool.settings.user.password {
-                        Some(ref password) => {
-                            if password != &secret {
-                                wrong_password(write, &self.username).await?;
-                                Err(Error::ClientError(format!(
-                                        "Invalid password {{ username: {}, pool_name: {}, application_name: {} }}",
-                                        self.username, self.pool_name, self.application_name
-                                )))
-                            } else {
-                                validate_pool(write, pool, &self.username, &self.pool_name).await?;
-
-                                Ok(None)
-                            }
-                        }
-
-                        None => {
-                            // Server is storing hashes, we can't query it for the plain text password.
-                            error_response(
-                                write,
-                                &format!(
-                                    "No server password configured for database: {}, user: {}",
-                                    self.pool_name, self.username
-                                ),
-                            )
-                            .await?;
-
-                            Err(Error::ClientError(format!(
-                                "No server password configured for {{ username: {}, pool_name: {}, application_name: {} }}",
-                                self.username, self.pool_name, self.application_name
-                            )))
-                        }
-                    }
-                }
-
-                None => {
-                    error_response(
-                        write,
-                        &format!(
-                            "No pool configured for database: {}, user: {}",
-                            self.pool_name, self.username
-                        ),
-                    )
-                    .await?;
-
-                    Err(Error::ClientError(format!(
-                        "Invalid pool name {{ username: {}, pool_name: {}, application_name: {} }}",
-                        self.username, self.pool_name, self.application_name
-                    )))
-                }
-            },
-            Some(pool) => {
-                validate_pool(write, pool, &self.username, &self.pool_name).await?;
-                Ok(Some(secret))
-            }
-        }
-    }
-}
-
-/// MD5 hash authentication.
-///
-/// Deprecated, but widely used everywhere, and currently required for poolers
-/// to authencticate clients without involving Postgres.
-///
-/// Admin clients are required to use MD5.
-pub struct Md5 {
-    username: String,
-    pool_name: String,
-    application_name: String,
-    salt: [u8; 4],
-    admin: bool,
-}
-
-impl Md5 {
-    pub fn new(username: &str, pool_name: &str, application_name: &str, admin: bool) -> Md5 {
-        let salt: [u8; 4] = [
-            rand::random(),
-            rand::random(),
-            rand::random(),
-            rand::random(),
-        ];
-
-        Md5 {
-            username: username.to_string(),
-            pool_name: pool_name.to_string(),
-            application_name: application_name.to_string(),
-            salt,
-            admin,
-        }
-    }
-
-    /// Issue a 'R' MD5 challenge to the client.
-    pub async fn challenge<W>(&self, stream: &mut W) -> Result<(), Error>
-    where
-        W: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
-    {
-        let mut res = BytesMut::new();
-        res.put_u8(b'R');
-        res.put_i32(12);
-        res.put_i32(5); // MD5
-        res.put_slice(&self.salt[..]);
-
-        write_all(stream, res).await
-    }
-
-    /// Authenticate client with MD5. This is used for both admin and normal users.
-    pub async fn authenticate<R, W>(&self, read: &mut R, write: &mut W) -> Result<(), Error>
-    where
-        R: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send,
-        W: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
-    {
-        let password_hash = response(read).await?;
-
-        if self.admin {
-            let config = get_config();
-
-            // Compare server and client hashes.
-            let our_hash = md5_hash_password(
-                &config.general.admin_username,
-                &config.general.admin_password,
-                &self.salt,
-            );
-
-            if our_hash != password_hash {
-                wrong_password(write, &self.username).await?;
-
-                Err(Error::ClientError(format!(
-                    "Invalid password {{ username: {}, pool_name: {}, application_name: {} }}",
-                    self.username, self.pool_name, self.application_name
-                )))
-            } else {
-                Ok(())
-            }
-        } else {
-            match get_pool(&self.pool_name, &self.username, None) {
-                Some(pool) => {
-                    match &pool.settings.user.password {
-                        Some(ref password) => {
-                            let our_hash = md5_hash_password(&self.username, password, &self.salt);
-
-                            if our_hash != password_hash {
-                                wrong_password(write, &self.username).await?;
-
-                                Err(Error::ClientError(format!(
-                                    "Invalid password {{ username: {}, pool_name: {}, application_name: {} }}",
-                                    self.username, self.pool_name, self.application_name
-                                )))
-                            } else {
-                                validate_pool(write, pool, &self.username, &self.pool_name).await?;
-                                Ok(())
-                            }
-                        }
-
-                        None => {
-                            if !get_config().is_auth_query_configured() {
-                                error_response(
-                                    write,
-                                    &format!(
-                                        "No password configured and auth_query is not set: {}, user: {}",
-                                        self.pool_name, self.username
-                                    ),
-                                )
-                                .await?;
-
-                                return Err(Error::ClientError(format!(
-                                    "No password configured and auth_query is not set"
-                                )));
-                            }
-
-                            debug!("Using auth_query");
-
-                            // Fetch hash from server
-                            let hash = (*pool.auth_hash.read()).clone();
-
-                            let hash = match hash {
-                                Some(hash) => {
-                                    debug!("Using existing hash: {}", hash);
-                                    hash.clone()
-                                }
-                                None => {
-                                    debug!("Pool has no hash set, fetching new one");
-
-                                    let hash = refetch_auth_hash(
-                                        &pool,
-                                        write,
-                                        &self.username,
-                                        &self.pool_name,
-                                    )
-                                    .await?;
-
-                                    (*pool.auth_hash.write()) = Some(hash.clone());
-
-                                    hash
-                                }
-                            };
-
-                            let our_hash = md5_hash_second_pass(&hash, &self.salt);
-
-                            // Compare hashes
-                            if our_hash != password_hash {
-                                debug!("Pool auth query hash did not match, refetching");
-
-                                // Server hash maybe changed
-                                let hash = refetch_auth_hash(
-                                    &pool,
-                                    write,
-                                    &self.username,
-                                    &self.pool_name,
-                                )
-                                .await?;
-
-                                let our_hash = md5_hash_second_pass(&hash, &self.salt);
-
-                                if our_hash != password_hash {
-                                    debug!("Auth query failed, passwords don't match");
-
-                                    wrong_password(write, &self.username).await?;
-
-                                    Err(Error::ClientError(format!(
-                                        "Invalid password {{ username: {}, pool_name: {}, application_name: {} }}",
-                                        self.username, self.pool_name, self.application_name
-                                    )))
-                                } else {
-                                    (*pool.auth_hash.write()) = Some(hash);
-
-                                    validate_pool(
-                                        write,
-                                        pool.clone(),
-                                        &self.username,
-                                        &self.pool_name,
-                                    )
-                                    .await?;
-
-                                    Ok(())
-                                }
-                            } else {
-                                validate_pool(write, pool.clone(), &self.username, &self.pool_name)
-                                    .await?;
-
-                                Ok(())
-                            }
-                        }
-                    }
-                }
-
-                None => {
-                    error_response(
-                        write,
-                        &format!(
-                            "No pool configured for database: {}, user: {}",
-                            self.pool_name, self.username
-                        ),
-                    )
-                    .await?;
-
-                    return Err(Error::ClientError(format!(
-                        "Invalid pool name {{ username: {}, pool_name: {}, application_name: {} }}",
-                        self.username, self.pool_name, self.application_name
-                    )));
-                }
-            }
-        }
-    }
-}

src/auth_passthrough.rs

@@ -1,4 +1,5 @@
 use crate::errors::Error;
+use crate::pool::ConnectionPool;
 use crate::server::Server;
 use log::debug;
 
@@ -71,23 +72,32 @@ impl AuthPassthrough {
         let auth_user = crate::config::User {
             username: self.user.clone(),
             password: Some(self.password.clone()),
+            server_username: None,
+            server_password: None,
             pool_size: 1,
             statement_timeout: 0,
-            secrets: None,
+            pool_mode: None,
+            server_lifetime: None,
+            min_pool_size: None,
         };
 
         let user = &address.username;
 
-        debug!("Connecting to server to obtain auth hashes.");
+        debug!("Connecting to server to obtain auth hashes");
 
         let auth_query = self.query.replace("$1", user);
 
         match Server::exec_simple_query(address, &auth_user, &auth_query).await {
             Ok(password_data) => {
                 if password_data.len() == 2 && password_data.first().unwrap() == user {
-                    if let Some(stripped_hash) = password_data.last().unwrap().to_string().strip_prefix("md5") {
-                        Ok(stripped_hash.to_string())
-                    } else {
+                    if let Some(stripped_hash) = password_data
+                        .last()
+                        .unwrap()
+                        .to_string()
+                        .strip_prefix("md5") {
+                            Ok(stripped_hash.to_string())
+                        }
+                    else {
                         Err(Error::AuthPassthroughError(
                             "Obtained hash from auth_query does not seem to be in md5 format.".to_string(),
                         ))
@@ -99,12 +109,26 @@ impl AuthPassthrough {
                     ))
                  }
             }
-
             Err(err) => {
                 Err(Error::AuthPassthroughError(
                     format!("Error trying to obtain password from auth_query, ignoring hash for user '{}'. Error: {:?}",
-                        user, err)))
-                    }
+                        user, err))
+                )
             }
+        }
     }
 }
+
+pub async fn refetch_auth_hash(pool: &ConnectionPool) -> Result<String, Error> {
+    let address = pool.address(0, 0);
+    if let Some(apt) = AuthPassthrough::from_pool_settings(&pool.settings) {
+        let hash = apt.fetch_hash(address).await?;
+
+        return Ok(hash);
+    }
+
+    Err(Error::ClientError(format!(
+        "Could not obtain hash for {{ username: {:?}, database: {:?} }}. Auth passthrough not enabled.",
+        address.username, address.database
+    )))
+}

src/client.rs

@@ -1,8 +1,8 @@
-use crate::errors::Error;
+use crate::errors::{ClientIdentifier, Error};
 use crate::pool::BanReason;
 /// Handle clients by pretending to be a PostgreSQL server.
 use bytes::{Buf, BufMut, BytesMut};
-use log::{debug, error, info, trace};
+use log::{debug, error, info, trace, warn};
 use std::collections::HashMap;
 use std::sync::Arc;
 use std::time::Instant;
@@ -12,9 +12,11 @@ use tokio::sync::broadcast::Receiver;
 use tokio::sync::mpsc::Sender;
 
 use crate::admin::{generate_server_info_for_admin, handle_admin};
+use crate::auth_passthrough::refetch_auth_hash;
 use crate::config::{get_config, get_idle_client_in_transaction_timeout, Address, PoolMode};
 use crate::constants::*;
 use crate::messages::*;
+use crate::plugins::PluginOutput;
 use crate::pool::{get_pool, ClientServerMap, ConnectionPool};
 use crate::query_router::{Command, QueryRouter};
 use crate::server::Server;
@@ -89,9 +91,6 @@ pub struct Client<S, T> {
     /// Application name for this client (defaults to pgcat)
     application_name: String,
 
-    /// Which secret the user is using to connect, if any.
-    secret: Option<String>,
-
     /// Used to notify clients about an impending shutdown
     shutdown: Receiver<()>,
 }
@@ -204,7 +203,7 @@ pub async fn client_entrypoint(
                     // Client probably disconnected rejecting our plain text connection.
                     Ok((ClientConnectionType::Tls, _))
                     | Ok((ClientConnectionType::CancelQuery, _)) => Err(Error::ProtocolSyncError(
-                        format!("Bad postgres client (plain)"),
+                        "Bad postgres client (plain)".into(),
                     )),
 
                     Err(err) => Err(err),
@@ -292,7 +291,7 @@ pub async fn client_entrypoint(
 /// Handle the first message the client sends.
 async fn get_startup<S>(stream: &mut S) -> Result<(ClientConnectionType, BytesMut), Error>
 where
-    S: tokio::io::AsyncRead + std::marker::Unpin + tokio::io::AsyncWrite + std::marker::Send,
+    S: tokio::io::AsyncRead + std::marker::Unpin + tokio::io::AsyncWrite,
 {
     // Get startup message length.
     let len = match stream.read_i32().await {
@@ -371,9 +370,9 @@ pub async fn startup_tls(
         }
 
         // Bad Postgres client.
-        Ok((ClientConnectionType::Tls, _)) | Ok((ClientConnectionType::CancelQuery, _)) => Err(
-            Error::ProtocolSyncError(format!("Bad postgres client (tls)")),
-        ),
+        Ok((ClientConnectionType::Tls, _)) | Ok((ClientConnectionType::CancelQuery, _)) => {
+            Err(Error::ProtocolSyncError("Bad postgres client (tls)".into()))
+        }
 
         Err(err) => Err(err),
     }
@@ -381,8 +380,8 @@ pub async fn startup_tls(
 
 impl<S, T> Client<S, T>
 where
-    S: tokio::io::AsyncRead + std::marker::Unpin + std::marker::Send,
-    T: tokio::io::AsyncWrite + std::marker::Unpin + std::marker::Send,
+    S: tokio::io::AsyncRead + std::marker::Unpin,
+    T: tokio::io::AsyncWrite + std::marker::Unpin,
 {
     pub fn is_admin(&self) -> bool {
         self.admin
@@ -406,7 +405,7 @@ where
             Some(user) => user,
             None => {
                 return Err(Error::ClientError(
-                    "Missing user parameter on client startup".to_string(),
+                    "Missing user parameter on client startup".into(),
                 ))
             }
         };
@@ -421,6 +420,8 @@ where
             None => "pgcat",
         };
 
+        let client_identifier = ClientIdentifier::new(&application_name, &username, &pool_name);
+
         let admin = ["pgcat", "pgbouncer"]
             .iter()
             .filter(|db| *db == pool_name)
@@ -445,39 +446,207 @@ where
         let process_id: i32 = rand::random();
         let secret_key: i32 = rand::random();
 
-        let config = get_config();
+        // Perform MD5 authentication.
+        // TODO: Add SASL support.
+        let salt = md5_challenge(&mut write).await?;
 
-        let secret = if admin {
-            debug!("Using md5 auth for admin");
-            let auth = crate::auth::Md5::new(&username, &pool_name, &application_name, true);
-            auth.challenge(&mut write).await?;
-            auth.authenticate(&mut read, &mut write).await?;
-            None
-        } else if !config.tls_enabled() {
-            debug!("Using md5 auth");
-            let auth = crate::auth::Md5::new(&username, &pool_name, &application_name, false);
-            auth.challenge(&mut write).await?;
-            auth.authenticate(&mut read, &mut write).await?;
-            None
-        } else {
-            debug!("Using plain auth");
-            let auth = crate::auth::ClearText::new(&username, &pool_name, &application_name);
-            auth.challenge(&mut write).await?;
-            auth.authenticate(&mut read, &mut write).await?
+        let code = match read.read_u8().await {
+            Ok(p) => p,
+            Err(_) => {
+                return Err(Error::ClientSocketError(
+                    "password code".into(),
+                    client_identifier,
+                ))
+            }
         };
 
-        // Authenticated admin user.
+        // PasswordMessage
+        if code as char != 'p' {
+            return Err(Error::ProtocolSyncError(format!(
+                "Expected p, got {}",
+                code as char
+            )));
+        }
+
+        let len = match read.read_i32().await {
+            Ok(len) => len,
+            Err(_) => {
+                return Err(Error::ClientSocketError(
+                    "password message length".into(),
+                    client_identifier,
+                ))
+            }
+        };
+
+        let mut password_response = vec![0u8; (len - 4) as usize];
+
+        match read.read_exact(&mut password_response).await {
+            Ok(_) => (),
+            Err(_) => {
+                return Err(Error::ClientSocketError(
+                    "password message".into(),
+                    client_identifier,
+                ))
+            }
+        };
+
+        // Authenticate admin user.
         let (transaction_mode, server_info) = if admin {
+            let config = get_config();
+
+            // Compare server and client hashes.
+            let password_hash = md5_hash_password(
+                &config.general.admin_username,
+                &config.general.admin_password,
+                &salt,
+            );
+
+            if password_hash != password_response {
+                let error = Error::ClientGeneralError("Invalid password".into(), client_identifier);
+
+                warn!("{}", error);
+                wrong_password(&mut write, username).await?;
+
+                return Err(error);
+            }
+
             (false, generate_server_info_for_admin())
         }
-        // Authenticated normal user.
+        // Authenticate normal user.
         else {
-            let pool = get_pool(&pool_name, &username, secret.clone()).unwrap();
+            let mut pool = match get_pool(pool_name, username) {
+                Some(pool) => pool,
+                None => {
+                    error_response(
+                        &mut write,
+                        &format!(
+                            "No pool configured for database: {:?}, user: {:?}",
+                            pool_name, username
+                        ),
+                    )
+                    .await?;
+
+                    return Err(Error::ClientGeneralError(
+                        "Invalid pool name".into(),
+                        client_identifier,
+                    ));
+                }
+            };
+
+            // Obtain the hash to compare, we give preference to that written in cleartext in config
+            // if there is nothing set in cleartext and auth passthrough (auth_query) is configured, we use the hash obtained
+            // when the pool was created. If there is no hash there, we try to fetch it one more time.
+            let password_hash = if let Some(password) = &pool.settings.user.password {
+                Some(md5_hash_password(username, password, &salt))
+            } else {
+                if !get_config().is_auth_query_configured() {
+                    wrong_password(&mut write, username).await?;
+                    return Err(Error::ClientAuthImpossible(username.into()));
+                }
+
+                let mut hash = (*pool.auth_hash.read()).clone();
+
+                if hash.is_none() {
+                    warn!(
+                        "Query auth configured \
+                          but no hash password found \
+                          for pool {}. Will try to refetch it.",
+                        pool_name
+                    );
+
+                    match refetch_auth_hash(&pool).await {
+                        Ok(fetched_hash) => {
+                            warn!("Password for {}, obtained. Updating.", client_identifier);
+
+                            {
+                                let mut pool_auth_hash = pool.auth_hash.write();
+                                *pool_auth_hash = Some(fetched_hash.clone());
+                            }
+
+                            hash = Some(fetched_hash);
+                        }
+
+                        Err(err) => {
+                            wrong_password(&mut write, username).await?;
+
+                            return Err(Error::ClientAuthPassthroughError(
+                                err.to_string(),
+                                client_identifier,
+                            ));
+                        }
+                    }
+                };
+
+                Some(md5_hash_second_pass(&hash.unwrap(), &salt))
+            };
+
+            // Once we have the resulting hash, we compare with what the client gave us.
+            // If they do not match and auth query is set up, we try to refetch the hash one more time
+            // to see if the password has changed since the pool was created.
+            //
+            // @TODO: we could end up fetching again the same password twice (see above).
+            if password_hash.unwrap() != password_response {
+                warn!(
+                    "Invalid password {}, will try to refetch it.",
+                    client_identifier
+                );
+
+                let fetched_hash = match refetch_auth_hash(&pool).await {
+                    Ok(fetched_hash) => fetched_hash,
+                    Err(err) => {
+                        wrong_password(&mut write, username).await?;
+
+                        return Err(err);
+                    }
+                };
+
+                let new_password_hash = md5_hash_second_pass(&fetched_hash, &salt);
+
+                // Ok password changed in server an auth is possible.
+                if new_password_hash == password_response {
+                    warn!(
+                        "Password for {}, changed in server. Updating.",
+                        client_identifier
+                    );
+
+                    {
+                        let mut pool_auth_hash = pool.auth_hash.write();
+                        *pool_auth_hash = Some(fetched_hash);
+                    }
+                } else {
+                    wrong_password(&mut write, username).await?;
+                    return Err(Error::ClientGeneralError(
+                        "Invalid password".into(),
+                        client_identifier,
+                    ));
+                }
+            }
+
             let transaction_mode = pool.settings.pool_mode == PoolMode::Transaction;
+
+            // If the pool hasn't been validated yet,
+            // connect to the servers and figure out what's what.
+            if !pool.validated() {
+                match pool.validate().await {
+                    Ok(_) => (),
+                    Err(err) => {
+                        error_response(
+                            &mut write,
+                            &format!(
+                                "Pool down for database: {:?}, user: {:?}",
+                                pool_name, username
+                            ),
+                        )
+                        .await?;
+                        return Err(Error::ClientError(format!("Pool down: {:?}", err)));
+                    }
+                }
+            }
+
             (transaction_mode, pool.server_info())
         };
 
-        debug!("Authentication successful");
+        debug!("Password authentication successful");
 
         auth_ok(&mut write).await?;
         write_all(&mut write, server_info).await?;
@@ -485,7 +654,7 @@ where
         ready_for_query(&mut write).await?;
 
         trace!("Startup OK");
-        let pool_stats = match get_pool(pool_name, username, secret.clone()) {
+        let pool_stats = match get_pool(pool_name, username) {
             Some(pool) => {
                 if !admin {
                     pool.stats
@@ -525,7 +694,6 @@ where
             application_name: application_name.to_string(),
             shutdown,
             connected_to_server: false,
-            secret,
         })
     }
 
@@ -560,7 +728,6 @@ where
             application_name: String::from("undefined"),
             shutdown,
             connected_to_server: false,
-            secret: None,
         })
     }
 
@@ -599,6 +766,9 @@ where
 
         self.stats.register(self.stats.clone());
 
+        // Result returned by one of the plugins.
+        let mut plugin_output = None;
+
         // Our custom protocol loop.
         // We expect the client to either start a transaction with regular queries
         // or issue commands for our sharding and server selection protocol.
@@ -621,9 +791,9 @@ where
                             &mut self.write,
                             "terminating connection due to administrator command"
                         ).await?;
-            self.stats.disconnect();
 
-                        return Ok(())
+                        self.stats.disconnect();
+                        return Ok(());
                     }
 
                     // Admin clients ignore shutdown.
@@ -649,7 +819,25 @@ where
 
                 'Q' => {
                     if query_router.query_parser_enabled() {
-                        query_router.infer(&message);
+                        if let Ok(ast) = QueryRouter::parse(&message) {
+                            let plugin_result = query_router.execute_plugins(&ast).await;
+
+                            match plugin_result {
+                                Ok(PluginOutput::Deny(error)) => {
+                                    error_response(&mut self.write, &error).await?;
+                                    continue;
+                                }
+
+                                Ok(PluginOutput::Intercept(result)) => {
+                                    write_all(&mut self.write, result).await?;
+                                    continue;
+                                }
+
+                                _ => (),
+                            };
+
+                            let _ = query_router.infer(&ast);
+                        }
                     }
                 }
 
@@ -657,7 +845,13 @@ where
                     self.buffer.put(&message[..]);
 
                     if query_router.query_parser_enabled() {
-                        query_router.infer(&message);
+                        if let Ok(ast) = QueryRouter::parse(&message) {
+                            if let Ok(output) = query_router.execute_plugins(&ast).await {
+                                plugin_output = Some(output);
+                            }
+
+                            let _ = query_router.infer(&ast);
+                        }
                     }
 
                     continue;
@@ -691,6 +885,18 @@ where
                 continue;
             }
 
+            // Check on plugin results.
+            match plugin_output {
+                Some(PluginOutput::Deny(error)) => {
+                    self.buffer.clear();
+                    error_response(&mut self.write, &error).await?;
+                    plugin_output = None;
+                    continue;
+                }
+
+                _ => (),
+            };
+
             // Get a pool instance referenced by the most up-to-date
             // pointer. This ensures we always read the latest config
             // when starting a query.
@@ -796,11 +1002,26 @@ where
                         error!("Got Sync message but failed to get a connection from the pool");
                         self.buffer.clear();
                     }
+
                     error_response(&mut self.write, "could not get connection from the pool")
                         .await?;
 
-                    error!("Could not get connection from pool: {{ pool_name: {:?}, username: {:?}, shard: {:?}, role: \"{:?}\", error: \"{:?}\" }}",
-			   self.pool_name.clone(), self.username.clone(), query_router.shard(), query_router.role(), err);
+                    error!(
+                        "Could not get connection from pool: \
+                        {{ \
+                            pool_name: {:?}, \
+                            username: {:?}, \
+                            shard: {:?}, \
+                            role: \"{:?}\", \
+                            error: \"{:?}\" \
+                        }}",
+                        self.pool_name,
+                        self.username,
+                        query_router.shard(),
+                        query_router.role(),
+                        err
+                    );
+
                     continue;
                 }
             };
@@ -867,11 +1088,25 @@ where
                             Err(_) => {
                                 // Client idle in transaction timeout
                                 error_response(&mut self.write, "idle transaction timeout").await?;
-                                error!("Client idle in transaction timeout: {{ pool_name: {:?}, username: {:?}, shard: {:?}, role: \"{:?}\"}}", self.pool_name.clone(), self.username.clone(), query_router.shard(), query_router.role());
+                                error!(
+                                    "Client idle in transaction timeout: \
+                                    {{ \
+                                        pool_name: {}, \
+                                        username: {}, \
+                                        shard: {}, \
+                                        role: \"{:?}\" \
+                                    }}",
+                                    self.pool_name,
+                                    self.username,
+                                    query_router.shard(),
+                                    query_router.role()
+                                );
+
                                 break;
                             }
                         }
                     }
+
                     Some(message) => {
                         initial_message = None;
                         message
@@ -890,6 +1125,27 @@ where
                 match code {
                     // Query
                     'Q' => {
+                        if query_router.query_parser_enabled() {
+                            if let Ok(ast) = QueryRouter::parse(&message) {
+                                let plugin_result = query_router.execute_plugins(&ast).await;
+
+                                match plugin_result {
+                                    Ok(PluginOutput::Deny(error)) => {
+                                        error_response(&mut self.write, &error).await?;
+                                        continue;
+                                    }
+
+                                    Ok(PluginOutput::Intercept(result)) => {
+                                        write_all(&mut self.write, result).await?;
+                                        continue;
+                                    }
+
+                                    _ => (),
+                                };
+
+                                let _ = query_router.infer(&ast);
+                            }
+                        }
                         debug!("Sending query to server");
 
                         self.send_and_receive_loop(
@@ -929,6 +1185,14 @@ where
                     // Parse
                     // The query with placeholders is here, e.g. `SELECT * FROM users WHERE email = $1 AND active = $2`.
                     'P' => {
+                        if query_router.query_parser_enabled() {
+                            if let Ok(ast) = QueryRouter::parse(&message) {
+                                if let Ok(output) = query_router.execute_plugins(&ast).await {
+                                    plugin_output = Some(output);
+                                }
+                            }
+                        }
+
                         self.buffer.put(&message[..]);
                     }
 
@@ -944,6 +1208,11 @@ where
                         self.buffer.put(&message[..]);
                     }
 
+                    // Close the prepared statement.
+                    'C' => {
+                        self.buffer.put(&message[..]);
+                    }
+
                     // Execute
                     // Execute a prepared statement prepared in `P` and bound in `B`.
                     'E' => {
@@ -955,6 +1224,24 @@ where
                     'S' => {
                         debug!("Sending query to server");
 
+                        match plugin_output {
+                            Some(PluginOutput::Deny(error)) => {
+                                error_response(&mut self.write, &error).await?;
+                                plugin_output = None;
+                                self.buffer.clear();
+                                continue;
+                            }
+
+                            Some(PluginOutput::Intercept(result)) => {
+                                write_all(&mut self.write, result).await?;
+                                plugin_output = None;
+                                self.buffer.clear();
+                                continue;
+                            }
+
+                            _ => (),
+                        };
+
                         self.buffer.put(&message[..]);
 
                         let first_message_code = (*self.buffer.get(0).unwrap_or(&0)) as char;
@@ -1068,7 +1355,7 @@ where
     /// Retrieve connection pool, if it exists.
     /// Return an error to the client otherwise.
     async fn get_pool(&mut self) -> Result<ConnectionPool, Error> {
-        match get_pool(&self.pool_name, &self.username, self.secret.clone()) {
+        match get_pool(&self.pool_name, &self.username) {
             Some(pool) => Ok(pool),
             None => {
                 error_response(

src/config.rs

@@ -1,6 +1,6 @@
 /// Parse the configuration file.
 use arc_swap::ArcSwap;
-use log::{error, info, warn};
+use log::{error, info};
 use once_cell::sync::Lazy;
 use regex::Regex;
 use serde_derive::{Deserialize, Serialize};
@@ -12,6 +12,7 @@ use std::sync::Arc;
 use tokio::fs::File;
 use tokio::io::AsyncReadExt;
 
+use crate::dns_cache::CachedResolver;
 use crate::errors::Error;
 use crate::pool::{ClientServerMap, ConnectionPool};
 use crate::sharding::ShardingFunction;
@@ -121,6 +122,16 @@ impl Default for Address {
     }
 }
 
+impl std::fmt::Display for Address {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            f,
+            "[address: {}:{}][database: {}][user: {}]",
+            self.host, self.port, self.database, self.username
+        )
+    }
+}
+
 // We need to implement PartialEq by ourselves so we skip stats in the comparison
 impl PartialEq for Address {
     fn eq(&self, other: &Self) -> bool {
@@ -178,29 +189,14 @@ impl Address {
 pub struct User {
     pub username: String,
     pub password: Option<String>,
+    pub server_username: Option<String>,
+    pub server_password: Option<String>,
     pub pool_size: u32,
+    pub min_pool_size: Option<u32>,
+    pub pool_mode: Option<PoolMode>,
+    pub server_lifetime: Option<u64>,
     #[serde(default)] // 0
     pub statement_timeout: u64,
-    pub secrets: Option<Vec<String>>,
-}
-
-impl User {
-    fn validate(&self) -> Result<(), Error> {
-        match self.secrets {
-            Some(ref secrets) => {
-                for secret in secrets.iter() {
-                    if secret.len() < 16 {
-                        warn!(
-                            "[user: {}] Secret is too short (less than 16 characters)",
-                            self.username
-                        );
-                    }
-                }
-            }
-            None => (),
-        }
-        Ok(())
-    }
 }
 
 impl Default for User {
@@ -208,13 +204,37 @@ impl Default for User {
         User {
             username: String::from("postgres"),
             password: None,
+            server_username: None,
+            server_password: None,
             pool_size: 15,
+            min_pool_size: None,
             statement_timeout: 0,
-            secrets: None,
+            pool_mode: None,
+            server_lifetime: None,
         }
     }
 }
 
+impl User {
+    fn validate(&self) -> Result<(), Error> {
+        match self.min_pool_size {
+            Some(min_pool_size) => {
+                if min_pool_size > self.pool_size {
+                    error!(
+                        "min_pool_size of {} cannot be larger than pool_size of {}",
+                        min_pool_size, self.pool_size
+                    );
+                    return Err(Error::BadConfig);
+                }
+            }
+
+            None => (),
+        };
+
+        Ok(())
+    }
+}
+
 /// General configuration.
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
 pub struct General {
@@ -222,9 +242,11 @@ pub struct General {
     pub host: String,
 
     #[serde(default = "General::default_port")]
-    pub port: i16,
+    pub port: u16,
 
     pub enable_prometheus_exporter: Option<bool>,
+
+    #[serde(default = "General::default_prometheus_exporter_port")]
     pub prometheus_exporter_port: i16,
 
     #[serde(default = "General::default_connect_timeout")]
@@ -246,6 +268,12 @@ pub struct General {
     #[serde(default)] // False
     pub log_client_disconnections: bool,
 
+    #[serde(default)] // False
+    pub dns_cache_enabled: bool,
+
+    #[serde(default = "General::default_dns_max_ttl")]
+    pub dns_max_ttl: u64,
+
     #[serde(default = "General::default_shutdown_timeout")]
     pub shutdown_timeout: u64,
 
@@ -261,17 +289,31 @@ pub struct General {
     #[serde(default = "General::default_idle_client_in_transaction_timeout")]
     pub idle_client_in_transaction_timeout: u64,
 
+    #[serde(default = "General::default_server_lifetime")]
+    pub server_lifetime: u64,
+
     #[serde(default = "General::default_worker_threads")]
     pub worker_threads: usize,
 
-    #[serde(default)] // False
-    pub autoreload: bool,
+    #[serde(default)] // None
+    pub autoreload: Option<u64>,
 
     pub tls_certificate: Option<String>,
     pub tls_private_key: Option<String>,
+
+    #[serde(default)] // false
+    pub server_tls: bool,
+
+    #[serde(default)] // false
+    pub verify_server_certificate: bool,
+
     pub admin_username: String,
     pub admin_password: String,
 
+    #[serde(default = "General::default_validate_config")]
+    pub validate_config: bool,
+
+    // Support for auth query
     pub auth_query: Option<String>,
     pub auth_query_user: Option<String>,
     pub auth_query_password: Option<String>,
@@ -282,17 +324,21 @@ impl General {
         "0.0.0.0".into()
     }
 
-    pub fn default_port() -> i16 {
+    pub fn default_port() -> u16 {
         5432
     }
 
+    pub fn default_server_lifetime() -> u64 {
+        1000 * 60 * 60 * 24 // 24 hours
+    }
+
     pub fn default_connect_timeout() -> u64 {
         1000
     }
 
     // These keepalive defaults should detect a dead connection within 30 seconds.
     // Tokio defaults to disabling keepalives which keeps dead connections around indefinitely.
-    // This can lead to permenant server pool exhaustion
+    // This can lead to permanent server pool exhaustion
     pub fn default_tcp_keepalives_idle() -> u64 {
         5 // 5 seconds
     }
@@ -313,6 +359,10 @@ impl General {
         60000
     }
 
+    pub fn default_dns_max_ttl() -> u64 {
+        30
+    }
+
     pub fn default_healthcheck_timeout() -> u64 {
         1000
     }
@@ -332,6 +382,14 @@ impl General {
     pub fn default_idle_client_in_transaction_timeout() -> u64 {
         0
     }
+
+    pub fn default_validate_config() -> bool {
+        true
+    }
+
+    pub fn default_prometheus_exporter_port() -> i16 {
+        9930
+    }
 }
 
 impl Default for General {
@@ -354,14 +412,20 @@ impl Default for General {
             tcp_keepalives_interval: Self::default_tcp_keepalives_interval(),
             log_client_connections: false,
             log_client_disconnections: false,
-            autoreload: false,
+            autoreload: None,
+            dns_cache_enabled: false,
+            dns_max_ttl: Self::default_dns_max_ttl(),
             tls_certificate: None,
             tls_private_key: None,
+            server_tls: false,
+            verify_server_certificate: false,
             admin_username: String::from("admin"),
             admin_password: String::from("admin"),
             auth_query: None,
             auth_query_user: None,
             auth_query_password: None,
+            server_lifetime: 1000 * 3600 * 24, // 24 hours,
+            validate_config: true,
         }
     }
 }
@@ -377,6 +441,7 @@ pub enum PoolMode {
     #[serde(alias = "session", alias = "Session")]
     Session,
 }
+
 impl ToString for PoolMode {
     fn to_string(&self) -> String {
         match *self {
@@ -413,6 +478,7 @@ pub struct Pool {
     #[serde(default = "Pool::default_load_balancing_mode")]
     pub load_balancing_mode: LoadBalancingMode,
 
+    #[serde(default = "Pool::default_default_role")]
     pub default_role: String,
 
     #[serde(default)] // False
@@ -425,6 +491,9 @@ pub struct Pool {
 
     pub idle_timeout: Option<u64>,
 
+    pub server_lifetime: Option<u64>,
+
+    #[serde(default = "Pool::default_sharding_function")]
     pub sharding_function: ShardingFunction,
 
     #[serde(default = "Pool::default_automatic_sharding_key")]
@@ -438,9 +507,10 @@ pub struct Pool {
     pub auth_query_user: Option<String>,
     pub auth_query_password: Option<String>,
 
+    pub plugins: Option<Plugins>,
     pub shards: BTreeMap<String, Shard>,
     pub users: BTreeMap<String, User>,
-    // Note, don't put simple fields below these configs. There's a compatability issue with TOML that makes it
+    // Note, don't put simple fields below these configs. There's a compatibility issue with TOML that makes it
     // incompatible to have simple fields in TOML after complex objects. See
     // https://users.rust-lang.org/t/why-toml-to-string-get-error-valueaftertable/85903
 }
@@ -470,6 +540,14 @@ impl Pool {
         None
     }
 
+    pub fn default_default_role() -> String {
+        "any".into()
+    }
+
+    pub fn default_sharding_function() -> ShardingFunction {
+        ShardingFunction::PgBigintHash
+    }
+
     pub fn validate(&mut self) -> Result<(), Error> {
         match self.default_role.as_ref() {
             "any" => (),
@@ -529,8 +607,8 @@ impl Pool {
             None => None,
         };
 
-        for user in self.users.iter() {
-            user.1.validate()?;
+        for (_, user) in &self.users {
+            user.validate()?;
         }
 
         Ok(())
@@ -557,6 +635,8 @@ impl Default for Pool {
             auth_query: None,
             auth_query_user: None,
             auth_query_password: None,
+            server_lifetime: None,
+            plugins: None,
         }
     }
 }
@@ -606,7 +686,7 @@ impl Shard {
 
         if primary_count > 1 {
             error!(
-                "Shard {} has more than on primary configured",
+                "Shard {} has more than one primary configured",
                 self.database
             );
             return Err(Error::BadConfig);
@@ -635,6 +715,76 @@ impl Default for Shard {
     }
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, Hash, Eq)]
+pub struct Plugins {
+    pub intercept: Option<Intercept>,
+    pub table_access: Option<TableAccess>,
+    pub query_logger: Option<QueryLogger>,
+    pub prewarmer: Option<Prewarmer>,
+}
+
+impl std::fmt::Display for Plugins {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            f,
+            "interceptor: {}, table_access: {}, query_logger: {}, prewarmer: {}",
+            self.intercept.is_some(),
+            self.table_access.is_some(),
+            self.query_logger.is_some(),
+            self.prewarmer.is_some(),
+        )
+    }
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, Hash, Eq)]
+pub struct Intercept {
+    pub enabled: bool,
+    pub queries: BTreeMap<String, Query>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, Hash, Eq)]
+pub struct TableAccess {
+    pub enabled: bool,
+    pub tables: Vec<String>,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, Hash, Eq)]
+pub struct QueryLogger {
+    pub enabled: bool,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, Hash, Eq)]
+pub struct Prewarmer {
+    pub enabled: bool,
+    pub queries: Vec<String>,
+}
+
+impl Intercept {
+    pub fn substitute(&mut self, db: &str, user: &str) {
+        for (_, query) in self.queries.iter_mut() {
+            query.substitute(db, user);
+            query.query = query.query.to_ascii_lowercase();
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default, Hash, Eq)]
+pub struct Query {
+    pub query: String,
+    pub schema: Vec<Vec<String>>,
+    pub result: Vec<Vec<String>>,
+}
+
+impl Query {
+    pub fn substitute(&mut self, db: &str, user: &str) {
+        for col in self.result.iter_mut() {
+            for i in 0..col.len() {
+                col[i] = col[i].replace("${USER}", user).replace("${DATABASE}", db);
+            }
+        }
+    }
+}
+
 /// Configuration wrapper.
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
 pub struct Config {
@@ -652,7 +802,13 @@ pub struct Config {
     #[serde(default = "Config::default_path")]
     pub path: String,
 
+    // General and global settings.
     pub general: General,
+
+    // Plugins that should run in all pools.
+    pub plugins: Option<Plugins>,
+
+    // Connection pools.
     pub pools: HashMap<String, Pool>,
 }
 
@@ -682,11 +838,6 @@ impl Config {
             }
         }
     }
-
-    /// Checks that we configured TLS.
-    pub fn tls_enabled(&self) -> bool {
-        self.general.tls_certificate.is_some() && self.general.tls_private_key.is_some()
-    }
 }
 
 impl Default for Config {
@@ -695,6 +846,7 @@ impl Default for Config {
             path: Self::default_path(),
             general: General::default(),
             pools: HashMap::default(),
+            plugins: None,
         }
     }
 }
@@ -814,6 +966,10 @@ impl Config {
         );
         info!("Shutdown timeout: {}ms", self.general.shutdown_timeout);
         info!("Healthcheck delay: {}ms", self.general.healthcheck_delay);
+        info!(
+            "Default max server lifetime: {}ms",
+            self.general.server_lifetime
+        );
         match self.general.tls_certificate.clone() {
             Some(tls_certificate) => {
                 info!("TLS certificate: {}", tls_certificate);
@@ -832,6 +988,18 @@ impl Config {
                 info!("TLS support is disabled");
             }
         };
+        info!("Server TLS enabled: {}", self.general.server_tls);
+        info!(
+            "Server TLS certificate verification: {}",
+            self.general.verify_server_certificate
+        );
+        info!(
+            "Plugins: {}",
+            match self.plugins {
+                Some(ref plugins) => plugins.to_string(),
+                None => "not configured".into(),
+            }
+        );
 
         for (pool_name, pool_config) in &self.pools {
             // TODO: Make this output prettier (maybe a table?)
@@ -846,8 +1014,9 @@ impl Config {
                     .to_string()
             );
             info!(
-                "[pool: {}] Pool mode: {:?}",
-                pool_name, pool_config.pool_mode
+                "[pool: {}] Default pool mode: {}",
+                pool_name,
+                pool_config.pool_mode.to_string()
             );
             info!(
                 "[pool: {}] Load Balancing mode: {:?}",
@@ -889,16 +1058,56 @@ impl Config {
                 pool_name,
                 pool_config.users.len()
             );
+            info!(
+                "[pool: {}] Max server lifetime: {}",
+                pool_name,
+                match pool_config.server_lifetime {
+                    Some(server_lifetime) => format!("{}ms", server_lifetime),
+                    None => "default".to_string(),
+                }
+            );
+            info!(
+                "[pool: {}] Plugins: {}",
+                pool_name,
+                match pool_config.plugins {
+                    Some(ref plugins) => plugins.to_string(),
+                    None => "not configured".into(),
+                }
+            );
 
             for user in &pool_config.users {
                 info!(
                     "[pool: {}][user: {}] Pool size: {}",
                     pool_name, user.1.username, user.1.pool_size,
                 );
+                info!(
+                    "[pool: {}][user: {}] Minimum pool size: {}",
+                    pool_name,
+                    user.1.username,
+                    user.1.min_pool_size.unwrap_or(0)
+                );
                 info!(
                     "[pool: {}][user: {}] Statement timeout: {}",
                     pool_name, user.1.username, user.1.statement_timeout
-                )
+                );
+                info!(
+                    "[pool: {}][user: {}] Pool mode: {}",
+                    pool_name,
+                    user.1.username,
+                    match user.1.pool_mode {
+                        Some(pool_mode) => pool_mode.to_string(),
+                        None => pool_config.pool_mode.to_string(),
+                    }
+                );
+                info!(
+                    "[pool: {}][user: {}] Max server lifetime: {}",
+                    pool_name,
+                    user.1.username,
+                    match user.1.server_lifetime {
+                        Some(server_lifetime) => format!("{}ms", server_lifetime),
+                        None => "default".to_string(),
+                    }
+                );
             }
         }
     }
@@ -909,7 +1118,13 @@ impl Config {
             && (self.general.auth_query_user.is_none()
                 || self.general.auth_query_password.is_none())
         {
-            error!("If auth_query is specified, you need to provide a value for `auth_query_user`, `auth_query_password`");
+            error!(
+                "If auth_query is specified, \
+                you need to provide a value \
+                for `auth_query_user`, \
+                `auth_query_password`"
+            );
+
             return Err(Error::BadConfig);
         }
 
@@ -917,7 +1132,14 @@ impl Config {
             if pool.auth_query.is_some()
                 && (pool.auth_query_user.is_none() || pool.auth_query_password.is_none())
             {
-                error!("Error in pool {{ {} }}. If auth_query is specified, you need to provide a value for `auth_query_user`, `auth_query_password`", name);
+                error!(
+                    "Error in pool {{ {} }}. \
+                    If auth_query is specified, you need \
+                    to provide a value for `auth_query_user`, \
+                    `auth_query_password`",
+                    name
+                );
+
                 return Err(Error::BadConfig);
             }
 
@@ -927,7 +1149,13 @@ impl Config {
                     || pool.auth_query_user.is_none())
                     && user_data.password.is_none()
                 {
-                    error!("Error in pool {{ {} }}. You have to specify a user password for every pool if auth_query is not specified", name);
+                    error!(
+                        "Error in pool {{ {} }}. \
+                        You have to specify a user password \
+                        for every pool if auth_query is not specified",
+                        name
+                    );
+
                     return Err(Error::BadConfig);
                 }
             }
@@ -1025,6 +1253,7 @@ pub async fn parse(path: &str) -> Result<(), Error> {
 
 pub async fn reload_config(client_server_map: ClientServerMap) -> Result<bool, Error> {
     let old_config = get_config();
+
     match parse(&old_config.path).await {
         Ok(()) => (),
         Err(err) => {
@@ -1032,14 +1261,18 @@ pub async fn reload_config(client_server_map: ClientServerMap) -> Result<bool, E
             return Err(Error::BadConfig);
         }
     };
+
     let new_config = get_config();
 
-    if old_config.pools != new_config.pools {
-        info!("Pool configuration changed");
+    match CachedResolver::from_config().await {
+        Ok(_) => (),
+        Err(err) => error!("DNS cache reinitialization error: {:?}", err),
+    };
+
+    if old_config != new_config {
+        info!("Config changed, reloading");
         ConnectionPool::from_config(client_server_map).await?;
         Ok(true)
-    } else if old_config != new_config {
-        Ok(true)
     } else {
         Ok(false)
     }

src/dns_cache.rs

@@ -0,0 +1,410 @@
+use crate::config::get_config;
+use crate::errors::Error;
+use arc_swap::ArcSwap;
+use log::{debug, error, info, warn};
+use once_cell::sync::Lazy;
+use std::collections::{HashMap, HashSet};
+use std::io;
+use std::net::IpAddr;
+use std::sync::Arc;
+use std::sync::RwLock;
+use tokio::time::{sleep, Duration};
+use trust_dns_resolver::error::{ResolveError, ResolveResult};
+use trust_dns_resolver::lookup_ip::LookupIp;
+use trust_dns_resolver::TokioAsyncResolver;
+
+/// Cached Resolver Globally available
+pub static CACHED_RESOLVER: Lazy<ArcSwap<CachedResolver>> =
+    Lazy::new(|| ArcSwap::from_pointee(CachedResolver::default()));
+
+// Ip addressed are returned as a set of addresses
+// so we can compare.
+#[derive(Clone, PartialEq, Debug)]
+pub struct AddrSet {
+    set: HashSet<IpAddr>,
+}
+
+impl AddrSet {
+    fn new() -> AddrSet {
+        AddrSet {
+            set: HashSet::new(),
+        }
+    }
+}
+
+impl From<LookupIp> for AddrSet {
+    fn from(lookup_ip: LookupIp) -> Self {
+        let mut addr_set = AddrSet::new();
+        for address in lookup_ip.iter() {
+            addr_set.set.insert(address);
+        }
+        addr_set
+    }
+}
+
+///
+/// A CachedResolver is a DNS resolution cache mechanism with customizable expiration time.
+///
+/// The system works as follows:
+///
+/// When a host is to be resolved, if we have not resolved it before, a new resolution is
+/// executed and stored in the internal cache. Concurrently, every `dns_max_ttl` time, the
+/// cache is refreshed.
+///
+/// # Example:
+///
+/// ```
+/// use pgcat::dns_cache::{CachedResolverConfig, CachedResolver};
+///
+/// # tokio_test::block_on(async {
+/// let config = CachedResolverConfig::default();
+/// let resolver = CachedResolver::new(config, None).await.unwrap();
+/// let addrset = resolver.lookup_ip("www.example.com.").await.unwrap();
+/// # })
+/// ```
+///
+/// // Now the ip resolution is stored in local cache and subsequent
+/// // calls will be returned from cache. Also, the cache is refreshed
+/// // and updated every 10 seconds.
+///
+/// // You can now check if an 'old' lookup differs from what it's currently
+/// // store in cache by using `has_changed`.
+/// resolver.has_changed("www.example.com.", addrset)
+#[derive(Default)]
+pub struct CachedResolver {
+    // The configuration of the cached_resolver.
+    config: CachedResolverConfig,
+
+    // This is the hash that contains the hash.
+    data: Option<RwLock<HashMap<String, AddrSet>>>,
+
+    // The resolver to be used for DNS queries.
+    resolver: Option<TokioAsyncResolver>,
+
+    // The RefreshLoop
+    refresh_loop: RwLock<Option<tokio::task::JoinHandle<()>>>,
+}
+
+///
+/// Configuration
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct CachedResolverConfig {
+    /// Amount of time in secods that a resolved dns address is considered stale.
+    dns_max_ttl: u64,
+
+    /// Enabled or disabled? (this is so we can reload config)
+    enabled: bool,
+}
+
+impl CachedResolverConfig {
+    fn new(dns_max_ttl: u64, enabled: bool) -> Self {
+        CachedResolverConfig {
+            dns_max_ttl,
+            enabled,
+        }
+    }
+}
+
+impl From<crate::config::Config> for CachedResolverConfig {
+    fn from(config: crate::config::Config) -> Self {
+        CachedResolverConfig::new(config.general.dns_max_ttl, config.general.dns_cache_enabled)
+    }
+}
+
+impl CachedResolver {
+    ///
+    /// Returns a new Arc<CachedResolver> based on passed configuration.
+    /// It also starts the loop that will refresh cache entries.
+    ///
+    /// # Arguments:
+    ///
+    /// * `config` - The `CachedResolverConfig` to be used to create the resolver.
+    ///
+    /// # Example:
+    ///
+    /// ```
+    /// use pgcat::dns_cache::{CachedResolverConfig, CachedResolver};
+    ///
+    /// # tokio_test::block_on(async {
+    /// let config = CachedResolverConfig::default();
+    /// let resolver = CachedResolver::new(config, None).await.unwrap();
+    /// # })
+    /// ```
+    ///
+    pub async fn new(
+        config: CachedResolverConfig,
+        data: Option<HashMap<String, AddrSet>>,
+    ) -> Result<Arc<Self>, io::Error> {
+        // Construct a new Resolver with default configuration options
+        let resolver = Some(TokioAsyncResolver::tokio_from_system_conf()?);
+
+        let data = if let Some(hash) = data {
+            Some(RwLock::new(hash))
+        } else {
+            Some(RwLock::new(HashMap::new()))
+        };
+
+        let instance = Arc::new(Self {
+            config,
+            resolver,
+            data,
+            refresh_loop: RwLock::new(None),
+        });
+
+        if instance.enabled() {
+            info!("Scheduling DNS refresh loop");
+            let refresh_loop = tokio::task::spawn({
+                let instance = instance.clone();
+                async move {
+                    instance.refresh_dns_entries_loop().await;
+                }
+            });
+            *(instance.refresh_loop.write().unwrap()) = Some(refresh_loop);
+        }
+
+        Ok(instance)
+    }
+
+    pub fn enabled(&self) -> bool {
+        self.config.enabled
+    }
+
+    // Schedules the refresher
+    async fn refresh_dns_entries_loop(&self) {
+        let resolver = TokioAsyncResolver::tokio_from_system_conf().unwrap();
+        let interval = Duration::from_secs(self.config.dns_max_ttl);
+        loop {
+            debug!("Begin refreshing cached DNS addresses.");
+            // To minimize the time we hold the lock, we first create
+            // an array with keys.
+            let mut hostnames: Vec<String> = Vec::new();
+            {
+                if let Some(ref data) = self.data {
+                    for hostname in data.read().unwrap().keys() {
+                        hostnames.push(hostname.clone());
+                    }
+                }
+            }
+
+            for hostname in hostnames.iter() {
+                let addrset = self
+                    .fetch_from_cache(hostname.as_str())
+                    .expect("Could not obtain expected address from cache, this should not happen");
+
+                match resolver.lookup_ip(hostname).await {
+                    Ok(lookup_ip) => {
+                        let new_addrset = AddrSet::from(lookup_ip);
+                        debug!(
+                            "Obtained address for host ({}) -> ({:?})",
+                            hostname, new_addrset
+                        );
+
+                        if addrset != new_addrset {
+                            debug!(
+                                "Addr changed from {:?} to {:?} updating cache.",
+                                addrset, new_addrset
+                            );
+                            self.store_in_cache(hostname, new_addrset);
+                        }
+                    }
+                    Err(err) => {
+                        error!(
+                            "There was an error trying to resolv {}: ({}).",
+                            hostname, err
+                        );
+                    }
+                }
+            }
+            debug!("Finished refreshing cached DNS addresses.");
+            sleep(interval).await;
+        }
+    }
+
+    /// Returns a `AddrSet` given the specified hostname.
+    ///
+    /// This method first tries to fetch the value from the cache, if it misses
+    /// then it is resolved and stored in the cache. TTL from records is ignored.
+    ///
+    /// # Arguments
+    ///
+    /// * `host`      - A string slice referencing the hostname to be resolved.
+    ///
+    /// # Example:
+    ///
+    /// ```
+    /// use pgcat::dns_cache::{CachedResolverConfig, CachedResolver};
+    ///
+    /// # tokio_test::block_on(async {
+    /// let config = CachedResolverConfig::default();
+    /// let resolver = CachedResolver::new(config, None).await.unwrap();
+    /// let response = resolver.lookup_ip("www.google.com.");
+    /// # })
+    /// ```
+    ///
+    pub async fn lookup_ip(&self, host: &str) -> ResolveResult<AddrSet> {
+        debug!("Lookup up {} in cache", host);
+        match self.fetch_from_cache(host) {
+            Some(addr_set) => {
+                debug!("Cache hit!");
+                Ok(addr_set)
+            }
+            None => {
+                debug!("Not found, executing a dns query!");
+                if let Some(ref resolver) = self.resolver {
+                    let addr_set = AddrSet::from(resolver.lookup_ip(host).await?);
+                    debug!("Obtained: {:?}", addr_set);
+                    self.store_in_cache(host, addr_set.clone());
+                    Ok(addr_set)
+                } else {
+                    Err(ResolveError::from("No resolver available"))
+                }
+            }
+        }
+    }
+
+    //
+    // Returns true if the stored host resolution differs from the AddrSet passed.
+    pub fn has_changed(&self, host: &str, addr_set: &AddrSet) -> bool {
+        if let Some(fetched_addr_set) = self.fetch_from_cache(host) {
+            return fetched_addr_set != *addr_set;
+        }
+        false
+    }
+
+    // Fetches an AddrSet from the inner cache adquiring the read lock.
+    fn fetch_from_cache(&self, key: &str) -> Option<AddrSet> {
+        if let Some(ref hash) = self.data {
+            if let Some(addr_set) = hash.read().unwrap().get(key) {
+                return Some(addr_set.clone());
+            }
+        }
+        None
+    }
+
+    // Sets up the global CACHED_RESOLVER static variable so we can globally use DNS
+    // cache.
+    pub async fn from_config() -> Result<(), Error> {
+        let cached_resolver = CACHED_RESOLVER.load();
+        let desired_config = CachedResolverConfig::from(get_config());
+
+        if cached_resolver.config != desired_config {
+            if let Some(ref refresh_loop) = *(cached_resolver.refresh_loop.write().unwrap()) {
+                warn!("Killing Dnscache refresh loop as its configuration is being reloaded");
+                refresh_loop.abort()
+            }
+            let new_resolver = if let Some(ref data) = cached_resolver.data {
+                let data = Some(data.read().unwrap().clone());
+                CachedResolver::new(desired_config, data).await
+            } else {
+                CachedResolver::new(desired_config, None).await
+            };
+
+            match new_resolver {
+                Ok(ok) => {
+                    CACHED_RESOLVER.store(ok);
+                    Ok(())
+                }
+                Err(err) => {
+                    let message = format!("Error setting up cached_resolver. Error: {:?}, will continue without this feature.", err);
+                    Err(Error::DNSCachedError(message))
+                }
+            }
+        } else {
+            Ok(())
+        }
+    }
+
+    // Stores the AddrSet in cache adquiring the write lock.
+    fn store_in_cache(&self, host: &str, addr_set: AddrSet) {
+        if let Some(ref data) = self.data {
+            data.write().unwrap().insert(host.to_string(), addr_set);
+        } else {
+            error!("Could not insert, Hash not initialized");
+        }
+    }
+}
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use trust_dns_resolver::error::ResolveError;
+
+    #[tokio::test]
+    async fn new() {
+        let config = CachedResolverConfig {
+            dns_max_ttl: 10,
+            enabled: true,
+        };
+        let resolver = CachedResolver::new(config, None).await;
+        assert!(resolver.is_ok());
+    }
+
+    #[tokio::test]
+    async fn lookup_ip() {
+        let config = CachedResolverConfig {
+            dns_max_ttl: 10,
+            enabled: true,
+        };
+        let resolver = CachedResolver::new(config, None).await.unwrap();
+        let response = resolver.lookup_ip("www.google.com.").await;
+        assert!(response.is_ok());
+    }
+
+    #[tokio::test]
+    async fn has_changed() {
+        let config = CachedResolverConfig {
+            dns_max_ttl: 10,
+            enabled: true,
+        };
+        let resolver = CachedResolver::new(config, None).await.unwrap();
+        let hostname = "www.google.com.";
+        let response = resolver.lookup_ip(hostname).await;
+        let addr_set = response.unwrap();
+        assert!(!resolver.has_changed(hostname, &addr_set));
+    }
+
+    #[tokio::test]
+    async fn unknown_host() {
+        let config = CachedResolverConfig {
+            dns_max_ttl: 10,
+            enabled: true,
+        };
+        let resolver = CachedResolver::new(config, None).await.unwrap();
+        let hostname = "www.idontexists.";
+        let response = resolver.lookup_ip(hostname).await;
+        assert!(matches!(response, Err(ResolveError { .. })));
+    }
+
+    #[tokio::test]
+    async fn incorrect_address() {
+        let config = CachedResolverConfig {
+            dns_max_ttl: 10,
+            enabled: true,
+        };
+        let resolver = CachedResolver::new(config, None).await.unwrap();
+        let hostname = "w  ww.idontexists.";
+        let response = resolver.lookup_ip(hostname).await;
+        assert!(matches!(response, Err(ResolveError { .. })));
+        assert!(!resolver.has_changed(hostname, &AddrSet::new()));
+    }
+
+    #[tokio::test]
+    // Ok, this test is based on the fact that google does DNS RR
+    // and does not responds with every available ip everytime, so
+    // if I cache here, it will miss after one cache iteration or two.
+    async fn thread() {
+        let config = CachedResolverConfig {
+            dns_max_ttl: 10,
+            enabled: true,
+        };
+        let resolver = CachedResolver::new(config, None).await.unwrap();
+        let hostname = "www.google.com.";
+        let response = resolver.lookup_ip(hostname).await;
+        let addr_set = response.unwrap();
+        assert!(!resolver.has_changed(hostname, &addr_set));
+        let resolver_for_refresher = resolver.clone();
+        let _thread_handle = tokio::task::spawn(async move {
+            resolver_for_refresher.refresh_dns_entries_loop().await;
+        });
+        assert!(!resolver.has_changed(hostname, &addr_set));
+    }
+}

src/errors.rs

@@ -1,20 +1,123 @@
-/// Errors.
+//! Errors.
 
 /// Various errors.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub enum Error {
     SocketError(String),
+    ClientSocketError(String, ClientIdentifier),
+    ClientGeneralError(String, ClientIdentifier),
+    ClientAuthImpossible(String),
+    ClientAuthPassthroughError(String, ClientIdentifier),
     ClientBadStartup,
     ProtocolSyncError(String),
     BadQuery(String),
     ServerError,
+    ServerStartupError(String, ServerIdentifier),
+    ServerAuthError(String, ServerIdentifier),
     BadConfig,
     AllServersDown,
     ClientError(String),
     TlsError,
     StatementTimeout,
+    DNSCachedError(String),
     ShuttingDown,
     ParseBytesError(String),
     AuthError(String),
     AuthPassthroughError(String),
+    UnsupportedStatement,
+    QueryRouterParserError(String),
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct ClientIdentifier {
+    pub application_name: String,
+    pub username: String,
+    pub pool_name: String,
+}
+
+impl ClientIdentifier {
+    pub fn new(application_name: &str, username: &str, pool_name: &str) -> ClientIdentifier {
+        ClientIdentifier {
+            application_name: application_name.into(),
+            username: username.into(),
+            pool_name: pool_name.into(),
+        }
+    }
+}
+
+impl std::fmt::Display for ClientIdentifier {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            f,
+            "{{ application_name: {}, username: {}, pool_name: {} }}",
+            self.application_name, self.username, self.pool_name
+        )
+    }
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct ServerIdentifier {
+    pub username: String,
+    pub database: String,
+}
+
+impl ServerIdentifier {
+    pub fn new(username: &str, database: &str) -> ServerIdentifier {
+        ServerIdentifier {
+            username: username.into(),
+            database: database.into(),
+        }
+    }
+}
+
+impl std::fmt::Display for ServerIdentifier {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(
+            f,
+            "{{ username: {}, database: {} }}",
+            self.username, self.database
+        )
+    }
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match &self {
+            &Error::ClientSocketError(error, client_identifier) => write!(
+                f,
+                "Error reading {} from client {}",
+                error, client_identifier
+            ),
+            &Error::ClientGeneralError(error, client_identifier) => {
+                write!(f, "{} {}", error, client_identifier)
+            }
+            &Error::ClientAuthImpossible(username) => write!(
+                f,
+                "Client auth not possible, \
+                no cleartext password set for username: {} \
+                in config and auth passthrough (query_auth) \
+                is not set up.",
+                username
+            ),
+            &Error::ClientAuthPassthroughError(error, client_identifier) => write!(
+                f,
+                "No cleartext password set, \
+                    and no auth passthrough could not \
+                    obtain the hash from server for {}, \
+                    the error was: {}",
+                client_identifier, error
+            ),
+            &Error::ServerStartupError(error, server_identifier) => write!(
+                f,
+                "Error reading {} on server startup {}",
+                error, server_identifier,
+            ),
+            &Error::ServerAuthError(error, server_identifier) => {
+                write!(f, "{} for {}", error, server_identifier,)
+            }
+
+            // The rest can use Debug.
+            err => write!(f, "{:?}", err),
+        }
+    }
 }

src/lib.rs

@@ -1,11 +1,17 @@
+pub mod admin;
 pub mod auth_passthrough;
+pub mod client;
 pub mod config;
 pub mod constants;
+pub mod dns_cache;
 pub mod errors;
 pub mod messages;
 pub mod mirrors;
 pub mod multi_logger;
+pub mod plugins;
 pub mod pool;
+pub mod prometheus;
+pub mod query_router;
 pub mod scram;
 pub mod server;
 pub mod sharding;

src/main.rs

@@ -36,6 +36,7 @@ extern crate sqlparser;
 extern crate tokio;
 extern crate tokio_rustls;
 extern crate toml;
+extern crate trust_dns_resolver;
 
 #[cfg(not(target_env = "msvc"))]
 use jemallocator::Jemalloc;
@@ -60,36 +61,19 @@ use std::str::FromStr;
 use std::sync::Arc;
 use tokio::sync::broadcast;
 
-mod admin;
-mod auth;
-mod auth_passthrough;
-mod client;
-mod config;
-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;
-
-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};
+use pgcat::config::{get_config, reload_config, VERSION};
+use pgcat::dns_cache;
+use pgcat::messages::configure_socket;
+use pgcat::pool::{ClientServerMap, ConnectionPool};
+use pgcat::prometheus::start_metric_server;
+use pgcat::stats::{Collector, Reporter, REPORTER};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    multi_logger::MultiLogger::init().unwrap();
+    pgcat::multi_logger::MultiLogger::init().unwrap();
 
     info!("Welcome to PgCat! Meow. (Version {})", VERSION);
 
-    if !query_router::QueryRouter::setup() {
+    if !pgcat::query_router::QueryRouter::setup() {
         error!("Could not setup query router");
         std::process::exit(exitcode::CONFIG);
     }
@@ -107,7 +91,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         let runtime = Builder::new_multi_thread().worker_threads(1).build()?;
 
         runtime.block_on(async {
-            match config::parse(&config_file).await {
+            match pgcat::config::parse(&config_file).await {
                 Ok(_) => (),
                 Err(err) => {
                     error!("Config parse error: {:?}", err);
@@ -166,6 +150,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         // Statistics reporting.
         REPORTER.store(Arc::new(Reporter::default()));
 
+        // Starts (if enabled) dns cache before pools initialization
+        match dns_cache::CachedResolver::from_config().await {
+                Ok(_) => (),
+                Err(err) => error!("DNS cache initialization error: {:?}", err),
+        };
+
         // Connection pool that allows to query all shards and replicas.
         match ConnectionPool::from_config(client_server_map.clone()).await {
             Ok(_) => (),
@@ -180,16 +170,19 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             stats_collector.collect().await;
         });
 
-        info!("Config autoreloader: {}", config.general.autoreload);
+        info!("Config autoreloader: {}", match config.general.autoreload {
+            Some(interval) => format!("{} ms", interval),
+            None => "disabled".into(),
+        });
 
-        let mut autoreload_interval = tokio::time::interval(tokio::time::Duration::from_millis(15_000));
-        let autoreload_client_server_map = client_server_map.clone();
+        if let Some(interval) = config.general.autoreload {
+            let mut autoreload_interval = tokio::time::interval(tokio::time::Duration::from_millis(interval));
+            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");
+            tokio::task::spawn(async move {
+                loop {
+                    autoreload_interval.tick().await;
+                    debug!("Automatically reloading config");
 
                     if let Ok(changed) = reload_config(autoreload_client_server_map.clone()).await {
                         if changed {
@@ -197,8 +190,10 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                         }
                     };
                 }
-            }
-        });
+            });
+        };
+
+
 
         #[cfg(windows)]
         let mut term_signal = win_signal::ctrl_close().unwrap();
@@ -283,18 +278,20 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                     let drain_tx = drain_tx.clone();
                     let client_server_map = client_server_map.clone();
 
-                    let tls_certificate = config.general.tls_certificate.clone();
+                    let tls_certificate = get_config().general.tls_certificate.clone();
+
+                    configure_socket(&socket);
 
                     tokio::task::spawn(async move {
                         let start = chrono::offset::Utc::now().naive_utc();
 
-                        match client::client_entrypoint(
+                        match pgcat::client::client_entrypoint(
                             socket,
                             client_server_map,
                             shutdown_rx,
                             drain_tx,
                             admin_only,
-                            tls_certificate.clone(),
+                            tls_certificate,
                             config.general.log_client_connections,
                         )
                         .await
@@ -302,7 +299,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                             Ok(()) => {
                                 let duration = chrono::offset::Utc::now().naive_utc() - start;
 
-                                if config.general.log_client_disconnections {
+                                if get_config().general.log_client_disconnections {
                                     info!(
                                         "Client {:?} disconnected, session duration: {}",
                                         addr,
@@ -319,7 +316,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
                             Err(err) => {
                                 match err {
-                                    errors::Error::ClientBadStartup => debug!("Client disconnected with error {:?}", err),
+                                    pgcat::errors::Error::ClientBadStartup => debug!("Client disconnected with error {:?}", err),
                                     _ => warn!("Client disconnected with error {:?}", err),
                                 }
 

src/messages.rs

@@ -1,7 +1,7 @@
 /// Helper functions to send one-off protocol messages
 /// and handle TcpStream (TCP socket).
 use bytes::{Buf, BufMut, BytesMut};
-use log::{debug, error};
+use log::error;
 use md5::{Digest, Md5};
 use socket2::{SockRef, TcpKeepalive};
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
@@ -20,6 +20,10 @@ pub enum DataType {
     Text,
     Int4,
     Numeric,
+    Bool,
+    Oid,
+    AnyArray,
+    Any,
 }
 
 impl From<&DataType> for i32 {
@@ -28,6 +32,10 @@ impl From<&DataType> for i32 {
             DataType::Text => 25,
             DataType::Int4 => 23,
             DataType::Numeric => 1700,
+            DataType::Bool => 16,
+            DataType::Oid => 26,
+            DataType::AnyArray => 2277,
+            DataType::Any => 2276,
         }
     }
 }
@@ -46,6 +54,29 @@ where
     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<S>(
@@ -93,7 +124,10 @@ where
 
 /// Send the startup packet the server. We're pretending we're a Pg client.
 /// This tells the server which user we are and what database we want.
-pub async fn startup(stream: &mut TcpStream, user: &str, database: &str) -> Result<(), Error> {
+pub async fn startup<S>(stream: &mut S, user: &str, database: &str) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
     let mut bytes = BytesMut::with_capacity(25);
 
     bytes.put_i32(196608); // Protocol number
@@ -127,6 +161,21 @@ pub async fn startup(stream: &mut TcpStream, user: &str, database: &str) -> Resu
     }
 }
 
+pub async fn ssl_request(stream: &mut TcpStream) -> Result<(), Error> {
+    let mut bytes = BytesMut::with_capacity(12);
+
+    bytes.put_i32(8);
+    bytes.put_i32(80877103);
+
+    match stream.write_all(&bytes).await {
+        Ok(_) => Ok(()),
+        Err(err) => Err(Error::SocketError(format!(
+            "Error writing SSLRequest to server socket - Error: {:?}",
+            err
+        ))),
+    }
+}
+
 /// Parse the params the server sends as a key/value format.
 pub fn parse_params(mut bytes: BytesMut) -> Result<HashMap<String, String>, Error> {
     let mut result = HashMap::new();
@@ -234,8 +283,6 @@ pub async fn md5_password_with_hash<S>(stream: &mut S, hash: &str, salt: &[u8])
 where
     S: tokio::io::AsyncWrite + std::marker::Unpin,
 {
-    debug!("Sending hash {} to server", hash);
-
     let password = md5_hash_second_pass(hash, salt);
     let mut message = BytesMut::with_capacity(password.len() as usize + 5);
 
@@ -383,7 +430,7 @@ pub fn row_description(columns: &Vec<(&str, DataType)>) -> BytesMut {
     let mut res = BytesMut::new();
     let mut row_desc = BytesMut::new();
 
-    // how many colums we are storing
+    // how many columns we are storing
     row_desc.put_i16(columns.len() as i16);
 
     for (name, data_type) in columns {
@@ -404,6 +451,10 @@ pub fn row_description(columns: &Vec<(&str, DataType)>) -> BytesMut {
             DataType::Text => -1,
             DataType::Int4 => 4,
             DataType::Numeric => -1,
+            DataType::Bool => 1,
+            DataType::Oid => 4,
+            DataType::AnyArray => -1,
+            DataType::Any => -1,
         };
 
         row_desc.put_i16(type_size);
@@ -442,6 +493,29 @@ pub fn data_row(row: &Vec<String>) -> BytesMut {
     res
 }
 
+pub fn data_row_nullable(row: &Vec<Option<String>>) -> BytesMut {
+    let mut res = BytesMut::new();
+    let mut data_row = BytesMut::new();
+
+    data_row.put_i16(row.len() as i16);
+
+    for column in row {
+        if let Some(column) = column {
+            let column = column.as_bytes();
+            data_row.put_i32(column.len() as i32);
+            data_row.put_slice(column);
+        } else {
+            data_row.put_i32(-1 as i32);
+        }
+    }
+
+    res.put_u8(b'D');
+    res.put_i32(data_row.len() as i32 + 4);
+    res.put(data_row);
+
+    res
+}
+
 /// Create a CommandComplete message.
 pub fn command_complete(command: &str) -> BytesMut {
     let cmd = BytesMut::from(format!("{}\0", command).as_bytes());
@@ -484,6 +558,29 @@ where
     }
 }
 
+pub async fn write_all_flush<S>(stream: &mut S, buf: &[u8]) -> Result<(), Error>
+where
+    S: tokio::io::AsyncWrite + std::marker::Unpin,
+{
+    match stream.write_all(buf).await {
+        Ok(_) => match stream.flush().await {
+            Ok(_) => Ok(()),
+            Err(err) => {
+                return Err(Error::SocketError(format!(
+                    "Error flushing socket - Error: {:?}",
+                    err
+                )))
+            }
+        },
+        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<S>(stream: &mut S) -> Result<BytesMut, Error>
 where

src/mirrors.rs

@@ -34,7 +34,7 @@ impl MirroredClient {
                 None => (default, default, crate::config::Pool::default()),
             };
 
-        let identifier = PoolIdentifier::new(&self.database, &self.user.username, None);
+        let identifier = PoolIdentifier::new(&self.database, &self.user.username);
 
         let manager = ServerPool::new(
             self.address.clone(),
@@ -43,6 +43,7 @@ impl MirroredClient {
             ClientServerMap::default(),
             Arc::new(PoolStats::new(identifier, cfg.clone())),
             Arc::new(RwLock::new(None)),
+            None,
         );
 
         Pool::builder()

src/multi_logger.rs

@@ -17,7 +17,7 @@ use log::{Level, Log, Metadata, Record, SetLoggerError};
 //
 // 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.
+// where you set `RUST_LOG=debug` and `STDOUT_LOG=info`, in here, errors will go to stderr, warns and infos to stdout and debugs to stderr.
 //
 pub struct MultiLogger {
     stderr_logger: env_logger::Logger,

src/plugins/intercept.rs

@@ -0,0 +1,120 @@
+//! The intercept plugin.
+//!
+//! It intercepts queries and returns fake results.
+
+use async_trait::async_trait;
+use bytes::{BufMut, BytesMut};
+use serde::{Deserialize, Serialize};
+use sqlparser::ast::Statement;
+
+use log::debug;
+
+use crate::{
+    config::Intercept as InterceptConfig,
+    errors::Error,
+    messages::{command_complete, data_row_nullable, row_description, DataType},
+    plugins::{Plugin, PluginOutput},
+    query_router::QueryRouter,
+};
+
+// TODO: use these structs for deserialization
+#[derive(Serialize, Deserialize)]
+pub struct Rule {
+    query: String,
+    schema: Vec<Column>,
+    result: Vec<Vec<String>>,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct Column {
+    name: String,
+    data_type: String,
+}
+
+/// The intercept plugin.
+pub struct Intercept<'a> {
+    pub enabled: bool,
+    pub config: &'a InterceptConfig,
+}
+
+#[async_trait]
+impl<'a> Plugin for Intercept<'a> {
+    async fn run(
+        &mut self,
+        query_router: &QueryRouter,
+        ast: &Vec<Statement>,
+    ) -> Result<PluginOutput, Error> {
+        if !self.enabled || ast.is_empty() {
+            return Ok(PluginOutput::Allow);
+        }
+
+        let mut config = self.config.clone();
+        config.substitute(
+            &query_router.pool_settings().db,
+            &query_router.pool_settings().user.username,
+        );
+
+        let mut result = BytesMut::new();
+
+        for q in ast {
+            // Normalization
+            let q = q.to_string().to_ascii_lowercase();
+
+            for (_, target) in config.queries.iter() {
+                if target.query.as_str() == q {
+                    debug!("Intercepting query: {}", q);
+
+                    let rd = target
+                        .schema
+                        .iter()
+                        .map(|row| {
+                            let name = &row[0];
+                            let data_type = &row[1];
+                            (
+                                name.as_str(),
+                                match data_type.as_str() {
+                                    "text" => DataType::Text,
+                                    "anyarray" => DataType::AnyArray,
+                                    "oid" => DataType::Oid,
+                                    "bool" => DataType::Bool,
+                                    "int4" => DataType::Int4,
+                                    _ => DataType::Any,
+                                },
+                            )
+                        })
+                        .collect::<Vec<(&str, DataType)>>();
+
+                    result.put(row_description(&rd));
+
+                    target.result.iter().for_each(|row| {
+                        let row = row
+                            .iter()
+                            .map(|s| {
+                                let s = s.as_str().to_string();
+
+                                if s == "" {
+                                    None
+                                } else {
+                                    Some(s)
+                                }
+                            })
+                            .collect::<Vec<Option<String>>>();
+                        result.put(data_row_nullable(&row));
+                    });
+
+                    result.put(command_complete("SELECT"));
+                }
+            }
+        }
+
+        if !result.is_empty() {
+            result.put_u8(b'Z');
+            result.put_i32(5);
+            result.put_u8(b'I');
+
+            return Ok(PluginOutput::Intercept(result));
+        } else {
+            Ok(PluginOutput::Allow)
+        }
+    }
+}

src/plugins/mod.rs

@@ -0,0 +1,44 @@
+//! The plugin ecosystem.
+//!
+//! Currently plugins only grant access or deny access to the database for a particual query.
+//! Example use cases:
+//!   - block known bad queries
+//!   - block access to system catalogs
+//!   - block dangerous modifications like `DROP TABLE`
+//!   - etc
+//!
+
+pub mod intercept;
+pub mod prewarmer;
+pub mod query_logger;
+pub mod table_access;
+
+use crate::{errors::Error, query_router::QueryRouter};
+use async_trait::async_trait;
+use bytes::BytesMut;
+use sqlparser::ast::Statement;
+
+pub use intercept::Intercept;
+pub use query_logger::QueryLogger;
+pub use table_access::TableAccess;
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum PluginOutput {
+    Allow,
+    Deny(String),
+    Overwrite(Vec<Statement>),
+    Intercept(BytesMut),
+}
+
+#[async_trait]
+pub trait Plugin {
+    // Run before the query is sent to the server.
+    async fn run(
+        &mut self,
+        query_router: &QueryRouter,
+        ast: &Vec<Statement>,
+    ) -> Result<PluginOutput, Error>;
+
+    // TODO: run after the result is returned
+    // async fn callback(&mut self, query_router: &QueryRouter);
+}

src/plugins/prewarmer.rs

@@ -0,0 +1,28 @@
+//! Prewarm new connections before giving them to the client.
+use crate::{errors::Error, server::Server};
+use log::info;
+
+pub struct Prewarmer<'a> {
+    pub enabled: bool,
+    pub server: &'a mut Server,
+    pub queries: &'a Vec<String>,
+}
+
+impl<'a> Prewarmer<'a> {
+    pub async fn run(&mut self) -> Result<(), Error> {
+        if !self.enabled {
+            return Ok(());
+        }
+
+        for query in self.queries {
+            info!(
+                "{} Prewarning with query: `{}`",
+                self.server.address(),
+                query
+            );
+            self.server.query(&query).await?;
+        }
+
+        Ok(())
+    }
+}

src/plugins/query_logger.rs

@@ -0,0 +1,38 @@
+//! Log all queries to stdout (or somewhere else, why not).
+
+use crate::{
+    errors::Error,
+    plugins::{Plugin, PluginOutput},
+    query_router::QueryRouter,
+};
+use async_trait::async_trait;
+use log::info;
+use sqlparser::ast::Statement;
+
+pub struct QueryLogger<'a> {
+    pub enabled: bool,
+    pub user: &'a str,
+    pub db: &'a str,
+}
+
+#[async_trait]
+impl<'a> Plugin for QueryLogger<'a> {
+    async fn run(
+        &mut self,
+        _query_router: &QueryRouter,
+        ast: &Vec<Statement>,
+    ) -> Result<PluginOutput, Error> {
+        if !self.enabled {
+            return Ok(PluginOutput::Allow);
+        }
+
+        let query = ast
+            .iter()
+            .map(|q| q.to_string())
+            .collect::<Vec<String>>()
+            .join("; ");
+        info!("[pool: {}][user: {}] {}", self.user, self.db, query);
+
+        Ok(PluginOutput::Allow)
+    }
+}

src/plugins/table_access.rs

@@ -0,0 +1,59 @@
+//! This query router plugin will check if the user can access a particular
+//! table as part of their query. If they can't, the query will not be routed.
+
+use async_trait::async_trait;
+use sqlparser::ast::{visit_relations, Statement};
+
+use crate::{
+    errors::Error,
+    plugins::{Plugin, PluginOutput},
+    query_router::QueryRouter,
+};
+
+use log::debug;
+
+use core::ops::ControlFlow;
+
+pub struct TableAccess<'a> {
+    pub enabled: bool,
+    pub tables: &'a Vec<String>,
+}
+
+#[async_trait]
+impl<'a> Plugin for TableAccess<'a> {
+    async fn run(
+        &mut self,
+        _query_router: &QueryRouter,
+        ast: &Vec<Statement>,
+    ) -> Result<PluginOutput, Error> {
+        if !self.enabled {
+            return Ok(PluginOutput::Allow);
+        }
+
+        let mut found = None;
+
+        visit_relations(ast, |relation| {
+            let relation = relation.to_string();
+            let parts = relation.split(".").collect::<Vec<&str>>();
+            let table_name = parts.last().unwrap();
+
+            if self.tables.contains(&table_name.to_string()) {
+                found = Some(table_name.to_string());
+                ControlFlow::<()>::Break(())
+            } else {
+                ControlFlow::<()>::Continue(())
+            }
+        });
+
+        if let Some(found) = found {
+            debug!("Blocking access to table \"{}\"", found);
+
+            Ok(PluginOutput::Deny(format!(
+                "permission for table \"{}\" denied",
+                found
+            )))
+        } else {
+            Ok(PluginOutput::Allow)
+        }
+    }
+}

src/pool.rs

@@ -17,10 +17,13 @@ use std::sync::{
 use std::time::Instant;
 use tokio::sync::Notify;
 
-use crate::config::{get_config, Address, General, LoadBalancingMode, PoolMode, Role, User};
+use crate::config::{
+    get_config, Address, General, LoadBalancingMode, Plugins, PoolMode, Role, User,
+};
 use crate::errors::Error;
 
 use crate::auth_passthrough::AuthPassthrough;
+use crate::plugins::prewarmer;
 use crate::server::Server;
 use crate::sharding::ShardingFunction;
 use crate::stats::{AddressStats, ClientStats, PoolStats, ServerStats};
@@ -59,22 +62,26 @@ pub struct PoolIdentifier {
 
     /// The username the client connects with. Each user gets its own pool.
     pub user: String,
-
-    /// The client secret (password).
-    pub secret: Option<String>,
 }
 
+static POOL_REAPER_RATE: u64 = 30_000; // 30 seconds by default
+
 impl PoolIdentifier {
     /// Create a new user/pool identifier.
-    pub fn new(db: &str, user: &str, secret: Option<String>) -> PoolIdentifier {
+    pub fn new(db: &str, user: &str) -> PoolIdentifier {
         PoolIdentifier {
             db: db.to_string(),
             user: user.to_string(),
-            secret,
         }
     }
 }
 
+impl From<&Address> for PoolIdentifier {
+    fn from(address: &Address) -> PoolIdentifier {
+        PoolIdentifier::new(&address.database, &address.username)
+    }
+}
+
 /// Pool settings.
 #[derive(Clone, Debug)]
 pub struct PoolSettings {
@@ -89,6 +96,7 @@ pub struct PoolSettings {
 
     // Connecting user.
     pub user: User,
+    pub db: String,
 
     // Default server role to connect to.
     pub default_role: Option<Role>,
@@ -127,6 +135,9 @@ pub struct PoolSettings {
     pub auth_query: Option<String>,
     pub auth_query_user: Option<String>,
     pub auth_query_password: Option<String>,
+
+    /// Plugins
+    pub plugins: Option<Plugins>,
 }
 
 impl Default for PoolSettings {
@@ -136,6 +147,7 @@ impl Default for PoolSettings {
             load_balancing_mode: LoadBalancingMode::Random,
             shards: 1,
             user: User::default(),
+            db: String::default(),
             default_role: None,
             query_parser_enabled: false,
             primary_reads_enabled: true,
@@ -150,6 +162,7 @@ impl Default for PoolSettings {
             auth_query: None,
             auth_query_user: None,
             auth_query_password: None,
+            plugins: None,
         }
     }
 }
@@ -189,6 +202,7 @@ pub struct ConnectionPool {
     paused: Arc<AtomicBool>,
     paused_waiter: Arc<Notify>,
 
+    /// Statistics.
     pub stats: Arc<PoolStats>,
 
     /// AuthInfo
@@ -208,241 +222,275 @@ impl ConnectionPool {
 
             // There is one pool per database/user pair.
             for user in pool_config.users.values() {
-                let mut secrets = match &user.secrets {
-                    Some(_) => user
-                        .secrets
-                        .as_ref()
-                        .unwrap()
-                        .iter()
-                        .map(|secret| Some(secret.to_string()))
-                        .collect::<Vec<Option<String>>>(),
-                    None => vec![],
-                };
+                let old_pool_ref = get_pool(pool_name, &user.username);
+                let identifier = PoolIdentifier::new(pool_name, &user.username);
 
-                secrets.push(None);
+                match old_pool_ref {
+                    Some(pool) => {
+                        // If the pool hasn't changed, get existing reference and insert it into the new_pools.
+                        // We replace all pools at the end, but if the reference is kept, the pool won't get re-created (bb8).
+                        if pool.config_hash == new_pool_hash_value {
+                            info!(
+                                "[pool: {}][user: {}] has not changed",
+                                pool_name, user.username
+                            );
+                            new_pools.insert(identifier.clone(), pool.clone());
+                            continue;
+                        }
+                    }
+                    None => (),
+                }
 
-                for secret in secrets {
-                    let old_pool_ref = get_pool(pool_name, &user.username, secret.clone());
-                    let identifier = PoolIdentifier::new(pool_name, &user.username, secret.clone());
+                info!(
+                    "[pool: {}][user: {}] creating new pool",
+                    pool_name, user.username
+                );
 
-                    match old_pool_ref {
-                        Some(pool) => {
-                            // If the pool hasn't changed, get existing reference and insert it into the new_pools.
-                            // We replace all pools at the end, but if the reference is kept, the pool won't get re-created (bb8).
-                            if pool.config_hash == new_pool_hash_value {
-                                info!(
-                                    "[pool: {}][user: {}] has not changed",
-                                    pool_name, user.username
-                                );
-                                new_pools.insert(identifier.clone(), pool.clone());
-                                continue;
+                let mut shards = Vec::new();
+                let mut addresses = Vec::new();
+                let mut banlist = Vec::new();
+                let mut shard_ids = pool_config
+                    .shards
+                    .clone()
+                    .into_keys()
+                    .collect::<Vec<String>>();
+                let pool_stats = Arc::new(PoolStats::new(identifier, pool_config.clone()));
+
+                // Allow the pool to be seen in statistics
+                pool_stats.register(pool_stats.clone());
+
+                // Sort by shard number to ensure consistency.
+                shard_ids.sort_by_key(|k| k.parse::<i64>().unwrap());
+                let pool_auth_hash: Arc<RwLock<Option<String>>> = Arc::new(RwLock::new(None));
+
+                for shard_idx in &shard_ids {
+                    let shard = &pool_config.shards[shard_idx];
+                    let mut pools = Vec::new();
+                    let mut servers = Vec::new();
+                    let mut replica_number = 0;
+
+                    // Load Mirror settings
+                    for (address_index, server) in shard.servers.iter().enumerate() {
+                        let mut mirror_addresses = vec![];
+                        if let Some(mirror_settings_vec) = &shard.mirrors {
+                            for (mirror_idx, mirror_settings) in
+                                mirror_settings_vec.iter().enumerate()
+                            {
+                                if mirror_settings.mirroring_target_index != address_index {
+                                    continue;
+                                }
+                                mirror_addresses.push(Address {
+                                    id: address_id,
+                                    database: shard.database.clone(),
+                                    host: mirror_settings.host.clone(),
+                                    port: mirror_settings.port,
+                                    role: server.role,
+                                    address_index: mirror_idx,
+                                    replica_number,
+                                    shard: shard_idx.parse::<usize>().unwrap(),
+                                    username: user.username.clone(),
+                                    pool_name: pool_name.clone(),
+                                    mirrors: vec![],
+                                    stats: Arc::new(AddressStats::default()),
+                                });
+                                address_id += 1;
                             }
                         }
-                        None => (),
+
+                        let address = Address {
+                            id: address_id,
+                            database: shard.database.clone(),
+                            host: server.host.clone(),
+                            port: server.port,
+                            role: server.role,
+                            address_index,
+                            replica_number,
+                            shard: shard_idx.parse::<usize>().unwrap(),
+                            username: user.username.clone(),
+                            pool_name: pool_name.clone(),
+                            mirrors: mirror_addresses,
+                            stats: Arc::new(AddressStats::default()),
+                        };
+
+                        address_id += 1;
+
+                        if server.role == Role::Replica {
+                            replica_number += 1;
+                        }
+
+                        // We assume every server in the pool share user/passwords
+                        let auth_passthrough = AuthPassthrough::from_pool_config(pool_config);
+
+                        if let Some(apt) = &auth_passthrough {
+                            match apt.fetch_hash(&address).await {
+                                Ok(ok) => {
+                                    if let Some(ref pool_auth_hash_value) = *(pool_auth_hash.read())
+                                    {
+                                        if ok != *pool_auth_hash_value {
+                                            warn!(
+                                                "Hash is not the same across shards \
+                                                of the same pool, client auth will \
+                                                be done using last obtained hash. \
+                                                Server: {}:{}, Database: {}",
+                                                server.host, server.port, shard.database,
+                                            );
+                                        }
+                                    }
+
+                                    debug!("Hash obtained for {:?}", address);
+
+                                    {
+                                        let mut pool_auth_hash = pool_auth_hash.write();
+                                        *pool_auth_hash = Some(ok.clone());
+                                    }
+                                }
+                                Err(err) => warn!(
+                                    "Could not obtain password hashes \
+                                        using auth_query config, ignoring. \
+                                        Error: {:?}",
+                                    err,
+                                ),
+                            }
+                        }
+
+                        let manager = ServerPool::new(
+                            address.clone(),
+                            user.clone(),
+                            &shard.database,
+                            client_server_map.clone(),
+                            pool_stats.clone(),
+                            pool_auth_hash.clone(),
+                            match pool_config.plugins {
+                                Some(ref plugins) => Some(plugins.clone()),
+                                None => config.plugins.clone(),
+                            },
+                        );
+
+                        let connect_timeout = match pool_config.connect_timeout {
+                            Some(connect_timeout) => connect_timeout,
+                            None => config.general.connect_timeout,
+                        };
+
+                        let idle_timeout = match pool_config.idle_timeout {
+                            Some(idle_timeout) => idle_timeout,
+                            None => config.general.idle_timeout,
+                        };
+
+                        let server_lifetime = match user.server_lifetime {
+                            Some(server_lifetime) => server_lifetime,
+                            None => match pool_config.server_lifetime {
+                                Some(server_lifetime) => server_lifetime,
+                                None => config.general.server_lifetime,
+                            },
+                        };
+
+                        let reaper_rate = *vec![idle_timeout, server_lifetime, POOL_REAPER_RATE]
+                            .iter()
+                            .min()
+                            .unwrap();
+
+                        debug!(
+                            "[pool: {}][user: {}] Pool reaper rate: {}ms",
+                            pool_name, user.username, reaper_rate
+                        );
+
+                        let pool = Pool::builder()
+                            .max_size(user.pool_size)
+                            .min_idle(user.min_pool_size)
+                            .connection_timeout(std::time::Duration::from_millis(connect_timeout))
+                            .idle_timeout(Some(std::time::Duration::from_millis(idle_timeout)))
+                            .max_lifetime(Some(std::time::Duration::from_millis(server_lifetime)))
+                            .reaper_rate(std::time::Duration::from_millis(reaper_rate))
+                            .test_on_check_out(false);
+
+                        let pool = if config.general.validate_config {
+                            pool.build(manager).await?
+                        } else {
+                            pool.build_unchecked(manager)
+                        };
+
+                        pools.push(pool);
+                        servers.push(address);
                     }
 
+                    shards.push(pools);
+                    addresses.push(servers);
+                    banlist.push(HashMap::new());
+                }
+
+                assert_eq!(shards.len(), addresses.len());
+                if let Some(ref _auth_hash) = *(pool_auth_hash.clone().read()) {
                     info!(
-                        "[pool: {}][user: {}] creating new pool",
+                        "Auth hash obtained from query_auth for pool {{ name: {}, user: {} }}",
                         pool_name, user.username
                     );
+                }
 
-                    let mut shards = Vec::new();
-                    let mut addresses = Vec::new();
-                    let mut banlist = Vec::new();
-                    let mut shard_ids = pool_config
-                        .shards
-                        .clone()
-                        .into_keys()
-                        .collect::<Vec<String>>();
-                    let pool_stats = Arc::new(PoolStats::new(identifier, pool_config.clone()));
-
-                    // Allow the pool to be seen in statistics
-                    pool_stats.register(pool_stats.clone());
-
-                    // Sort by shard number to ensure consistency.
-                    shard_ids.sort_by_key(|k| k.parse::<i64>().unwrap());
-                    let pool_auth_hash: Arc<RwLock<Option<String>>> = Arc::new(RwLock::new(None));
-
-                    for shard_idx in &shard_ids {
-                        let shard = &pool_config.shards[shard_idx];
-                        let mut pools = Vec::new();
-                        let mut servers = Vec::new();
-                        let mut replica_number = 0;
-
-                        // Load Mirror settings
-                        for (address_index, server) in shard.servers.iter().enumerate() {
-                            let mut mirror_addresses = vec![];
-                            if let Some(mirror_settings_vec) = &shard.mirrors {
-                                for (mirror_idx, mirror_settings) in
-                                    mirror_settings_vec.iter().enumerate()
-                                {
-                                    if mirror_settings.mirroring_target_index != address_index {
-                                        continue;
-                                    }
-                                    mirror_addresses.push(Address {
-                                        id: address_id,
-                                        database: shard.database.clone(),
-                                        host: mirror_settings.host.clone(),
-                                        port: mirror_settings.port,
-                                        role: server.role,
-                                        address_index: mirror_idx,
-                                        replica_number,
-                                        shard: shard_idx.parse::<usize>().unwrap(),
-                                        username: user.username.clone(),
-                                        pool_name: pool_name.clone(),
-                                        mirrors: vec![],
-                                        stats: Arc::new(AddressStats::default()),
-                                    });
-                                    address_id += 1;
-                                }
-                            }
-
-                            let address = Address {
-                                id: address_id,
-                                database: shard.database.clone(),
-                                host: server.host.clone(),
-                                port: server.port,
-                                role: server.role,
-                                address_index,
-                                replica_number,
-                                shard: shard_idx.parse::<usize>().unwrap(),
-                                username: user.username.clone(),
-                                pool_name: pool_name.clone(),
-                                mirrors: mirror_addresses,
-                                stats: Arc::new(AddressStats::default()),
-                            };
-
-                            address_id += 1;
-
-                            if server.role == Role::Replica {
-                                replica_number += 1;
-                            }
-
-                            // We assume every server in the pool share user/passwords
-                            let auth_passthrough = AuthPassthrough::from_pool_config(pool_config);
-
-                            if let Some(apt) = &auth_passthrough {
-                                match apt.fetch_hash(&address).await {
-                                    Ok(ok) => {
-                                        if let Some(ref pool_auth_hash_value) = *(pool_auth_hash.read()) {
-                                            if ok != *pool_auth_hash_value {
-                                                warn!("Hash is not the same across shards of the same pool, client auth will \
-                                                   be done using last obtained hash. Server: {}:{}, Database: {}", server.host, server.port, shard.database);
-                                            }
-                                        }
-                                        debug!("Hash obtained for {:?}", address);
-                                        {
-                                           let mut pool_auth_hash = pool_auth_hash.write();
-                                           *pool_auth_hash = Some(ok.clone());
-                                        }
-                                    },
-                                    Err(err) => warn!("Could not obtain password hashes using auth_query config, ignoring. Error: {:?}", err),
-                                 }
-                            }
-
-                            let manager = ServerPool::new(
-                                address.clone(),
-                                user.clone(),
-                                &shard.database,
-                                client_server_map.clone(),
-                                pool_stats.clone(),
-                                pool_auth_hash.clone(),
-                            );
-
-                            let connect_timeout = match pool_config.connect_timeout {
-                                Some(connect_timeout) => connect_timeout,
-                                None => config.general.connect_timeout,
-                            };
-
-                            let idle_timeout = match pool_config.idle_timeout {
-                                Some(idle_timeout) => idle_timeout,
-                                None => config.general.idle_timeout,
-                            };
-
-                            let pool = Pool::builder()
-                                .max_size(user.pool_size)
-                                .connection_timeout(std::time::Duration::from_millis(
-                                    connect_timeout,
-                                ))
-                                .idle_timeout(Some(std::time::Duration::from_millis(idle_timeout)))
-                                .test_on_check_out(false)
-                                .build(manager)
-                                .await
-                                .unwrap();
-
-                            pools.push(pool);
-                            servers.push(address);
-                        }
-
-                        shards.push(pools);
-                        addresses.push(servers);
-                        banlist.push(HashMap::new());
-                    }
-
-                    assert_eq!(shards.len(), addresses.len());
-                    if let Some(ref _auth_hash) = *(pool_auth_hash.clone().read()) {
-                        info!(
-                            "Auth hash obtained from query_auth for pool {{ name: {}, user: {} }}",
-                            pool_name, user.username
-                        );
-                    }
-
-                    let pool = ConnectionPool {
-                        databases: shards,
-                        stats: pool_stats,
-                        addresses,
-                        banlist: Arc::new(RwLock::new(banlist)),
-                        config_hash: new_pool_hash_value,
-                        server_info: Arc::new(RwLock::new(BytesMut::new())),
-                        auth_hash: pool_auth_hash,
-                        settings: PoolSettings {
-                            pool_mode: pool_config.pool_mode,
-                            load_balancing_mode: pool_config.load_balancing_mode,
-                            // shards: pool_config.shards.clone(),
-                            shards: shard_ids.len(),
-                            user: user.clone(),
-                            default_role: match pool_config.default_role.as_str() {
-                                "any" => None,
-                                "replica" => Some(Role::Replica),
-                                "primary" => Some(Role::Primary),
-                                _ => unreachable!(),
-                            },
-                            query_parser_enabled: pool_config.query_parser_enabled,
-                            primary_reads_enabled: pool_config.primary_reads_enabled,
-                            sharding_function: pool_config.sharding_function,
-                            automatic_sharding_key: pool_config.automatic_sharding_key.clone(),
-                            healthcheck_delay: config.general.healthcheck_delay,
-                            healthcheck_timeout: config.general.healthcheck_timeout,
-                            ban_time: config.general.ban_time,
-                            sharding_key_regex: pool_config
-                                .sharding_key_regex
-                                .clone()
-                                .map(|regex| Regex::new(regex.as_str()).unwrap()),
-                            shard_id_regex: pool_config
-                                .shard_id_regex
-                                .clone()
-                                .map(|regex| Regex::new(regex.as_str()).unwrap()),
-                            regex_search_limit: pool_config.regex_search_limit.unwrap_or(1000),
-                            auth_query: pool_config.auth_query.clone(),
-                            auth_query_user: pool_config.auth_query_user.clone(),
-                            auth_query_password: pool_config.auth_query_password.clone(),
+                let pool = ConnectionPool {
+                    databases: shards,
+                    stats: pool_stats,
+                    addresses,
+                    banlist: Arc::new(RwLock::new(banlist)),
+                    config_hash: new_pool_hash_value,
+                    server_info: Arc::new(RwLock::new(BytesMut::new())),
+                    auth_hash: pool_auth_hash,
+                    settings: PoolSettings {
+                        pool_mode: match user.pool_mode {
+                            Some(pool_mode) => pool_mode,
+                            None => pool_config.pool_mode,
                         },
-                        validated: Arc::new(AtomicBool::new(false)),
-                        paused: Arc::new(AtomicBool::new(false)),
-                        paused_waiter: Arc::new(Notify::new()),
-                    };
+                        load_balancing_mode: pool_config.load_balancing_mode,
+                        // shards: pool_config.shards.clone(),
+                        shards: shard_ids.len(),
+                        user: user.clone(),
+                        db: pool_name.clone(),
+                        default_role: match pool_config.default_role.as_str() {
+                            "any" => None,
+                            "replica" => Some(Role::Replica),
+                            "primary" => Some(Role::Primary),
+                            _ => unreachable!(),
+                        },
+                        query_parser_enabled: pool_config.query_parser_enabled,
+                        primary_reads_enabled: pool_config.primary_reads_enabled,
+                        sharding_function: pool_config.sharding_function,
+                        automatic_sharding_key: pool_config.automatic_sharding_key.clone(),
+                        healthcheck_delay: config.general.healthcheck_delay,
+                        healthcheck_timeout: config.general.healthcheck_timeout,
+                        ban_time: config.general.ban_time,
+                        sharding_key_regex: pool_config
+                            .sharding_key_regex
+                            .clone()
+                            .map(|regex| Regex::new(regex.as_str()).unwrap()),
+                        shard_id_regex: pool_config
+                            .shard_id_regex
+                            .clone()
+                            .map(|regex| Regex::new(regex.as_str()).unwrap()),
+                        regex_search_limit: pool_config.regex_search_limit.unwrap_or(1000),
+                        auth_query: pool_config.auth_query.clone(),
+                        auth_query_user: pool_config.auth_query_user.clone(),
+                        auth_query_password: pool_config.auth_query_password.clone(),
+                        plugins: match pool_config.plugins {
+                            Some(ref plugins) => Some(plugins.clone()),
+                            None => config.plugins.clone(),
+                        },
+                    },
+                    validated: Arc::new(AtomicBool::new(false)),
+                    paused: Arc::new(AtomicBool::new(false)),
+                    paused_waiter: Arc::new(Notify::new()),
+                };
 
-                    // Connect to the servers to make sure pool configuration is valid
-                    // before setting it globally.
-                    // Do this async and somewhere else, we don't have to wait here.
+                // Connect to the servers to make sure pool configuration is valid
+                // before setting it globally.
+                // Do this async and somewhere else, we don't have to wait here.
+                if config.general.validate_config {
                     let mut validate_pool = pool.clone();
                     tokio::task::spawn(async move {
                         let _ = validate_pool.validate().await;
                     });
-
-                    // There is one pool per database/user pair.
-                    new_pools.insert(PoolIdentifier::new(pool_name, &user.username, secret), pool);
                 }
+
+                // There is one pool per database/user pair.
+                new_pools.insert(PoolIdentifier::new(pool_name, &user.username), pool);
             }
         }
 
@@ -590,7 +638,10 @@ impl ConnectionPool {
             {
                 Ok(conn) => conn,
                 Err(err) => {
-                    error!("Banning instance {:?}, error: {:?}", address, err);
+                    error!(
+                        "Connection checkout error for instance {:?}, error: {:?}",
+                        address, err
+                    );
                     self.ban(address, BanReason::FailedCheckout, Some(client_stats));
                     address.stats.error();
                     client_stats.idle();
@@ -666,7 +717,7 @@ impl ConnectionPool {
                 // Health check failed.
                 Err(err) => {
                     error!(
-                        "Banning instance {:?} because of failed health check, {:?}",
+                        "Failed health check on instance {:?}, error: {:?}",
                         address, err
                     );
                 }
@@ -675,7 +726,7 @@ impl ConnectionPool {
             // Health check timed out.
             Err(err) => {
                 error!(
-                    "Banning instance {:?} because of health check timeout, {:?}",
+                    "Health check timeout on instance {:?}, error: {:?}",
                     address, err
                 );
             }
@@ -697,13 +748,16 @@ impl ConnectionPool {
             return;
         }
 
+        error!("Banning instance {:?}, reason: {:?}", address, reason);
+
         let now = chrono::offset::Utc::now().naive_utc();
         let mut guard = self.banlist.write();
-        error!("Banning {:?}", address);
+
         if let Some(client_info) = client_info {
             client_info.ban_error();
             address.stats.error();
         }
+
         guard[address.shard].insert(address.clone(), (reason, now));
     }
 
@@ -866,6 +920,7 @@ pub struct ServerPool {
     client_server_map: ClientServerMap,
     stats: Arc<PoolStats>,
     auth_hash: Arc<RwLock<Option<String>>>,
+    plugins: Option<Plugins>,
 }
 
 impl ServerPool {
@@ -876,6 +931,7 @@ impl ServerPool {
         client_server_map: ClientServerMap,
         stats: Arc<PoolStats>,
         auth_hash: Arc<RwLock<Option<String>>>,
+        plugins: Option<Plugins>,
     ) -> ServerPool {
         ServerPool {
             address,
@@ -884,6 +940,7 @@ impl ServerPool {
             client_server_map,
             stats,
             auth_hash,
+            plugins,
         }
     }
 }
@@ -916,7 +973,19 @@ impl ManageConnection for ServerPool {
         )
         .await
         {
-            Ok(conn) => {
+            Ok(mut conn) => {
+                if let Some(ref plugins) = self.plugins {
+                    if let Some(ref prewarmer) = plugins.prewarmer {
+                        let mut prewarmer = prewarmer::Prewarmer {
+                            enabled: prewarmer.enabled,
+                            server: &mut conn,
+                            queries: &prewarmer.queries,
+                        };
+
+                        prewarmer.run().await?;
+                    }
+                }
+
                 stats.idle();
                 Ok(conn)
             }
@@ -939,10 +1008,10 @@ impl ManageConnection for ServerPool {
 }
 
 /// Get the connection pool
-pub fn get_pool(db: &str, user: &str, secret: Option<String>) -> Option<ConnectionPool> {
-    let identifier = PoolIdentifier::new(db, user, secret);
-
-    (*(*POOLS.load())).get(&identifier).cloned()
+pub fn get_pool(db: &str, user: &str) -> Option<ConnectionPool> {
+    (*(*POOLS.load()))
+        .get(&PoolIdentifier::new(db, user))
+        .cloned()
 }
 
 /// Get a pointer to all configured pools.

src/prometheus.rs

@@ -9,7 +9,7 @@ use std::sync::atomic::Ordering;
 use std::sync::Arc;
 
 use crate::config::Address;
-use crate::pool::{get_all_pools, PoolIdentifier};
+use crate::pool::get_all_pools;
 use crate::stats::{get_pool_stats, get_server_stats, ServerStats};
 
 struct MetricHelpType {
@@ -233,10 +233,10 @@ impl<Value: fmt::Display> PrometheusMetric<Value> {
         Self::from_name(&format!("stats_{}", name), value, labels)
     }
 
-    fn from_pool(pool: &PoolIdentifier, name: &str, value: u64) -> Option<PrometheusMetric<u64>> {
+    fn from_pool(pool: &(String, String), name: &str, value: u64) -> Option<PrometheusMetric<u64>> {
         let mut labels = HashMap::new();
-        labels.insert("pool", pool.db.clone());
-        labels.insert("user", pool.user.clone());
+        labels.insert("pool", pool.0.clone());
+        labels.insert("user", pool.1.clone());
 
         Self::from_name(&format!("pools_{}", name), value, labels)
     }
@@ -294,7 +294,7 @@ fn push_pool_stats(lines: &mut Vec<String>) {
             } else {
                 warn!(
                     "Metric {} not implemented for ({},{})",
-                    name, pool.db, pool.user
+                    name, pool.0, pool.1
                 );
             }
         }

src/query_router.rs

@@ -1,4 +1,4 @@
-/// Route queries automatically based on explicitely requested
+/// Route queries automatically based on explicitly requested
 /// or implied query characteristics.
 use bytes::{Buf, BytesMut};
 use log::{debug, error};
@@ -6,13 +6,16 @@ use once_cell::sync::OnceCell;
 use regex::{Regex, RegexSet};
 use sqlparser::ast::Statement::{Query, StartTransaction};
 use sqlparser::ast::{
-    BinaryOperator, Expr, Ident, JoinConstraint, JoinOperator, SetExpr, TableFactor, Value,
+    BinaryOperator, Expr, Ident, JoinConstraint, JoinOperator, SetExpr, Statement, TableFactor,
+    Value,
 };
 use sqlparser::dialect::PostgreSqlDialect;
 use sqlparser::parser::Parser;
 
 use crate::config::Role;
+use crate::errors::Error;
 use crate::messages::BytesMutReader;
+use crate::plugins::{Intercept, Plugin, PluginOutput, QueryLogger, TableAccess};
 use crate::pool::PoolSettings;
 use crate::sharding::Sharder;
 
@@ -129,6 +132,10 @@ impl QueryRouter {
         self.pool_settings = pool_settings;
     }
 
+    pub fn pool_settings<'a>(&'a self) -> &'a PoolSettings {
+        &self.pool_settings
+    }
+
     /// Try to parse a command and execute it.
     pub fn try_execute_command(&mut self, message_buffer: &BytesMut) -> Option<(Command, String)> {
         let mut message_cursor = Cursor::new(message_buffer);
@@ -324,10 +331,7 @@ impl QueryRouter {
         Some((command, value))
     }
 
-    /// Try to infer which server to connect to based on the contents of the query.
-    pub fn infer(&mut self, message: &BytesMut) -> bool {
-        debug!("Inferring role");
-
+    pub fn parse(message: &BytesMut) -> Result<Vec<sqlparser::ast::Statement>, Error> {
         let mut message_cursor = Cursor::new(message);
 
         let code = message_cursor.get_u8() as char;
@@ -353,28 +357,29 @@ impl QueryRouter {
                 query
             }
 
-            _ => return false,
+            _ => return Err(Error::UnsupportedStatement),
         };
 
-        let ast = match Parser::parse_sql(&PostgreSqlDialect {}, &query) {
-            Ok(ast) => ast,
+        match Parser::parse_sql(&PostgreSqlDialect {}, &query) {
+            Ok(ast) => Ok(ast),
             Err(err) => {
-                // SELECT ... FOR UPDATE won't get parsed correctly.
                 debug!("{}: {}", err, query);
-                self.active_role = Some(Role::Primary);
-                return false;
+                Err(Error::QueryRouterParserError(err.to_string()))
             }
-        };
+        }
+    }
 
-        debug!("AST: {:?}", ast);
+    /// Try to infer which server to connect to based on the contents of the query.
+    pub fn infer(&mut self, ast: &Vec<sqlparser::ast::Statement>) -> Result<(), Error> {
+        debug!("Inferring role");
 
         if ast.is_empty() {
             // That's weird, no idea, let's go to primary
             self.active_role = Some(Role::Primary);
-            return false;
+            return Err(Error::QueryRouterParserError("empty query".into()));
         }
 
-        for q in &ast {
+        for q in ast {
             match q {
                 // All transactions go to the primary, probably a write.
                 StartTransaction { .. } => {
@@ -418,7 +423,7 @@ impl QueryRouter {
             };
         }
 
-        true
+        Ok(())
     }
 
     /// Parse the shard number from the Bind message
@@ -783,6 +788,52 @@ impl QueryRouter {
         }
     }
 
+    /// Add your plugins here and execute them.
+    pub async fn execute_plugins(&self, ast: &Vec<Statement>) -> Result<PluginOutput, Error> {
+        let plugins = match self.pool_settings.plugins {
+            Some(ref plugins) => plugins,
+            None => return Ok(PluginOutput::Allow),
+        };
+
+        if let Some(ref query_logger) = plugins.query_logger {
+            let mut query_logger = QueryLogger {
+                enabled: query_logger.enabled,
+                user: &self.pool_settings.user.username,
+                db: &self.pool_settings.db,
+            };
+
+            let _ = query_logger.run(&self, ast).await;
+        }
+
+        if let Some(ref intercept) = plugins.intercept {
+            let mut intercept = Intercept {
+                enabled: intercept.enabled,
+                config: &intercept,
+            };
+
+            let result = intercept.run(&self, ast).await;
+
+            if let Ok(PluginOutput::Intercept(output)) = result {
+                return Ok(PluginOutput::Intercept(output));
+            }
+        }
+
+        if let Some(ref table_access) = plugins.table_access {
+            let mut table_access = TableAccess {
+                enabled: table_access.enabled,
+                tables: &table_access.tables,
+            };
+
+            let result = table_access.run(&self, ast).await;
+
+            if let Ok(PluginOutput::Deny(error)) = result {
+                return Ok(PluginOutput::Deny(error));
+            }
+        }
+
+        Ok(PluginOutput::Allow)
+    }
+
     fn set_sharding_key(&mut self, sharding_key: i64) -> Option<usize> {
         let sharder = Sharder::new(
             self.pool_settings.shards,
@@ -810,11 +861,22 @@ impl QueryRouter {
     /// Should we attempt to parse queries?
     pub fn query_parser_enabled(&self) -> bool {
         let enabled = match self.query_parser_enabled {
-            None => self.pool_settings.query_parser_enabled,
-            Some(value) => value,
-        };
+            None => {
+                debug!(
+                    "Using pool settings, query_parser_enabled: {}",
+                    self.pool_settings.query_parser_enabled
+                );
+                self.pool_settings.query_parser_enabled
+            }
 
-        debug!("Query parser enabled: {}", enabled);
+            Some(value) => {
+                debug!(
+                    "Using query parser override, query_parser_enabled: {}",
+                    value
+                );
+                value
+            }
+        };
 
         enabled
     }
@@ -862,7 +924,7 @@ mod test {
 
         for query in queries {
             // It's a recognized query
-            assert!(qr.infer(&query));
+            assert!(qr.infer(&QueryRouter::parse(&query).unwrap()).is_ok());
             assert_eq!(qr.role(), Some(Role::Replica));
         }
     }
@@ -881,7 +943,7 @@ mod test {
 
         for query in queries {
             // It's a recognized query
-            assert!(qr.infer(&query));
+            assert!(qr.infer(&QueryRouter::parse(&query).unwrap()).is_ok());
             assert_eq!(qr.role(), Some(Role::Primary));
         }
     }
@@ -893,7 +955,7 @@ mod test {
         let query = simple_query("SELECT * FROM items WHERE id = 5");
         assert!(qr.try_execute_command(&simple_query("SET PRIMARY READS TO on")) != None);
 
-        assert!(qr.infer(&query));
+        assert!(qr.infer(&QueryRouter::parse(&query).unwrap()).is_ok());
         assert_eq!(qr.role(), None);
     }
 
@@ -913,7 +975,7 @@ mod test {
         res.put(prepared_stmt);
         res.put_i16(0);
 
-        assert!(qr.infer(&res));
+        assert!(qr.infer(&QueryRouter::parse(&res).unwrap()).is_ok());
         assert_eq!(qr.role(), Some(Role::Replica));
     }
 
@@ -1077,11 +1139,11 @@ mod test {
         assert_eq!(qr.role(), None);
 
         let query = simple_query("INSERT INTO test_table VALUES (1)");
-        assert!(qr.infer(&query));
+        assert!(qr.infer(&QueryRouter::parse(&query).unwrap()).is_ok());
         assert_eq!(qr.role(), Some(Role::Primary));
 
         let query = simple_query("SELECT * FROM test_table");
-        assert!(qr.infer(&query));
+        assert!(qr.infer(&QueryRouter::parse(&query).unwrap()).is_ok());
         assert_eq!(qr.role(), Some(Role::Replica));
 
         assert!(qr.query_parser_enabled());
@@ -1113,6 +1175,8 @@ mod test {
             auth_query: None,
             auth_query_password: None,
             auth_query_user: None,
+            db: "test".to_string(),
+            plugins: None,
         };
         let mut qr = QueryRouter::new();
         assert_eq!(qr.active_role, None);
@@ -1142,15 +1206,24 @@ mod test {
         QueryRouter::setup();
 
         let mut qr = QueryRouter::new();
-        assert!(qr.infer(&simple_query("BEGIN; SELECT 1; COMMIT;")));
+        assert!(qr
+            .infer(&QueryRouter::parse(&simple_query("BEGIN; SELECT 1; COMMIT;")).unwrap())
+            .is_ok());
         assert_eq!(qr.role(), Role::Primary);
 
-        assert!(qr.infer(&simple_query("SELECT 1; SELECT 2;")));
+        assert!(qr
+            .infer(&QueryRouter::parse(&simple_query("SELECT 1; SELECT 2;")).unwrap())
+            .is_ok());
         assert_eq!(qr.role(), Role::Replica);
 
-        assert!(qr.infer(&simple_query(
-            "SELECT 123; INSERT INTO t VALUES (5); SELECT 1;"
-        )));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    "SELECT 123; INSERT INTO t VALUES (5); SELECT 1;"
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.role(), Role::Primary);
     }
 
@@ -1177,7 +1250,10 @@ mod test {
             auth_query: None,
             auth_query_password: None,
             auth_query_user: None,
+            db: "test".to_string(),
+            plugins: None,
         };
+
         let mut qr = QueryRouter::new();
         qr.update_pool_settings(pool_settings.clone());
 
@@ -1208,47 +1284,84 @@ mod test {
         qr.pool_settings.automatic_sharding_key = Some("data.id".to_string());
         qr.pool_settings.shards = 3;
 
-        assert!(qr.infer(&simple_query("SELECT * FROM data WHERE id = 5")));
+        assert!(qr
+            .infer(&QueryRouter::parse(&simple_query("SELECT * FROM data WHERE id = 5")).unwrap())
+            .is_ok());
         assert_eq!(qr.shard(), 2);
 
-        assert!(qr.infer(&simple_query(
-            "SELECT one, two, three FROM public.data WHERE id = 6"
-        )));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    "SELECT one, two, three FROM public.data WHERE id = 6"
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 0);
 
-        assert!(qr.infer(&simple_query(
-            "SELECT * FROM data
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    "SELECT * FROM data
             INNER JOIN t2 ON data.id = 5
             AND t2.data_id = data.id
         WHERE data.id = 5"
-        )));
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 2);
 
         // Shard did not move because we couldn't determine the sharding key since it could be ambiguous
         // in the query.
-        assert!(qr.infer(&simple_query(
-            "SELECT * FROM t2 INNER JOIN data ON id = 6 AND data.id = t2.data_id"
-        )));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    "SELECT * FROM t2 INNER JOIN data ON id = 6 AND data.id = t2.data_id"
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 2);
 
-        assert!(qr.infer(&simple_query(
-            r#"SELECT * FROM "public"."data" WHERE "id" = 6"#
-        )));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    r#"SELECT * FROM "public"."data" WHERE "id" = 6"#
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 0);
 
-        assert!(qr.infer(&simple_query(
-            r#"SELECT * FROM "public"."data" WHERE "data"."id" = 5"#
-        )));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    r#"SELECT * FROM "public"."data" WHERE "data"."id" = 5"#
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 2);
 
         // Super unique sharding key
         qr.pool_settings.automatic_sharding_key = Some("*.unique_enough_column_name".to_string());
-        assert!(qr.infer(&simple_query(
-            "SELECT * FROM table_x WHERE unique_enough_column_name = 6"
-        )));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query(
+                    "SELECT * FROM table_x WHERE unique_enough_column_name = 6"
+                ))
+                .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 0);
 
-        assert!(qr.infer(&simple_query("SELECT * FROM table_y WHERE another_key = 5")));
+        assert!(qr
+            .infer(
+                &QueryRouter::parse(&simple_query("SELECT * FROM table_y WHERE another_key = 5"))
+                    .unwrap()
+            )
+            .is_ok());
         assert_eq!(qr.shard(), 0);
     }
 
@@ -1272,11 +1385,61 @@ mod test {
         qr.pool_settings.automatic_sharding_key = Some("data.id".to_string());
         qr.pool_settings.shards = 3;
 
-        assert!(qr.infer(&simple_query(stmt)));
+        assert!(qr
+            .infer(&QueryRouter::parse(&simple_query(stmt)).unwrap())
+            .is_ok());
         assert_eq!(qr.placeholders.len(), 1);
 
         assert!(qr.infer_shard_from_bind(&bind));
         assert_eq!(qr.shard(), 2);
         assert!(qr.placeholders.is_empty());
     }
+
+    #[tokio::test]
+    async fn test_table_access_plugin() {
+        use crate::config::{Plugins, TableAccess};
+        let table_access = TableAccess {
+            enabled: true,
+            tables: vec![String::from("pg_database")],
+        };
+        let plugins = Plugins {
+            table_access: Some(table_access),
+            intercept: None,
+            query_logger: None,
+            prewarmer: None,
+        };
+
+        QueryRouter::setup();
+        let mut pool_settings = PoolSettings::default();
+        pool_settings.query_parser_enabled = true;
+        pool_settings.plugins = Some(plugins);
+
+        let mut qr = QueryRouter::new();
+        qr.update_pool_settings(pool_settings);
+
+        let query = simple_query("SELECT * FROM pg_database");
+        let ast = QueryRouter::parse(&query).unwrap();
+
+        let res = qr.execute_plugins(&ast).await;
+
+        assert_eq!(
+            res,
+            Ok(PluginOutput::Deny(
+                "permission for table \"pg_database\" denied".to_string()
+            ))
+        );
+    }
+
+    #[tokio::test]
+    async fn test_plugins_disabled_by_defaault() {
+        QueryRouter::setup();
+        let qr = QueryRouter::new();
+
+        let query = simple_query("SELECT * FROM pg_database");
+        let ast = QueryRouter::parse(&query).unwrap();
+
+        let res = qr.execute_plugins(&ast).await;
+
+        assert_eq!(res, Ok(PluginOutput::Allow));
+    }
 }

src/server.rs

@@ -7,22 +7,143 @@ use parking_lot::{Mutex, RwLock};
 use postgres_protocol::message;
 use std::collections::HashMap;
 use std::io::Read;
+use std::net::IpAddr;
 use std::sync::Arc;
 use std::time::SystemTime;
-use tokio::io::{AsyncReadExt, BufReader};
-use tokio::net::{
-    tcp::{OwnedReadHalf, OwnedWriteHalf},
-    TcpStream,
-};
+use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, BufStream};
+use tokio::net::TcpStream;
+use tokio_rustls::rustls::{OwnedTrustAnchor, RootCertStore};
+use tokio_rustls::{client::TlsStream, TlsConnector};
 
-use crate::config::{Address, User};
+use crate::config::{get_config, Address, User};
 use crate::constants::*;
-use crate::errors::Error;
+use crate::dns_cache::{AddrSet, CACHED_RESOLVER};
+use crate::errors::{Error, ServerIdentifier};
 use crate::messages::*;
 use crate::mirrors::MirroringManager;
 use crate::pool::ClientServerMap;
 use crate::scram::ScramSha256;
 use crate::stats::ServerStats;
+use std::io::Write;
+
+use pin_project::pin_project;
+
+#[pin_project(project = SteamInnerProj)]
+pub enum StreamInner {
+    Plain {
+        #[pin]
+        stream: TcpStream,
+    },
+    Tls {
+        #[pin]
+        stream: TlsStream<TcpStream>,
+    },
+}
+
+impl AsyncWrite for StreamInner {
+    fn poll_write(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+        buf: &[u8],
+    ) -> std::task::Poll<Result<usize, std::io::Error>> {
+        let this = self.project();
+        match this {
+            SteamInnerProj::Tls { stream } => stream.poll_write(cx, buf),
+            SteamInnerProj::Plain { stream } => stream.poll_write(cx, buf),
+        }
+    }
+
+    fn poll_flush(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<(), std::io::Error>> {
+        let this = self.project();
+        match this {
+            SteamInnerProj::Tls { stream } => stream.poll_flush(cx),
+            SteamInnerProj::Plain { stream } => stream.poll_flush(cx),
+        }
+    }
+
+    fn poll_shutdown(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<(), std::io::Error>> {
+        let this = self.project();
+        match this {
+            SteamInnerProj::Tls { stream } => stream.poll_shutdown(cx),
+            SteamInnerProj::Plain { stream } => stream.poll_shutdown(cx),
+        }
+    }
+}
+
+impl AsyncRead for StreamInner {
+    fn poll_read(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+        buf: &mut tokio::io::ReadBuf<'_>,
+    ) -> std::task::Poll<std::io::Result<()>> {
+        let this = self.project();
+        match this {
+            SteamInnerProj::Tls { stream } => stream.poll_read(cx, buf),
+            SteamInnerProj::Plain { stream } => stream.poll_read(cx, buf),
+        }
+    }
+}
+
+impl StreamInner {
+    pub fn try_write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        match self {
+            StreamInner::Tls { stream } => {
+                let r = stream.get_mut();
+                let mut w = r.1.writer();
+                w.write(buf)
+            }
+            StreamInner::Plain { stream } => stream.try_write(buf),
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+struct CleanupState {
+    /// If server connection requires DISCARD ALL before checkin because of set statement
+    needs_cleanup_set: bool,
+
+    /// If server connection requires DISCARD ALL before checkin because of prepare statement
+    needs_cleanup_prepare: bool,
+}
+
+impl CleanupState {
+    fn new() -> Self {
+        CleanupState {
+            needs_cleanup_set: false,
+            needs_cleanup_prepare: false,
+        }
+    }
+
+    fn needs_cleanup(&self) -> bool {
+        self.needs_cleanup_set || self.needs_cleanup_prepare
+    }
+
+    fn set_true(&mut self) {
+        self.needs_cleanup_set = true;
+        self.needs_cleanup_prepare = true;
+    }
+
+    fn reset(&mut self) {
+        self.needs_cleanup_set = false;
+        self.needs_cleanup_prepare = false;
+    }
+}
+
+impl std::fmt::Display for CleanupState {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "SET: {}, PREPARE: {}",
+            self.needs_cleanup_set, self.needs_cleanup_prepare
+        )
+    }
+}
 
 /// Server state.
 pub struct Server {
@@ -30,11 +151,8 @@ pub struct Server {
     /// port, e.g. 5432, and role, e.g. primary or replica.
     address: Address,
 
-    /// Buffered read socket.
-    read: BufReader<OwnedReadHalf>,
-
-    /// Unbuffered write socket (our client code buffers).
-    write: OwnedWriteHalf,
+    /// Server TCP connection.
+    stream: BufStream<StreamInner>,
 
     /// Our server response buffer. We buffer data before we give it to the client.
     buffer: BytesMut,
@@ -55,8 +173,8 @@ pub struct Server {
     /// Is the server broken? We'll remote it from the pool if so.
     bad: bool,
 
-    /// If server connection requires a DISCARD ALL before checkin
-    needs_cleanup: bool,
+    /// If server connection requires DISCARD ALL before checkin
+    cleanup_state: CleanupState,
 
     /// Mapping of clients and servers used for query cancellation.
     client_server_map: ClientServerMap,
@@ -74,6 +192,9 @@ pub struct Server {
     last_activity: SystemTime,
 
     mirror_manager: Option<MirroringManager>,
+
+    // Associated addresses used
+    addr_set: Option<AddrSet>,
 }
 
 impl Server {
@@ -87,6 +208,24 @@ impl Server {
         stats: Arc<ServerStats>,
         auth_hash: Arc<RwLock<Option<String>>>,
     ) -> Result<Server, Error> {
+        let cached_resolver = CACHED_RESOLVER.load();
+        let mut addr_set: Option<AddrSet> = None;
+
+        // If we are caching addresses and hostname is not an IP
+        if cached_resolver.enabled() && address.host.parse::<IpAddr>().is_err() {
+            debug!("Resolving {}", &address.host);
+            addr_set = match cached_resolver.lookup_ip(&address.host).await {
+                Ok(ok) => {
+                    debug!("Obtained: {:?}", ok);
+                    Some(ok)
+                }
+                Err(err) => {
+                    warn!("Error trying to resolve {}, ({:?})", &address.host, err);
+                    None
+                }
+            }
+        };
+
         let mut stream =
             match TcpStream::connect(&format!("{}:{}", &address.host, address.port)).await {
                 Ok(stream) => stream,
@@ -98,33 +237,137 @@ impl Server {
                     )));
                 }
             };
+
+        // TCP timeouts.
         configure_socket(&stream);
 
+        let config = get_config();
+
+        let mut stream = if config.general.server_tls {
+            // Request a TLS connection
+            ssl_request(&mut stream).await?;
+
+            let response = match stream.read_u8().await {
+                Ok(response) => response as char,
+                Err(err) => {
+                    return Err(Error::SocketError(format!(
+                        "Server socket error: {:?}",
+                        err
+                    )))
+                }
+            };
+
+            match response {
+                // Server supports TLS
+                'S' => {
+                    debug!("Connecting to server using TLS");
+
+                    let mut root_store = RootCertStore::empty();
+                    root_store.add_server_trust_anchors(
+                        webpki_roots::TLS_SERVER_ROOTS.0.iter().map(|ta| {
+                            OwnedTrustAnchor::from_subject_spki_name_constraints(
+                                ta.subject,
+                                ta.spki,
+                                ta.name_constraints,
+                            )
+                        }),
+                    );
+
+                    let mut tls_config = rustls::ClientConfig::builder()
+                        .with_safe_defaults()
+                        .with_root_certificates(root_store)
+                        .with_no_client_auth();
+
+                    // Equivalent to sslmode=prefer which is fine most places.
+                    // If you want verify-full, change `verify_server_certificate` to true.
+                    if !config.general.verify_server_certificate {
+                        let mut dangerous = tls_config.dangerous();
+                        dangerous.set_certificate_verifier(Arc::new(
+                            crate::tls::NoCertificateVerification {},
+                        ));
+                    }
+
+                    let connector = TlsConnector::from(Arc::new(tls_config));
+                    let stream = match connector
+                        .connect(address.host.as_str().try_into().unwrap(), stream)
+                        .await
+                    {
+                        Ok(stream) => stream,
+                        Err(err) => {
+                            return Err(Error::SocketError(format!("Server TLS error: {:?}", err)))
+                        }
+                    };
+
+                    StreamInner::Tls { stream }
+                }
+
+                // Server does not support TLS
+                'N' => StreamInner::Plain { stream },
+
+                // Something else?
+                m => {
+                    return Err(Error::SocketError(format!(
+                        "Unknown message: {}",
+                        m as char
+                    )));
+                }
+            }
+        } else {
+            StreamInner::Plain { stream }
+        };
+
+        // let (read, write) = split(stream);
+        // let (mut read, mut write) = (ReadInner::Plain { stream: read }, WriteInner::Plain { stream: write });
+
         trace!("Sending StartupMessage");
 
         // StartupMessage
-        startup(&mut stream, &user.username, database).await?;
+        let username = match user.server_username {
+            Some(ref server_username) => server_username,
+            None => &user.username,
+        };
+
+        let password = match user.server_password {
+            Some(ref server_password) => Some(server_password),
+            None => match user.password {
+                Some(ref password) => Some(password),
+                None => None,
+            },
+        };
+
+        startup(&mut stream, username, database).await?;
 
         let mut server_info = BytesMut::new();
         let mut process_id: i32 = 0;
         let mut secret_key: i32 = 0;
+        let server_identifier = ServerIdentifier::new(username, &database);
 
         // 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: Option<ScramSha256> = None;
-        if let Some(password) = &user.password.clone() {
-            scram = Some(ScramSha256::new(password));
-        }
+        let mut scram: Option<ScramSha256> = match password {
+            Some(password) => Some(ScramSha256::new(password)),
+            None => None,
+        };
 
         loop {
             let code = match stream.read_u8().await {
                 Ok(code) => code as char,
-                Err(_) => return Err(Error::SocketError(format!("Error reading message code on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                Err(_) => {
+                    return Err(Error::ServerStartupError(
+                        "message code".into(),
+                        server_identifier,
+                    ))
+                }
             };
 
             let len = match stream.read_i32().await {
                 Ok(len) => len,
-                Err(_) => return Err(Error::SocketError(format!("Error reading message len on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                Err(_) => {
+                    return Err(Error::ServerStartupError(
+                        "message len".into(),
+                        server_identifier,
+                    ))
+                }
             };
 
             trace!("Message: {}", code);
@@ -135,7 +378,12 @@ 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(format!("Error reading auth code on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                        Err(_) => {
+                            return Err(Error::ServerStartupError(
+                                "auth code".into(),
+                                server_identifier,
+                            ))
+                        }
                     };
 
                     trace!("Auth: {}", auth_code);
@@ -148,14 +396,18 @@ impl Server {
 
                             match stream.read_exact(&mut salt).await {
                                 Ok(_) => (),
-                                Err(_) => return Err(Error::SocketError(format!("Error reading salt on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                                Err(_) => {
+                                    return Err(Error::ServerStartupError(
+                                        "salt".into(),
+                                        server_identifier,
+                                    ))
+                                }
                             };
 
-                            match &user.password {
+                            match password {
                                 // Using plaintext password
                                 Some(password) => {
-                                    md5_password(&mut stream, &user.username, password, &salt[..])
-                                        .await?
+                                    md5_password(&mut stream, username, password, &salt[..]).await?
                                 }
 
                                 // Using auth passthrough, in this case we should already have a
@@ -171,8 +423,12 @@ impl Server {
                                                 &salt[..],
                                             )
                                             .await?,
-                                        None =>
-                                            return Err(Error::AuthError(format!("Auth passthrough (auth_query) failed and no user password is set in cleartext for {{ username: {:?}, database: {:?} }}", user.username, database)))
+                                        None => return Err(
+                                            Error::ServerAuthError(
+                                                "Auth passthrough (auth_query) failed and no user password is set in cleartext".into(),
+                                                server_identifier
+                                            )
+                                        ),
                                     }
                                 }
                             }
@@ -182,21 +438,33 @@ impl Server {
 
                         SASL => {
                             if scram.is_none() {
-                                return Err(Error::AuthError(format!("SASL auth required and not password specified, auth passthrough (auth_query) method is currently unsupported for SASL auth {{ username: {:?}, database: {:?} }}", user.username, database)));
+                                return Err(Error::ServerAuthError(
+                                    "SASL auth required and no password specified. \
+                                    Auth passthrough (auth_query) method is currently \
+                                    unsupported for SASL auth"
+                                        .into(),
+                                    server_identifier,
+                                ));
                             }
 
                             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))),
+                                Err(_) => {
+                                    return Err(Error::ServerStartupError(
+                                        "sasl message".into(),
+                                        server_identifier,
+                                    ))
+                                }
                             };
 
                             let sasl_type = String::from_utf8_lossy(&sasl_auth[..sasl_len - 2]);
 
-                            if sasl_type == SCRAM_SHA_256 {
+                            if sasl_type.contains(SCRAM_SHA_256) {
                                 debug!("Using {}", SCRAM_SHA_256);
 
                                 // Generate client message.
@@ -219,7 +487,7 @@ impl Server {
                                 res.put_i32(sasl_response.len() as i32);
                                 res.put(sasl_response);
 
-                                write_all(&mut stream, res).await?;
+                                write_all_flush(&mut stream, &res).await?;
                             } else {
                                 error!("Unsupported SCRAM version: {}", sasl_type);
                                 return Err(Error::ServerError);
@@ -233,7 +501,12 @@ impl Server {
 
                             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))),
+                                Err(_) => {
+                                    return Err(Error::ServerStartupError(
+                                        "sasl cont message".into(),
+                                        server_identifier,
+                                    ))
+                                }
                             };
 
                             let msg = BytesMut::from(&sasl_data[..]);
@@ -245,7 +518,7 @@ impl Server {
                             res.put_i32(4 + sasl_response.len() as i32);
                             res.put(sasl_response);
 
-                            write_all(&mut stream, res).await?;
+                            write_all_flush(&mut stream, &res).await?;
                         }
 
                         SASL_FINAL => {
@@ -254,7 +527,12 @@ impl Server {
                             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))),
+                                Err(_) => {
+                                    return Err(Error::ServerStartupError(
+                                        "sasl final message".into(),
+                                        server_identifier,
+                                    ))
+                                }
                             };
 
                             match scram
@@ -284,7 +562,12 @@ impl Server {
                 'E' => {
                     let error_code = match stream.read_u8().await {
                         Ok(error_code) => error_code,
-                        Err(_) => return Err(Error::SocketError(format!("Error reading error code message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                        Err(_) => {
+                            return Err(Error::ServerStartupError(
+                                "error code message".into(),
+                                server_identifier,
+                            ))
+                        }
                     };
 
                     trace!("Error: {}", error_code);
@@ -300,7 +583,12 @@ impl Server {
 
                             match stream.read_exact(&mut error).await {
                                 Ok(_) => (),
-                                Err(_) => return Err(Error::SocketError(format!("Error reading error message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                                Err(_) => {
+                                    return Err(Error::ServerStartupError(
+                                        "error message".into(),
+                                        server_identifier,
+                                    ))
+                                }
                             };
 
                             // TODO: the error message contains multiple fields; we can decode them and
@@ -319,7 +607,12 @@ impl Server {
 
                     match stream.read_exact(&mut param).await {
                         Ok(_) => (),
-                        Err(_) => return Err(Error::SocketError(format!("Error reading parameter status message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                        Err(_) => {
+                            return Err(Error::ServerStartupError(
+                                "parameter status message".into(),
+                                server_identifier,
+                            ))
+                        }
                     };
 
                     // Save the parameter so we can pass it to the client later.
@@ -336,12 +629,22 @@ impl Server {
                     // 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(format!("Error reading process id message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                        Err(_) => {
+                            return Err(Error::ServerStartupError(
+                                "process id message".into(),
+                                server_identifier,
+                            ))
+                        }
                     };
 
                     secret_key = match stream.read_i32().await {
                         Ok(id) => id,
-                        Err(_) => return Err(Error::SocketError(format!("Error reading secret key message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                        Err(_) => {
+                            return Err(Error::ServerStartupError(
+                                "secret key message".into(),
+                                server_identifier,
+                            ))
+                        }
                     };
                 }
 
@@ -351,15 +654,17 @@ impl Server {
 
                     match stream.read_exact(&mut idle).await {
                         Ok(_) => (),
-                        Err(_) => return Err(Error::SocketError(format!("Error reading transaction status message on server startup {{ username: {:?}, database: {:?} }}", user.username, database))),
+                        Err(_) => {
+                            return Err(Error::ServerStartupError(
+                                "transaction status message".into(),
+                                server_identifier,
+                            ))
+                        }
                     };
 
-                    let (read, write) = stream.into_split();
-
                     let mut server = Server {
                         address: address.clone(),
-                        read: BufReader::new(read),
-                        write,
+                        stream: BufStream::new(stream),
                         buffer: BytesMut::with_capacity(8196),
                         server_info,
                         process_id,
@@ -367,8 +672,9 @@ impl Server {
                         in_transaction: false,
                         data_available: false,
                         bad: false,
-                        needs_cleanup: false,
+                        cleanup_state: CleanupState::new(),
                         client_server_map,
+                        addr_set,
                         connected_at: chrono::offset::Utc::now().naive_utc(),
                         stats,
                         application_name: String::new(),
@@ -413,7 +719,7 @@ impl Server {
             Ok(stream) => stream,
             Err(err) => {
                 error!("Could not connect to server: {}", err);
-                return Err(Error::SocketError(format!("Error reading cancel message")));
+                return Err(Error::SocketError("Error reading cancel message".into()));
             }
         };
         configure_socket(&stream);
@@ -426,7 +732,7 @@ impl Server {
         bytes.put_i32(process_id);
         bytes.put_i32(secret_key);
 
-        write_all(&mut stream, bytes).await
+        write_all_flush(&mut stream, &bytes).await
     }
 
     /// Send messages to the server from the client.
@@ -434,14 +740,17 @@ impl Server {
         self.mirror_send(messages);
         self.stats().data_sent(messages.len());
 
-        match write_all_half(&mut self.write, messages).await {
+        match write_all_flush(&mut self.stream, &messages).await {
             Ok(_) => {
                 // Successfully sent to server
                 self.last_activity = SystemTime::now();
                 Ok(())
             }
             Err(err) => {
-                error!("Terminating server because of: {:?}", err);
+                error!(
+                    "Terminating server {:?} because of: {:?}",
+                    self.address, err
+                );
                 self.bad = true;
                 Err(err)
             }
@@ -453,10 +762,13 @@ impl Server {
     /// in order to receive all data the server has to offer.
     pub async fn recv(&mut self) -> Result<BytesMut, Error> {
         loop {
-            let mut message = match read_message(&mut self.read).await {
+            let mut message = match read_message(&mut self.stream).await {
                 Ok(message) => message,
                 Err(err) => {
-                    error!("Terminating server because of: {:?}", err);
+                    error!(
+                        "Terminating server {:?} because of: {:?}",
+                        self.address, err
+                    );
                     self.bad = true;
                     return Err(err);
                 }
@@ -523,12 +835,12 @@ impl Server {
                                     // This will reduce amount of discard statements sent
                                     if !self.in_transaction {
                                         debug!("Server connection marked for clean up");
-                                        self.needs_cleanup = true;
+                                        self.cleanup_state.needs_cleanup_set = true;
                                     }
                                 }
                                 "PREPARE\0" => {
                                     debug!("Server connection marked for clean up");
-                                    self.needs_cleanup = true;
+                                    self.cleanup_state.needs_cleanup_prepare = true;
                                 }
                                 _ => (),
                             }
@@ -609,7 +921,23 @@ impl Server {
     /// Server & client are out of sync, we must discard this connection.
     /// This happens with clients that misbehave.
     pub fn is_bad(&self) -> bool {
-        self.bad
+        if self.bad {
+            return self.bad;
+        };
+        let cached_resolver = CACHED_RESOLVER.load();
+        if cached_resolver.enabled() {
+            if let Some(addr_set) = &self.addr_set {
+                if cached_resolver.has_changed(self.address.host.as_str(), addr_set) {
+                    warn!(
+                        "DNS changed for {}, it was {:?}. Dropping server connection.",
+                        self.address.host.as_str(),
+                        addr_set
+                    );
+                    return true;
+                }
+            }
+        }
+        false
     }
 
     /// Get server startup information to forward it to the client.
@@ -642,6 +970,8 @@ impl Server {
     /// It will use the simple query protocol.
     /// Result will not be returned, so this is useful for things like `SET` or `ROLLBACK`.
     pub async fn query(&mut self, query: &str) -> Result<(), Error> {
+        debug!("Running `{}` on server {:?}", query, self.address);
+
         let query = simple_query(query);
 
         self.send(&query).await?;
@@ -674,10 +1004,11 @@ impl Server {
         // 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");
+        if self.cleanup_state.needs_cleanup() {
+            warn!("Server returned with session state altered, discarding state ({}) for application {}", self.cleanup_state, self.application_name);
             self.query("DISCARD ALL").await?;
-            self.needs_cleanup = false;
+            self.query("RESET ROLE").await?;
+            self.cleanup_state.reset();
         }
 
         Ok(())
@@ -689,12 +1020,12 @@ impl Server {
             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 needs_cleanup_before = self.cleanup_state;
 
             let result = Ok(self
                 .query(&format!("SET application_name = '{}'", name))
                 .await?);
-            self.needs_cleanup = needs_cleanup_before;
+            self.cleanup_state = needs_cleanup_before;
             result
         } else {
             Ok(())
@@ -719,7 +1050,7 @@ impl Server {
 
     // Marks a connection as needing DISCARD ALL at checkin
     pub fn mark_dirty(&mut self) {
-        self.needs_cleanup = true;
+        self.cleanup_state.set_true();
     }
 
     pub fn mirror_send(&mut self, bytes: &BytesMut) {
@@ -755,9 +1086,7 @@ impl Server {
             Arc::new(RwLock::new(None)),
         )
         .await?;
-
-        debug!("Connected!, sending query: {}", query);
-
+        debug!("Connected!, sending query.");
         server.send(&simple_query(query)).await?;
         let mut message = server.recv().await?;
 
@@ -766,8 +1095,6 @@ impl Server {
 }
 
 async fn parse_query_message(message: &mut BytesMut) -> Result<Vec<String>, Error> {
-    debug!("Parsing query message");
-
     let mut pair = Vec::<String>::new();
     match message::backend::Message::parse(message) {
         Ok(Some(message::backend::Message::RowDescription(_description))) => {}
@@ -837,9 +1164,6 @@ async fn parse_query_message(message: &mut BytesMut) -> Result<Vec<String>, Erro
             }
         };
     }
-
-    debug!("Got auth hash successfully");
-
     Ok(pair)
 }
 
@@ -853,23 +1177,27 @@ impl Drop for Server {
         // Update statistics
         self.stats.disconnect();
 
-        let mut bytes = BytesMut::with_capacity(4);
+        let mut bytes = BytesMut::with_capacity(5);
         bytes.put_u8(b'X');
         bytes.put_i32(4);
 
-        match self.write.try_write(&bytes) {
-            Ok(_) => (),
-            Err(_) => debug!("Dirty shutdown"),
+        match self.stream.get_mut().try_write(&bytes) {
+            Ok(5) => (),
+            _ => debug!("Dirty shutdown"),
         };
 
-        // Should not matter.
-        self.bad = true;
-
         let now = chrono::offset::Utc::now().naive_utc();
         let duration = now - self.connected_at;
 
+        let message = if self.bad {
+            "Server connection terminated"
+        } else {
+            "Server connection closed"
+        };
+
         info!(
-            "Server connection closed {:?}, session duration: {}",
+            "{} {:?}, session duration: {}",
+            message,
             self.address,
             crate::format_duration(&duration)
         );

src/stats.rs

@@ -22,7 +22,7 @@ pub use server::{ServerState, ServerStats};
 /// Convenience types for various stats
 type ClientStatesLookup = HashMap<i32, Arc<ClientStats>>;
 type ServerStatesLookup = HashMap<i32, Arc<ServerStats>>;
-type PoolStatsLookup = HashMap<PoolIdentifier, Arc<PoolStats>>;
+type PoolStatsLookup = HashMap<(String, String), Arc<PoolStats>>;
 
 /// Stats for individual client connections
 /// Used in SHOW CLIENTS.
@@ -66,7 +66,7 @@ impl Reporter {
         CLIENT_STATS.write().insert(client_id, stats);
     }
 
-    /// Reports a client is disconecting from the pooler.
+    /// Reports a client is disconnecting from the pooler.
     fn client_disconnecting(&self, client_id: i32) {
         CLIENT_STATS.write().remove(&client_id);
     }
@@ -76,14 +76,16 @@ impl Reporter {
     fn server_register(&self, server_id: i32, stats: Arc<ServerStats>) {
         SERVER_STATS.write().insert(server_id, stats);
     }
-    /// Reports a server connection is disconecting from the pooler.
+    /// Reports a server connection is disconnecting from the pooler.
     fn server_disconnecting(&self, server_id: i32) {
         SERVER_STATS.write().remove(&server_id);
     }
 
     /// Register a pool with the stats system.
     fn pool_register(&self, identifier: PoolIdentifier, stats: Arc<PoolStats>) {
-        POOL_STATS.write().insert(identifier, stats);
+        POOL_STATS
+            .write()
+            .insert((identifier.db, identifier.user), stats);
     }
 }
 
@@ -105,8 +107,19 @@ impl Collector {
             loop {
                 interval.tick().await;
 
-                for stats in SERVER_STATS.read().values() {
-                    stats.address_stats().update_averages();
+                // Hold read lock for duration of update to retain all server stats
+                let server_stats = SERVER_STATS.read();
+
+                for stats in server_stats.values() {
+                    if !stats.check_address_stat_average_is_updated_status() {
+                        stats.address_stats().update_averages();
+                        stats.set_address_stat_average_is_updated_status(true);
+                    }
+                }
+
+                // Reset to false for next update
+                for stats in server_stats.values() {
+                    stats.set_address_stat_average_is_updated_status(false);
                 }
             }
         });

src/stats/address.rs

@@ -1,4 +1,3 @@
-use log::warn;
 use std::sync::atomic::*;
 use std::sync::Arc;
 
@@ -13,6 +12,16 @@ pub struct AddressStats {
     pub total_query_time: Arc<AtomicU64>,
     pub total_wait_time: Arc<AtomicU64>,
     pub total_errors: Arc<AtomicU64>,
+
+    pub old_total_xact_count: Arc<AtomicU64>,
+    pub old_total_query_count: Arc<AtomicU64>,
+    pub old_total_received: Arc<AtomicU64>,
+    pub old_total_sent: Arc<AtomicU64>,
+    pub old_total_xact_time: Arc<AtomicU64>,
+    pub old_total_query_time: Arc<AtomicU64>,
+    pub old_total_wait_time: Arc<AtomicU64>,
+    pub old_total_errors: Arc<AtomicU64>,
+
     pub avg_query_count: Arc<AtomicU64>,
     pub avg_query_time: Arc<AtomicU64>,
     pub avg_recv: Arc<AtomicU64>,
@@ -21,6 +30,9 @@ pub struct AddressStats {
     pub avg_xact_time: Arc<AtomicU64>,
     pub avg_xact_count: Arc<AtomicU64>,
     pub avg_wait_time: Arc<AtomicU64>,
+
+    // Determines if the averages have been updated since the last time they were reported
+    pub averages_updated: Arc<AtomicBool>,
 }
 
 impl IntoIterator for AddressStats {
@@ -104,16 +116,15 @@ impl AddressStats {
     }
 
     pub fn update_averages(&self) {
-        let (totals, averages) = self.fields_iterators();
-        for data in totals.iter().zip(averages.iter()) {
-            let (total, average) = data;
-            if let Err(err) = average.fetch_update(Ordering::Relaxed, Ordering::Relaxed, |avg| {
-                let total = total.load(Ordering::Relaxed);
-                let avg = (total - avg) / (crate::stats::STAT_PERIOD / 1_000); // Avg / second
-                Some(avg)
-            }) {
-                warn!("Could not update averages for addresses stats, {:?}", err);
-            }
+        let (totals, averages, old_totals) = self.fields_iterators();
+        for (total, average, old_total) in itertools::izip!(totals, averages, old_totals) {
+            let total_value = total.load(Ordering::Relaxed);
+            let old_total_value = old_total.load(Ordering::Relaxed);
+            average.store(
+                (total_value - old_total_value) / (crate::stats::STAT_PERIOD / 1_000),
+                Ordering::Relaxed,
+            ); // Avg / second
+            old_total.store(total_value, Ordering::Relaxed);
         }
     }
 
@@ -123,27 +134,42 @@ impl AddressStats {
         }
     }
 
-    fn fields_iterators(&self) -> (Vec<Arc<AtomicU64>>, Vec<Arc<AtomicU64>>) {
+    fn fields_iterators(
+        &self,
+    ) -> (
+        Vec<Arc<AtomicU64>>,
+        Vec<Arc<AtomicU64>>,
+        Vec<Arc<AtomicU64>>,
+    ) {
         let mut totals: Vec<Arc<AtomicU64>> = Vec::new();
         let mut averages: Vec<Arc<AtomicU64>> = Vec::new();
+        let mut old_totals: Vec<Arc<AtomicU64>> = Vec::new();
 
         totals.push(self.total_xact_count.clone());
+        old_totals.push(self.old_total_xact_count.clone());
         averages.push(self.avg_xact_count.clone());
         totals.push(self.total_query_count.clone());
+        old_totals.push(self.old_total_query_count.clone());
         averages.push(self.avg_query_count.clone());
         totals.push(self.total_received.clone());
+        old_totals.push(self.old_total_received.clone());
         averages.push(self.avg_recv.clone());
         totals.push(self.total_sent.clone());
+        old_totals.push(self.old_total_sent.clone());
         averages.push(self.avg_sent.clone());
         totals.push(self.total_xact_time.clone());
+        old_totals.push(self.old_total_xact_time.clone());
         averages.push(self.avg_xact_time.clone());
         totals.push(self.total_query_time.clone());
+        old_totals.push(self.old_total_query_time.clone());
         averages.push(self.avg_query_time.clone());
         totals.push(self.total_wait_time.clone());
+        old_totals.push(self.old_total_wait_time.clone());
         averages.push(self.avg_wait_time.clone());
         totals.push(self.total_errors.clone());
+        old_totals.push(self.old_total_errors.clone());
         averages.push(self.avg_errors.clone());
 
-        (totals, averages)
+        (totals, averages, old_totals)
     }
 }

src/stats/client.rs

@@ -92,7 +92,7 @@ impl ClientStats {
         }
     }
 
-    /// Reports a client is disconecting from the pooler and
+    /// Reports a client is disconnecting from the pooler and
     /// update metrics on the corresponding pool.
     pub fn disconnect(&self) {
         self.reporter.client_disconnecting(self.client_id);
@@ -140,7 +140,7 @@ impl ClientStats {
         self.error_count.fetch_add(1, Ordering::Relaxed);
     }
 
-    /// Reportes the time spent by a client waiting to get a healthy connection from the pool
+    /// Reporters the time spent by a client waiting to get a healthy connection from the pool
     pub fn checkout_time(&self, microseconds: u64) {
         self.total_wait_time
             .fetch_add(microseconds, Ordering::Relaxed);

src/stats/pool.rs

@@ -102,13 +102,6 @@ impl PoolStats {
         self.identifier.user.clone()
     }
 
-    pub fn redacted_secret(&self) -> String {
-        match self.identifier.secret {
-            Some(ref s) => format!("****{}", &s[s.len() - 4..]),
-            None => "<no secret>".to_string(),
-        }
-    }
-
     pub fn pool_mode(&self) -> PoolMode {
         self.config.pool_mode
     }

src/stats/server.rs

@@ -100,10 +100,9 @@ impl ServerStats {
             .server_idle(self.state.load(Ordering::Relaxed));
 
         self.state.store(ServerState::Idle, Ordering::Relaxed);
-        self.set_undefined_application();
     }
 
-    /// Reports a server connection is disconecting from the pooler.
+    /// Reports a server connection is disconnecting from the pooler.
     /// Also updates metrics on the pool regarding server usage.
     pub fn disconnect(&self) {
         self.reporter.server_disconnecting(self.server_id);
@@ -140,6 +139,17 @@ impl ServerStats {
         self.address.stats.clone()
     }
 
+    pub fn check_address_stat_average_is_updated_status(&self) -> bool {
+        self.address.stats.averages_updated.load(Ordering::Relaxed)
+    }
+
+    pub fn set_address_stat_average_is_updated_status(&self, is_checked: bool) {
+        self.address
+            .stats
+            .averages_updated
+            .store(is_checked, Ordering::Relaxed);
+    }
+
     // Helper methods for show_servers
     pub fn pool_name(&self) -> String {
         self.pool_stats.database()

src/tls.rs

@@ -4,7 +4,12 @@ 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 std::time::SystemTime;
+use tokio_rustls::rustls::{
+    self,
+    client::{ServerCertVerified, ServerCertVerifier},
+    Certificate, PrivateKey, ServerName,
+};
 use tokio_rustls::TlsAcceptor;
 
 use crate::config::get_config;
@@ -64,3 +69,19 @@ impl Tls {
         })
     }
 }
+
+pub struct NoCertificateVerification;
+
+impl ServerCertVerifier for NoCertificateVerification {
+    fn verify_server_cert(
+        &self,
+        _end_entity: &Certificate,
+        _intermediates: &[Certificate],
+        _server_name: &ServerName,
+        _scts: &mut dyn Iterator<Item = &[u8]>,
+        _ocsp_response: &[u8],
+        _now: SystemTime,
+    ) -> Result<ServerCertVerified, rustls::Error> {
+        Ok(ServerCertVerified::assertion())
+    }
+}

tests/ruby/admin_spec.rb

@@ -14,11 +14,12 @@ describe "Admin" do
   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
+        connections = Array.new(3) { PG::connect("#{pgcat_conn_str}?application_name=one_query") }
+        connections.each do |c|
+          Thread.new { c.async_exec("SELECT pg_sleep(0.25)") }
+        end
+        sleep(1)
+        connections.map(&:close)
 
         # wait for averages to be calculated, we shouldn't do this too often
         sleep(15.5)
@@ -26,7 +27,7 @@ describe "Admin" do
         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["avg_query_time"].to_i).to be_within(20).of(50)
 
         expect(results["total_wait_time"].to_i).to_not eq(0)
         expect(results["avg_wait_time"].to_i).to_not eq(0)
@@ -37,9 +38,9 @@ describe "Admin" do
   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)
+        bad_password_url = URI(pgcat_conn_str)
+        bad_password_url.password = "wrong"
+        expect { PG::connect("#{bad_password_url.to_s}?application_name=bad_password") }.to raise_error(PG::ConnectionBad)
 
         sleep(1)
         admin_conn = PG::connect(processes.pgcat.admin_connection_string)
@@ -71,15 +72,17 @@ describe "Admin" do
 
     context "client connects but issues no queries" do
       it "only affects cl_idle stats" do
+        admin_conn = PG::connect(processes.pgcat.admin_connection_string)
+
+        before_test = admin_conn.async_exec("SHOW POOLS")[0]["sv_idle"]
         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")
+        expect(results["sv_idle"]).to eq(before_test)
 
         connections.map(&:close)
         sleep(1.1)
@@ -87,7 +90,7 @@ describe "Admin" do
         %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")
+        expect(results["sv_idle"]).to eq(before_test)
       end
     end
 

tests/ruby/auth_query_spec.rb

@@ -67,7 +67,7 @@ describe "Auth Query" do
         end
 
         context 'and with cleartext passwords not set' do
-          let(:config_user) { { 'username' => 'sharding_user' } }
+          let(:config_user) { { 'username' => 'sharding_user', 'password' => 'sharding_user' } }
 
           it 'it uses obtained passwords' do
             connection_string = processes.pgcat.connection_string("sharded_db", pg_user['username'], pg_user['password'])
@@ -76,7 +76,7 @@ describe "Auth Query" do
           end
 
           it 'allows passwords to be changed without closing existing connections' do
-            pgconn = PG.connect(processes.pgcat.connection_string("sharded_db", pg_user['username'], pg_user['password']))
+            pgconn = PG.connect(processes.pgcat.connection_string("sharded_db", pg_user['username']))
             expect(pgconn.exec("SELECT 1 + 2")).not_to be_nil
             Helpers::AuthQuery.exec_in_instances(query: "ALTER USER #{pg_user['username']} WITH ENCRYPTED PASSWORD 'secret2';")
             expect(pgconn.exec("SELECT 1 + 4")).not_to be_nil
@@ -84,7 +84,7 @@ describe "Auth Query" do
           end
 
           it 'allows passwords to be changed and that new password is needed when reconnecting' do
-            pgconn = PG.connect(processes.pgcat.connection_string("sharded_db", pg_user['username'], pg_user['password']))
+            pgconn = PG.connect(processes.pgcat.connection_string("sharded_db", pg_user['username']))
             expect(pgconn.exec("SELECT 1 + 2")).not_to be_nil
             Helpers::AuthQuery.exec_in_instances(query: "ALTER USER #{pg_user['username']} WITH ENCRYPTED PASSWORD 'secret2';")
             newconn = PG.connect(processes.pgcat.connection_string("sharded_db", pg_user['username'], 'secret2'))

tests/ruby/auth_spec.rb

@@ -1,39 +0,0 @@
-# frozen_string_literal: true
-require_relative 'spec_helper'
-
-
-describe "Authentication" do
-  describe "multiple secrets configured" do
-    let(:secrets) { ["one_secret", "two_secret"] }
-    let(:processes) { Helpers::Pgcat.three_shard_setup("sharded_db", 5, pool_mode="transaction", lb_mode="random", log_level="info", secrets=["one_secret", "two_secret"]) }
-
-    after do
-      processes.all_databases.map(&:reset)
-      processes.pgcat.shutdown
-    end
-
-    it "can connect using all secrets and postgres password" do
-      secrets.push("sharding_user").each do |secret|
-        conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user", password=secret))
-        conn.exec("SELECT current_user")
-      end
-    end
-  end
-
-  describe "no secrets configured" do
-    let(:secrets) { [] }
-    let(:processes) { Helpers::Pgcat.three_shard_setup("sharded_db", 5, pool_mode="transaction", lb_mode="random", log_level="info") }
-
-    after do
-      processes.all_databases.map(&:reset)
-      processes.pgcat.shutdown
-    end
-
-    it "can connect using only the password" do
-      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
-      conn.exec("SELECT current_user")
-
-      expect { PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user", password="secret_one")) }.to raise_error PG::ConnectionBad
-    end
-  end
-end

tests/ruby/helpers/pg_socket.rb

@@ -0,0 +1,259 @@
+require 'socket'
+require 'digest/md5'
+
+BACKEND_MESSAGE_CODES = {
+  'Z' => "ReadyForQuery",
+  'C' => "CommandComplete",
+  'T' => "RowDescription",
+  'D' => "DataRow",
+  '1' => "ParseComplete",
+  '2' => "BindComplete",
+  'E' => "ErrorResponse",
+  's' => "PortalSuspended",
+}
+
+class PostgresSocket
+  def initialize(host, port)
+    @port = port
+    @host = host
+    @socket = TCPSocket.new @host, @port
+    @parameters = {}
+    @verbose = true
+  end
+
+  def send_md5_password_message(username, password, salt)
+    m = Digest::MD5.hexdigest(password + username)
+    m = Digest::MD5.hexdigest(m + salt.map(&:chr).join(""))
+    m = 'md5' + m
+    bytes = (m.split("").map(&:ord) + [0]).flatten
+    message_size = bytes.count + 4
+
+    message = []
+
+    message << 'p'.ord
+    message << [message_size].pack('l>').unpack('CCCC') # 4
+    message << bytes
+    message.flatten!
+
+
+    @socket.write(message.pack('C*'))
+  end
+
+  def send_startup_message(username, database, password)
+    message = []
+
+    message << [196608].pack('l>').unpack('CCCC') # 4
+    message << "user".split('').map(&:ord) # 4, 8
+    message << 0 # 1, 9
+    message << username.split('').map(&:ord) # 2, 11
+    message << 0 # 1, 12
+    message << "database".split('').map(&:ord) # 8, 20
+    message << 0 # 1, 21
+    message << database.split('').map(&:ord) # 2, 23
+    message << 0 # 1, 24
+    message << 0 # 1, 25
+    message.flatten!
+
+    total_message_size = message.size + 4
+
+    message_len = [total_message_size].pack('l>').unpack('CCCC')
+
+    @socket.write([message_len + message].flatten.pack('C*'))
+
+    sleep 0.1
+
+    read_startup_response(username, password)
+  end
+
+  def read_startup_response(username, password)
+    message_code, message_len = @socket.recv(5).unpack("al>")
+    while message_code == 'R'
+      auth_code = @socket.recv(4).unpack('l>').pop
+      case auth_code
+      when 5 # md5
+        salt = @socket.recv(4).unpack('CCCC')
+        send_md5_password_message(username, password, salt)
+        message_code, message_len = @socket.recv(5).unpack("al>")
+      when 0 # trust
+        break
+      end
+    end
+    loop do
+      message_code, message_len = @socket.recv(5).unpack("al>")
+      if message_code == 'Z'
+        @socket.recv(1).unpack("a") # most likely I
+        break # We are good to go
+      end
+      if message_code == 'S'
+        actual_message = @socket.recv(message_len - 4).unpack("C*")
+        k,v = actual_message.pack('U*').split(/\x00/)
+        @parameters[k] = v
+      end
+      if message_code == 'K'
+        process_id, secret_key = @socket.recv(message_len - 4).unpack("l>l>")
+        @parameters["process_id"] = process_id
+        @parameters["secret_key"] = secret_key
+      end
+    end
+    return @parameters
+  end
+
+  def cancel_query
+    socket = TCPSocket.new @host, @port
+    process_key = @parameters["process_id"]
+    secret_key =  @parameters["secret_key"]
+    message = []
+    message << [16].pack('l>').unpack('CCCC') # 4
+    message << [80877102].pack('l>').unpack('CCCC') # 4
+    message << [process_key.to_i].pack('l>').unpack('CCCC') # 4
+    message << [secret_key.to_i].pack('l>').unpack('CCCC') # 4
+    message.flatten!
+    socket.write(message.flatten.pack('C*'))
+    socket.close
+    log "[F] Sent CancelRequest message"
+  end
+
+  def send_query_message(query)
+    query_size = query.length
+    message_size = 1 + 4 + query_size
+    message = []
+    message << "Q".ord
+    message << [message_size].pack('l>').unpack('CCCC') # 4
+    message << query.split('').map(&:ord) # 2, 11
+    message << 0 # 1, 12
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent Q message (#{query})"
+  end
+
+  def send_parse_message(query)
+    query_size = query.length
+    message_size = 2 + 2 + 4 + query_size
+    message = []
+    message << "P".ord
+    message << [message_size].pack('l>').unpack('CCCC') # 4
+    message << 0 # unnamed statement
+    message << query.split('').map(&:ord) # 2, 11
+    message << 0 # 1, 12
+    message << [0, 0]
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent P message (#{query})"
+  end
+
+  def send_bind_message
+    message = []
+    message << "B".ord
+    message << [12].pack('l>').unpack('CCCC') # 4
+    message << 0 # unnamed statement
+    message << 0 # unnamed statement
+    message << [0, 0] # 2
+    message << [0, 0] # 2
+    message << [0, 0] # 2
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent B message"
+  end
+
+  def send_describe_message(mode)
+    message = []
+    message << "D".ord
+    message << [6].pack('l>').unpack('CCCC') # 4
+    message << mode.ord
+    message << 0 # unnamed statement
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent D message"
+  end
+
+  def send_execute_message(limit=0)
+    message = []
+    message << "E".ord
+    message << [9].pack('l>').unpack('CCCC') # 4
+    message << 0 # unnamed statement
+    message << [limit].pack('l>').unpack('CCCC') # 4
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent E message"
+  end
+
+  def send_sync_message
+    message = []
+    message << "S".ord
+    message << [4].pack('l>').unpack('CCCC') # 4
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent S message"
+  end
+
+  def send_copydone_message
+    message = []
+    message << "c".ord
+    message << [4].pack('l>').unpack('CCCC') # 4
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent c message"
+  end
+
+  def send_copyfail_message
+    message = []
+    message << "f".ord
+    message << [5].pack('l>').unpack('CCCC') # 4
+    message << 0
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent f message"
+  end
+
+  def send_flush_message
+    message = []
+    message << "H".ord
+    message << [4].pack('l>').unpack('CCCC') # 4
+    message.flatten!
+    @socket.write(message.flatten.pack('C*'))
+    log "[F] Sent H message"
+  end
+
+  def read_from_server()
+    output_messages = []
+    retry_count = 0
+    message_code = nil
+    message_len = 0
+    loop do
+      begin
+        message_code, message_len = @socket.recv_nonblock(5).unpack("al>")
+      rescue IO::WaitReadable
+        return output_messages if retry_count > 50
+
+        retry_count += 1
+        sleep(0.01)
+        next
+      end
+      message = {
+        code: message_code,
+        len: message_len,
+        bytes: []
+      }
+      log "[B] #{BACKEND_MESSAGE_CODES[message_code] || ('UnknownMessage(' + message_code + ')')}"
+
+      actual_message_length = message_len - 4
+      if actual_message_length > 0
+        message[:bytes] = @socket.recv(message_len - 4).unpack("C*")
+        log "\t#{message[:bytes].join(",")}"
+        log "\t#{message[:bytes].map(&:chr).join(" ")}"
+      end
+      output_messages << message
+      return output_messages if message_code == 'Z'
+    end
+  end
+
+  def log(msg)
+    return unless @verbose
+
+    puts msg
+  end
+
+  def close
+    @socket.close
+  end
+end

tests/ruby/helpers/pgcat_helper.rb

@@ -2,6 +2,7 @@ require 'json'
 require 'ostruct'
 require_relative 'pgcat_process'
 require_relative 'pg_instance'
+require_relative 'pg_socket'
 
 class ::Hash
     def deep_merge(second)
@@ -12,18 +13,14 @@ end
 
 module Helpers
   module Pgcat
-    def self.three_shard_setup(pool_name, pool_size, pool_mode="transaction", lb_mode="random", log_level="info", secrets=nil)
+    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",
+        "username" => "sharding_user"
       }
 
-      if !secrets.nil?
-        user["secrets"] = secrets
-      end
-
       pgcat    = PgcatProcess.new(log_level)
       primary0 = PgInstance.new(5432, user["username"], user["password"], "shard0")
       primary1 = PgInstance.new(7432, user["username"], user["password"], "shard1")
@@ -31,7 +28,7 @@ module Helpers
 
       pgcat_cfg = pgcat.current_config
       pgcat_cfg["pools"] = {
-        "#{pool_name}" =>  {
+        "#{pool_name}" => {
           "default_role" => "any",
           "pool_mode" => pool_mode,
           "load_balancing_mode" => lb_mode,
@@ -44,15 +41,26 @@ module Helpers
             "1" => { "database" => "shard1", "servers" => [["localhost", primary1.port.to_s, "primary"]] },
             "2" => { "database" => "shard2", "servers" => [["localhost", primary2.port.to_s, "primary"]] },
           },
-          "users" => { "0" => user }
-        },
+          "users" => { "0" => user },
+          "plugins" => {
+            "intercept" => {
+              "enabled" => true,
+              "queries" => {
+                "0" => {
+                  "query" => "select current_database() as a, current_schemas(false) as b",
+                  "schema" => [
+                      ["a", "text"],
+                      ["b", "text"],
+                  ],
+                  "result" => [
+                    ["${DATABASE}", "{public}"],
+                  ]
+                }
+              }
+            }
+          }
+        }
       }
-
-      if !secrets.nil?
-        pgcat_cfg["general"]["tls_certificate"] = "../../.circleci/server.cert"
-        pgcat_cfg["general"]["tls_private_key"] = "../../.circleci/server.key"
-      end
-
       pgcat.update_config(pgcat_cfg)
 
       pgcat.start

tests/ruby/helpers/pgcat_process.rb

@@ -78,6 +78,7 @@ class PgcatProcess
     10.times do
       Process.kill 0, @pid
       PG::connect(connection_string || example_connection_string).close
+
       return self
     rescue Errno::ESRCH
       raise StandardError, "Process #{@pid} died. #{logs}"
@@ -111,13 +112,10 @@ class PgcatProcess
     "postgresql://#{username}:#{password}@0.0.0.0:#{@port}/pgcat"
   end
 
-  def connection_string(pool_name, username, password=nil)
+  def connection_string(pool_name, username, password = nil)
     cfg = current_config
     user_idx, user_obj = cfg["pools"][pool_name]["users"].detect { |k, user| user["username"] == username }
-
-    password = if password.nil? then user_obj["password"] else password end
-
-    "postgresql://#{username}:#{password}@0.0.0.0:#{@port}/#{pool_name}"
+    "postgresql://#{username}:#{password || user_obj["password"]}@0.0.0.0:#{@port}/#{pool_name}"
   end
 
   def example_connection_string

tests/ruby/load_balancing_spec.rb

@@ -65,7 +65,7 @@ describe "Least Outstanding Queries Load Balancing" do
     processes.pgcat.shutdown
   end
 
-  context "under homogenous load" do
+  context "under homogeneous load" do
     it "balances query volume between all instances" do
       conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
 

tests/ruby/mirrors_spec.rb

@@ -25,7 +25,7 @@ describe "Query Mirroing" do
     processes.pgcat.shutdown
   end
 
-  it "can mirror a query" do
+  xit "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") }

tests/ruby/misc_spec.rb

@@ -241,6 +241,18 @@ describe "Miscellaneous" do
 
         expect(processes.primary.count_query("DISCARD ALL")).to eq(10)
       end
+
+      it "Resets server roles correctly" 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.async_exec("SET statement_timeout to 5000")
+          conn.close
+        end
+
+        expect(processes.primary.count_query("RESET ROLE")).to eq(10)
+      end 
     end
 
     context "transaction mode" do

tests/ruby/plugins_spec.rb

@@ -0,0 +1,14 @@
+require_relative 'spec_helper'
+
+
+describe "Plugins" do
+  let(:processes) { Helpers::Pgcat.three_shard_setup("sharded_db", 5) }
+
+  context "intercept" do
+    it "will intercept an intellij query" do
+      conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+      res = conn.exec("select current_database() as a, current_schemas(false) as b")
+      expect(res.values).to eq([["sharded_db", "{public}"]])
+    end
+  end
+end

tests/ruby/protocol_spec.rb

@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+require_relative 'spec_helper'
+
+
+describe "Portocol handling" do
+  let(:processes) { Helpers::Pgcat.single_instance_setup("sharded_db", 1, "session") }
+  let(:sequence) { [] }
+  let(:pgcat_socket) { PostgresSocket.new('localhost', processes.pgcat.port) }
+  let(:pgdb_socket) { PostgresSocket.new('localhost', processes.all_databases.first.port) }
+
+  after do
+    pgdb_socket.close
+    pgcat_socket.close
+    processes.all_databases.map(&:reset)
+    processes.pgcat.shutdown
+  end
+
+  def run_comparison(sequence, socket_a, socket_b)
+    sequence.each do |msg, *args|
+      socket_a.send(msg, *args)
+      socket_b.send(msg, *args)
+
+      compare_messages(
+        socket_a.read_from_server,
+        socket_b.read_from_server
+      )
+    end
+  end
+
+  def compare_messages(msg_arr0, msg_arr1)
+    if msg_arr0.count != msg_arr1.count
+      error_output = []
+
+      error_output << "#{msg_arr0.count} : #{msg_arr1.count}"
+      error_output << "PgCat Messages"
+      error_output += msg_arr0.map { |message| "\t#{message[:code]} - #{message[:bytes].map(&:chr).join(" ")}" }
+      error_output << "PgServer Messages"
+      error_output += msg_arr1.map { |message| "\t#{message[:code]} - #{message[:bytes].map(&:chr).join(" ")}" }
+      error_desc = error_output.join("\n")
+      raise StandardError, "Message count mismatch #{error_desc}"
+    end
+
+    (0..msg_arr0.count - 1).all? do |i|
+      msg0 = msg_arr0[i]
+      msg1 = msg_arr1[i]
+
+      result = [
+        msg0[:code] == msg1[:code],
+        msg0[:len] == msg1[:len],
+        msg0[:bytes] == msg1[:bytes],
+      ].all?
+
+      next result if result
+
+      if result == false
+        error_string = []
+        if msg0[:code] != msg1[:code]
+          error_string << "code #{msg0[:code]} != #{msg1[:code]}"
+        end
+        if msg0[:len] != msg1[:len]
+          error_string << "len #{msg0[:len]} != #{msg1[:len]}"
+        end
+        if msg0[:bytes] != msg1[:bytes]
+          error_string << "bytes #{msg0[:bytes]} != #{msg1[:bytes]}"
+        end
+        err = error_string.join("\n")
+
+        raise StandardError, "Message mismatch #{err}"
+      end
+    end
+  end
+
+  RSpec.shared_examples "at parity with database" do
+    before do
+      pgcat_socket.send_startup_message("sharding_user", "sharded_db", "sharding_user")
+      pgdb_socket.send_startup_message("sharding_user", "shard0", "sharding_user")
+    end
+
+    it "works" do
+      run_comparison(sequence, pgcat_socket, pgdb_socket)
+    end
+  end
+
+  context "Cancel Query" do
+    let(:sequence) {
+      [
+        [:send_query_message, "SELECT pg_sleep(5)"],
+        [:cancel_query]
+      ]
+    }
+
+    it_behaves_like "at parity with database"
+  end
+
+  xcontext "Simple query after parse" do
+    let(:sequence) {
+      [
+        [:send_parse_message, "SELECT 5"],
+        [:send_query_message, "SELECT 1"],
+        [:send_bind_message],
+        [:send_describe_message, "P"],
+        [:send_execute_message],
+        [:send_sync_message],
+      ]
+    }
+
+    # Known to fail due to PgCat not supporting flush
+    it_behaves_like "at parity with database"
+  end
+
+  xcontext "Flush message" do
+    let(:sequence) {
+      [
+        [:send_parse_message, "SELECT 1"],
+        [:send_flush_message]
+      ]
+    }
+
+    # Known to fail due to PgCat not supporting flush
+    it_behaves_like "at parity with database"
+  end
+
+  xcontext "Bind without parse" do
+    let(:sequence) {
+      [
+        [:send_bind_message]
+      ]
+    }
+    # This is known to fail.
+    # Server responds immediately, Proxy buffers the message
+    it_behaves_like "at parity with database"
+  end
+
+  context "Simple message" do
+    let(:sequence) {
+      [[:send_query_message, "SELECT 1"]]
+    }
+
+    it_behaves_like "at parity with database"
+  end
+
+  context "Extended protocol" do
+    let(:sequence) {
+      [
+        [:send_parse_message, "SELECT 1"],
+        [:send_bind_message],
+        [:send_describe_message, "P"],
+        [:send_execute_message],
+        [:send_sync_message],
+      ]
+    }
+
+    it_behaves_like "at parity with database"
+  end
+end

tests/ruby/sharding_spec.rb

@@ -27,7 +27,7 @@ describe "Sharding" do
     processes.pgcat.shutdown
   end
 
-  describe "automatic routing of extended procotol" do
+  describe "automatic routing of extended protocol" do
     it "can do it" do
       conn = PG.connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
       conn.exec("SET SERVER ROLE TO 'auto'")

utilities/requirements.txt

@@ -0,0 +1 @@
+tomli