Files
pgcat/tests/ruby/helpers/auth_query_helper.rb
Mostafa Abdelraouf 0b01d70b55 Allow configuring routing decision when no shard is selected (#578)
The TL;DR for the change is that we allow QueryRouter to set the active shard to None. This signals to the Pool::get method that we have no shard selected. The get method follows a no_shard_specified_behavior config to know how to route the query.

Original PR description
Ruby-pg library makes a startup query to SET client_encoding to ... if Encoding.default_internal value is set (Code). This query is troublesome because we cannot possibly attach a routing comment to it. PgCat, by default, will route that query to the default shard.

Everything is fine until shard 0 has issues, Clients will all be attempting to send this query to shard0 which increases the connection latency significantly for all clients, even those not interested in shard0

This PR introduces no_shard_specified_behavior that defines the behavior in case we have routing-by-comment enabled but we get a query without a comment. The allowed behaviors are

random: Picks a shard at random
random_healthy: Picks a shard at random favoring shards with the least number of recent connection/checkout errors
shard_<number>: e.g. shard_0, shard_4, etc. picks a specific shard, everytime
In order to achieve this, this PR introduces an error_count on the Address Object that tracks the number of errors since the last checkout and uses that metric to sort shards by error count before making a routing decision.
I didn't want to use address stats to avoid introducing a routing dependency on internal stats (We might do that in the future but I prefer to avoid this for the time being.

I also made changes to the test environment to replace Ruby's TOML reader library, It appears to be abandoned and does not support mixed arrays (which we use in the config toml), and it also does not play nicely with single-quoted regular expressions. I opted for using yj which is a CLI tool that can convert from toml to JSON and back. So I refactor the tests to use that library.
2023-09-11 13:47:28 -05:00

174 lines
5.5 KiB
Ruby

module Helpers
module AuthQuery
def self.single_shard_auth_query(
pg_user:,
config_user:,
pool_name:,
extra_conf: {},
log_level: 'debug',
wait_until_ready: true
)
user = {
"pool_size" => 10,
"statement_timeout" => 0,
}
pgcat = PgcatProcess.new(log_level)
pgcat_cfg = pgcat.current_config.deep_merge(extra_conf)
primary = PgInstance.new(5432, pg_user["username"], pg_user["password"], "shard0")
replica = PgInstance.new(10432, pg_user["username"], pg_user["password"], "shard0")
# Main proxy configs
pgcat_cfg["pools"] = {
"#{pool_name}" => {
"default_role" => "any",
"pool_mode" => "transaction",
"load_balancing_mode" => "random",
"primary_reads_enabled" => false,
"query_parser_enabled" => false,
"sharding_function" => "pg_bigint_hash",
"shards" => {
"0" => {
"database" => "shard0",
"servers" => [
["localhost", primary.port.to_i, "primary"],
["localhost", replica.port.to_i, "replica"],
]
},
},
"users" => { "0" => user.merge(config_user) }
}
}
pgcat_cfg["general"]["port"] = pgcat.port.to_i
pgcat.update_config(pgcat_cfg)
pgcat.start
pgcat.wait_until_ready(
pgcat.connection_string(
"sharded_db",
pg_user['username'],
pg_user['password']
)
) if wait_until_ready
OpenStruct.new.tap do |struct|
struct.pgcat = pgcat
struct.primary = primary
struct.replicas = [replica]
struct.all_databases = [primary]
end
end
def self.two_pools_auth_query(
pg_user:,
config_user:,
pool_names:,
extra_conf: {},
log_level: 'debug'
)
user = {
"pool_size" => 10,
"statement_timeout" => 0,
}
pgcat = PgcatProcess.new(log_level)
pgcat_cfg = pgcat.current_config
primary = PgInstance.new(5432, pg_user["username"], pg_user["password"], "shard0")
replica = PgInstance.new(10432, pg_user["username"], pg_user["password"], "shard0")
pool_template = Proc.new do |database|
{
"default_role" => "any",
"pool_mode" => "transaction",
"load_balancing_mode" => "random",
"primary_reads_enabled" => false,
"query_parser_enabled" => false,
"sharding_function" => "pg_bigint_hash",
"shards" => {
"0" => {
"database" => database,
"servers" => [
["localhost", primary.port.to_i, "primary"],
["localhost", replica.port.to_i, "replica"],
]
},
},
"users" => { "0" => user.merge(config_user) }
}
end
# Main proxy configs
pgcat_cfg["pools"] = {
"#{pool_names[0]}" => pool_template.call("shard0"),
"#{pool_names[1]}" => pool_template.call("shard1")
}
pgcat_cfg["general"]["port"] = pgcat.port
pgcat.update_config(pgcat_cfg.deep_merge(extra_conf))
pgcat.start
pgcat.wait_until_ready(pgcat.connection_string("sharded_db0", pg_user['username'], pg_user['password']))
OpenStruct.new.tap do |struct|
struct.pgcat = pgcat
struct.primary = primary
struct.replicas = [replica]
struct.all_databases = [primary]
end
end
def self.create_query_auth_function(user)
return <<-SQL
CREATE OR REPLACE FUNCTION public.user_lookup(in i_username text, out uname text, out phash text)
RETURNS record AS $$
BEGIN
SELECT usename, passwd FROM pg_catalog.pg_shadow
WHERE usename = i_username INTO uname, phash;
RETURN;
END;
$$ LANGUAGE plpgsql SECURITY DEFINER;
GRANT EXECUTE ON FUNCTION public.user_lookup(text) TO #{user};
SQL
end
def self.exec_in_instances(query:, instance_ports: [ 5432, 10432 ], database: 'postgres', user: 'postgres', password: 'postgres')
instance_ports.each do |port|
c = PG.connect("postgres://#{user}:#{password}@localhost:#{port}/#{database}")
c.exec(query)
c.close
end
end
def self.set_up_auth_query_for_user(user:, password:, instance_ports: [ 5432, 10432 ], database: 'shard0' )
instance_ports.each do |port|
connection = PG.connect("postgres://postgres:postgres@localhost:#{port}/#{database}")
connection.exec(self.drop_query_auth_function(user)) rescue PG::UndefinedFunction
connection.exec("DROP ROLE #{user}") rescue PG::UndefinedObject
connection.exec("CREATE ROLE #{user} ENCRYPTED PASSWORD '#{password}' LOGIN;")
connection.exec(self.create_query_auth_function(user))
connection.close
end
end
def self.tear_down_auth_query_for_user(user:, password:, instance_ports: [ 5432, 10432 ], database: 'shard0' )
instance_ports.each do |port|
connection = PG.connect("postgres://postgres:postgres@localhost:#{port}/#{database}")
connection.exec(self.drop_query_auth_function(user)) rescue PG::UndefinedFunction
connection.exec("DROP ROLE #{user}")
connection.close
end
end
def self.drop_query_auth_function(user)
return <<-SQL
REVOKE ALL ON FUNCTION public.user_lookup(text) FROM public, #{user};
DROP FUNCTION public.user_lookup(in i_username text, out uname text, out phash text);
SQL
end
end
end