Allow some services to not use a connection pool to the DB

Some services managed by supervisor do need the DB during startup only
to make at most a handfull of queries (if even). However, because
they're using a connection pool behind the scenes, the connections are
kept in that pool for some time unnecessarily.

This commit adds a way to disable connection pooling with an environment
variable. This env var is enabled for all services that currently use
the DB during startup only.

Author: FlorianSW

config/supervisord.conf

@@ -25,15 +25,15 @@ autorestart=unexpected
 
 [program:log_event_loop]
 command=/code/manage.py log_loop
-environment=LOGGING_FILENAME=log_event_loop_%(ENV_SERVER_NUMBER)s.log
+environment=LOGGING_FILENAME=log_event_loop_%(ENV_SERVER_NUMBER)s.log,HLL_DB_DISABLE_CONNECTION_POOL=1
 startretries=1000000
 startsecs=1
 autostart=true
 autorestart=true
 
 [program:log_stream]
 command=/code/manage.py log_stream
-environment=LOGGING_FILENAME=log_stream_%(ENV_SERVER_NUMBER)s.log
+environment=LOGGING_FILENAME=log_stream_%(ENV_SERVER_NUMBER)s.log,HLL_DB_DISABLE_CONNECTION_POOL=1
 startretries=5
 startsecs=0
 autostart=true
@@ -49,7 +49,7 @@ autorestart=true
 
 [program:auto_settings]
 command=/code/manage.py auto_settings
-environment=LOGGING_FILENAME=auto_settings_%(ENV_SERVER_NUMBER)s.log
+environment=LOGGING_FILENAME=auto_settings_%(ENV_SERVER_NUMBER)s.log,HLL_DB_DISABLE_CONNECTION_POOL=1
 startretries=100
 startsecs=1
 autostart=true
@@ -70,7 +70,7 @@ autostart=true
 
 [program:live_stats_refresh]
 command=/code/manage.py live_stats_loop
-environment=LOGGING_FILENAME=live_stats_loop_%(ENV_SERVER_NUMBER)s.log
+environment=LOGGING_FILENAME=live_stats_loop_%(ENV_SERVER_NUMBER)s.log,HLL_DB_DISABLE_CONNECTION_POOL=1
 startretries=100
 startsecs=1
 autostart=true

rcon/cli.py

@@ -15,7 +15,7 @@
 import rcon.user_config
 import rcon.user_config.utils
 import rcon.watch_killrate
-from rcon import auto_settings, broadcast, maps, routines
+from rcon import auto_settings, broadcast, routines
 from rcon.automods import automod
 from rcon.blacklist import BlacklistCommandHandler
 from rcon.cache_utils import RedisCached, get_redis_pool, invalidates
@@ -30,7 +30,6 @@
 from rcon.user_config.auto_settings import AutoSettingsConfig
 from rcon.user_config.log_stream import LogStreamUserConfig
 from rcon.user_config.scoreboard import _port_legacy_scorebot_urls
-from rcon.user_config.vote_map import VoteMapUserConfig
 from rcon.user_config.webhooks import (
     BaseMentionWebhookUserConfig,
     BaseUserConfig,

rcon/models.py

@@ -7,7 +7,7 @@
 from typing import Any, Generator, List, Literal, Optional, Sequence, overload, TypedDict
 
 import pydantic
-from sqlalchemy import TIMESTAMP, Enum, ForeignKey, String, create_engine, select, text, JSON
+from sqlalchemy import TIMESTAMP, Enum, ForeignKey, String, create_engine, select, text, JSON, Engine, NullPool, Pool
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.exc import InvalidRequestError, ProgrammingError
 from sqlalchemy.ext.hybrid import hybrid_property
@@ -70,7 +70,7 @@
 
 PLAYER_ID = "player_id"
 
-_ENGINE = None
+_ENGINE: Engine | None = None
 
 
 def get_engine():
@@ -84,7 +84,11 @@ def get_engine():
         logger.error(msg)
         raise ValueError(msg)
 
-    _ENGINE = create_engine(url, echo=False)
+    pool: type[Pool] | None = None
+    if os.getenv("HLL_DB_DISABLE_CONNECTION_POOL") is not None:
+        pool = NullPool
+
+    _ENGINE = create_engine(url, poolclass=pool, echo=False)
     return _ENGINE