Add per-module log level overrides for staging/production

Support LOG_LEVEL_{MODULE} env vars (GAME, AI, HANDLERS, ROOM, AUTH,
STORES) to override the global log level for specific modules. Active
overrides are logged at startup. Includes staging/production presets
in .env.example files and a V3.18 stub doc for PostgreSQL storage
efficiency investigation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/.env.example

@@ -7,6 +7,24 @@ PORT=8000
 DEBUG=true
 LOG_LEVEL=DEBUG
 
+# Per-module log level overrides (optional)
+# These override LOG_LEVEL for specific modules.
+# LOG_LEVEL_GAME=DEBUG       # Core game logic
+# LOG_LEVEL_AI=DEBUG         # AI decisions (very verbose at DEBUG)
+# LOG_LEVEL_HANDLERS=DEBUG   # WebSocket message handlers
+# LOG_LEVEL_ROOM=DEBUG       # Room/lobby management
+# LOG_LEVEL_AUTH=DEBUG       # Auth stack (auth, routers.auth, services.auth_service)
+# LOG_LEVEL_STORES=DEBUG     # Database/Redis operations
+
+# --- Preset examples ---
+# Staging (debug game logic, quiet everything else):
+#   LOG_LEVEL=INFO
+#   LOG_LEVEL_GAME=DEBUG
+#   LOG_LEVEL_AI=DEBUG
+#
+# Production (minimal logging):
+#   LOG_LEVEL=WARNING
+
 # Environment (development, staging, production)
 # Affects logging format, security headers (HSTS), etc.
 ENVIRONMENT=development

server/logging_config.py

@@ -148,6 +148,39 @@ class DevelopmentFormatter(logging.Formatter):
         return output
 
 
+# Per-module log level overrides via env vars.
+# Key: env var suffix, Value: list of Python logger names to apply to.
+MODULE_LOGGER_MAP = {
+    "GAME": ["game"],
+    "AI": ["ai"],
+    "HANDLERS": ["handlers"],
+    "ROOM": ["room"],
+    "AUTH": ["auth", "routers.auth", "services.auth_service"],
+    "STORES": ["stores"],
+}
+
+
+def _apply_module_overrides() -> dict[str, str]:
+    """
+    Apply per-module log level overrides from LOG_LEVEL_{MODULE} env vars.
+
+    Returns:
+        Dict of module name -> level for any overrides that were applied.
+    """
+    active = {}
+    for module, logger_names in MODULE_LOGGER_MAP.items():
+        env_val = os.environ.get(f"LOG_LEVEL_{module}", "").upper()
+        if not env_val:
+            continue
+        level = getattr(logging, env_val, None)
+        if level is None:
+            continue
+        active[module] = env_val
+        for name in logger_names:
+            logging.getLogger(name).setLevel(level)
+    return active
+
+
 def setup_logging(
     level: str = "INFO",
     environment: str = "development",
@@ -182,12 +215,19 @@ def setup_logging(
     logging.getLogger("websockets").setLevel(logging.WARNING)
     logging.getLogger("asyncio").setLevel(logging.WARNING)
 
+    # Apply per-module overrides from env vars
+    overrides = _apply_module_overrides()
+
     # Log startup
     logger = logging.getLogger(__name__)
     logger.info(
         f"Logging configured: level={level}, environment={environment}",
         extra={"level": level, "environment": environment},
     )
+    if overrides:
+        logger.info(
+            f"Per-module log level overrides: {', '.join(f'{m}={l}' for m, l in overrides.items())}",
+        )
 
 
 class ContextLogger(logging.LoggerAdapter):