fix: keep lite-bootstrap's root log handler on Litestar and write litestar records once

lite_bootstrap/bootstrappers/litestar_bootstrapper.py

@@ -31,6 +31,7 @@
     from litestar import status_codes
     from litestar.config.app import AppConfig
     from litestar.config.cors import CORSConfig
+    from litestar.logging.config import LoggingConfig as LitestarStandardLoggingConfig
     from litestar.logging.config import StructLoggingConfig
     from litestar.middleware.logging import LoggingMiddlewareConfig
     from litestar.openapi import OpenAPIConfig
@@ -187,6 +188,16 @@ def _build_logging_middleware_config(self) -> "LoggingMiddlewareConfig":
             exclude=excluded_paths or None,
         )
 
+    def _build_standard_lib_logging_config(self) -> "LitestarStandardLoggingConfig":
+        """Leave stdlib output to lite-bootstrap: Litestar's default config replaces the root handler."""
+        return LitestarStandardLoggingConfig(
+            configure_root_logger=False,
+            handlers={"console": {"class": "logging.NullHandler"}, "queue_listener": {"class": "logging.NullHandler"}},
+            loggers={
+                "litestar": {"level": self.bootstrap_config.logging_log_level, "handlers": [], "propagate": False}
+            },
+        )
+
     def _configure_structlog_loggers(self) -> None:
         """Register Litestar's StructlogPlugin instead of calling ``structlog.configure`` directly."""
         self.bootstrap_config.application_config.plugins.append(
@@ -198,7 +209,7 @@ def _configure_structlog_loggers(self) -> None:
                         wrapper_class=structlog.stdlib.BoundLogger,
                         cache_logger_on_first_use=True,
                         pretty_print_tty=False,
-                        standard_lib_logging_config=None,
+                        standard_lib_logging_config=self._build_standard_lib_logging_config(),
                     ),
                     # Litestar defaults this to True, which logs full request/response bodies.
                     enable_middleware_logging=self.bootstrap_config.litestar_logging_middleware_enabled,

tests/test_litestar_bootstrap.py

@@ -3,6 +3,7 @@
 import inspect
 import json
 import logging
+import logging.handlers
 import sys
 import typing
 import warnings
@@ -309,6 +310,31 @@ async def _login_handler(data: dict[str, str]) -> dict[str, str]:
     return log_lines
 
 
+def test_litestar_logging_keeps_lite_bootstrap_root_handler(litestar_config: LitestarConfig) -> None:
+    application = LitestarBootstrapper(bootstrap_config=litestar_config).bootstrap()
+    with TestClient(app=application):
+        root_handlers = logging.getLogger().handlers
+        assert not any(isinstance(handler, logging.handlers.QueueHandler) for handler in root_handlers)
+        assert any(isinstance(handler.formatter, structlog.stdlib.ProcessorFormatter) for handler in root_handlers)
+
+
+def test_litestar_access_log_has_one_handler(litestar_config: LitestarConfig) -> None:
+    @litestar.get("/ping")
+    async def _ping_handler() -> dict[str, bool]:
+        return {"ok": True}
+
+    config = dataclasses.replace(
+        litestar_config,
+        litestar_logging_middleware_enabled=True,
+        application_config=AppConfig(route_handlers=[_ping_handler]),
+    )
+    application = LitestarBootstrapper(bootstrap_config=config).bootstrap()
+    with TestClient(app=application) as client:
+        assert client.get("/ping").status_code == status_codes.HTTP_200_OK
+        litestar_handlers = logging.getLogger("litestar").handlers
+        assert [type(handler) for handler in litestar_handlers] == [logging.handlers.MemoryHandler]
+
+
 def test_litestar_access_logging_disabled_by_default(litestar_config: LitestarConfig) -> None:
     log_lines = _post_password(litestar_config)