Write structlog lines through a plain StreamHandler and remove logging_buffer_capacity and logging_flush_level (#378)

Author: lesnik512

benchmarks/README.md

@@ -619,15 +619,15 @@ record per MCP message), FastStream's own "Received" and "Processed" (filtered a
 
 Linux, a 2-CPU container on the same Apple M2 under OrbStack, CPython 3.14.9, structlog 26.1.0,
 orjson 3.11.9, sentry-sdk 2.67.1, opentelemetry-sdk 1.44.0. Output to a real `/dev/null` file,
-50000 calls per round, loop overhead (0.06 µs) subtracted.
+50000 calls per round, loop overhead (0.06 µs) subtracted. The `MemoryHandler` was removed afterwards
+(#377), and 2.0 writes through the `StreamHandler` directly; the rows have not been rerun.
 
 | call | µs/call |
 |---|---:|
 | `log.info("did a thing", a=1)` through lite-bootstrap's chain | 9.5 |
 | same with 5 keyword values | 10.4 |
 | `log.debug(...)` at INFO, filtered | 1.1 |
 | info, JSON through stdlib `json` (the fallback without orjson) | 11.5 |
-| info, `logging_buffer_capacity=1` | 10.5 |
 | info inside a recording OpenTelemetry span | 10.7 |
 | info with Sentry's LoggingIntegration, breadcrumb level INFO (default) | 15.7 |
 | info with Sentry, `sentry_logging_breadcrumb_level=None` | 10.5 |

benchmarks/frameworks/logging_suite.py

@@ -28,7 +28,6 @@ class LogScenario:
     span: bool = False
     native: bool = False
     stdlib_json: bool = False
-    buffer_capacity: int = 10
 
 
 SCENARIOS: typing.Final = {
@@ -37,7 +36,6 @@ class LogScenario:
     "info_kw5": LogScenario(call="info_kw5"),
     "debug_filtered": LogScenario(call="debug"),
     "info_stdjson": LogScenario(call="info", stdlib_json=True),
-    "info_capacity1": LogScenario(call="info", buffer_capacity=1),
     "info_span": LogScenario(call="info", span=True),
     "info_sentry": LogScenario(call="info", sentry={}),
     "info_sentry_nocrumb": LogScenario(call="info", sentry={"sentry_logging_breadcrumb_level": None}),
@@ -113,7 +111,7 @@ def setup(scenario: LogScenario) -> list[typing.Callable[[], object]]:
         configure_native(devnull_bytes)
     elif scenario.call != "noop":
         with contextlib.redirect_stdout(devnull):
-            config = LoggingConfig(logging_enabled=True, logging_buffer_capacity=scenario.buffer_capacity)
+            config = LoggingConfig(logging_enabled=True)
             LoggingInstrument(bootstrap_config=config).bootstrap()
 
     if scenario.sentry is not None:

docs/integrations/fastmcp.md

@@ -36,7 +36,6 @@ bootstrapper_config = FastMcpConfig(
     sentry_dsn="https://testdsn@localhost/1",
     prometheus_metrics_path="/custom-metrics/",
     health_checks_path="/custom-health/",
-    logging_buffer_capacity=0,
 )
 bootstrapper = FastMcpBootstrapper(bootstrap_config=bootstrapper_config)
 application: FastMCP = bootstrapper.bootstrap()

docs/integrations/faststream.md

@@ -43,7 +43,6 @@ bootstrapper_config = FastStreamConfig(
     prometheus_middleware_cls=RedisPrometheusMiddleware,
     sentry_dsn="https://testdsn@localhost/1",
     health_checks_path="/custom-health/",
-    logging_buffer_capacity=0,
     application=AsgiFastStream(broker),
 )
 bootstrapper = FastStreamBootstrapper(bootstrapper_config)

docs/introduction/configuration.md

@@ -352,8 +352,6 @@ Additional parameters:
 
 - `logging_enabled` - whether to configure structlog (default: `True`).
 - `logging_log_level`
-- `logging_flush_level`
-- `logging_buffer_capacity`
 - `logging_extra_processors`
 - `logging_unset_handlers`
 - `logging_record_filters` - standard-library `logging.Filter` instances to attach to named loggers (see below).

lite_bootstrap/instruments/logging_factory.py

@@ -1,7 +1,6 @@
 import dataclasses
 import json
 import logging
-import logging.handlers
 import sys
 import typing
 
@@ -14,8 +13,6 @@
 
 @dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
 class _MemoryLoggerFactoryConfig:
-    logging_buffer_capacity: int
-    logging_flush_level: int
     logging_log_level: int
     # default_factory, not a bare default: a bare one binds sys.stdout at import time, so a
     # process that rebinds stdout before bootstrap would keep logging to the stale stream.
@@ -102,20 +99,15 @@ def __init__(
             kwargs["ignore_frame_names"] = [*(kwargs.get("ignore_frame_names") or ()), __name__]
             super().__init__(*args, **kwargs)
             self.config = config
-            self._created_handlers: dict[logging.Logger, logging.handlers.MemoryHandler] = {}
+            self._created_handlers: dict[logging.Logger, logging.StreamHandler[typing.Any]] = {}
             self._leveled_loggers: set[logging.Logger] = set()
 
         def __call__(self, *args: typing.Any) -> logging.Logger:  # noqa: ANN401
             logger: typing.Final = super().__call__(*args)
             if logger in self._created_handlers:
                 return logger
-            stream_handler: typing.Final = logging.StreamHandler(stream=self.config.log_stream)
-            stream_handler.setFormatter(_RenderedLineFormatter())
-            handler: typing.Final = logging.handlers.MemoryHandler(
-                capacity=self.config.logging_buffer_capacity,
-                flushLevel=self.config.logging_flush_level,
-                target=stream_handler,
-            )
+            handler: typing.Final = logging.StreamHandler(stream=self.config.log_stream)
+            handler.setFormatter(_RenderedLineFormatter())
             logger.addHandler(handler)
             if logger.level == logging.NOTSET:
                 logger.setLevel(self.config.logging_log_level)
@@ -130,9 +122,6 @@ def close_handlers(self) -> None:
                 created_logger.propagate = True
                 if created_logger in self._leveled_loggers:
                     created_logger.setLevel(logging.NOTSET)
-                target = handler.target
                 handler.close()
-                if target is not None:
-                    target.close()
             self._created_handlers.clear()
             self._leveled_loggers.clear()

lite_bootstrap/instruments/logging_instrument.py

@@ -61,8 +61,6 @@ def tracer_injection(_: "WrappedLogger", __: str, event_dict: "EventDict") -> "E
 @dataclasses.dataclass(kw_only=True, frozen=True)
 class LoggingConfig(BaseConfig):
     logging_log_level: int = logging.INFO
-    logging_flush_level: int = logging.ERROR
-    logging_buffer_capacity: int = 10
     logging_extra_processors: list[typing.Any] = dataclasses.field(default_factory=list)
     logging_unset_handlers: list[str] = dataclasses.field(
         default_factory=list,
@@ -150,8 +148,6 @@ def memory_logger_factory(self) -> "MemoryLoggerFactory":
             config = self.bootstrap_config
             cached = MemoryLoggerFactory(
                 config=_MemoryLoggerFactoryConfig(
-                    logging_buffer_capacity=config.logging_buffer_capacity,
-                    logging_flush_level=config.logging_flush_level,
                     logging_log_level=config.logging_log_level,
                 ),
             )

scripts/floor_smoke.py

@@ -138,7 +138,6 @@ def _free() -> None:
             service_name="floor-smoke",
             service_version="1.0.0",
             service_environment="test",
-            logging_buffer_capacity=0,
             sentry_dsn=SENTRY_DSN,
             sentry_additional_params=SENTRY_PARAMS,
             sentry_tags={"floor": "smoke"},
@@ -170,7 +169,6 @@ async def floor_error() -> None:
         bootstrap_config=FastAPIConfig(
             service_name="floor-smoke",
             service_version="1.0.0",
-            logging_buffer_capacity=0,
             sentry_dsn=SENTRY_DSN,
             sentry_additional_params=SENTRY_PARAMS,
             application=application,
@@ -189,7 +187,6 @@ def _fastapi() -> None:
             service_name="floor-smoke",
             service_version="1.0.0",
             service_debug=False,
-            logging_buffer_capacity=0,
             cors_allowed_origins=["http://test"],
             health_checks_path=HEALTH_PATH,
             health_checks_include_in_schema=True,
@@ -225,7 +222,6 @@ async def floor_error() -> None:
             service_name="floor-smoke",
             service_version="1.0.0",
             service_debug=False,
-            logging_buffer_capacity=0,
             sentry_dsn=SENTRY_DSN,
             sentry_additional_params=SENTRY_PARAMS,
             application_config=AppConfig(route_handlers=[floor_error]),
@@ -244,7 +240,6 @@ def _litestar() -> None:
             service_name="floor-smoke",
             service_version="1.0.0",
             service_debug=False,
-            logging_buffer_capacity=0,
             cors_allowed_origins=["http://test"],
             health_checks_path=HEALTH_PATH,
             sentry_dsn=SENTRY_DSN,
@@ -267,7 +262,6 @@ def _faststream() -> None:
         bootstrap_config=FastStreamConfig(
             service_name="floor-smoke",
             service_version="1.0.0",
-            logging_buffer_capacity=0,
             health_checks_path=HEALTH_PATH,
             sentry_dsn=SENTRY_DSN,
             sentry_additional_params=SENTRY_PARAMS,
@@ -290,7 +284,6 @@ def _fastmcp_lean_sentry_capture() -> None:
         bootstrap_config=FastMcpConfig(
             service_name="floor-smoke",
             service_version="1.0.0",
-            logging_buffer_capacity=0,
             sentry_dsn=SENTRY_DSN,
             sentry_additional_params=SENTRY_PARAMS,
         )
@@ -314,7 +307,6 @@ def _fastmcp() -> None:
         bootstrap_config=FastMcpConfig(
             service_name="floor-smoke",
             service_version="1.0.0",
-            logging_buffer_capacity=0,
             health_checks_path=HEALTH_PATH,
             sentry_dsn=SENTRY_DSN,
             sentry_additional_params=SENTRY_PARAMS,

scripts/ft_smoke.py

@@ -30,7 +30,6 @@ def main() -> None:
         bootstrap_config=FastAPIConfig(
             service_name="ft-smoke",
             service_debug=False,
-            logging_buffer_capacity=0,
             health_checks_path="/health/",
         )
     )