With ENABLE_OTEL and ENABLE_OTEL_LOGS set, InterceptHandler builds the message once for loguru and then hands the same LogRecord to the OpenTelemetry handler, whose _translate calls record.getMessage() a second time. That used to be free, because the message was already a finished f-string with nothing to substitute. Now that log calls pass lazy %-args, the second call re-runs the whole interpolation, so every exported record is formatted twice.
The two getMessage() calls on a 78 kB retrieval record:
before 373.0 us
after 0.1 us
Stamping the built message back onto the record makes the second call a plain string return. msg and args are both in OpenTelemetry's _RESERVED_ATTRS, so neither ever reaches the exported attributes. The isinstance guard matters: _translate exports a non-str msg such as the dicts routers/audio.py logs as a typed body rather than a string, so those records are left untouched, and they have no %-args to format twice anyway. Body, attributes and severity were compared against LoggingHandler._translate for str, dict, list, int, None, exception and exc_info records.
* feat: add LOG_FORMAT env var with JSON formatter for early logging
Introduce LOG_FORMAT environment variable (set to "json" to enable).
When active, logging.basicConfig() uses a JSONFormatter that outputs
single-line JSON objects with fields: ts, level, msg, caller, error,
stacktrace. This covers all log messages emitted during module imports
before Loguru's start_logger() takes over.
* feat: add JSON sink for Loguru when LOG_FORMAT=json
Add _json_sink() as a Loguru sink function that writes single-line JSON
to stdout. In start_logger(), conditionally use the JSON sink instead of
the plain-text stdout_format when LOG_FORMAT is set to "json".
* feat: suppress ASCII banner and fix alembic logging in JSON mode
- Wrap the ASCII art banner print in main.py with a LOG_FORMAT != "json"
guard so JSON output stays machine-parseable.
- Skip alembic's fileConfig() call in migrations/env.py when
LOG_FORMAT=json to prevent it from replacing the JSON log handlers
installed during early startup.
Classic298