logger.level vs logger.getEffectiveLevel() on config load() about uvicorn

[Kludex]

Can you give an MRE on which the change will benefit you?

[josumoreno-BP]

Hey, see here an example:

import uvicorn 

async def app(scope, receive, send):
    assert scope['type'] == 'http'
    await send({
        'type': 'http.response.start',
        'status': 200,
        'headers': [
            [b'content-type', b'text/plain'],
        ],
    })
    await send({
        'type': 'http.response.body',
        'body': b'Hello, world!',
    })

if __name__ == "__main__":
    LOG_CONFIG = {
        "version": 1,
        "disable_existing_loggers": False,
        "formatters": {
            "simple": {
                "format": "[%(levelname)s] %(message)s",
            },
        },
        "handlers": {
            "stdout": {
                "level": "NOTSET",
                "class": "logging.StreamHandler",
                "formatter": "simple",
                "stream": "ext://sys.stdout",
            }
        },
        "root": {
            "handlers": ["stdout"],
            "level": "WARNING",
        },
        "loggers": {
            "uvicorn": {
                "handlers": ["stdout"],
                "level": "INFO",
                "propagate": False,
            },
        },
    }
    uvicorn.run("main:app", log_config=LOG_CONFIG)

I'm setting uvicorn logger to log on level INFO, so every child logger (uvicorn.error, uvicorn.access, uvicorn.asgi, etc) will use that (unless something specific is declared for them). What this means is that no message logged by MessageLoggerMiddleware will be printed to stdout because they are logged at created level TRACE (5).

So the thing is that even having this config, uvicorn will still load the MessageLoggerMiddleware because I have not passed explicitly the log_level parameter. I think that "the need" of passing the log_level parameter along with the log_config (or having to declare the child logger levels explicitly in the log_config) is an unexpected behavior that leads to execute MessageLoggerMiddleware without needing it.

Checking getEffectiveLevel() will return the "real final" level that the logger will log in. So that's why I'm suggesting to change logger.level to logger.getEffectiveLevel() here.

Hope this helps to understand it. If this is still not clear, let me know.

[Kludex]

Got it. Thanks. Do you mind creating a PR for it? 🙏