Uvicorn is stopping logging to file

[stuartofmt]

I'm using uvicorn as part of a wider python application.

In my application, I configure a logger using logging that has both a streamhandler (c_handler = logging.StreamHandler(sys.stdout)) and a filehandler (f_handler = logging.FileHandler(logfile, mode='w', encoding='utf-8'))
This all works fine until uvicorn starts, at which point the filehandler stops logging to the file - although the output to the console still works.

How to prevent uvicorn from "killing" the filehandler? I.e. My 'perfect' outcome is that uvicorn continues to use the same handlers as I defined in the main code.

I start uvicorn thus:
uvicorn.run(app,
host=UI.HOST,
port=UI.PORT
)

Would 'no-access-log' work? If so - what is the appropriate keyword (the documentation seems silent on this :-(

Thanks in advance

[ezsouza]

This is expected behavior. When Uvicorn starts, it applies its own logging configuration, which can end up overriding any custom handlers you defined earlier.

A way to avoid this is to pass log_config=None to uvicorn.run(). This tells Uvicorn not to modify the logging setup, so your existing handlers remain intact:

import uvicorn
uvicorn.run(app, host=UI.HOST, port=UI.PORT, log_config=None)

If you'd still like to use Uvicorn's default logging while adding your own (for example, a file handler), you can customize the log_config and include your handler in it.

Also, just as a heads-up, the --no-access-log flag only disables Uvicorn's access logs. It doesn't affect any custom logging you've set up.