Duplicate logs when use logging.basicConfig in application

Checklist

• The bug is reproducible against the latest release or master.
• There are no similar issues or pull requests to fix it yet.

Describe the bug

When use logging.basicConfig to config logging in application, uvicorn logs will duplicate in console.

Steps to reproduce the bug

app.py:

import logging
from fastapi import FastAPI

logging.basicConfig(level=logging.INFO)

app = FastAPI(debug=True)

run it:

uvicorn app:app

Expected behavior

expect no duplicate logs.

Actual behavior

uvicorn.error logs duplicated:

INFO:     Started server process [85610]
INFO:uvicorn.error:Started server process [85610]
INFO:     Waiting for application startup.
INFO:uvicorn.error:Waiting for application startup.
INFO:     Application startup complete.
INFO:uvicorn.error:Application startup complete.
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:uvicorn.error:Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

Debugging material

I think the uvicorn logger should not propagate, because it already handled by uvicorn handler. And the behavior of gunicorn is no duplicate logs.

Add "propagate": False to https://github.com/encode/uvicorn/blob/master/uvicorn/config.py#L107 can fix the issue.

"uvicorn": {"handlers": ["default"], "level": "INFO", "propagate": False},

Environment

Running uvicorn 0.15.0 with CPython 3.9.7 on Darwin

Additional context

Maybe related: https://github.com/encode/uvicorn/issues/614

[yuval-illumex]

Any Update on this one? It’s really annoying 😦

[bachya]

@matthew-viglione My workaround in the meantime has been:

uvicorn_logger = logging.getLogger("uvicorn")
uvicorn_logger.removeHandler(uvicorn_logger.handlers[0])