--use-colors/--no-use-colors has no effect with log_config passed as file

[nectarindev]

Currently, this option works if log_config is passed as a dict.

https://github.com/encode/uvicorn/blob/c1144fd4f130388cffc05ee17b08747ce8c1be11/uvicorn/config.py#L363

In my projects, I usually create log_config.json based on what uvicorn uses by default and add the loggers I need.

https://github.com/encode/uvicorn/blob/c1144fd4f130388cffc05ee17b08747ce8c1be11/uvicorn/config.py#L68

In this scenario, it would be nice to be able to enable and disable colors via cli without hardcoding use_colors: true/false in log_config.json.

This option will also not affect user-created formatters that use uvicorn.logging.DefaultFormatter and uvicorn.logging.AccessFormatter.

I would suggest finding formatters that use DefaultFormatter and AccessFormatter and controlling their color if it is not explicitly specified in log_config.

{
    "version": 1,
    "disable_existing_loggers": false,
    "formatters": {
        "default": {
            "()": "uvicorn.logging.DefaultFormatter",
            "fmt": "%(levelprefix)s %(message)s"
        },
        "access": {
            "()": "uvicorn.logging.AccessFormatter",
            "fmt": "%(levelprefix)s %(client_addr)s - \"%(request_line)s\" %(status_code)s"
        }
    },
    "handlers": {
        "default": {
            "formatter": "default",
            "class": "logging.StreamHandler",
            "stream": "ext://sys.stderr"
        },
        "access": {
            "formatter": "access",
            "class": "logging.StreamHandler",
            "stream": "ext://sys.stdout"
        }
    },
    "loggers": {
        "uvicorn": {"handlers": ["default"], "level": "INFO", "propagate": false},
        "uvicorn.error": {"level": "INFO"},
        "uvicorn.access": {"handlers": ["access"], "level": "INFO", "propagate": false},
        "my_logger": {"handlers": ["default"], "level": "INFO", "propagate": false}
    }
}

# main.py
import logging

from fastapi import FastAPI

LOGGER = logging.getLogger("my_logger")

def create_app():
    LOGGER.info("Creating ASGI app")
    return FastAPI()

# uvicorn --factory main:create_app --no-use-colors --log-config log_config.json

*console output still uses colors

If this proposal is accepted, I would like to take it on.