dictConfig() to create a logging configuration for Flask (https://flask.palletsprojects.com/en/1.1.x/logging/#basic-configuration)

__init__.py

import os
from logging.config import (
    dictConfig
)
from flask import (
    Flask
)


def create_app(
):
    
    # Creates an instance of the application.
    app = Flask(
        __name__
    )
    
    # Loads the configuration of the application from the given object.
    app.config.from_object(
        f"api.config.{os.getenv('CONFIG_MODE')}Config"
    )
    
    # Configures the logging module from a dictionary.
    dictConfig(
        {
            "version": app.config['LOG_VERSION'],
            "disable_existing_loggers": app.config['LOG_DISABLE_EXISTING_LOGGERS'], 
            "formatters": {
                "default": {
                    "format": app.config['LOG_FORMATTERS_DEFAULT_FORMAT'],
                    "datefmt": app.config['LOG_FORMATTERS_DEFAULT_DATEFMT']
                }
            },
            "handlers": {
                "wsgi": {
                    "class": app.config['LOG_HANDLERS_WSGI_CLASS'],
                    "stream": app.config['LOG_HANDLERS_WSGI_STREAM'],
                    "formatter": app.config['LOG_HANDLERS_WSGI_FORMATTER']
                }
            },
            "root": {
                "level": app.config['LOG_ROOT_LEVEL'],
                "handlers": app.config['LOG_ROOT_LEVEL_HANDLERS']
            },
        }
    )
    
  # Returns the application factory.
  return app

config.py

    LOG_VERSION = 1
    LOG_DISABLE_EXISTING_LOGGERS = True
    LOG_FORMATTERS_DEFAULT_FORMAT = '[%(asctime)s] [%(levelname)s] [%(module)s]: %(message)s'
    LOG_FORMATTERS_DEFAULT_DATEFMT = '%Y-%m-%d %H:%M:%S %z'
    LOG_HANDLERS_WSGI_CLASS = 'logging.StreamHandler'
    LOG_HANDLERS_WSGI_STREAM = 'ext://flask.logging.wsgi_errors_stream'
    LOG_HANDLERS_WSGI_FORMATTER = 'default'
    LOG_ROOT_LEVEL = 'INFO'
    LOG_ROOT_LEVEL_HANDLERS = ['wsgi']