flask_gunicorn_logging.py

## Reference: https://medium.com/@trstringer/logging-flask-and-gunicorn-the-manageable-way-2e6f0b8beb2f
## in wsgi.py (gunicorn base file)
## this is to mainitain sync between the levels of logging module and gunicorn logger.
import logging

if __name__ != '__main__':
    gunicorn_logger = logging.getLogger('gunicorn.error')
    app.logger.handlers = gunicorn_logger.handlers
    app.logger.setLevel(gunicorn_logger.level)

## print logs using
app.logger.info("Hello this will be saved in log file with [INFO] tag.")

## set gunicorn log-level to debug to get all levels of logs. 
## DEBUG, INFO, WARNING, ERROR, CRITICAL is the log level hierarchy.
## gunicorn command
## <path_to_gunicorn> --workers 2 --bind unix:running.sock --log-file <path to log file> --log-level debug --capture-output -m 007 wsgi:app --preload