Python Logging Duplicate Output

user_16912844 0
Viewed 51

I am getting duplicate output for Python logging with custom logger. Below is the section of logging code and output. For some reason if I remove the logger.setLevel(logging.DEBUG) line, the logger doesn't seem to respect the console_handler.setLevel(logging.DEBUG) line, and there is no output at all.

Code

...
args = parser.parse_args()

if args.log:
    # Create custom logger
    logger = logging.getLogger('a')
    logger.setLevel(logging.DEBUG)
    # Create handler
    console_handler = logging.StreamHandler()
    console_handler.setLevel(logging.DEBUG)
    # Create formatter and add it to handler
    console_formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
    console_handler.setFormatter(console_formatter)
    # Add handler to logger
    logger.addHandler(console_handler)

    try:
        ...
    except IndexError as ie:
        logger.info(f'Test')
        ...
    except Exception as ex:
        logger.error(f'Exception: {ex}')

Output

2022-07-11 11:29:59,409 - INFO - Test
INFO:a:Test
logging python
1 Answers

As far as I remember the setting propagates to higher level (ancestor) loggers. You can read about it here.

I would suggest adding logger.propagate = False after initializing logger a:

logger = logging.getLogger('a')
logger.propagate = False
logger.setLevel(logging.DEBUG)
user_10112530
Related