Duplicate log output when using Python logging module

Since Python 3.2 you can just check if handlers are already present and if so, clear them before adding new handlers. This is pretty convenient when debugging and the code includes your logger initialization

if (logger.hasHandlers()):
    logger.handlers.clear()

logger.addHandler(handler)

The logging.getLogger() is returns the same instance for a given name. (Documentation)

The problem is that every time you call myLogger(), it's adding another handler to the instance, which causes the duplicate logs.

Perhaps something like this?

import os
import time
import datetime
import logging

loggers = {}

def myLogger(name):
    global loggers
    
    if loggers.get(name):
        return loggers.get(name)
    else:
        logger = logging.getLogger(name)
        logger.setLevel(logging.DEBUG)
        now = datetime.datetime.now()
        handler = logging.FileHandler(
            '/root/credentials/Logs/ProvisioningPython' 
            + now.strftime("%Y-%m-%d") 
            + '.log')
        formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
        handler.setFormatter(formatter)
        logger.addHandler(handler)
        loggers[name] = logger
                       
        return logger

Tags:

Python