python logging ensure a handler is added only once

Question

I have a piece of code that is initializing a logger as below.

logger = logging.getLogger()
hdlr = logging.FileHandler(\'logfile.log\')
formatter = logging.         


        

Answer 1

If you are familiar with AWS Lambda, then you might already know that in some contexts, the handlers come pre-configured [1]. Assuming logger.handlers is not empty, is not enough. I recommend setting an attribute on the logger instance, like so:

def init_logger(logger):
    if hasattr(logger, 'initialized'):
        return logger  # No need for addHandler
    else:
        setattr(logger, 'initialized', True)

    # Initialize the logger
    # ...

[1] Using python Logging with AWS Lambda