Handy decorator for exception logging using `logging`

log_exc.py

import logger
from functools import wraps


def log_exc(fn=None, reraise=None, msg=None, exc=None, logger=None):
    """
    Decorator to log exceptions in a function.
    
    Usage:
    @log_exc
    def fn():
        # Logged and caught
        raise Exception()
    
    @log_exc(msg="Hello!")
    def fn():
        # Logged and caught with message "Hello!"
        raise Exception()
    
    :param reraise: Reraise the exception once caught
    :param msg: Message to log with, default is "An error occurred!"
    :param exc: Exception class to catch, default is `Exception`
    :param logger: `logging.Logger` to use, default is based on fn.__qualname__.
    """
    optional_args = [
        reraise, msg, exc, logger
    ]
    if any(optional_args) and fn is None:
        return lambda fn: log_exc(fn, reraise=reraise, msg=msg, exc=exc, logger=logger)
    elif fn is None:
        raise ValueError("No function and no configuration provided")

    reraise = reraise or False
    msg = msg or "An error occurred!"
    exc = exc or Exception
    logger = logger or logging.getLogger(fn.__qualname__)

    @wraps(fn)
    def inner(*args, **kwargs):
        try:
            return fn(*args, **kwargs)
        except exc:
            logger.exception(msg)
            if reraise:
                raise
    return inner