Python: install custom logging handlers for stdout and stderr based on --debug/--verbose flags

custom_logging.py

import logging
import sys

def init_logging(name, log_level):

    # install handlers for stdout (DEBUG, INFO) and stderr (WARNING, ERROR)
    # http://stackoverflow.com/a/16066513/143397
    logger = logging.getLogger(name)
    logger.setLevel(log_level)

    class DebugFilter(logging.Filter):
        def filter(self, rec):
            return rec.levelno in (logging.DEBUG,)

    formatter = logging.Formatter("%(levelname)s:%(name)s:%(message)s", None)

    # debug uses a special format:
    debug_handler = logging.StreamHandler(sys.stdout)
    debug_handler.setLevel(logging.DEBUG)
    debug_handler.addFilter(DebugFilter())
    debug_handler.setFormatter(formatter)

    class InfoFilter(logging.Filter):
        def filter(self, rec):
            return rec.levelno in (logging.INFO,)

    # info uses default format:
    info_handler = logging.StreamHandler(sys.stdout)
    info_handler.setLevel(logging.DEBUG)
    info_handler.addFilter(InfoFilter())

    h2 = logging.StreamHandler()
    h2.setLevel(logging.WARNING)
    h2.setFormatter(formatter)

    logger.addHandler(debug_handler)
    logger.addHandler(info_handler)
    logger.addHandler(h2)
    return logger
    
parser = argparse.ArgumentParser()
parser.add_argument('-d', '--debug',   action="store_const", dest="loglevel", const=logging.DEBUG,     default=logging.WARNING, help="Show debug output")
parser.add_argument('-v', '--verbose', action="store_const", dest="loglevel", const=logging.INFO,                               help="Show more output")
args = parser.parse_args()

# set up logging on root logger
init_logging(None, args.loglevel)