Python logging: configuration file and root_logger setup.

gistfile1.txt

import logging
import logging.config

def get_root_logger(loglevel, logfile=None, log_config="log.conf"):
    # Requires 'import logging' and 'import logging.config'

    def log_level(loglevel):
        case = {"DEBUG": logging.DEBUG,
                "INFO": logging.INFO,
                "WARNING": logging.WARNING,
                "ERROR": logging.ERROR}
        return case[loglevel.upper()]                
    logging.config.fileConfig(log_config)
    root_logger = logging.getLogger()
    log_format = root_logger.handlers[0].format
    for handler in root_logger.handlers:
        handler.setLevel(log_level(loglevel)) # Change the loglevel for the default (Console) level logger
    if logfile: # If a logfile is specified, add as a handler for VERBOSE/DEBUG output and set to default format
        file_handler = logging.FileHandler(logfile,mode="a")
        file_handler.setLevel(logging.DEBUG)
        file_handler.format = log_format
        root_logger.addHandler(file_handler)
    return root_logger
    
if __name__ == '__main__':
    # Parse Command-Line Arguments
    parser = argparse.ArgumentParser()
    parser.add_argument('--option1', help="Option", default="something")
    parser.add_argument('mandatory', help="Mandatory argument")
    parser.add_argument('--log-level', help="Prints warnings to console by default",default="WARNING",choices=["DEBUG","INFO","WARNING","ERROR"])
    parser.add_argument('--log-file', help="Print log to file.", default="/somewhere/logconf.log")
    args = parser.parse_args()
    # Set up the logger
    root_logger = get_root_logger(args.log_level,logfile=args.log_file)
    # Do work
    main()

log.conf

[loggers]
keys=root

[handlers]
keys=console

[formatters]
keys=complex

[logger_root]
level=DEBUG
handlers=console

[handler_console]
class=StreamHandler
level=WARNING
formatter=complex
args=(sys.stderr,)

[formatter_complex]
format=%(levelname)s: %(asctime)s || %(name)s %(module)s %(funcName)sL%(lineno)s: %(message)s