Demonstrate a quick example of how to use argparse and to setup python logging (both console and to a file) and pass the logger between functions.

logging_and_argparse_example.py

#!/usr/bin/env python
"""
MIT License (MIT)
Copyright (c) 2015. Michael Ewald <[email protected]>, GeomaticsResearch LLC
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""
import logging

def hello_world_worker(msg, logger=None):
    """Say hello world and demonstrate passing a logger around.
    :param msg: The message to say to the user
    :param logger: A logger object.
    :return: The msg
    """
    theLogger = logger or logging.getLogger(__name__)
    theLogger.info(msg)
    return msg

def hello_world(msg, logger=None):
    """Say hello world using a child function of this function and demonstrate passing a logger around.
    :param msg: The message to say to the user
    :param logger: A logger object.
    :return: The msg
    """
    theLogger = logger or logging.getLogger(__name__)
    func_result = hello_world_worker(msg, logger=theLogger)
    return func_result

if __name__ == "__main__":
    """Run the script from the command line using argparse
    """
    import argparse
    parser = argparse.ArgumentParser(description="Demonstrate how to use argparse and pass a logger around functions")
    parser.add_argument("msg", type=str, help="The message you want to say to the user")
    parser.add_argument("-log", type=str, dest='logfile', help='The filepath of the logfile to write to (Default: None)', default=None)
    args = parser.parse_args()

    # Set up the logger
    logger = logging.getLogger(__file__)  # Create the logger
    logger.setLevel(logging.DEBUG)        # Set log level to DEBUG
    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')  # create formatter
    if args.logfile:
        flh = logging.FileHandler(args.logfile)    # create file console logger
        flh.setLevel(logging.DEBUG)
        flh.setFormatter(formatter)
        logger.addHandler(flh)
    else:
        ch = logging.StreamHandler()          # create console handler
        ch.setLevel(logging.DEBUG)            # set level to debug
        ch.setFormatter(formatter)
        logger.addHandler(ch)

    # Run the function
    hello_world(args.msg, logger=logger)