Python 2.7 - Argparse Usage

Hello,

I'm using Python 2.7 and the Argparse module to parse command line parameters. I have the following stripped down code, but I'd like to use subparsers and parents to make the help more obvious. I have the following usage cases that I am trying to accommodate, but I can't figure out how to do this properly with subparsers. If someone could nudge me in the right direction with a couple of generic examples, I would appreciate it.

script.py # script should execute and assume the -i switch
script.py -i # script should execute in interactive mode
script.py -f [fname] # The script should execute in file mode. The script takes fname as a parameter and executes. In my code below, I have the fname validated via another function, but I can't figure that out with subparsers
script.py -E [endpoint] -s [start_time] -e [end_time] # The script executes in endpoint mode. The -s is mandatory with -E and -e is optional. However, if parameters are passed they must be validated with the valid_date function. I have this working in the code below, but I can't figure it out with subparsers. I may at some point also try to validate the endpoint parameter.

"-a" and "-x" are optional parameters and may be used with any of the three modes listed above. I know this is accomplished via parents. However, I can't get this working the closest I've come is code that doesn't error out. However, --help does not display existence of the switches either.

import argparse
from time import time as timer
import sys
def valid_date(iso8601):
    pass
def valid_file(parser, fname):
    pass
    return fname
def file_mode(fname, audit, staging):
    print("Start in file mode.  Audit is {} and staging is {}.".format(audit, staging))
    sys.exit(0)
def endpoint_mode(endpoint, start_time, end_time, audit, staging):
    print("Start in endpoint mode.  Audit is {} and staging is {}.".format(audit, staging))
    sys.exit(0)
def interactive_mode(audit, staging):
    print("Start in interactive mode.  Audit is {} and staging is {}.".format(audit, staging))
def main():
    parser = argparse.ArgumentParser(description="This is my test ArgParse script.")
    group = parser.add_mutually_exclusive_group()
    
    group.add_argument("-i", \
                        dest="interactive", \
                        action="store_true", \
                        help="Run the script interactively.  This is the default " + \
                             "mode if no options are specfied.")
    group.add_argument("-f", \
                        dest="fname", \
                        help="Run the script against an input file.", \
                        metavar="FILE", \
                        type=lambda x: valid_file(parser, x))
    group.add_argument("-E", \
                        dest="endpoint",
                        help="Run the script against a specific endpoint.",
                        metavar="ENDPOINT")
    parser.add_argument("-a", \
                        dest="audit", \
                        action="store_true", \
                        help="Audit only.")
    parser.add_argument("-x", \
                        dest="staging", \
                        action="store_true", \
                        help="Switches queries to use staging.")
    parser.add_argument("-s", \
                        dest="start_time", \
                        help="Specify a start date.  This is mandatory with the -E switch.", \
                        metavar="DATE",
                        type=valid_date)
    parser.add_argument("-e", \
                        dest="end_time", \
                        help="Specify an end date.  This optional with the -E switch.", \
                        metavar="DATE")
    args = parser.parse_args()
    audit = args.audit
    staging = args.staging
    interactive = args.interactive
    fname = args.fname
    endpoint = args.endpoint
    start_time = args.start_time
    end_time = args.end_time
    if not len(sys.argv) > 1:
        interactive_mode(audit, staging)
    if args.interactive is True:
        interactive_mode(audit, staging)
    if '-f' in sys.argv:
        file_mode(fname, audit, staging)
    if '-E' in sys.argv:
        endpoint_mode(endpoint, start_time, end_time, audit, staging)

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"""Usage: prog [-a] [-x] prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x] Process FILE and optionally apply correction to either left-hand side or right-hand side. Arguments: FNAME must be validated by another function ENDPOINT The -s is mandatory with -E and -e is optional. START_TIME If passed, must be validated with the valid_date function END_TIME ditto Options: -h --help -i script should execute in interactive mode -f script should execute in file mode -E script executes in endpoint mode -a Audit only -x use staging """ from docopt import docopt if __name__ == '__main__': d = docopt(__doc__) # parse arguments based on docstring above print d

Microsoft Windows [Version 6.1.7601] Copyright (c) 2009 Microsoft Corporation. All rights reserved. C:\>python docopttest.py {'-E': False, '-a': False, '-e': False, '-f': False, '-i': False, '-s': False, '-x': False, 'ENDPOINT': None, 'END_TIME': None, 'FNAME': None, 'START_TIME': None} C:\>python docopttest.py -i {'-E': False, '-a': False, '-e': False, '-f': False, '-i': True, '-s': False, '-x': False, 'ENDPOINT': None, 'END_TIME': None, 'FNAME': None, 'START_TIME': None} C:\>python docopttest.py -i -a -z Usage: prog [-a] [-x] prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x] C:\>python docopttest.py -i -a -x {'-E': False, '-a': True, '-e': False, '-f': False, '-i': True, '-s': False, '-x': True, 'ENDPOINT': None, 'END_TIME': None, 'FNAME': None, 'START_TIME': None} C:\>python docopttest.py -f Usage: prog [-a] [-x] prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x] C:\>python docopttest.py -f foo.bar {'-E': False, '-a': False, '-e': False, '-f': True, '-i': False, '-s': False, '-x': False, 'ENDPOINT': None, 'END_TIME': None, 'FNAME': 'foo.bar', 'START_TIME': None} C:\>python docopttest.py -E EP_here Usage: prog [-a] [-x] prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x] C:\>python docopttest.py -E EP_here -s 2017-01-01 {'-E': True, '-a': False, '-e': False, '-f': False, '-i': False, '-s': True, '-x': False, 'ENDPOINT': 'EP_here', 'END_TIME': None, 'FNAME': None, 'START_TIME': '2017-01-01'} C:\>python docopttest.py -E EP_here -s 2017-01-01 -x {'-E': True, '-a': False, '-e': False, '-f': False, '-i': False, '-s': True, '-x': True, 'ENDPOINT': 'EP_here', 'END_TIME': None, 'FNAME': None, 'START_TIME': '2017-01-01'} C:\>python docopttest.py -E EP_here -s 2017-01-01 -e 2017-10-01 {'-E': True, '-a': False, '-e': True, '-f': False, '-i': False, '-s': True, '-x': False, 'ENDPOINT': 'EP_here', 'END_TIME': '2017-10-01', 'FNAME': None, 'START_TIME': '2017-01-01'}

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LVL 9

Flabio GatesCommented: 2017-10-01

Have you seen docopt? Until now, I haven't seen this myself but I am glad I did now.
You'll have to explicitly do the argument-validation yourself but it gets most of what I understand of your requirements.

testing:

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Flabio GatesCommented: 2017-10-20

Question inactive

Python 2.7 - Argparse Usage

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