Multi-level arg parse

README.md

Multi-level arg parse

Shows how to structure a python app using arg parse that goes down many levels.

The "trick" is to

• add a subparsers S1[]
• add parsers P1[] to your subparser S1[x]
• add a new set of subparsers S2[] to one of those parsers P1[x]

You can keep going from there.

Some other tips:

• use lots of if statements
• group parsers and add common arguments in loops

multilevel_argparse.py

#!/usr/bin/env python

import argparse

"""Multi-level argparse example

# 2 commands down

python multilevel_argparse.py do thing
python multilevel_argparse.py do thing -f

# All levels get help text

python multilevel_argparse.py -h
python multilevel_argparse.py do -h
python multilevel_argparse.py do thing -h

"""

def do(options):
    if options.method == "thing":
        if options.force:
            print("Doing it")
        else:
            print("Not doing it")

if __name__ == "__main__":
    p = argparse.ArgumentParser(description="So deep!.")
    action_sp = p.add_subparsers(help='commands', dest='action')

    # Top level
    do_action_p = action_sp.add_parser('do', help='Do something')
    
    ##
    # Do parsers
    ## 

    do_action_sp = do_action_p.add_subparsers(help='Method to perform', dest='action')
    do_action_thing_p = do_action_sp.add_parser('thing', help='Do the thing.')

    do_force_parsers = [do_action_thing_p]
    for p in do_force_parsers:
        p.add_argument('-f', '--force',
            default=False,
            dest="force",
            action='store_true',
            help="Do with abandon."
        )

    ##
    # End argparse setup. Parse and start doing actions.
    ## 

    options = p.parse_args()

    if options.action == 'do':
        do(options)

Because there is only 1 command on each level argparse compressed the help message a bit so calling help even on the top level shows this

$ python multilevel_argparse.py -h
usage: multilevel_argparse.py do thing [-h] [-f]

optional arguments:
  -h, --help   show this help message and exit
  -f, --force  Do with abandon.

If you add more commands on each level that changes.