How to have different mandatory parameters for two categories using argparse python?

You could do something like this, using set_defaults to attribute a handler for each subcommand.

import argparse

def push(args):
    return (args.environment, args.instance, args.config)

def status(args):
    return (args.environment, args.instance)

parser = argparse.ArgumentParser()

subparsers = parser.add_subparsers()

# create the parser for the push command
push_parser = subparsers.add_parser('push')
push_parser.set_defaults(func=push)

push_parser.add_argument('--environment', type=str)
push_parser.add_argument('--instance', type=str)
push_parser.add_argument('--config', type=str)


# create the parser for the status command
status_parser = subparsers.add_parser('status')
status_parser.set_defaults(func=status)

status_parser.add_argument('--environment', type=str)
status_parser.add_argument('--instance', type=str)

    
args = parser.parse_args(['push', '--environment=a', '--instance=b', '--config=c'])
print(args.func(args))

Here's a simple example that uses argparse with two subcommands:

"""
How to have different mandatory parameters for two categories
using argparse python?
"""
import argparse
import sys

def main():
    """
    Description here
    """
    parser = argparse.ArgumentParser(
        description='Stack Overflow 64995368 Parser'
    )
    parser.add_argument(
        "-v",
        "--verbose",
        help="verbose output",
        action="store_true"
    )
    subparser = parser.add_subparsers(
        title="action",
        dest='action',
        required=True,
        help='action sub-command help'
    )

    # create the subparser for the "push" command
    parser_push = subparser.add_parser(
        'push',
        help='push help'
    )
    parser_push.add_argument(
        'environment',
        type=str,
        help='push environment help'
    )
    parser_push.add_argument(
        'instance',
        type=str,
        help='push instance help'
    )
    parser_push.add_argument(
        'config',
        type=str,
        help='push config help'
    )

    # create the subparser for the "status" command
    parser_status = subparser.add_parser(
        'status',
        help='status help'
    )
    parser_status.add_argument(
        'environment',
        type=str,
        help='status environment help'
    )
    parser_status.add_argument(
        'instance',
        type=str,
        help='status instance help'
    )

    args = parser.parse_args()

    if args.action == 'push':
        print('You chose push:',
            args.environment, args.instance, args.config)
    elif args.action == 'status':
        print('You chose status:',
            args.environment, args.instance)
    else:
        print('Something unexpected happened')

if __name__ == "__main__":
    try:
        sys.exit(main())
    except KeyboardInterrupt:
        print("\nCaught ctrl+c, exiting")

Example output for various command lines:

$ python3 test.py
usage: test.py [-h] [-v] {push,status} ...
test.py: error: the following arguments are required: action

$ python3 test.py -h
usage: test.py [-h] [-v] {push,status} ...

Stack Overflow 64995368 Parser

optional arguments:
  -h, --help     show this help message and exit
  -v, --verbose  verbose output

action:
  {push,status}  action sub-command help
    push         push help
    status       status help

$ python3 test.py push -h
usage: test.py push [-h] environment instance config

positional arguments:
  environment  push environment help
  instance     push instance help
  config       push config help

optional arguments:
  -h, --help   show this help message and exit

$ python3 test.py push
usage: test.py push [-h] environment instance config
test.py push: error: the following arguments are required: environment, instance, config

$ python3 test.py push myenv
usage: test.py push [-h] environment instance config
test.py push: error: the following arguments are required: instance, config

It's often easier just to use sys.argv contents directly. https://www.tutorialspoint.com/python/python_command_line_arguments.htm

#! /usr/bin/env python3

import sys
s_args  = sys .argv  ##  s_args[0] = script_name.py

def push( environment,  instance,  config ):
    print( 'PUSH command:',  environment,  instance,  config )

def status( environment,  instance ):
    print( 'STATUS command:',  environment,  instance )

##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

if __name__ == '__main__':
    if len( s_args ) < 4:
        print( 'missing args:' )
        print( '    PUSH environment instance config' )
        print( '    STATUS environment instance' )

    elif s_args[1] .lower() == 'push':
        if len( s_args ) < 5:
            print( 'missing args for PUSH command:' )
            print( '    PUSH environment instance config' )
        else:
            push( s_args[2],  s_args[3],  s_args[4] )

    elif s_args[1] .lower() == 'status':
        if len( s_args ) < 4:
            print( 'missing args for STATUS command:' )
            print( '    STATUS environment instance' )
        else:
            status( s_args[2],  s_args[3] )

    else:
        print( 'incorrect command:' )
        print( '    PUSH environment instance config' )
        print( '    STATUS environment instance' )