so I am writing a python script that uses argparse in order to pass information and process input. I have been using sub-commands to force/use different operations in the program. So far my script is formatted like so:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import argparse
def main(username, password, api, apiId):
print("Hello, world!")
def _cli():
# Create parser to obtain arguments
parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter, argument_default=argparse.SUPPRESS)
subparsers = parser.add_subparsers(dest = "api", required = True)
base_subparser = argparse.ArgumentParser(add_help = False)
# Shared arguments
base_subparser.add_argument('-u', '--username', help = "Username", default = "admin")
base_subparser.add_argument('-p', '--password', help = "Password", default = "admin")
# Create subcommands
create_parser = subparsers.add_parser("create", parents = [base_subparser])
update_parser = subparsers.add_parser("update", parents = [base_subparser])
# Flag for sub-parser to pass API ID
update_parser.add_argument('-i', '--apiId', help = "ID for API you are trying to access.", required = True)
# Obtain all the argument values
args = parser.parse_args()
# Return them in a dictionary format
return vars(args)
if __name__ == '__main__':
# Pass arguments to main function using dictonary format.
main(**_cli())
Where usage is specified as such:
usage: test.py [-h] {create,update} ...
positional arguments: {create, update}
optional arguments: -h, --help show this help message and exit
My issue is that while the update command is working fine, where I am required to pass an ID, my create has a bug/issue where it complains about not setting the flag/passing one even though it is not required/needed.
main(**_cli())
TypeError: main() missing 1 required positional argument: 'apiId'
What am I doing wrong here and how do I fix it? I've tried to google but I can't seem to understand the problem/how to resolve it.
The error you are getting is telling you that apiId is not being provided when you are using the create subcommand. You can either specify a default parameter, like so:
def main(username, password, api, apiId=None):
print("API: {}".format(api))
print("API ID: {}".format(apiId))
~ python args.py create -u a -p b
API: create
API ID: None
~ python args.py update -u a -p b -i c
API: update
API ID: c
or you could get a dict of keyword arguments using ** expansion in the function definition:
def main(**kwds):
print(kwds)
~ python args.py create -u a -p b
{'api': 'create', 'username': 'a', 'password': 'b'}
~ python args.py update -u a -p b -i c
{'api': 'update', 'username': 'a', 'password': 'b', 'apiId': 'c'}