Python args: django debugging arg set up for django manage.py

I want to enable debugging using visual studio debugging tool, ptvsd. Using that I have to attach the debugger to the application using

ptvsd.enable_attach(address=(settings.REMOTE_URL, settings.DEBUG_PORT), redirect_output=True)
ptvsd.wait_for_attach()

Using ptvsd means I can't use threading and reloading, so I append the args

sys.argv.append("--nothreading")
sys.argv.append("--noreload")

For convenience to enable debugging I created an args to execute those line of codes. I created named argument debug

if __name__ == "__main__":
    #previous line omitted
    parser = argparse.ArgumentParser()
    parser.add_argument("--debug", help="enable debugging through vscode")
    args = parser.parse_args()
    if args.debug:
        sys.argv.append("--nothreading")
        sys.argv.append("--noreload")
        ptvsd.enable_attach(address=(settings.REMOTE_URL, settings.DEBUG_PORT), redirect_output=True)
        ptvsd.wait_for_attach()
    execute_from_command_line(sys.argv)

What I want to achieve is, when I want to debug my app I use the command python manage.py runserver 0:8000 --enable-debugging and when I just want to run my app I use python manage.py runserver 0:8000

but it returns an error when I tried to run using python manage.py runserver 0:8000 it says unrecognized arguments for runserver and 0:8000

by that, do I have to include all possible django positional argument to the parser ? and how to do that with the 0:8000? add all possible port? Is using named argument not viable for this case?

Solution

So apparently I can use parser.parse_known_args(), it should be fine when there are unrecognized arguments. and because I want the --debug as a flag, I add action='store_true' in the add_argument so it returns true whenever the argument exists.

With that, I can solve this by using that and then remove the --debug argument when passing it down to execute_from_command_line. Something like this:

if __name__ == "__main__":
    #previous line omitted
    parser = argparse.ArgumentParser()
    parser.add_argument("--debug", action='store_true', help="enable debugging through vscode")
    args = vars(parser.parse_known_args()[0])
    if args.debug:
        sys.argv.append("--nothreading")
        sys.argv.append("--noreload")
        ptvsd.enable_attach(address=(settings.REMOTE_URL, settings.DEBUG_PORT), redirect_output=True)
        ptvsd.wait_for_attach()
    execute_from_command_line(sys.argv)

Now it works :)