Django management command arguments

Question

I'm trying to understand how Django management commands work.

When there's no argument, or self on it's own. my command works fine. When I add arguments to the second function 'def add_arguments' it seems one arg works but the other isn't registering.

My command is as follows:

from backend.tasks import MBCommand
import sys

class Command(MBCommand):
    help = 'Refreshes MB data'

    def add_arguments(self , parser):
        parser.add_argument('event_id' , nargs='+' , type=int, 
        help='evid')
        parser.add_argument('market_id', nargs='+', type=int, 
        help='marid')

   def handle(self, *args, **kwargs):

       self.mb_get_events()

       event_ids =  kwargs['event_id']
       market_ids = kwargs['market_id']

        for event_id in event_ids:
            for market_id in market_ids:


            self.mb_get_runners(event_id,market_id)
            sys.exit()

My two functions are,

from django.core.management.base import BaseCommand, CommandError
class MBCommand(BaseCommand):

    def mb_get_events(self):
        do something


   def mb_get_runners(self, event_id, market_id):
        do something

What am I missing here?

how I run the command (update_mb is the file name of command)

python manage.py update_mb  event_id market_id

the error.

usage: manage.py update_mb [-h] [--version] [-v {0,1,2,3}]
                     [--settings SETTINGS] [--pythonpath 
     PYTHONPATH]
                     [--traceback] [--no-color]
                     event_id [event_id ...] market_id [market_id 
  ...]
 manage.py update_mb: error: argument event_id: invalid int 
 value: 
'event_id'
(butterbotenv) macs-MBP:butterbot mac$ 

Answer 1

As I already said in the comments to the question:

The command expects one (or multiple) arguments of type int; but as the error says, it cannot cast the received argument into a int.

Try passing numbers; instead of

python manage.py update_mb event_id market_id

try using this (or something similar)

python manage.py update_mb 2 3 4

---

But I notice an issue with your code: you use parser.add_argument(... nargs='+', ...) for both of your arguments. Consider the example I gave previously:

python manage.py update_mb 2 3 4

How is the command supossed to know which are event_id and which are market_id? How does it work for you?

One improvement could be to use optional arguments; read more about Djangos custom management commands and the underlying Python argparse module. It could look like this:

def add_arguments(self , parser):
    parser.add_argument('--event', action='append', type=int)
    parser.add_argument('--market', action='append', type=int)

To be used like this:

>>> python manage.py update_mb --event 2 --event 3 --market 4