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$ 

Solution

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

Comments

[petr]

This seems about right. Can you print kwargs at the beginning of handle, run the command and add the output to your answer (please also add how you run the command).

[Ralf]

The command expects a (or multiple) int; instead of python manage.py update_mb event_id market_id try python manage.py update_mb 2 2 or something like that.

[tomoc4]

@Ralf thanks a lot that worked!!

[Ralf]

@RodrigoRodrigues I added an answer