gistfile1.txt

# -*- coding: utf-8 -*-
"""Define a management command to handle safe migrations."""

from __future__ import print_function

import sys

from django.core.cache import cache
from django.core.management import call_command
from django.core.management.base import BaseCommand
from django.core.management.commands.migrate import Command as MigrateCommand
from django.db import DEFAULT_DB_ALIAS


class Command(BaseCommand):
    """Define the safe migration command."""

    help = '{0} [with locking]'.format(MigrateCommand.help)

    def add_arguments(self, parser):
        """Handle arguments passed to the safe migration command."""
        super(Command, self).add_arguments(parser)

        # Not all arguments are available, steal from here as needed:
        # https://github.com/django/django/blob/master/django/core/management/commands/migrate.py

        parser.add_argument('--noinput', action='store_false', dest='interactive', default=True,
                            help='Tells Django to NOT prompt the user for input of any kind.')

        parser.add_argument('--fake', action='store_true',
                            help='Tells Django to NOT prompt the user for input of any kind.')

        parser.add_argument(
            '--database', action='store', dest='database',
            default=DEFAULT_DB_ALIAS,
            help='Nominates a database to synchronize. Defaults to the "default" database.',
        )

    def handle(self, *args, **options):
        """Perform safe migration via the management command."""
        locked = not cache.add('__django_locking_migrations', 1)
        if locked:
            print('Migrations are locked, don\'t run.')
            # Explicity end cleanly. Just because it was locked,
            # doesn't mean a failure.
            sys.exit(0)
        try:
            print('args', args)
            print('options', options)
            call_command('migrate', *args, **options)
        except:
            import traceback
            traceback.print_exc()
            sys.exit(1)
        finally:
            cache.delete('__django_locking_migrations')