# Django 4.0.11.dev20230214085346 documentation

# How to create custom `django-admin` commands

Applications can register their own actions with `manage.py`. For example, you might want to add a `manage.py` action for a Django app that you’re distributing. In this document, we will be building a custom `closepoll` command for the `polls` application from the tutorial.

To do this, add a `management/commands` directory to the application. Django will register a `manage.py` command for each Python module in that directory whose name doesn’t begin with an underscore. For example:

    polls/
        __init__.py
        models.py
        management/
            __init__.py
            commands/
                __init__.py
                _private.py
                closepoll.py
        tests.py
        views.py

In this example, the `closepoll` command will be made available to any project that includes the `polls` application in `INSTALLED_APPS`.

The `_private.py` module will not be available as a management command.

The `closepoll.py` module has only one requirement – it must define a class `Command` that extends `BaseCommand` or one of its subclasses.

Standalone scripts

Custom management commands are especially useful for running standalone scripts or for scripts that are periodically executed from the UNIX crontab or from Windows scheduled tasks control panel.

To implement the command, edit `polls/management/commands/closepoll.py` to look like this:

    from django.core.management.base import BaseCommand, CommandError
    from polls.models import Question as Poll

    class Command(BaseCommand):
        help = 'Closes the specified poll for voting'

        def add_arguments(self, parser):
            parser.add_argument('poll_ids', nargs='+', type=int)

        def handle(self, *args, **options):
            for poll_id in options['poll_ids']:
                try:
                    poll = Poll.objects.get(pk=poll_id)
                except Poll.DoesNotExist:
                    raise CommandError('Poll "%s" does not exist' % poll_id)

                poll.opened = False
                poll.save()

                self.stdout.write(self.style.SUCCESS('Successfully closed poll "%s"' % poll_id))

Note

When you are using management commands and wish to provide console output, you should write to `self.stdout` and `self.stderr`, instead of printing to `stdout` and `stderr` directly. By using these proxies, it becomes much easier to test your custom command. Note also that you don’t need to end messages with a newline character, it will be added automatically, unless you specify the `ending` parameter:

    self.stdout.write("Unterminated line", ending='')

The new custom command can be called using `python manage.py closepoll <poll_ids>`.

The `handle()` method takes one or more `poll_ids` and sets `poll.opened` to `False` for each one. If the user referenced any nonexistent polls, a `CommandError` is raised. The `poll.opened` attribute does not exist in the tutorial and was added to `polls.models.Question` for this example.

## Accepting optional arguments

The same `closepoll` could be easily modified to delete a given poll instead of closing it by accepting additional command line options. These custom options can be added in the `add_arguments()` method like this:

    class Command(BaseCommand):
        def add_arguments(self, parser):
            # Positional arguments
            parser.add_argument('poll_ids', nargs='+', type=int)

            # Named (optional) arguments
            parser.add_argument(
                '--delete',
                action='store_true',
                help='Delete poll instead of closing it',
            )

        def handle(self, *args, **options):
            # ...
            if options['delete']:
                poll.delete()
            # ...

The option (`delete` in our example) is available in the options dict parameter of the handle method. See the `argparse` Python documentation for more about `add_argument` usage.

In addition to being able to add custom command line options, all management commands can accept some default options such as `--verbosity` and `--traceback`.

## Management commands and locales

By default, management commands are executed with the current active locale.

If, for some reason, your custom management command must run without an active locale (for example, to prevent translated content from being inserted into the database), deactivate translations using the `@no_translations` decorator on your `handle()` method:

    from django.core.management.base import BaseCommand, no_translations

    class Command(BaseCommand):
        ...

        @no_translations
        def handle(self, *args, **options):
            ...

Since translation deactivation requires access to configured settings, the decorator can’t be used for commands that work without configured settings.

## Testing

Information on how to test custom management commands can be found in the testing docs.

## Overriding commands

Django registers the built-in commands and then searches for commands in `INSTALLED_APPS` in reverse. During the search, if a command name duplicates an already registered command, the newly discovered command overrides the first.

In other words, to override a command, the new command must have the same name and its app must be before the overridden command’s app in `INSTALLED_APPS`.

Management commands from third-party apps that have been unintentionally overridden can be made available under a new name by creating a new command in one of your project’s apps (ordered before the third-party app in `INSTALLED_APPS`) which imports the `Command` of the overridden command.

## Command objects

class `BaseCommand`

The base class from which all management commands ultimately derive.

Use this class if you want access to all of the mechanisms which parse the command-line arguments and work out what code to call in response; if you don’t need to change any of that behavior, consider using one of its subclasses.

Subclassing the `BaseCommand` class requires that you implement the `handle()` method.

### Attributes

All attributes can be set in your derived class and can be used in `BaseCommand`’s subclasses.

`BaseCommand.``help`

  A short description of the command, which will be printed in the help message when the user runs the command `python manage.py help <command>`.

`BaseCommand.``missing_args_message`

  If your command defines mandatory positional arguments, you can customize the message error returned in the case of missing arguments. The default is output by `argparse` (“too few arguments”).

`BaseCommand.``output_transaction`

  A boolean indicating whether the command outputs SQL statements; if `True`, the output will automatically be wrapped with `BEGIN;` and `COMMIT;`. Default value is `False`.

`BaseCommand.``requires_migrations_checks`

  A boolean; if `True`, the command prints a warning if the set of migrations on disk don’t match the migrations in the database. A warning doesn’t prevent the command from executing. Default value is `False`.

`BaseCommand.``requires_system_checks`

  A list or tuple of tags, e.g. `[Tags.staticfiles, Tags.models]`. System checks registered in the chosen tags will be checked for errors prior to executing the command. The value `'__all__'` can be used to specify that all system checks should be performed. Default value is `'__all__'`.

  Changed in Django 3.2:

  In older versions, the `requires_system_checks` attribute expects a boolean value instead of a list or tuple of tags.

`BaseCommand.``style`

  An instance attribute that helps create colored output when writing to `stdout` or `stderr`. For example:

      self.stdout.write(self.style.SUCCESS('...'))

  See Syntax coloring to learn how to modify the color palette and to see the available styles (use uppercased versions of the “roles” described in that section).

  If you pass the `--no-color` option when running your command, all `self.style()` calls will return the original string uncolored.

`BaseCommand.``suppressed_base_arguments`
  New in Django 4.0.

  The default command options to suppress in the help output. This should be a set of option names (e.g. `'--verbosity'`). The default values for the suppressed options are still passed.

### Methods

`BaseCommand` has a few methods that can be overridden but only the `handle()` method must be implemented.

Implementing a constructor in a subclass

If you implement `__init__` in your subclass of `BaseCommand`, you must call `BaseCommand`’s `__init__`:

    class Command(BaseCommand):
        def __init__(self, *args, **kwargs):
            super().__init__(*args, **kwargs)
            # ...

`BaseCommand.``create_parser`(prog_name, subcommand, **kwargs)

  Returns a `CommandParser` instance, which is an `ArgumentParser` subclass with a few customizations for Django.

  You can customize the instance by overriding this method and calling `super()` with `kwargs` of `ArgumentParser` parameters.

`BaseCommand.``add_arguments`(parser)

  Entry point to add parser arguments to handle command line arguments passed to the command. Custom commands should override this method to add both positional and optional arguments accepted by the command. Calling `super()` is not needed when directly subclassing `BaseCommand`.

`BaseCommand.``get_version`()

  Returns the Django version, which should be correct for all built-in Django commands. User-supplied commands can override this method to return their own version.

`BaseCommand.``execute`(*args, **options)

  Tries to execute this command, performing system checks if needed (as controlled by the `requires_system_checks` attribute). If the command raises a `CommandError`, it’s intercepted and printed to `stderr`.

Calling a management command in your code

`execute()` should not be called directly from your code to execute a command. Use `call_command()` instead.

`BaseCommand.``handle`(*args, **options)

  The actual logic of the command. Subclasses must implement this method.

  It may return a string which will be printed to `stdout` (wrapped by `BEGIN;` and `COMMIT;` if `output_transaction` is `True`).

`BaseCommand.``check`(app_configs=None, tags=None, display_num_errors=False)

  Uses the system check framework to inspect the entire Django project for potential problems. Serious problems are raised as a `CommandError`; warnings are output to `stderr`; minor notifications are output to `stdout`.

  If `app_configs` and `tags` are both `None`, all system checks are performed. `tags` can be a list of check tags, like `compatibility` or `models`.

### `BaseCommand` subclasses

class `AppCommand`

A management command which takes one or more installed application labels as arguments, and does something with each of them.

Rather than implementing `handle()`, subclasses must implement `handle_app_config()`, which will be called once for each application.

`AppCommand.``handle_app_config`(app_config, **options)

  Perform the command’s actions for `app_config`, which will be an `AppConfig` instance corresponding to an application label given on the command line.

class `LabelCommand`

A management command which takes one or more arbitrary arguments (labels) on the command line, and does something with each of them.

Rather than implementing `handle()`, subclasses must implement `handle_label()`, which will be called once for each label.

`LabelCommand.``label`

  A string describing the arbitrary arguments passed to the command. The string is used in the usage text and error messages of the command. Defaults to `'label'`.

`LabelCommand.``handle_label`(label, **options)

  Perform the command’s actions for `label`, which will be the string as given on the command line.

### Command exceptions

exception `CommandError`(returncode=1)

Exception class indicating a problem while executing a management command.

If this exception is raised during the execution of a management command from a command line console, it will be caught and turned into a nicely-printed error message to the appropriate output stream (i.e., `stderr`); as a result, raising this exception (with a sensible description of the error) is the preferred way to indicate that something has gone wrong in the execution of a command. It accepts the optional `returncode` argument to customize the exit status for the management command to exit with, using `sys.exit()`.

If a management command is called from code through `call_command()`, it’s up to you to catch the exception when needed.