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# -*- coding: utf-8 -*-
Base classes for writing management commands (named commands which can
be executed through ``django-admin`` or ````).
from __future__ import unicode_literals
import os
import sys
import warnings
from argparse import ArgumentParser
from optparse import OptionParser
import django
from django.core import checks
from import color_style, no_style
from django.db import connections
from django.utils.deprecation import RemovedInDjango110Warning
from django.utils.encoding import force_str
class CommandError(Exception):
Exception class indicating a problem while executing a management
If this exception is raised during the execution of a management
command, 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.
class SystemCheckError(CommandError):
The system check framework detected unrecoverable errors.
class CommandParser(ArgumentParser):
Customized ArgumentParser class to improve some error messages and prevent
SystemExit in several occasions, as SystemExit is unacceptable when a
command is called programmatically.
def __init__(self, cmd, **kwargs):
self.cmd = cmd
super(CommandParser, self).__init__(**kwargs)
def parse_args(self, args=None, namespace=None):
# Catch missing argument for a better error message
if (hasattr(self.cmd, 'missing_args_message') and
not (args or any(not arg.startswith('-') for arg in args))):
return super(CommandParser, self).parse_args(args, namespace)
def error(self, message):
if self.cmd._called_from_command_line:
super(CommandParser, self).error(message)
raise CommandError("Error: %s" % message)
def handle_default_options(options):
Include any default options that all commands should accept here
so that ManagementUtility can handle them before searching for
user commands.
if options.settings:
os.environ['DJANGO_SETTINGS_MODULE'] = options.settings
if options.pythonpath:
sys.path.insert(0, options.pythonpath)
class OutputWrapper(object):
Wrapper around stdout/stderr
def style_func(self):
return self._style_func
def style_func(self, style_func):
if style_func and self.isatty():
self._style_func = style_func
self._style_func = lambda x: x
def __init__(self, out, style_func=None, ending='\n'):
self._out = out
self.style_func = None
self.ending = ending
def __getattr__(self, name):
return getattr(self._out, name)
def isatty(self):
return hasattr(self._out, 'isatty') and self._out.isatty()
def write(self, msg, style_func=None, ending=None):
ending = self.ending if ending is None else ending
if ending and not msg.endswith(ending):
msg += ending
style_func = style_func or self.style_func
class BaseCommand(object):
The base class from which all management commands ultimately
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 the subclasses defined in this file.
If you are interested in overriding/customizing various aspects of
the command-parsing and -execution behavior, the normal flow works
as follows:
1. ``django-admin`` or ```` loads the command class
and calls its ``run_from_argv()`` method.
2. The ``run_from_argv()`` method calls ``create_parser()`` to get
an ``ArgumentParser`` for the arguments, parses them, performs
any environment changes requested by options like
``pythonpath``, and then calls the ``execute()`` method,
passing the parsed arguments.
3. The ``execute()`` method attempts to carry out the command by
calling the ``handle()`` method with the parsed arguments; any
output produced by ``handle()`` will be printed to standard
output and, if the command is intended to produce a block of
SQL statements, will be wrapped in ``BEGIN`` and ``COMMIT``.
4. If ``handle()`` or ``execute()`` raised any exception (e.g.
``CommandError``), ``run_from_argv()`` will instead print an error
message to ``stderr``.
Thus, the ``handle()`` method is typically the starting point for
subclasses; many built-in commands and command types either place
all of their logic in ``handle()``, or perform some additional
parsing work in ``handle()`` and then delegate from it to more
specialized methods as needed.
Several attributes affect behavior at various steps along the way:
A string listing the arguments accepted by the command,
suitable for use in help messages; e.g., a command which takes
a list of application names might set this to '<app_label
app_label ...>'.
A boolean indicating whether the command needs to be able to
import Django settings; if ``True``, ``execute()`` will verify
that this is possible before proceeding. Default value is
A short description of the command, which will be printed in
help messages.
This is the list of ``optparse`` options which will be fed
into the command's ``OptionParser`` for parsing arguments.
Deprecated and will be removed in Django 1.10.
A boolean indicating whether the command outputs SQL
statements; if ``True``, the output will automatically be
wrapped with ``BEGIN;`` and ``COMMIT;``. Default value is
A boolean; if ``True``, entire Django project will be checked for errors
prior to executing the command. Default value is ``True``.
To validate an individual application's models
rather than all applications' models, call
``self.check(app_configs)`` from ``handle()``, where ``app_configs``
is the list of application's configuration provided by the
app registry.
A boolean indicating whether the locale set in settings should be
preserved during the execution of the command instead of translations
being deactivated.
Default value is ``False``.
Make sure you know what you are doing if you decide to change the value
of this option in your custom command if it creates database content
that is locale-sensitive and such content shouldn't contain any
translations (like it happens e.g. with django.contrib.auth
permissions) as activating any locale might cause unintended effects.
This option can't be False when the can_import_settings option is set
to False too because attempting to deactivate translations needs access
to settings. This condition will generate a CommandError.
# Metadata about this command.
option_list = ()
help = ''
args = ''
# Configuration shortcuts that alter various logic.
_called_from_command_line = False
can_import_settings = True
output_transaction = False # Whether to wrap the output in a "BEGIN; COMMIT;"
leave_locale_alone = False
requires_system_checks = True
def __init__(self, stdout=None, stderr=None, no_color=False):
self.stdout = OutputWrapper(stdout or sys.stdout)
self.stderr = OutputWrapper(stderr or sys.stderr)
if no_color: = no_style()
else: = color_style()
self.stderr.style_func =
def use_argparse(self):
return not bool(self.option_list)
def get_version(self):
Return the Django version, which should be correct for all
built-in Django commands. User-supplied commands should
override this method.
return django.get_version()
def usage(self, subcommand):
Return a brief description of how to use this command, by
default from the attribute ````.
usage = '%%prog %s [options] %s' % (subcommand, self.args)
return '%s\n\n%s' % (usage,
return usage
def create_parser(self, prog_name, subcommand):
Create and return the ``ArgumentParser`` which will be used to
parse the arguments to this command.
if not self.use_argparse:
def store_as_int(option, opt_str, value, parser):
setattr(parser.values, option.dest, int(value))
# Backwards compatibility: use deprecated optparse module
warnings.warn("OptionParser usage for Django management commands "
"is deprecated, use ArgumentParser instead",
parser = OptionParser(prog=prog_name,
parser.add_option('-v', '--verbosity', action='callback', dest='verbosity', default=1,
type='choice', choices=['0', '1', '2', '3'], callback=store_as_int,
help='Verbosity level; 0=minimal output, 1=normal output, 2=verbose output, 3=very verbose output')
'The Python path to a settings module, e.g. '
'"myproject.settings.main". If this isn\'t provided, the '
'DJANGO_SETTINGS_MODULE environment variable will be used.'
help='A directory to add to the Python path, e.g. "/home/djangoprojects/myproject".'),
parser.add_option('--traceback', action='store_true',
help='Raise on CommandError exceptions')
parser.add_option('--no-color', action='store_true', dest='no_color', default=False,
help="Don't colorize the command output.")
for opt in self.option_list:
parser = CommandParser(self, prog="%s %s" % (os.path.basename(prog_name), subcommand), or None)
parser.add_argument('--version', action='version', version=self.get_version())
parser.add_argument('-v', '--verbosity', action='store', dest='verbosity', default='1',
type=int, choices=[0, 1, 2, 3],
help='Verbosity level; 0=minimal output, 1=normal output, 2=verbose output, 3=very verbose output')
'The Python path to a settings module, e.g. '
'"myproject.settings.main". If this isn\'t provided, the '
'DJANGO_SETTINGS_MODULE environment variable will be used.'
help='A directory to add to the Python path, e.g. "/home/djangoprojects/myproject".')
parser.add_argument('--traceback', action='store_true',
help='Raise on CommandError exceptions')
parser.add_argument('--no-color', action='store_true', dest='no_color', default=False,
help="Don't colorize the command output.")
if self.args:
# Keep compatibility and always accept positional arguments, like optparse when args is set
parser.add_argument('args', nargs='*')
return parser
def add_arguments(self, parser):
Entry point for subclassed commands to add custom arguments.
def print_help(self, prog_name, subcommand):
Print the help message for this command, derived from
parser = self.create_parser(prog_name, subcommand)
def run_from_argv(self, argv):
Set up any environment changes requested (e.g., Python path
and Django settings), then run this command. If the
command raises a ``CommandError``, intercept it and print it sensibly
to stderr. If the ``--traceback`` option is present or the raised
``Exception`` is not ``CommandError``, raise it.
self._called_from_command_line = True
parser = self.create_parser(argv[0], argv[1])
if self.use_argparse:
options = parser.parse_args(argv[2:])
cmd_options = vars(options)
# Move positional args out of options to mimic legacy optparse
args = cmd_options.pop('args', ())
options, args = parser.parse_args(argv[2:])
cmd_options = vars(options)
self.execute(*args, **cmd_options)
except Exception as e:
if options.traceback or not isinstance(e, CommandError):
# SystemCheckError takes care of its own formatting.
if isinstance(e, SystemCheckError):
self.stderr.write(str(e), lambda x: x)
self.stderr.write('%s: %s' % (e.__class__.__name__, e))
def execute(self, *args, **options):
Try to execute this command, performing system checks if needed (as
controlled by the ``requires_system_checks`` attribute, except if
if options.get('no_color'): = no_style()
self.stderr.style_func = None
if options.get('stdout'):
self.stdout = OutputWrapper(options['stdout'])
if options.get('stderr'):
self.stderr = OutputWrapper(options.get('stderr'), self.stderr.style_func)
saved_locale = None
if not self.leave_locale_alone:
# Only mess with locales if we can assume we have a working
# settings file, because django.utils.translation requires settings
# (The final saying about whether the i18n machinery is active will be
# found in the value of the USE_I18N setting)
if not self.can_import_settings:
raise CommandError("Incompatible values of 'leave_locale_alone' "
"(%s) and 'can_import_settings' (%s) command "
"options." % (self.leave_locale_alone,
# Deactivate translations, because django-admin creates database
# content like permissions, and those shouldn't contain any
# translations.
from django.utils import translation
saved_locale = translation.get_language()
if (self.requires_system_checks and
not options.get('skip_validation') and # Remove at the end of deprecation for `skip_validation`.
not options.get('skip_checks')):
output = self.handle(*args, **options)
if output:
if self.output_transaction:
# This needs to be imported here, because it relies on
# settings.
from django.db import connections, DEFAULT_DB_ALIAS
connection = connections[options.get('database', DEFAULT_DB_ALIAS)]
if connection.ops.start_transaction_sql():
if self.output_transaction:
self.stdout.write('\n' +
if saved_locale is not None:
def check(self, app_configs=None, tags=None, display_num_errors=False,
Uses the system check framework to validate entire Django project.
Raises CommandError for any serious message (error or critical errors).
If there are only light messages (like warnings), they are printed to
stderr and no exception is raised.
all_issues = checks.run_checks(
header, body, footer = "", "", ""
visible_issue_count = 0 # excludes silenced warnings
if all_issues:
debugs = [e for e in all_issues if e.level < checks.INFO and not e.is_silenced()]
infos = [e for e in all_issues if checks.INFO <= e.level < checks.WARNING and not e.is_silenced()]
warnings = [e for e in all_issues if checks.WARNING <= e.level < checks.ERROR and not e.is_silenced()]
errors = [e for e in all_issues if checks.ERROR <= e.level < checks.CRITICAL and not e.is_silenced()]
criticals = [e for e in all_issues if checks.CRITICAL <= e.level and not e.is_silenced()]
sorted_issues = [
(criticals, 'CRITICALS'),
(errors, 'ERRORS'),
(warnings, 'WARNINGS'),
(infos, 'INFOS'),
(debugs, 'DEBUGS'),
for issues, group_name in sorted_issues:
if issues:
visible_issue_count += len(issues)
formatted = (
if e.is_serious()
for e in issues)
formatted = "\n".join(sorted(formatted))
body += '\n%s:\n%s\n' % (group_name, formatted)
if visible_issue_count:
header = "System check identified some issues:\n"
if display_num_errors:
if visible_issue_count:
footer += '\n'
footer += "System check identified %s (%s silenced)." % (
"no issues" if visible_issue_count == 0 else
"1 issue" if visible_issue_count == 1 else
"%s issues" % visible_issue_count,
len(all_issues) - visible_issue_count,
if any(e.is_serious() and not e.is_silenced() for e in all_issues):
msg ="SystemCheckError: %s" % header) + body + footer
raise SystemCheckError(msg)
msg = header + body + footer
if msg:
if visible_issue_count:
self.stderr.write(msg, lambda x: x)
def handle(self, *args, **options):
The actual logic of the command. Subclasses must implement
this method.
raise NotImplementedError('subclasses of BaseCommand must provide a handle() method')
class AppCommand(BaseCommand):
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.
missing_args_message = "Enter at least one application label."
def add_arguments(self, parser):
parser.add_argument('args', metavar='app_label', nargs='+',
help='One or more application label.')
def handle(self, *app_labels, **options):
from django.apps import apps
app_configs = [apps.get_app_config(app_label) for app_label in app_labels]
except (LookupError, ImportError) as e:
raise CommandError("%s. Are you sure your INSTALLED_APPS setting is correct?" % e)
output = []
for app_config in app_configs:
app_output = self.handle_app_config(app_config, **options)
if app_output:
return '\n'.join(output)
def handle_app_config(self, app_config, **options):
Perform the command's actions for app_config, an AppConfig instance
corresponding to an application label given on the command line.
raise NotImplementedError(
"Subclasses of AppCommand must provide"
"a handle_app_config() method.")
class LabelCommand(BaseCommand):
A management command which takes one or more arbitrary arguments
(labels) on the command line, and does something with each of
Rather than implementing ``handle()``, subclasses must implement
``handle_label()``, which will be called once for each label.
If the arguments should be names of installed applications, use
``AppCommand`` instead.
label = 'label'
missing_args_message = "Enter at least one %s." % label
def add_arguments(self, parser):
parser.add_argument('args', metavar=self.label, nargs='+')
def handle(self, *labels, **options):
output = []
for label in labels:
label_output = self.handle_label(label, **options)
if label_output:
return '\n'.join(output)
def handle_label(self, label, **options):
Perform the command's actions for ``label``, which will be the
string as given on the command line.
raise NotImplementedError('subclasses of LabelCommand must provide a handle_label() method')
class NoArgsCommand(BaseCommand):
A command which takes no arguments on the command line.
Rather than implementing ``handle()``, subclasses must implement
``handle_noargs()``; ``handle()`` itself is overridden to ensure
no arguments are passed to the command.
Attempting to pass arguments will raise ``CommandError``.
args = ''
def __init__(self):
"NoArgsCommand class is deprecated and will be removed in Django 1.10. "
"Use BaseCommand instead, which takes no arguments by default.",
super(NoArgsCommand, self).__init__()
def handle(self, *args, **options):
if args:
raise CommandError("Command doesn't accept any arguments")
return self.handle_noargs(**options)
def handle_noargs(self, **options):
Perform this command's actions.
raise NotImplementedError('subclasses of NoArgsCommand must provide a handle_noargs() method')
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