• Language: en

Source code for django.core.management.base

# -*- coding: utf-8 -*-

from __future__ import unicode_literals

Base classes for writing management commands (named commands which can
be executed through ``django-admin.py`` or ``manage.py``).

import os
import sys
import warnings

from optparse import make_option, OptionParser

import django
from django.core import checks
from django.core.exceptions import ImproperlyConfigured
from django.core.management.color import color_style, no_style
from django.utils.deprecation import RemovedInDjango19Warning
from django.utils.encoding import force_str

[docs]class CommandError(Exception): """ Exception class indicating a problem while executing a management command. 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. """ pass
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 __init__(self, out, style_func=None, ending='\n'): self._out = out self.style_func = None if hasattr(out, 'isatty') and out.isatty(): self.style_func = style_func self.ending = ending def __getattr__(self, name): return getattr(self._out, name) 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 = [f for f in (style_func, self.style_func, lambda x:x) if f is not None][0] self._out.write(force_str(style_func(msg)))
[docs]class BaseCommand(object): """ 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 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.py`` or ``manage.py`` loads the command class and calls its ``run_from_argv()`` method. 2. The ``run_from_argv()`` method calls ``create_parser()`` to get an ``OptionParser`` 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: ``args`` 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 ...>'. ``can_import_settings`` 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 ``True``. ``help`` A short description of the command, which will be printed in help messages. ``option_list`` This is the list of ``optparse`` options which will be fed into the command's ``OptionParser`` for parsing arguments. ``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``. ``requires_system_checks`` 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. ``requires_model_validation`` DEPRECATED - This value will only be used if requires_system_checks has not been provided. Defining both ``requires_system_checks`` and ``requires_model_validation`` will result in an error. A boolean; if ``True``, validation of installed models will be performed prior to executing the command. Default value is ``True``. To validate an individual application's models rather than all applications' models, call ``self.validate(app_config)`` from ``handle()``, where ``app_config`` is the application's configuration provided by the app registry. ``leave_locale_alone`` A boolean indicating whether the locale set in settings should be preserved during the execution of the command instead of being forcibly set to 'en-us'. 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.contrim.auth permissions) as making the locale differ from the de facto default 'en-us' might cause unintended effects. This option can't be False when the can_import_settings option is set to False too because attempting to set the locale needs access to settings. This condition will generate a CommandError. """ # Metadata about this command. option_list = ( make_option('-v', '--verbosity', action='store', dest='verbosity', default='1', type='choice', choices=['0', '1', '2', '3'], help='Verbosity level; 0=minimal output, 1=normal output, 2=verbose output, 3=very verbose output'), make_option('--settings', help='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.'), make_option('--pythonpath', help='A directory to add to the Python path, e.g. "/home/djangoprojects/myproject".'), make_option('--traceback', action='store_true', help='Raise on exception'), make_option('--no-color', action='store_true', dest='no_color', default=False, help="Don't colorize the command output."), ) help = '' args = '' # Configuration shortcuts that alter various logic. can_import_settings = True output_transaction = False # Whether to wrap the output in a "BEGIN; COMMIT;" leave_locale_alone = False # Uncomment the following line of code after deprecation plan for # requires_model_validation comes to completion: # # requires_system_checks = True def __init__(self): self.style = color_style() # `requires_model_validation` is deprecated in favor of # `requires_system_checks`. If both options are present, an error is # raised. Otherwise the present option is used. If none of them is # defined, the default value (True) is used. has_old_option = hasattr(self, 'requires_model_validation') has_new_option = hasattr(self, 'requires_system_checks') if has_old_option: warnings.warn( '"requires_model_validation" is deprecated ' 'in favor of "requires_system_checks".', RemovedInDjango19Warning) if has_old_option and has_new_option: raise ImproperlyConfigured( 'Command %s defines both "requires_model_validation" ' 'and "requires_system_checks", which is illegal. Use only ' '"requires_system_checks".' % self.__class__.__name__) self.requires_system_checks = ( self.requires_system_checks if has_new_option else self.requires_model_validation if has_old_option else True)
[docs] 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 ``self.help``. """ usage = '%%prog %s [options] %s' % (subcommand, self.args) if self.help: return '%s\n\n%s' % (usage, self.help) else: return usage def create_parser(self, prog_name, subcommand): """ Create and return the ``OptionParser`` which will be used to parse the arguments to this command. """ return OptionParser(prog=prog_name, usage=self.usage(subcommand), version=self.get_version(), option_list=self.option_list) def print_help(self, prog_name, subcommand): """ Print the help message for this command, derived from ``self.usage()``. """ parser = self.create_parser(prog_name, subcommand) parser.print_help() 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. """ parser = self.create_parser(argv[0], argv[1]) options, args = parser.parse_args(argv[2:]) handle_default_options(options) try: self.execute(*args, **options.__dict__) except Exception as e: if options.traceback or not isinstance(e, CommandError): raise # self.stderr is not guaranteed to be set here stderr = getattr(self, 'stderr', OutputWrapper(sys.stderr, self.style.ERROR)) stderr.write('%s: %s' % (e.__class__.__name__, e)) sys.exit(1)
[docs] def execute(self, *args, **options): """ Try to execute this command, performing system checks if needed (as controlled by attributes ``self.requires_system_checks`` and ``self.requires_model_validation``, except if force-skipped). """ self.stdout = OutputWrapper(options.get('stdout', sys.stdout)) if options.get('no_color'): self.style = no_style() self.stderr = OutputWrapper(options.get('stderr', sys.stderr)) os.environ[str("DJANGO_COLORS")] = str("nocolor") else: self.stderr = OutputWrapper(options.get('stderr', sys.stderr), self.style.ERROR) if self.can_import_settings: from django.conf import settings # NOQA 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, self.can_import_settings)) # Switch to US English, because django-admin.py creates database # content like permissions, and those shouldn't contain any # translations. from django.utils import translation saved_locale = translation.get_language() translation.activate('en-us') try: if (self.requires_system_checks and not options.get('skip_validation') and # This will be removed at the end of deprecation process for `skip_validation`. not options.get('skip_checks')): self.check() 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(): self.stdout.write(self.style.SQL_KEYWORD(connection.ops.start_transaction_sql())) self.stdout.write(output) if self.output_transaction: self.stdout.write('\n' + self.style.SQL_KEYWORD(connection.ops.end_transaction_sql())) finally: if saved_locale is not None: translation.activate(saved_locale)
[docs] def validate(self, app_config=None, display_num_errors=False): """ Deprecated. Delegates to ``check``.""" if app_config is None: app_configs = None else: app_configs = [app_config] return self.check(app_configs=app_configs, display_num_errors=display_num_errors)
[docs] 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(app_configs=app_configs, tags=tags) msg = "" 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] criticals = [e for e in all_issues if checks.CRITICAL <= e.level] 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 = ( color_style().ERROR(force_str(e)) if e.is_serious() else color_style().WARNING(force_str(e)) for e in issues) formatted = "\n".join(sorted(formatted)) msg += '\n%s:\n%s\n' % (group_name, formatted) if msg: msg = "System check identified some issues:\n%s" % msg if display_num_errors: if msg: msg += '\n' msg += "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): raise CommandError(msg) elif msg and visible_issue_count: self.stderr.write(msg) elif msg: self.stdout.write(msg)
[docs] 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. """ args = '<app_label app_label ...>' def handle(self, *app_labels, **options): from django.apps import apps if not app_labels: raise CommandError("Enter at least one application label.") try: 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: output.append(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. """ try: # During the deprecation path, keep delegating to handle_app if # handle_app_config isn't implemented in a subclass. handle_app = self.handle_app except AttributeError: # Keep only this exception when the deprecation completes. raise NotImplementedError( "Subclasses of AppCommand must provide" "a handle_app_config() method.") else: warnings.warn( "AppCommand.handle_app() is superseded by " "AppCommand.handle_app_config().", RemovedInDjango19Warning, stacklevel=2) if app_config.models_module is None: raise CommandError( "AppCommand cannot handle app '%s' in legacy mode " "because it doesn't have a models module." % app_config.label) return handle_app(app_config.models_module, **options) class LabelCommand(BaseCommand): """ 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. If the arguments should be names of installed applications, use ``AppCommand`` instead. """ args = '<label label ...>' label = 'label' def handle(self, *labels, **options): if not labels: raise CommandError('Enter at least one %s.' % self.label) output = [] for label in labels: label_output = self.handle_label(label, **options) if label_output: output.append(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 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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