This document describes the current stable version of Celery (4.0). For development docs, go here.

Source code for

# -*- coding: utf-8 -*-
"""App utilities: Compat settings, bug-report tool, pickling apps."""
from __future__ import absolute_import, unicode_literals

import os
import platform as _platform
import re

from collections import Mapping, namedtuple
from copy import deepcopy
from types import ModuleType

from kombu.utils.url import maybe_sanitize_url

from celery.exceptions import ImproperlyConfigured
from celery.five import items, keys, string_t, values
from celery.platforms import pyimplementation
from celery.utils.collections import ConfigurationView
from celery.utils.text import pretty
from celery.utils.imports import import_from_cwd, symbol_by_name, qualname

from .defaults import (

__all__ = [
    'Settings', 'appstr', 'bugreport',
    'filter_hidden_settings', 'find_app',

#: Format used to generate bug-report information.
software -> celery:{celery_v} kombu:{kombu_v} py:{py_v}
            billiard:{billiard_v} {driver_v}
platform -> system:{system} arch:{arch} imp:{py_i}
loader   -> {loader}
settings -> transport:{transport} results:{results}


HIDDEN_SETTINGS = re.compile(


Cannot mix new and old setting keys, please rename the
following settings to the new format:




Cannot mix new setting names with old setting names, please
rename the following settings to use the old format:


Or change all of the settings to use the new format :)


FMT_REPLACE_SETTING = '{replace:<36} -> {with_}'

[docs]def appstr(app): """String used in __repr__ etc, to id app instances.""" return '{0}:{1:#x}'.format(app.main or '__main__', id(app))
[docs]class Settings(ConfigurationView): """Celery settings object. .. seealso: :ref:`configuration` for a full list of configuration keys. """ @property def broker_read_url(self): return ( os.environ.get('CELERY_BROKER_READ_URL') or self.get('broker_read_url') or self.broker_url ) @property def broker_write_url(self): return ( os.environ.get('CELERY_BROKER_WRITE_URL') or self.get('broker_write_url') or self.broker_url ) @property def broker_url(self): return ( os.environ.get('CELERY_BROKER_URL') or self.first('broker_url', 'broker_host') ) @property def task_default_exchange(self): return self.first( 'task_default_exchange', 'task_default_queue', ) @property def task_default_routing_key(self): return self.first( 'task_default_routing_key', 'task_default_queue', ) @property def timezone(self): # this way we also support django's time zone. return self.first('timezone', 'time_zone')
[docs] def without_defaults(self): """Return the current configuration, but without defaults.""" # the last stash is the default settings, so just skip that return Settings({}, self.maps[:-1])
[docs] def value_set_for(self, key): return key in self.without_defaults()
[docs] def find_option(self, name, namespace=''): """Search for option by name. Example: >>> from proj.celery import app >>> app.conf.find_option('disable_rate_limits') ('worker', 'prefetch_multiplier', <Option: type->bool default->False>)) Arguments: name (str): Name of option, cannot be partial. namespace (str): Preferred name-space (``None`` by default). Returns: Tuple: of ``(namespace, key, type)``. """ return find(name, namespace)
[docs] def find_value_for_key(self, name, namespace='celery'): """Shortcut to ``get_by_parts(*find_option(name)[:-1])``.""" return self.get_by_parts(*self.find_option(name, namespace)[:-1])
[docs] def get_by_parts(self, *parts): """Return the current value for setting specified as a path. Example: >>> from proj.celery import app >>> app.conf.get_by_parts('worker', 'disable_rate_limits') False """ return self['_'.join(part for part in parts if part)]
[docs] def finalize(self): # See PendingConfiguration in celery/app/ # first access will read actual configuration. try: self['__bogus__'] except KeyError: pass return self
[docs] def table(self, with_defaults=False, censored=True): filt = filter_hidden_settings if censored else lambda v: v dict_members = dir(dict) self.finalize() return filt({ k: v for k, v in items( self if with_defaults else self.without_defaults()) if not k.startswith('_') and k not in dict_members })
[docs] def humanize(self, with_defaults=False, censored=True): """Return a human readable text showing configuration changes.""" return '\n'.join( '{0}: {1}'.format(key, pretty(value, width=50)) for key, value in items(self.table(with_defaults, censored)))
def _new_key_to_old(key, convert=_TO_OLD_KEY.get): return convert(key, key) def _old_key_to_new(key, convert=_TO_NEW_KEY.get): return convert(key, key) _settings_info_t = namedtuple('settings_info_t', ( 'defaults', 'convert', 'key_t', 'mix_error', )) _settings_info = _settings_info_t( DEFAULTS, _TO_NEW_KEY, _old_key_to_new, E_MIX_OLD_INTO_NEW, ) _old_settings_info = _settings_info_t( _OLD_DEFAULTS, _TO_OLD_KEY, _new_key_to_old, E_MIX_NEW_INTO_OLD, ) def detect_settings(conf, preconf={}, ignore_keys=set(), prefix=None, all_keys=SETTING_KEYS, old_keys=_OLD_SETTING_KEYS): source = conf if conf is None: source, conf = preconf, {} have = set(keys(source)) - ignore_keys is_in_new = have.intersection(all_keys) is_in_old = have.intersection(old_keys) info = None if is_in_new: # have new setting names info, left = _settings_info, is_in_old if is_in_old and len(is_in_old) > len(is_in_new): # Majority of the settings are old. info, left = _old_settings_info, is_in_new if is_in_old: # have old setting names, or a majority of the names are old. if not info: info, left = _old_settings_info, is_in_new if is_in_new and len(is_in_new) > len(is_in_old): # Majority of the settings are new info, left = _settings_info, is_in_old else: # no settings, just use new format. info, left = _settings_info, is_in_old if prefix: # always use new format if prefix is used. info, left = _settings_info, set() # only raise error for keys that the user didn't provide two keys # for (e.g., both ``result_expires`` and ``CELERY_TASK_RESULT_EXPIRES``). really_left = {key for key in left if info.convert[key] not in have} if really_left: # user is mixing old/new, or new/old settings, give renaming # suggestions. raise ImproperlyConfigured(info.mix_error.format(renames='\n'.join( FMT_REPLACE_SETTING.format(replace=key, with_=info.convert[key]) for key in sorted(really_left) ))) preconf = {info.convert.get(k, k): v for k, v in items(preconf)} defaults = dict(deepcopy(info.defaults), **preconf) return Settings( preconf, [conf, defaults], (_old_key_to_new, _new_key_to_old), prefix=prefix, ) class AppPickler(object): """Old application pickler/unpickler (< 3.1).""" def __call__(self, cls, *args): kwargs = self.build_kwargs(*args) app = self.construct(cls, **kwargs) self.prepare(app, **kwargs) return app def prepare(self, app, **kwargs): app.conf.update(kwargs['changes']) def build_kwargs(self, *args): return self.build_standard_kwargs(*args) def build_standard_kwargs(self, main, changes, loader, backend, amqp, events, log, control, accept_magic_kwargs, config_source=None): return dict(main=main, loader=loader, backend=backend, amqp=amqp, changes=changes, events=events, log=log, control=control, set_as_current=False, config_source=config_source) def construct(self, cls, **kwargs): return cls(**kwargs) def _unpickle_app(cls, pickler, *args): """Rebuild app for versions 2.5+.""" return pickler()(cls, *args) def _unpickle_app_v2(cls, kwargs): """Rebuild app for versions 3.1+.""" kwargs['set_as_current'] = False return cls(**kwargs)
[docs]def filter_hidden_settings(conf): """Filter sensitive settings.""" def maybe_censor(key, value, mask='*' * 8): if isinstance(value, Mapping): return filter_hidden_settings(value) if isinstance(key, string_t): if return mask elif 'broker_url' in key.lower(): from kombu import Connection return Connection(value).as_uri(mask=mask) elif 'backend' in key.lower(): return maybe_sanitize_url(value, mask=mask) return value return {k: maybe_censor(k, v) for k, v in items(conf)}
[docs]def bugreport(app): """Return a string containing information useful in bug-reports.""" import billiard import celery import kombu try: conn = app.connection() driver_v = '{0}:{1}'.format(conn.transport.driver_name, conn.transport.driver_version()) transport = conn.transport_cls except Exception: # pylint: disable=broad-except transport = driver_v = '' return BUGREPORT_INFO.format( system=_platform.system(), arch=', '.join(x for x in _platform.architecture() if x), py_i=pyimplementation(), celery_v=celery.VERSION_BANNER, kombu_v=kombu.__version__, billiard_v=billiard.__version__, py_v=_platform.python_version(), driver_v=driver_v, transport=transport, results=maybe_sanitize_url(app.conf.result_backend or 'disabled'), human_settings=app.conf.humanize(), loader=qualname(app.loader.__class__), )
[docs]def find_app(app, symbol_by_name=symbol_by_name, imp=import_from_cwd): """Find app by name.""" from .base import Celery try: sym = symbol_by_name(app, imp=imp) except AttributeError: # last part was not an attribute, but a module sym = imp(app) if isinstance(sym, ModuleType) and ':' not in app: try: found = if isinstance(found, ModuleType): raise AttributeError() except AttributeError: try: found = sym.celery if isinstance(found, ModuleType): raise AttributeError() except AttributeError: if getattr(sym, '__path__', None): try: return find_app( '{0}.celery'.format(app), symbol_by_name=symbol_by_name, imp=imp, ) except ImportError: pass for suspect in values(vars(sym)): if isinstance(suspect, Celery): return suspect raise else: return found else: return found return sym