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# -*- coding: utf-8 -*-
"""Actual App instance implementation."""
from __future__ import absolute_import, unicode_literals
import os
import threading
import warnings
from collections import defaultdict, deque
from datetime import datetime
from operator import attrgetter
from kombu import pools
from kombu.clocks import LamportClock
from kombu.common import oid_from
from kombu.utils.compat import register_after_fork
from kombu.utils.objects import cached_property
from kombu.utils.uuid import uuid
from vine import starpromise
from vine.utils import wraps
from celery import platforms, signals
from celery._state import (_announce_app_finalized, _deregister_app,
_register_app, _set_current_app, _task_stack,
connect_on_app_finalize, get_current_app,
get_current_worker_task, set_default_app)
from celery.exceptions import AlwaysEagerIgnored, ImproperlyConfigured
from celery.five import (UserDict, bytes_if_py2, python_2_unicode_compatible,
from celery.loaders import get_loader_cls
from celery.local import PromiseProxy, maybe_evaluate
from celery.utils import abstract
from celery.utils.collections import AttributeDictMixin
from celery.utils.dispatch import Signal
from celery.utils.functional import first, head_from_fun, maybe_list
from celery.utils.imports import gen_task_name, instantiate, symbol_by_name
from celery.utils.log import get_logger
from celery.utils.objects import FallbackContext, mro_lookup
from celery.utils.time import (get_exponential_backoff_interval, timezone,
# Load all builtin tasks
from . import builtins # noqa
from . import backends
from .annotations import prepare as prepare_annotations
from .defaults import find_deprecated_settings
from .registry import TaskRegistry
from .utils import (AppPickler, Settings, _new_key_to_old, _old_key_to_new,
_unpickle_app, _unpickle_app_v2, appstr, bugreport,
__all__ = ('Celery',)
logger = get_logger(__name__)
The environment variable {0!r} is not set,
and as such the configuration could not be loaded.
Please set this variable and make sure it points to
a valid configuration module.
def app_has_custom(app, attr):
"""Return true if app has customized method `attr`.
This is used for optimizations in cases where we know
how the default behavior works, but need to account
for someone using inheritance to override a method/property.
return mro_lookup(app.__class__, attr, stop={Celery, object},
def _unpickle_appattr(reverse_name, args):
"""Unpickle app."""
# Given an attribute name and a list of args, gets
# the attribute from the current app and calls it.
return get_current_app()._rgetattr(reverse_name)(*args)
def _after_fork_cleanup_app(app):
# This is used with multiprocessing.register_after_fork,
# so need to be at module level.
except Exception as exc: # pylint: disable=broad-except'after forker raised exception: %r', exc, exc_info=1)
class PendingConfiguration(UserDict, AttributeDictMixin):
# `app.conf` will be of this type before being explicitly configured,
# meaning the app can keep any configuration set directly
# on `app.conf` before the `app.config_from_object` call.
# accessing any key will finalize the configuration,
# replacing `app.conf` with a concrete settings object.
callback = None
_data = None
def __init__(self, conf, callback):
object.__setattr__(self, '_data', conf)
object.__setattr__(self, 'callback', callback)
def __setitem__(self, key, value):
self._data[key] = value
def clear(self):
def update(self, *args, **kwargs):
self._data.update(*args, **kwargs)
def setdefault(self, *args, **kwargs):
return self._data.setdefault(*args, **kwargs)
def __contains__(self, key):
# XXX will not show finalized configuration
# setdefault will cause `key in d` to happen,
# so for setdefault to be lazy, so does contains.
return key in self._data
def __len__(self):
return len(
def __repr__(self):
return repr(
def data(self):
return self.callback()
class Celery(object):
"""Celery application.
main (str): Name of the main module if running as `__main__`.
This is used as the prefix for auto-generated task names.
Keyword Arguments:
broker (str): URL of the default broker used.
backend (Union[str, type]): The result store backend class,
or the name of the backend class to use.
Default is the value of the :setting:`result_backend` setting.
autofinalize (bool): If set to False a :exc:`RuntimeError`
will be raised if the task registry or tasks are used before
the app is finalized.
set_as_current (bool): Make this the global current app.
include (List[str]): List of modules every worker should import.
amqp (Union[str, type]): AMQP object or class name.
events (Union[str, type]): Events object or class name.
log (Union[str, type]): Log object or class name.
control (Union[str, type]): Control object or class name.
tasks (Union[str, type]): A task registry, or the name of
a registry class.
fixups (List[str]): List of fix-up plug-ins (e.g., see
config_source (Union[str, type]): Take configuration from a class,
or object. Attributes may include any settings described in
the documentation.
#: This is deprecated, use :meth:`reduce_keys` instead
Pickler = AppPickler
SYSTEM = platforms.SYSTEM
IS_macOS, IS_WINDOWS = platforms.IS_macOS, platforms.IS_WINDOWS
#: Name of the `__main__` module. Required for standalone scripts.
#: If set this will be used instead of `__main__` when automatically
#: generating task names.
main = None
#: Custom options for command-line programs.
#: See :ref:`extending-commandoptions`
user_options = None
#: Custom bootsteps to extend and modify the worker.
#: See :ref:`extending-bootsteps`.
steps = None
builtin_fixups = BUILTIN_FIXUPS
amqp_cls = ''
backend_cls = None
events_cls = ''
loader_cls = None
log_cls = ''
control_cls = ''
task_cls = ''
registry_cls = ''
_fixups = None
_pool = None
_conf = None
_after_fork_registered = False
#: Signal sent when app is loading configuration.
on_configure = None
#: Signal sent after app has prepared the configuration.
on_after_configure = None
#: Signal sent after app has been finalized.
on_after_finalize = None
#: Signal sent by every new process after fork.
on_after_fork = None
def __init__(self, main=None, loader=None, backend=None,
amqp=None, events=None, log=None, control=None,
set_as_current=True, tasks=None, broker=None, include=None,
changes=None, config_source=None, fixups=None, task_cls=None,
autofinalize=True, namespace=None, strict_typing=True,
self.clock = LamportClock()
self.main = main
self.amqp_cls = amqp or self.amqp_cls
self.events_cls = events or self.events_cls
self.loader_cls = loader or self._get_default_loader()
self.log_cls = log or self.log_cls
self.control_cls = control or self.control_cls
self.task_cls = task_cls or self.task_cls
self.set_as_current = set_as_current
self.registry_cls = symbol_by_name(self.registry_cls)
self.user_options = defaultdict(set)
self.steps = defaultdict(set)
self.autofinalize = autofinalize
self.namespace = namespace
self.strict_typing = strict_typing
self.configured = False
self._config_source = config_source
self._pending_defaults = deque()
self._pending_periodic_tasks = deque()
self.finalized = False
self._finalize_mutex = threading.Lock()
self._pending = deque()
self._tasks = tasks
if not isinstance(self._tasks, TaskRegistry):
self._tasks = self.registry_cls(self._tasks or {})
# If the class defines a custom __reduce_args__ we need to use
# the old way of pickling apps: pickling a list of
# args instead of the new way that pickles a dict of keywords.
self._using_v1_reduce = app_has_custom(self, '__reduce_args__')
# these options are moved to the config to
# simplify pickling of the app object.
self._preconf = changes or {}
self._preconf_set_by_auto = set()
self.__autoset('broker_url', broker)
self.__autoset('result_backend', backend)
self.__autoset('include', include)
self._conf = Settings(
self._preconf, self._finalize_pending_conf),
keys=(_old_key_to_new, _new_key_to_old),
# - Apply fix-ups.
self.fixups = set(self.builtin_fixups) if fixups is None else fixups
# fixup instances in _fixups to keep weakrefs alive.
self._fixups = [symbol_by_name(fixup)(self) for fixup in self.fixups]
if self.set_as_current:
# Signals
if self.on_configure is None:
# used to be a method pre 4.0
self.on_configure = Signal(name='app.on_configure')
self.on_after_configure = Signal(
self.on_after_finalize = Signal(name='app.on_after_finalize')
self.on_after_fork = Signal(name='app.on_after_fork')
def _get_default_loader(self):
# the --loader command-line argument sets the environment variable.
return (
os.environ.get('CELERY_LOADER') or
self.loader_cls or
def on_init(self):
"""Optional callback called at init."""
def __autoset(self, key, value):
if value:
self._preconf[key] = value
def set_current(self):
"""Make this the current app for this thread."""
def set_default(self):
"""Make this the default app for all threads."""
def _ensure_after_fork(self):
if not self._after_fork_registered:
self._after_fork_registered = True
if register_after_fork is not None:
register_after_fork(self, _after_fork_cleanup_app)
def close(self):
"""Clean up after the application.
Only necessary for dynamically created apps, and you should
probably use the :keyword:`with` statement instead.
>>> with Celery(set_as_current=False) as app:
... with app.connection_for_write() as conn:
... pass
self._pool = None
def start(self, argv=None):
"""Run :program:`celery` using `argv`.
Uses :data:`sys.argv` if `argv` is not specified.
return instantiate(
'celery.bin.celery:CeleryCommand', app=self
def worker_main(self, argv=None):
"""Run :program:`celery worker` using `argv`.
Uses :data:`sys.argv` if `argv` is not specified.
return instantiate(
'celery.bin.worker:worker', app=self
def task(self, *args, **opts):
"""Decorator to create a task class out of any callable.
.. code-block:: python
def refresh_feed(url):
with setting extra options:
.. code-block:: python
def refresh_feed(url):
return store_feed(feedparser.parse(url))
App Binding: For custom apps the task decorator will return
a proxy object, so that the act of creating the task is not
performed until the task is used or the task registry is accessed.
If you're depending on binding to be deferred, then you must
not access any attributes on the returned object until the
application is fully set up (finalized).
if USING_EXECV and opts.get('lazy', True):
# When using execv the task in the original module will point to a
# different app, so doing things like 'add.request' will point to
# a different task instance. This makes sure it will always use
# the task instance from the current app.
# Really need a better solution for this :(
from . import shared_task
return shared_task(*args, lazy=False, **opts)
def inner_create_task_cls(shared=True, filter=None, lazy=True, **opts):
_filt = filter # stupid 2to3
def _create_task_cls(fun):
if shared:
def cons(app):
return app._task_from_fun(fun, **opts)
cons.__name__ = fun.__name__
if not lazy or self.finalized:
ret = self._task_from_fun(fun, **opts)
# return a proxy object that evaluates on first use
ret = PromiseProxy(self._task_from_fun, (fun,), opts,
if _filt:
return _filt(ret)
return ret
return _create_task_cls
if len(args) == 1:
if callable(args[0]):
return inner_create_task_cls(**opts)(*args)
raise TypeError('argument 1 to @task() must be a callable')
if args:
raise TypeError(
'@task() takes exactly 1 argument ({0} given)'.format(
sum([len(args), len(opts)])))
return inner_create_task_cls(**opts)
def _task_from_fun(self, fun, name=None, base=None, bind=False, **options):
if not self.finalized and not self.autofinalize:
raise RuntimeError('Contract breach: app not finalized')
name = name or self.gen_task_name(fun.__name__, fun.__module__)
base = base or self.Task
if name not in self._tasks:
run = fun if bind else staticmethod(fun)
task = type(fun.__name__, (base,), dict({
'app': self,
'name': name,
'run': run,
'_decorated': True,
'__doc__': fun.__doc__,
'__module__': fun.__module__,
'__header__': staticmethod(head_from_fun(fun, bound=bind)),
'__wrapped__': run}, **options))()
# for some reason __qualname__ cannot be set in type()
# so we have to set it here.
task.__qualname__ = fun.__qualname__
except AttributeError:
self._tasks[] = task
task.bind(self) # connects task to this app
autoretry_for = tuple(options.get('autoretry_for', ()))
retry_kwargs = options.get('retry_kwargs', {})
retry_backoff = int(options.get('retry_backoff', False))
retry_backoff_max = int(options.get('retry_backoff_max', 600))
retry_jitter = options.get('retry_jitter', True)
if autoretry_for and not hasattr(task, '_orig_run'):
def run(*args, **kwargs):
return task._orig_run(*args, **kwargs)
except autoretry_for as exc:
if retry_backoff:
retry_kwargs['countdown'] = \
raise task.retry(exc=exc, **retry_kwargs)
task._orig_run, =, run
task = self._tasks[name]
return task
def register_task(self, task):
"""Utility for registering a task-based class.
This is here for compatibility with old Celery 1.0
style task classes, you should not need to use this for
new projects.
if not
task_cls = type(task) = self.gen_task_name(
task_cls.__name__, task_cls.__module__)
self.tasks[] = task
task._app = self
return task
def gen_task_name(self, name, module):
return gen_task_name(self, name, module)
def finalize(self, auto=False):
"""Finalize the app.
This loads built-in tasks, evaluates pending task decorators,
reads configuration, etc.
with self._finalize_mutex:
if not self.finalized:
if auto and not self.autofinalize:
raise RuntimeError('Contract breach: app not finalized')
self.finalized = True
pending = self._pending
while pending:
for task in values(self._tasks):
def add_defaults(self, fun):
"""Add default configuration from dict ``d``.
If the argument is a callable function then it will be regarded
as a promise, and it won't be loaded until the configuration is
actually needed.
This method can be compared to:
.. code-block:: pycon
>>> celery.conf.update(d)
with a difference that 1) no copy will be made and 2) the dict will
not be transferred when the worker spawns child processes, so
it's important that the same configuration happens at import time
when pickle restores the object on the other side.
if not callable(fun):
d, fun = fun, lambda: d
if self.configured:
return self._conf.add_defaults(fun())
def config_from_object(self, obj,
silent=False, force=False, namespace=None):
"""Read configuration from object.
Object is either an actual object or the name of a module to import.
>>> celery.config_from_object('myapp.celeryconfig')
>>> from myapp import celeryconfig
>>> celery.config_from_object(celeryconfig)
silent (bool): If true then import errors will be ignored.
force (bool): Force reading configuration immediately.
By default the configuration will be read only when required.
self._config_source = obj
self.namespace = namespace or self.namespace
if force or self.configured:
self._conf = None
if self.loader.config_from_object(obj, silent=silent):
return self.conf
def config_from_envvar(self, variable_name, silent=False, force=False):
"""Read configuration from environment variable.
The value of the environment variable must be the name
of a module to import.
>>> os.environ['CELERY_CONFIG_MODULE'] = 'myapp.celeryconfig'
>>> celery.config_from_envvar('CELERY_CONFIG_MODULE')
module_name = os.environ.get(variable_name)
if not module_name:
if silent:
return False
raise ImproperlyConfigured(
return self.config_from_object(module_name, silent=silent, force=force)
def config_from_cmdline(self, argv, namespace='celery'):
self.loader.cmdline_config_parser(argv, namespace)
def setup_security(self, allowed_serializers=None, key=None, cert=None,
store=None, digest='sha1', serializer='json'):
"""Setup the message-signing serializer.
This will affect all application instances (a global operation).
Disables untrusted serializers and if configured to use the ``auth``
serializer will register the ``auth`` serializer with the provided
settings into the Kombu serializer registry.
allowed_serializers (Set[str]): List of serializer names, or
content_types that should be exempt from being disabled.
key (str): Name of private key file to use.
Defaults to the :setting:`security_key` setting.
cert (str): Name of certificate file to use.
Defaults to the :setting:`security_certificate` setting.
store (str): Directory containing certificates.
Defaults to the :setting:`security_cert_store` setting.
digest (str): Digest algorithm used when signing messages.
Default is ``sha1``.
serializer (str): Serializer used to encode messages after
they've been signed. See :setting:`task_serializer` for
the serializers supported. Default is ``json``.
from import setup_security
return setup_security(allowed_serializers, key, cert,
store, digest, serializer, app=self)
def autodiscover_tasks(self, packages=None,
related_name='tasks', force=False):
"""Auto-discover task modules.
Searches a list of packages for a "" module (or use
related_name argument).
If the name is empty, this will be delegated to fix-ups (e.g., Django).
For example if you have a directory layout like this:
.. code-block:: text
Then calling ``app.autodiscover_tasks(['foo', 'bar', 'baz'])`` will
result in the modules ``foo.tasks`` and ``bar.tasks`` being imported.
packages (List[str]): List of packages to search.
This argument may also be a callable, in which case the
value returned is used (for lazy evaluation).
related_name (str): The name of the module to find. Defaults
to "tasks": meaning "look for 'module.tasks' for every
module in ``packages``.". If ``None`` will only try to import
the package, i.e. "look for 'module'".
force (bool): By default this call is lazy so that the actual
auto-discovery won't happen until an application imports
the default modules. Forcing will cause the auto-discovery
to happen immediately.
if force:
return self._autodiscover_tasks(packages, related_name)
self._autodiscover_tasks, packages, related_name,
), weak=False, sender=self)
def _autodiscover_tasks(self, packages, related_name, **kwargs):
if packages:
return self._autodiscover_tasks_from_names(packages, related_name)
return self._autodiscover_tasks_from_fixups(related_name)
def _autodiscover_tasks_from_names(self, packages, related_name):
# packages argument can be lazy
return self.loader.autodiscover_tasks(
packages() if callable(packages) else packages, related_name,
def _autodiscover_tasks_from_fixups(self, related_name):
return self._autodiscover_tasks_from_names([
pkg for fixup in self._fixups
for pkg in fixup.autodiscover_tasks()
if hasattr(fixup, 'autodiscover_tasks')
], related_name=related_name)
def send_task(self, name, args=None, kwargs=None, countdown=None,
eta=None, task_id=None, producer=None, connection=None,
router=None, result_cls=None, expires=None,
publisher=None, link=None, link_error=None,
add_to_parent=True, group_id=None, retries=0, chord=None,
reply_to=None, time_limit=None, soft_time_limit=None,
root_id=None, parent_id=None, route_name=None,
shadow=None, chain=None, task_type=None, **options):
"""Send task by name.
Supports the same arguments as :meth:`@-Task.apply_async`.
name (str): Name of task to call (e.g., `"tasks.add"`).
result_cls (AsyncResult): Specify custom result class.
parent = have_parent = None
amqp = self.amqp
task_id = task_id or uuid()
producer = producer or publisher # XXX compat
router = router or amqp.router
conf = self.conf
if conf.task_always_eager: # pragma: no cover
'task_always_eager has no effect on send_task',
), stacklevel=2)
ignored_result = options.pop('ignore_result', False)
options = router.route(
options, route_name or name, args, kwargs, task_type)
if not root_id or not parent_id:
parent = self.current_worker_task
if parent:
if not root_id:
root_id = parent.request.root_id or
if not parent_id:
parent_id =
message = amqp.create_task_message(
task_id, name, args, kwargs, countdown, eta, group_id,
expires, retries, chord,
maybe_list(link), maybe_list(link_error),
reply_to or self.oid, time_limit, soft_time_limit,
root_id, parent_id, shadow, chain,
if connection:
producer = amqp.Producer(connection, auto_declare=False)
with self.producer_or_acquire(producer) as P:
with P.connection._reraise_as_library_errors():
if not ignored_result:
self.backend.on_task_call(P, task_id)
amqp.send_task_message(P, name, message, **options)
result = (result_cls or self.AsyncResult)(task_id)
# We avoid using the constructor since a custom result class
# can be used, in which case the constructor may still use
# the old signature.
result.ignored = ignored_result
if add_to_parent:
if not have_parent:
parent, have_parent = self.current_worker_task, True
if parent:
return result
def connection_for_read(self, url=None, **kwargs):
"""Establish connection used for consuming.
See Also:
:meth:`connection` for supported arguments.
return self._connection(url or self.conf.broker_read_url, **kwargs)
def connection_for_write(self, url=None, **kwargs):
"""Establish connection used for producing.
See Also:
:meth:`connection` for supported arguments.
return self._connection(url or self.conf.broker_write_url, **kwargs)
def connection(self, hostname=None, userid=None, password=None,
virtual_host=None, port=None, ssl=None,
connect_timeout=None, transport=None,
transport_options=None, heartbeat=None,
login_method=None, failover_strategy=None, **kwargs):
"""Establish a connection to the message broker.
Please use :meth:`connection_for_read` and
:meth:`connection_for_write` instead, to convey the intent
of use for this connection.
url: Either the URL or the hostname of the broker to use.
hostname (str): URL, Hostname/IP-address of the broker.
If a URL is used, then the other argument below will
be taken from the URL instead.
userid (str): Username to authenticate as.
password (str): Password to authenticate with
virtual_host (str): Virtual host to use (domain).
port (int): Port to connect to.
ssl (bool, Dict): Defaults to the :setting:`broker_use_ssl`
transport (str): defaults to the :setting:`broker_transport`
transport_options (Dict): Dictionary of transport specific options.
heartbeat (int): AMQP Heartbeat in seconds (``pyamqp`` only).
login_method (str): Custom login method to use (AMQP only).
failover_strategy (str, Callable): Custom failover strategy.
**kwargs: Additional arguments to :class:`kombu.Connection`.
kombu.Connection: the lazy connection instance.
return self.connection_for_write(
hostname or self.conf.broker_write_url,
userid=userid, password=password,
virtual_host=virtual_host, port=port, ssl=ssl,
connect_timeout=connect_timeout, transport=transport,
transport_options=transport_options, heartbeat=heartbeat,
login_method=login_method, failover_strategy=failover_strategy,
def _connection(self, url, userid=None, password=None,
virtual_host=None, port=None, ssl=None,
connect_timeout=None, transport=None,
transport_options=None, heartbeat=None,
login_method=None, failover_strategy=None, **kwargs):
conf = self.conf
return self.amqp.Connection(
userid or conf.broker_user,
password or conf.broker_password,
virtual_host or conf.broker_vhost,
port or conf.broker_port,
transport=transport or conf.broker_transport,
ssl=self.either('broker_use_ssl', ssl),
heartbeat=heartbeat or self.conf.broker_heartbeat,
login_method=login_method or conf.broker_login_method,
failover_strategy or conf.broker_failover_strategy
conf.broker_transport_options, **transport_options or {}
'broker_connection_timeout', connect_timeout
broker_connection = connection
def _acquire_connection(self, pool=True):
"""Helper for :meth:`connection_or_acquire`."""
if pool:
return self.pool.acquire(block=True)
return self.connection_for_write()
def connection_or_acquire(self, connection=None, pool=True, *_, **__):
"""Context used to acquire a connection from the pool.
For use within a :keyword:`with` statement to get a connection
from the pool if one is not already provided.
connection (kombu.Connection): If not provided, a connection
will be acquired from the connection pool.
return FallbackContext(connection, self._acquire_connection, pool=pool)
default_connection = connection_or_acquire # XXX compat
def producer_or_acquire(self, producer=None):
"""Context used to acquire a producer from the pool.
For use within a :keyword:`with` statement to get a producer
from the pool if one is not already provided
producer (kombu.Producer): If not provided, a producer
will be acquired from the producer pool.
return FallbackContext(
producer, self.producer_pool.acquire, block=True,
default_producer = producer_or_acquire # XXX compat
def prepare_config(self, c):
"""Prepare configuration before it is merged with the defaults."""
return find_deprecated_settings(c)
def now(self):
"""Return the current time and date as a datetime."""
now_in_utc = to_utc(datetime.utcnow())
return now_in_utc.astimezone(self.timezone)
def select_queues(self, queues=None):
"""Select subset of queues.
queues (Sequence[str]): a list of queue names to keep.
def either(self, default_key, *defaults):
"""Get key from configuration or use default values.
Fallback to the value of a configuration key if none of the
`*values` are true.
return first(None, [
first(None, defaults), starpromise(self.conf.get, default_key),
def bugreport(self):
"""Return information useful in bug reports."""
return bugreport(self)
def _get_backend(self):
backend, url = backends.by_url(
self.backend_cls or self.conf.result_backend,
return backend(app=self, url=url)
def _finalize_pending_conf(self):
"""Get config value by key and finalize loading the configuration.
This is used by PendingConfiguration:
as soon as you access a key the configuration is read.
conf = self._conf = self._load_config()
return conf
def _load_config(self):
if isinstance(self.on_configure, Signal):
# used to be a method pre 4.0
if self._config_source:
self.configured = True
settings = detect_settings(
self.prepare_config(self.loader.conf), self._preconf,
ignore_keys=self._preconf_set_by_auto, prefix=self.namespace,
if self._conf is not None:
# replace in place, as someone may have referenced app.conf,
# done some changes, accessed a key, and then try to make more
# changes to the reference and not the finalized value.
self._conf = settings
# load lazy config dict initializers.
pending_def = self._pending_defaults
while pending_def:
# load lazy periodic tasks
pending_beat = self._pending_periodic_tasks
while pending_beat:
self.on_after_configure.send(sender=self, source=self._conf)
return self._conf
def _after_fork(self):
self._pool = None
self.__dict__['amqp']._producer_pool = None
except (AttributeError, KeyError):
def signature(self, *args, **kwargs):
"""Return a new :class:`~celery.Signature` bound to this app."""
kwargs['app'] = self
return self._canvas.signature(*args, **kwargs)
def add_periodic_task(self, schedule, sig,
args=(), kwargs=(), name=None, **opts):
key, entry = self._sig_to_periodic_task_entry(
schedule, sig, args, kwargs, name, **opts)
if self.configured:
self._add_periodic_task(key, entry)
self._pending_periodic_tasks.append((key, entry))
return key
def _sig_to_periodic_task_entry(self, schedule, sig,
args=(), kwargs={}, name=None, **opts):
sig = (sig.clone(args, kwargs)
if isinstance(sig, abstract.CallableSignature)
else self.signature(, args, kwargs))
return name or repr(sig), {
'schedule': schedule,
'args': sig.args,
'kwargs': sig.kwargs,
'options': dict(sig.options, **opts),
def _add_periodic_task(self, key, entry):
self._conf.beat_schedule[key] = entry
def create_task_cls(self):
"""Create a base task class bound to this app."""
return self.subclass_with_self(
self.task_cls, name='Task', attribute='_app',
keep_reduce=True, abstract=True,
def subclass_with_self(self, Class, name=None, attribute='app',
reverse=None, keep_reduce=False, **kw):
"""Subclass an app-compatible class.
App-compatible means that the class has a class attribute that
provides the default app it should use, for example:
``class Foo: app = None``.
Class (type): The app-compatible class to subclass.
name (str): Custom name for the target class.
attribute (str): Name of the attribute holding the app,
Default is 'app'.
reverse (str): Reverse path to this object used for pickling
purposes. For example, to get ``app.AsyncResult``,
use ``"AsyncResult"``.
keep_reduce (bool): If enabled a custom ``__reduce__``
implementation won't be provided.
Class = symbol_by_name(Class)
reverse = reverse if reverse else Class.__name__
def __reduce__(self):
return _unpickle_appattr, (reverse, self.__reduce_args__())
attrs = dict(
{attribute: self},
if not keep_reduce:
attrs['__reduce__'] = __reduce__
return type(bytes_if_py2(name or Class.__name__), (Class,), attrs)
def _rgetattr(self, path):
return attrgetter(path)(self)
def __enter__(self):
return self
def __exit__(self, *exc_info):
def __repr__(self):
return '<{0} {1}>'.format(type(self).__name__, appstr(self))
def __reduce__(self):
if self._using_v1_reduce:
return self.__reduce_v1__()
return (_unpickle_app_v2, (self.__class__, self.__reduce_keys__()))
def __reduce_v1__(self):
# Reduce only pickles the configuration changes,
# so the default configuration doesn't have to be passed
# between processes.
return (
(self.__class__, self.Pickler) + self.__reduce_args__(),
def __reduce_keys__(self):
"""Keyword arguments used to reconstruct the object when unpickling."""
return {
'main': self.main,
self._conf.changes if self.configured else self._preconf,
'loader': self.loader_cls,
'backend': self.backend_cls,
'amqp': self.amqp_cls,
'events': self.events_cls,
'log': self.log_cls,
'control': self.control_cls,
'fixups': self.fixups,
'config_source': self._config_source,
'task_cls': self.task_cls,
'namespace': self.namespace,
def __reduce_args__(self):
"""Deprecated method, please use :meth:`__reduce_keys__` instead."""
return (self.main, self._conf.changes if self.configured else {},
self.loader_cls, self.backend_cls, self.amqp_cls,
self.events_cls, self.log_cls, self.control_cls,
False, self._config_source)
def Worker(self):
"""Worker application.
See Also:
return self.subclass_with_self('celery.apps.worker:Worker')
def WorkController(self, **kwargs):
"""Embeddable worker.
See Also:
return self.subclass_with_self('celery.worker:WorkController')
def Beat(self, **kwargs):
""":program:`celery beat` scheduler application.
See Also:
return self.subclass_with_self('celery.apps.beat:Beat')
def Task(self):
"""Base task class for this app."""
return self.create_task_cls()
def annotations(self):
return prepare_annotations(self.conf.task_annotations)
def AsyncResult(self):
"""Create new result instance.
See Also:
return self.subclass_with_self('celery.result:AsyncResult')
def ResultSet(self):
return self.subclass_with_self('celery.result:ResultSet')
def GroupResult(self):
"""Create new group result instance.
See Also:
return self.subclass_with_self('celery.result:GroupResult')
def pool(self):
"""Broker connection pool: :class:`~@pool`.
This attribute is not related to the workers concurrency pool.
if self._pool is None:
limit = self.conf.broker_pool_limit
self._pool = pools.connections[self.connection_for_write()]
return self._pool
def current_task(self):
"""Instance of task being executed, or :const:`None`."""
def current_worker_task(self):
"""The task currently being executed by a worker or :const:`None`.
Differs from :data:`current_task` in that it's not affected
by tasks calling other tasks directly, or eagerly.
return get_current_worker_task()
def oid(self):
"""Universally unique identifier for this app."""
# since 4.0: thread.get_ident() is not included when
# generating the process id. This is due to how the RPC
# backend now dedicates a single thread to receive results,
# which would not work if each thread has a separate id.
return oid_from(self, threads=False)
def amqp(self):
"""AMQP related functionality: :class:`~@amqp`."""
return instantiate(self.amqp_cls, app=self)
def backend(self):
"""Current backend instance."""
return self._get_backend()
def conf(self):
"""Current configuration."""
if self._conf is None:
self._conf = self._load_config()
return self._conf
def conf(self, d): # noqa
self._conf = d
def control(self):
"""Remote control: :class:`~@control`."""
return instantiate(self.control_cls, app=self)
def events(self):
"""Consuming and sending events: :class:`~@events`."""
return instantiate(self.events_cls, app=self)
def loader(self):
"""Current loader instance."""
return get_loader_cls(self.loader_cls)(app=self)
def log(self):
"""Logging: :class:`~@log`."""
return instantiate(self.log_cls, app=self)
def _canvas(self):
from celery import canvas
return canvas
def tasks(self):
"""Task registry.
Accessing this attribute will also auto-finalize the app.
return self._tasks
def producer_pool(self):
return self.amqp.producer_pool
def uses_utc_timezone(self):
"""Check if the application uses the UTC timezone."""
return self.timezone == timezone.utc
def timezone(self):
"""Current timezone for this app.
This is a cached property taking the time zone from the
:setting:`timezone` setting.
conf = self.conf
if not conf.timezone:
if conf.enable_utc:
return timezone.utc
return timezone.local
return timezone.get_timezone(conf.timezone)
App = Celery # noqa: E305 XXX compat