This document describes the current stable version of Celery (5.2). For development docs, go here.

Source code for celery.worker.worker

"""WorkController can be used to instantiate in-process workers.

The command-line interface for the worker is in :mod:`celery.bin.worker`,
while the worker program is in :mod:`celery.apps.worker`.

The worker program is responsible for adding signal handlers,
setting up logging, etc.  This is a bare-bones worker without
global side-effects (i.e., except for the global state stored in

The worker consists of several components, all managed by bootsteps

import os
import sys
from datetime import datetime

from billiard import cpu_count
from kombu.utils.compat import detect_environment

from celery import bootsteps
from celery import concurrency as _concurrency
from celery import signals
from celery.bootsteps import RUN, TERMINATE
from celery.exceptions import (ImproperlyConfigured, TaskRevokedError,
from celery.platforms import EX_FAILURE, create_pidlock
from celery.utils.imports import reload_from_cwd
from celery.utils.log import mlevel
from celery.utils.log import worker_logger as logger
from celery.utils.nodenames import default_nodename, worker_direct
from celery.utils.text import str_to_list
from celery.utils.threads import default_socket_timeout

from . import state

    import resource
except ImportError:  # pragma: no cover
    resource = None

__all__ = ('WorkController',)

#: Default socket timeout at shutdown.

Trying to select queue subset of {0!r}, but queue {1} isn't
defined in the `task_queues` setting.

If you want to automatically declare unknown queues you can
enable the `task_create_missing_queues` setting.

Trying to deselect queue subset of {0!r}, but queue {1} isn't
defined in the `task_queues` setting.

[docs]class WorkController: """Unmanaged worker instance.""" app = None pidlock = None blueprint = None pool = None semaphore = None #: contains the exit code if a :exc:`SystemExit` event is handled. exitcode = None
[docs] class Blueprint(bootsteps.Blueprint): """Worker bootstep blueprint.""" name = 'Worker' default_steps = { 'celery.worker.components:Hub', 'celery.worker.components:Pool', 'celery.worker.components:Beat', 'celery.worker.components:Timer', 'celery.worker.components:StateDB', 'celery.worker.components:Consumer', 'celery.worker.autoscale:WorkerComponent', }
def __init__(self, app=None, hostname=None, **kwargs): = app or self.hostname = default_nodename(hostname) self.startup_time = datetime.utcnow() self.on_before_init(**kwargs) self.setup_defaults(**kwargs) self.on_after_init(**kwargs) self.setup_instance(**self.prepare_args(**kwargs))
[docs] def setup_instance(self, queues=None, ready_callback=None, pidfile=None, include=None, use_eventloop=None, exclude_queues=None, **kwargs): self.pidfile = pidfile self.setup_queues(queues, exclude_queues) self.setup_includes(str_to_list(include)) # Set default concurrency if not self.concurrency: try: self.concurrency = cpu_count() except NotImplementedError: self.concurrency = 2 # Options self.loglevel = mlevel(self.loglevel) self.ready_callback = ready_callback or self.on_consumer_ready # this connection won't establish, only used for params self._conninfo = self.use_eventloop = ( self.should_use_eventloop() if use_eventloop is None else use_eventloop ) self.options = kwargs signals.worker_init.send(sender=self) # Initialize bootsteps self.pool_cls = _concurrency.get_implementation(self.pool_cls) self.steps = [] self.on_init_blueprint() self.blueprint = self.Blueprint(['worker'], on_start=self.on_start, on_close=self.on_close, on_stopped=self.on_stopped, ) self.blueprint.apply(self, **kwargs)
[docs] def on_init_blueprint(self): pass
[docs] def on_before_init(self, **kwargs): pass
[docs] def on_after_init(self, **kwargs): pass
[docs] def on_start(self): if self.pidfile: self.pidlock = create_pidlock(self.pidfile)
[docs] def on_consumer_ready(self, consumer): pass
[docs] def on_close(self):
[docs] def on_stopped(self): self.timer.stop() self.consumer.shutdown() if self.pidlock: self.pidlock.release()
[docs] def setup_queues(self, include, exclude=None): include = str_to_list(include) exclude = str_to_list(exclude) try: except KeyError as exc: raise ImproperlyConfigured( SELECT_UNKNOWN_QUEUE.strip().format(include, exc)) try: except KeyError as exc: raise ImproperlyConfigured( DESELECT_UNKNOWN_QUEUE.strip().format(exclude, exc)) if
[docs] def setup_includes(self, includes): # Update celery_include to have all known task modules, so that we # ensure all task modules are imported in case an execv happens. prev = tuple( if includes: prev += tuple(includes) [ for m in includes] self.include = includes task_modules = {task.__class__.__module__ for task in} = tuple(set(prev) | task_modules)
[docs] def prepare_args(self, **kwargs): return kwargs
def _send_worker_shutdown(self): signals.worker_shutdown.send(sender=self)
[docs] def start(self): try: self.blueprint.start(self) except WorkerTerminate: self.terminate() except Exception as exc: logger.critical('Unrecoverable error: %r', exc, exc_info=True) self.stop(exitcode=EX_FAILURE) except SystemExit as exc: self.stop(exitcode=exc.code) except KeyboardInterrupt: self.stop(exitcode=EX_FAILURE)
[docs] def register_with_event_loop(self, hub): self.blueprint.send_all( self, 'register_with_event_loop', args=(hub,), description='hub.register', )
def _process_task_sem(self, req): return self._quick_acquire(self._process_task, req) def _process_task(self, req): """Process task by sending it to the pool of workers.""" try: req.execute_using_pool(self.pool) except TaskRevokedError: try: self._quick_release() # Issue 877 except AttributeError: pass
[docs] def signal_consumer_close(self): try: self.consumer.close() except AttributeError: pass
[docs] def should_use_eventloop(self): return (detect_environment() == 'default' and self._conninfo.transport.implements.asynchronous and not
[docs] def stop(self, in_sighandler=False, exitcode=None): """Graceful shutdown of the worker server.""" if exitcode is not None: self.exitcode = exitcode if self.blueprint.state == RUN: self.signal_consumer_close() if not in_sighandler or self.pool.signal_safe: self._shutdown(warm=True) self._send_worker_shutdown()
[docs] def terminate(self, in_sighandler=False): """Not so graceful shutdown of the worker server.""" if self.blueprint.state != TERMINATE: self.signal_consumer_close() if not in_sighandler or self.pool.signal_safe: self._shutdown(warm=False)
def _shutdown(self, warm=True): # if blueprint does not exist it means that we had an # error before the bootsteps could be initialized. if self.blueprint is not None: with default_socket_timeout(SHUTDOWN_SOCKET_TIMEOUT): # Issue 975 self.blueprint.stop(self, terminate=not warm) self.blueprint.join()
[docs] def reload(self, modules=None, reload=False, reloader=None): list(self._reload_modules( modules, force_reload=reload, reloader=reloader)) if self.consumer: self.consumer.update_strategies() self.consumer.reset_rate_limits() try: self.pool.restart() except NotImplementedError: pass
def _reload_modules(self, modules=None, **kwargs): return ( self._maybe_reload_module(m, **kwargs) for m in set( if modules is None else (modules or ())) ) def _maybe_reload_module(self, module, force_reload=False, reloader=None): if module not in sys.modules: logger.debug('importing module %s', module) return elif force_reload: logger.debug('reloading module %s', module) return reload_from_cwd(sys.modules[module], reloader)
[docs] def info(self): uptime = datetime.utcnow() - self.startup_time return {'total': self.state.total_count, 'pid': os.getpid(), 'clock': str(, 'uptime': round(uptime.total_seconds())}
[docs] def rusage(self): if resource is None: raise NotImplementedError('rusage not supported by this platform') s = resource.getrusage(resource.RUSAGE_SELF) return { 'utime': s.ru_utime, 'stime': s.ru_stime, 'maxrss': s.ru_maxrss, 'ixrss': s.ru_ixrss, 'idrss': s.ru_idrss, 'isrss': s.ru_isrss, 'minflt': s.ru_minflt, 'majflt': s.ru_majflt, 'nswap': s.ru_nswap, 'inblock': s.ru_inblock, 'oublock': s.ru_oublock, 'msgsnd': s.ru_msgsnd, 'msgrcv': s.ru_msgrcv, 'nsignals': s.ru_nsignals, 'nvcsw': s.ru_nvcsw, 'nivcsw': s.ru_nivcsw, }
[docs] def stats(self): info = info.update( info.update( try: info['rusage'] = self.rusage() except NotImplementedError: info['rusage'] = 'N/A' return info
def __repr__(self): """``repr(worker)``.""" return '<Worker: {self.hostname} ({state})>'.format( self=self, state=self.blueprint.human_state() if self.blueprint else 'INIT', ) def __str__(self): """``str(worker) == worker.hostname``.""" return self.hostname @property def state(self): return state
[docs] def setup_defaults(self, concurrency=None, loglevel='WARN', logfile=None, task_events=None, pool=None, consumer_cls=None, timer_cls=None, timer_precision=None, autoscaler_cls=None, pool_putlocks=None, pool_restarts=None, optimization=None, O=None, # O maps to -O=fair statedb=None, time_limit=None, soft_time_limit=None, scheduler=None, pool_cls=None, # XXX use pool state_db=None, # XXX use statedb task_time_limit=None, # XXX use time_limit task_soft_time_limit=None, # XXX use soft_time_limit scheduler_cls=None, # XXX use scheduler schedule_filename=None, max_tasks_per_child=None, prefetch_multiplier=None, disable_rate_limits=None, worker_lost_wait=None, max_memory_per_child=None, **_kw): either = self.loglevel = loglevel self.logfile = logfile self.concurrency = either('worker_concurrency', concurrency) self.task_events = either('worker_send_task_events', task_events) self.pool_cls = either('worker_pool', pool, pool_cls) self.consumer_cls = either('worker_consumer', consumer_cls) self.timer_cls = either('worker_timer', timer_cls) self.timer_precision = either( 'worker_timer_precision', timer_precision, ) self.optimization = optimization or O self.autoscaler_cls = either('worker_autoscaler', autoscaler_cls) self.pool_putlocks = either('worker_pool_putlocks', pool_putlocks) self.pool_restarts = either('worker_pool_restarts', pool_restarts) self.statedb = either('worker_state_db', statedb, state_db) self.schedule_filename = either( 'beat_schedule_filename', schedule_filename, ) self.scheduler = either('beat_scheduler', scheduler, scheduler_cls) self.time_limit = either( 'task_time_limit', time_limit, task_time_limit) self.soft_time_limit = either( 'task_soft_time_limit', soft_time_limit, task_soft_time_limit, ) self.max_tasks_per_child = either( 'worker_max_tasks_per_child', max_tasks_per_child, ) self.max_memory_per_child = either( 'worker_max_memory_per_child', max_memory_per_child, ) self.prefetch_multiplier = int(either( 'worker_prefetch_multiplier', prefetch_multiplier, )) self.disable_rate_limits = either( 'worker_disable_rate_limits', disable_rate_limits, ) self.worker_lost_wait = either('worker_lost_wait', worker_lost_wait)