This document describes the current stable version of Celery (5.2). For development docs, go here.
Source code for celery.worker.request
"""Task request.
This module defines the :class:`Request` class, that specifies
how tasks are executed.
"""
import logging
import sys
from datetime import datetime
from time import monotonic, time
from weakref import ref
from billiard.common import TERM_SIGNAME
from billiard.einfo import ExceptionWithTraceback
from kombu.utils.encoding import safe_repr, safe_str
from kombu.utils.objects import cached_property
from celery import current_app, signals
from celery.app.task import Context
from celery.app.trace import fast_trace_task, trace_task, trace_task_ret
from celery.exceptions import (Ignore, InvalidTaskError, Reject, Retry,
TaskRevokedError, Terminated,
TimeLimitExceeded, WorkerLostError)
from celery.platforms import signals as _signals
from celery.utils.functional import maybe, noop
from celery.utils.log import get_logger
from celery.utils.nodenames import gethostname
from celery.utils.serialization import get_pickled_exception
from celery.utils.time import maybe_iso8601, maybe_make_aware, timezone
from . import state
__all__ = ('Request',)
# pylint: disable=redefined-outer-name
# We cache globals and attribute lookups, so disable this warning.
IS_PYPY = hasattr(sys, 'pypy_version_info')
logger = get_logger(__name__)
debug, info, warn, error = (logger.debug, logger.info,
logger.warning, logger.error)
_does_info = False
_does_debug = False
def __optimize__():
# this is also called by celery.app.trace.setup_worker_optimizations
global _does_debug
global _does_info
_does_debug = logger.isEnabledFor(logging.DEBUG)
_does_info = logger.isEnabledFor(logging.INFO)
__optimize__()
# Localize
tz_or_local = timezone.tz_or_local
send_revoked = signals.task_revoked.send
send_retry = signals.task_retry.send
task_accepted = state.task_accepted
task_ready = state.task_ready
revoked_tasks = state.revoked
[docs]class Request:
"""A request for task execution."""
acknowledged = False
time_start = None
worker_pid = None
time_limits = (None, None)
_already_revoked = False
_already_cancelled = False
_terminate_on_ack = None
_apply_result = None
_tzlocal = None
if not IS_PYPY: # pragma: no cover
__slots__ = (
'_app', '_type', 'name', 'id', '_root_id', '_parent_id',
'_on_ack', '_body', '_hostname', '_eventer', '_connection_errors',
'_task', '_eta', '_expires', '_request_dict', '_on_reject', '_utc',
'_content_type', '_content_encoding', '_argsrepr', '_kwargsrepr',
'_args', '_kwargs', '_decoded', '__payload',
'__weakref__', '__dict__',
)
def __init__(self, message, on_ack=noop,
hostname=None, eventer=None, app=None,
connection_errors=None, request_dict=None,
task=None, on_reject=noop, body=None,
headers=None, decoded=False, utc=True,
maybe_make_aware=maybe_make_aware,
maybe_iso8601=maybe_iso8601, **opts):
self._message = message
self._request_dict = (message.headers.copy() if headers is None
else headers.copy())
self._body = message.body if body is None else body
self._app = app
self._utc = utc
self._decoded = decoded
if decoded:
self._content_type = self._content_encoding = None
else:
self._content_type, self._content_encoding = (
message.content_type, message.content_encoding,
)
self.__payload = self._body if self._decoded else message.payload
self.id = self._request_dict['id']
self._type = self.name = self._request_dict['task']
if 'shadow' in self._request_dict:
self.name = self._request_dict['shadow'] or self.name
self._root_id = self._request_dict.get('root_id')
self._parent_id = self._request_dict.get('parent_id')
timelimit = self._request_dict.get('timelimit', None)
if timelimit:
self.time_limits = timelimit
self._argsrepr = self._request_dict.get('argsrepr', '')
self._kwargsrepr = self._request_dict.get('kwargsrepr', '')
self._on_ack = on_ack
self._on_reject = on_reject
self._hostname = hostname or gethostname()
self._eventer = eventer
self._connection_errors = connection_errors or ()
self._task = task or self._app.tasks[self._type]
self._ignore_result = self._request_dict.get('ignore_result', False)
# timezone means the message is timezone-aware, and the only timezone
# supported at this point is UTC.
eta = self._request_dict.get('eta')
if eta is not None:
try:
eta = maybe_iso8601(eta)
except (AttributeError, ValueError, TypeError) as exc:
raise InvalidTaskError(
f'invalid ETA value {eta!r}: {exc}')
self._eta = maybe_make_aware(eta, self.tzlocal)
else:
self._eta = None
expires = self._request_dict.get('expires')
if expires is not None:
try:
expires = maybe_iso8601(expires)
except (AttributeError, ValueError, TypeError) as exc:
raise InvalidTaskError(
f'invalid expires value {expires!r}: {exc}')
self._expires = maybe_make_aware(expires, self.tzlocal)
else:
self._expires = None
delivery_info = message.delivery_info or {}
properties = message.properties or {}
self._delivery_info = {
'exchange': delivery_info.get('exchange'),
'routing_key': delivery_info.get('routing_key'),
'priority': properties.get('priority'),
'redelivered': delivery_info.get('redelivered'),
}
self._request_dict.update({
'properties': properties,
'reply_to': properties.get('reply_to'),
'correlation_id': properties.get('correlation_id'),
'hostname': self._hostname,
'delivery_info': self._delivery_info
})
# this is a reference pass to avoid memory usage burst
self._request_dict['args'], self._request_dict['kwargs'], _ = self.__payload
self._args = self._request_dict['args']
self._kwargs = self._request_dict['kwargs']
@property
def delivery_info(self):
return self._delivery_info
@property
def message(self):
return self._message
@property
def request_dict(self):
return self._request_dict
@property
def body(self):
return self._body
@property
def app(self):
return self._app
@property
def utc(self):
return self._utc
@property
def content_type(self):
return self._content_type
@property
def content_encoding(self):
return self._content_encoding
@property
def type(self):
return self._type
@property
def root_id(self):
return self._root_id
@property
def parent_id(self):
return self._parent_id
@property
def argsrepr(self):
return self._argsrepr
@property
def args(self):
return self._args
@property
def kwargs(self):
return self._kwargs
@property
def kwargsrepr(self):
return self._kwargsrepr
@property
def on_ack(self):
return self._on_ack
@property
def on_reject(self):
return self._on_reject
@on_reject.setter
def on_reject(self, value):
self._on_reject = value
@property
def hostname(self):
return self._hostname
@property
def ignore_result(self):
return self._ignore_result
@property
def eventer(self):
return self._eventer
@eventer.setter
def eventer(self, eventer):
self._eventer = eventer
@property
def connection_errors(self):
return self._connection_errors
@property
def task(self):
return self._task
@property
def eta(self):
return self._eta
@property
def expires(self):
return self._expires
@expires.setter
def expires(self, value):
self._expires = value
@property
def tzlocal(self):
if self._tzlocal is None:
self._tzlocal = self._app.conf.timezone
return self._tzlocal
@property
def store_errors(self):
return (not self.task.ignore_result or
self.task.store_errors_even_if_ignored)
@property
def task_id(self):
# XXX compat
return self.id
@task_id.setter
def task_id(self, value):
self.id = value
@property
def task_name(self):
# XXX compat
return self.name
@task_name.setter
def task_name(self, value):
self.name = value
@property
def reply_to(self):
# used by rpc backend when failures reported by parent process
return self._request_dict['reply_to']
@property
def replaced_task_nesting(self):
return self._request_dict.get('replaced_task_nesting', 0)
@property
def correlation_id(self):
# used similarly to reply_to
return self._request_dict['correlation_id']
[docs] def execute_using_pool(self, pool, **kwargs):
"""Used by the worker to send this task to the pool.
Arguments:
pool (~celery.concurrency.base.TaskPool): The execution pool
used to execute this request.
Raises:
celery.exceptions.TaskRevokedError: if the task was revoked.
"""
task_id = self.id
task = self._task
if self.revoked():
raise TaskRevokedError(task_id)
time_limit, soft_time_limit = self.time_limits
trace = fast_trace_task if self._app.use_fast_trace_task else trace_task_ret
result = pool.apply_async(
trace,
args=(self._type, task_id, self._request_dict, self._body,
self._content_type, self._content_encoding),
accept_callback=self.on_accepted,
timeout_callback=self.on_timeout,
callback=self.on_success,
error_callback=self.on_failure,
soft_timeout=soft_time_limit or task.soft_time_limit,
timeout=time_limit or task.time_limit,
correlation_id=task_id,
)
# cannot create weakref to None
self._apply_result = maybe(ref, result)
return result
[docs] def execute(self, loglevel=None, logfile=None):
"""Execute the task in a :func:`~celery.app.trace.trace_task`.
Arguments:
loglevel (int): The loglevel used by the task.
logfile (str): The logfile used by the task.
"""
if self.revoked():
return
# acknowledge task as being processed.
if not self.task.acks_late:
self.acknowledge()
_, _, embed = self._payload
request = self._request_dict
# pylint: disable=unpacking-non-sequence
# payload is a property, so pylint doesn't think it's a tuple.
request.update({
'loglevel': loglevel,
'logfile': logfile,
'is_eager': False,
}, **embed or {})
retval, I, _, _ = trace_task(self.task, self.id, self._args, self._kwargs, request,
hostname=self._hostname, loader=self._app.loader,
app=self._app)
if I:
self.reject(requeue=False)
else:
self.acknowledge()
return retval
[docs] def maybe_expire(self):
"""If expired, mark the task as revoked."""
if self._expires:
now = datetime.now(self._expires.tzinfo)
if now > self._expires:
revoked_tasks.add(self.id)
return True
[docs] def terminate(self, pool, signal=None):
signal = _signals.signum(signal or TERM_SIGNAME)
if self.time_start:
pool.terminate_job(self.worker_pid, signal)
self._announce_revoked('terminated', True, signal, False)
else:
self._terminate_on_ack = pool, signal
if self._apply_result is not None:
obj = self._apply_result() # is a weakref
if obj is not None:
obj.terminate(signal)
[docs] def cancel(self, pool, signal=None):
signal = _signals.signum(signal or TERM_SIGNAME)
if self.time_start:
pool.terminate_job(self.worker_pid, signal)
self._announce_cancelled()
if self._apply_result is not None:
obj = self._apply_result() # is a weakref
if obj is not None:
obj.terminate(signal)
def _announce_cancelled(self):
task_ready(self)
self.send_event('task-cancelled')
reason = 'cancelled by Celery'
exc = Retry(message=reason)
self.task.backend.mark_as_retry(self.id,
exc,
request=self._context)
self.task.on_retry(exc, self.id, self.args, self.kwargs, None)
self._already_cancelled = True
send_retry(self.task, request=self._context, einfo=None)
def _announce_revoked(self, reason, terminated, signum, expired):
task_ready(self)
self.send_event('task-revoked',
terminated=terminated, signum=signum, expired=expired)
self.task.backend.mark_as_revoked(
self.id, reason, request=self._context,
store_result=self.store_errors,
)
self.acknowledge()
self._already_revoked = True
send_revoked(self.task, request=self._context,
terminated=terminated, signum=signum, expired=expired)
[docs] def revoked(self):
"""If revoked, skip task and mark state."""
expired = False
if self._already_revoked:
return True
if self._expires:
expired = self.maybe_expire()
if self.id in revoked_tasks:
info('Discarding revoked task: %s[%s]', self.name, self.id)
self._announce_revoked(
'expired' if expired else 'revoked', False, None, expired,
)
return True
return False
[docs] def send_event(self, type, **fields):
if self._eventer and self._eventer.enabled and self.task.send_events:
self._eventer.send(type, uuid=self.id, **fields)
[docs] def on_accepted(self, pid, time_accepted):
"""Handler called when task is accepted by worker pool."""
self.worker_pid = pid
# Convert monotonic time_accepted to absolute time
self.time_start = time() - (monotonic() - time_accepted)
task_accepted(self)
if not self.task.acks_late:
self.acknowledge()
self.send_event('task-started')
if _does_debug:
debug('Task accepted: %s[%s] pid:%r', self.name, self.id, pid)
if self._terminate_on_ack is not None:
self.terminate(*self._terminate_on_ack)
[docs] def on_timeout(self, soft, timeout):
"""Handler called if the task times out."""
if soft:
warn('Soft time limit (%ss) exceeded for %s[%s]',
timeout, self.name, self.id)
else:
task_ready(self)
error('Hard time limit (%ss) exceeded for %s[%s]',
timeout, self.name, self.id)
exc = TimeLimitExceeded(timeout)
self.task.backend.mark_as_failure(
self.id, exc, request=self._context,
store_result=self.store_errors,
)
if self.task.acks_late and self.task.acks_on_failure_or_timeout:
self.acknowledge()
[docs] def on_success(self, failed__retval__runtime, **kwargs):
"""Handler called if the task was successfully processed."""
failed, retval, runtime = failed__retval__runtime
if failed:
exc = retval.exception
if isinstance(exc, ExceptionWithTraceback):
exc = exc.exc
if isinstance(exc, (SystemExit, KeyboardInterrupt)):
raise exc
return self.on_failure(retval, return_ok=True)
task_ready(self, successful=True)
if self.task.acks_late:
self.acknowledge()
self.send_event('task-succeeded', result=retval, runtime=runtime)
[docs] def on_retry(self, exc_info):
"""Handler called if the task should be retried."""
if self.task.acks_late:
self.acknowledge()
self.send_event('task-retried',
exception=safe_repr(exc_info.exception.exc),
traceback=safe_str(exc_info.traceback))
[docs] def on_failure(self, exc_info, send_failed_event=True, return_ok=False):
"""Handler called if the task raised an exception."""
task_ready(self)
exc = exc_info.exception
if isinstance(exc, ExceptionWithTraceback):
exc = exc.exc
is_terminated = isinstance(exc, Terminated)
if is_terminated:
# If the task was terminated and the task was not cancelled due
# to a connection loss, it is revoked.
# We always cancel the tasks inside the master process.
# If the request was cancelled, it was not revoked and there's
# nothing to be done.
# According to the comment below, we need to check if the task
# is already revoked and if it wasn't, we should announce that
# it was.
if not self._already_cancelled and not self._already_revoked:
# This is a special case where the process
# would not have had time to write the result.
self._announce_revoked(
'terminated', True, str(exc), False)
return
elif isinstance(exc, MemoryError):
raise MemoryError(f'Process got: {exc}')
elif isinstance(exc, Reject):
return self.reject(requeue=exc.requeue)
elif isinstance(exc, Ignore):
return self.acknowledge()
elif isinstance(exc, Retry):
return self.on_retry(exc_info)
# (acks_late) acknowledge after result stored.
requeue = False
is_worker_lost = isinstance(exc, WorkerLostError)
if self.task.acks_late:
reject = (
self.task.reject_on_worker_lost and
is_worker_lost
)
ack = self.task.acks_on_failure_or_timeout
if reject:
requeue = True
self.reject(requeue=requeue)
send_failed_event = False
elif ack:
self.acknowledge()
else:
# supporting the behaviour where a task failed and
# need to be removed from prefetched local queue
self.reject(requeue=False)
# This is a special case where the process would not have had time
# to write the result.
if not requeue and (is_worker_lost or not return_ok):
# only mark as failure if task has not been requeued
self.task.backend.mark_as_failure(
self.id, exc, request=self._context,
store_result=self.store_errors,
)
signals.task_failure.send(sender=self.task, task_id=self.id,
exception=exc, args=self.args,
kwargs=self.kwargs,
traceback=exc_info.traceback,
einfo=exc_info)
if send_failed_event:
self.send_event(
'task-failed',
exception=safe_repr(get_pickled_exception(exc_info.exception)),
traceback=exc_info.traceback,
)
if not return_ok:
error('Task handler raised error: %r', exc,
exc_info=exc_info.exc_info)
[docs] def acknowledge(self):
"""Acknowledge task."""
if not self.acknowledged:
self._on_ack(logger, self._connection_errors)
self.acknowledged = True
[docs] def reject(self, requeue=False):
if not self.acknowledged:
self._on_reject(logger, self._connection_errors, requeue)
self.acknowledged = True
self.send_event('task-rejected', requeue=requeue)
[docs] def info(self, safe=False):
return {
'id': self.id,
'name': self.name,
'args': self._args if not safe else self._argsrepr,
'kwargs': self._kwargs if not safe else self._kwargsrepr,
'type': self._type,
'hostname': self._hostname,
'time_start': self.time_start,
'acknowledged': self.acknowledged,
'delivery_info': self.delivery_info,
'worker_pid': self.worker_pid,
}
def __str__(self):
"""``str(self)``."""
return ' '.join([
self.humaninfo(),
f' ETA:[{self._eta}]' if self._eta else '',
f' expires:[{self._expires}]' if self._expires else '',
]).strip()
def __repr__(self):
"""``repr(self)``."""
return '<{}: {} {} {}>'.format(
type(self).__name__, self.humaninfo(),
self._argsrepr, self._kwargsrepr,
)
@cached_property
def _payload(self):
return self.__payload
@cached_property
def chord(self):
# used by backend.mark_as_failure when failure is reported
# by parent process
# pylint: disable=unpacking-non-sequence
# payload is a property, so pylint doesn't think it's a tuple.
_, _, embed = self._payload
return embed.get('chord')
@cached_property
def errbacks(self):
# used by backend.mark_as_failure when failure is reported
# by parent process
# pylint: disable=unpacking-non-sequence
# payload is a property, so pylint doesn't think it's a tuple.
_, _, embed = self._payload
return embed.get('errbacks')
@cached_property
def group(self):
# used by backend.on_chord_part_return when failures reported
# by parent process
return self._request_dict.get('group')
@cached_property
def _context(self):
"""Context (:class:`~celery.app.task.Context`) of this task."""
request = self._request_dict
# pylint: disable=unpacking-non-sequence
# payload is a property, so pylint doesn't think it's a tuple.
_, _, embed = self._payload
request.update(**embed or {})
return Context(request)
@cached_property
def group_index(self):
# used by backend.on_chord_part_return to order return values in group
return self._request_dict.get('group_index')
def create_request_cls(base, task, pool, hostname, eventer,
ref=ref, revoked_tasks=revoked_tasks,
task_ready=task_ready, trace=None, app=current_app):
default_time_limit = task.time_limit
default_soft_time_limit = task.soft_time_limit
apply_async = pool.apply_async
acks_late = task.acks_late
events = eventer and eventer.enabled
if trace is None:
trace = fast_trace_task if app.use_fast_trace_task else trace_task_ret
class Request(base):
def execute_using_pool(self, pool, **kwargs):
task_id = self.task_id
if (self.expires or task_id in revoked_tasks) and self.revoked():
raise TaskRevokedError(task_id)
time_limit, soft_time_limit = self.time_limits
result = apply_async(
trace,
args=(self.type, task_id, self.request_dict, self.body,
self.content_type, self.content_encoding),
accept_callback=self.on_accepted,
timeout_callback=self.on_timeout,
callback=self.on_success,
error_callback=self.on_failure,
soft_timeout=soft_time_limit or default_soft_time_limit,
timeout=time_limit or default_time_limit,
correlation_id=task_id,
)
# cannot create weakref to None
# pylint: disable=attribute-defined-outside-init
self._apply_result = maybe(ref, result)
return result
def on_success(self, failed__retval__runtime, **kwargs):
failed, retval, runtime = failed__retval__runtime
if failed:
exc = retval.exception
if isinstance(exc, ExceptionWithTraceback):
exc = exc.exc
if isinstance(exc, (SystemExit, KeyboardInterrupt)):
raise exc
return self.on_failure(retval, return_ok=True)
task_ready(self)
if acks_late:
self.acknowledge()
if events:
self.send_event(
'task-succeeded', result=retval, runtime=runtime,
)
return Request
