GNXSOFT.COM

This commit is contained in:
Iliyan Angelov
2025-09-26 00:15:37 +03:00
commit fe26b7cca4
16323 changed files with 2011881 additions and 0 deletions

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"""Worker consumer."""
from .agent import Agent
from .connection import Connection
from .consumer import Consumer
from .control import Control
from .events import Events
from .gossip import Gossip
from .heart import Heart
from .mingle import Mingle
from .tasks import Tasks
__all__ = (
'Consumer', 'Agent', 'Connection', 'Control',
'Events', 'Gossip', 'Heart', 'Mingle', 'Tasks',
)

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"""Celery + :pypi:`cell` integration."""
from celery import bootsteps
from .connection import Connection
__all__ = ('Agent',)
class Agent(bootsteps.StartStopStep):
"""Agent starts :pypi:`cell` actors."""
conditional = True
requires = (Connection,)
def __init__(self, c, **kwargs):
self.agent_cls = self.enabled = c.app.conf.worker_agent
super().__init__(c, **kwargs)
def create(self, c):
agent = c.agent = self.instantiate(self.agent_cls, c.connection)
return agent

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"""Consumer Broker Connection Bootstep."""
from kombu.common import ignore_errors
from celery import bootsteps
from celery.utils.log import get_logger
__all__ = ('Connection',)
logger = get_logger(__name__)
info = logger.info
class Connection(bootsteps.StartStopStep):
"""Service managing the consumer broker connection."""
def __init__(self, c, **kwargs):
c.connection = None
super().__init__(c, **kwargs)
def start(self, c):
c.connection = c.connect()
info('Connected to %s', c.connection.as_uri())
def shutdown(self, c):
# We must set self.connection to None here, so
# that the green pidbox thread exits.
connection, c.connection = c.connection, None
if connection:
ignore_errors(connection, connection.close)
def info(self, c):
params = 'N/A'
if c.connection:
params = c.connection.info()
params.pop('password', None) # don't send password.
return {'broker': params}

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"""Worker Consumer Blueprint.
This module contains the components responsible for consuming messages
from the broker, processing the messages and keeping the broker connections
up and running.
"""
import errno
import logging
import os
import warnings
from collections import defaultdict
from time import sleep
from billiard.common import restart_state
from billiard.exceptions import RestartFreqExceeded
from kombu.asynchronous.semaphore import DummyLock
from kombu.exceptions import ContentDisallowed, DecodeError
from kombu.utils.compat import _detect_environment
from kombu.utils.encoding import safe_repr
from kombu.utils.limits import TokenBucket
from vine import ppartial, promise
from celery import bootsteps, signals
from celery.app.trace import build_tracer
from celery.exceptions import (CPendingDeprecationWarning, InvalidTaskError, NotRegistered, WorkerShutdown,
WorkerTerminate)
from celery.utils.functional import noop
from celery.utils.log import get_logger
from celery.utils.nodenames import gethostname
from celery.utils.objects import Bunch
from celery.utils.text import truncate
from celery.utils.time import humanize_seconds, rate
from celery.worker import loops
from celery.worker.state import active_requests, maybe_shutdown, requests, reserved_requests, task_reserved
__all__ = ('Consumer', 'Evloop', 'dump_body')
CLOSE = bootsteps.CLOSE
TERMINATE = bootsteps.TERMINATE
STOP_CONDITIONS = {CLOSE, TERMINATE}
logger = get_logger(__name__)
debug, info, warn, error, crit = (logger.debug, logger.info, logger.warning,
logger.error, logger.critical)
CONNECTION_RETRY = """\
consumer: Connection to broker lost. \
Trying to re-establish the connection...\
"""
CONNECTION_RETRY_STEP = """\
Trying again {when}... ({retries}/{max_retries})\
"""
CONNECTION_ERROR = """\
consumer: Cannot connect to %s: %s.
%s
"""
CONNECTION_FAILOVER = """\
Will retry using next failover.\
"""
UNKNOWN_FORMAT = """\
Received and deleted unknown message. Wrong destination?!?
The full contents of the message body was: %s
"""
#: Error message for when an unregistered task is received.
UNKNOWN_TASK_ERROR = """\
Received unregistered task of type %s.
The message has been ignored and discarded.
Did you remember to import the module containing this task?
Or maybe you're using relative imports?
Please see
https://docs.celeryq.dev/en/latest/internals/protocol.html
for more information.
The full contents of the message body was:
%s
The full contents of the message headers:
%s
The delivery info for this task is:
%s
"""
#: Error message for when an invalid task message is received.
INVALID_TASK_ERROR = """\
Received invalid task message: %s
The message has been ignored and discarded.
Please ensure your message conforms to the task
message protocol as described here:
https://docs.celeryq.dev/en/latest/internals/protocol.html
The full contents of the message body was:
%s
"""
MESSAGE_DECODE_ERROR = """\
Can't decode message body: %r [type:%r encoding:%r headers:%s]
body: %s
"""
MESSAGE_REPORT = """\
body: {0}
{{content_type:{1} content_encoding:{2}
delivery_info:{3} headers={4}}}
"""
TERMINATING_TASK_ON_RESTART_AFTER_A_CONNECTION_LOSS = """\
Task %s cannot be acknowledged after a connection loss since late acknowledgement is enabled for it.
Terminating it instead.
"""
CANCEL_TASKS_BY_DEFAULT = """
In Celery 5.1 we introduced an optional breaking change which
on connection loss cancels all currently executed tasks with late acknowledgement enabled.
These tasks cannot be acknowledged as the connection is gone, and the tasks are automatically redelivered
back to the queue. You can enable this behavior using the worker_cancel_long_running_tasks_on_connection_loss
setting. In Celery 5.1 it is set to False by default. The setting will be set to True by default in Celery 6.0.
"""
def dump_body(m, body):
"""Format message body for debugging purposes."""
# v2 protocol does not deserialize body
body = m.body if body is None else body
return '{} ({}b)'.format(truncate(safe_repr(body), 1024),
len(m.body))
class Consumer:
"""Consumer blueprint."""
Strategies = dict
#: Optional callback called the first time the worker
#: is ready to receive tasks.
init_callback = None
#: The current worker pool instance.
pool = None
#: A timer used for high-priority internal tasks, such
#: as sending heartbeats.
timer = None
restart_count = -1 # first start is the same as a restart
#: This flag will be turned off after the first failed
#: connection attempt.
first_connection_attempt = True
class Blueprint(bootsteps.Blueprint):
"""Consumer blueprint."""
name = 'Consumer'
default_steps = [
'celery.worker.consumer.connection:Connection',
'celery.worker.consumer.mingle:Mingle',
'celery.worker.consumer.events:Events',
'celery.worker.consumer.gossip:Gossip',
'celery.worker.consumer.heart:Heart',
'celery.worker.consumer.control:Control',
'celery.worker.consumer.tasks:Tasks',
'celery.worker.consumer.consumer:Evloop',
'celery.worker.consumer.agent:Agent',
]
def shutdown(self, parent):
self.send_all(parent, 'shutdown')
def __init__(self, on_task_request,
init_callback=noop, hostname=None,
pool=None, app=None,
timer=None, controller=None, hub=None, amqheartbeat=None,
worker_options=None, disable_rate_limits=False,
initial_prefetch_count=2, prefetch_multiplier=1, **kwargs):
self.app = app
self.controller = controller
self.init_callback = init_callback
self.hostname = hostname or gethostname()
self.pid = os.getpid()
self.pool = pool
self.timer = timer
self.strategies = self.Strategies()
self.conninfo = self.app.connection_for_read()
self.connection_errors = self.conninfo.connection_errors
self.channel_errors = self.conninfo.channel_errors
self._restart_state = restart_state(maxR=5, maxT=1)
self._does_info = logger.isEnabledFor(logging.INFO)
self._limit_order = 0
self.on_task_request = on_task_request
self.on_task_message = set()
self.amqheartbeat_rate = self.app.conf.broker_heartbeat_checkrate
self.disable_rate_limits = disable_rate_limits
self.initial_prefetch_count = initial_prefetch_count
self.prefetch_multiplier = prefetch_multiplier
self._maximum_prefetch_restored = True
# this contains a tokenbucket for each task type by name, used for
# rate limits, or None if rate limits are disabled for that task.
self.task_buckets = defaultdict(lambda: None)
self.reset_rate_limits()
self.hub = hub
if self.hub or getattr(self.pool, 'is_green', False):
self.amqheartbeat = amqheartbeat
if self.amqheartbeat is None:
self.amqheartbeat = self.app.conf.broker_heartbeat
else:
self.amqheartbeat = 0
if not hasattr(self, 'loop'):
self.loop = loops.asynloop if hub else loops.synloop
if _detect_environment() == 'gevent':
# there's a gevent bug that causes timeouts to not be reset,
# so if the connection timeout is exceeded once, it can NEVER
# connect again.
self.app.conf.broker_connection_timeout = None
self._pending_operations = []
self.steps = []
self.blueprint = self.Blueprint(
steps=self.app.steps['consumer'],
on_close=self.on_close,
)
self.blueprint.apply(self, **dict(worker_options or {}, **kwargs))
def call_soon(self, p, *args, **kwargs):
p = ppartial(p, *args, **kwargs)
if self.hub:
return self.hub.call_soon(p)
self._pending_operations.append(p)
return p
def perform_pending_operations(self):
if not self.hub:
while self._pending_operations:
try:
self._pending_operations.pop()()
except Exception as exc: # pylint: disable=broad-except
logger.exception('Pending callback raised: %r', exc)
def bucket_for_task(self, type):
limit = rate(getattr(type, 'rate_limit', None))
return TokenBucket(limit, capacity=1) if limit else None
def reset_rate_limits(self):
self.task_buckets.update(
(n, self.bucket_for_task(t)) for n, t in self.app.tasks.items()
)
def _update_prefetch_count(self, index=0):
"""Update prefetch count after pool/shrink grow operations.
Index must be the change in number of processes as a positive
(increasing) or negative (decreasing) number.
Note:
Currently pool grow operations will end up with an offset
of +1 if the initial size of the pool was 0 (e.g.
:option:`--autoscale=1,0 <celery worker --autoscale>`).
"""
num_processes = self.pool.num_processes
if not self.initial_prefetch_count or not num_processes:
return # prefetch disabled
self.initial_prefetch_count = (
self.pool.num_processes * self.prefetch_multiplier
)
return self._update_qos_eventually(index)
def _update_qos_eventually(self, index):
return (self.qos.decrement_eventually if index < 0
else self.qos.increment_eventually)(
abs(index) * self.prefetch_multiplier)
def _limit_move_to_pool(self, request):
task_reserved(request)
self.on_task_request(request)
def _schedule_bucket_request(self, bucket):
while True:
try:
request, tokens = bucket.pop()
except IndexError:
# no request, break
break
if bucket.can_consume(tokens):
self._limit_move_to_pool(request)
continue
else:
# requeue to head, keep the order.
bucket.contents.appendleft((request, tokens))
pri = self._limit_order = (self._limit_order + 1) % 10
hold = bucket.expected_time(tokens)
self.timer.call_after(
hold, self._schedule_bucket_request, (bucket,),
priority=pri,
)
# no tokens, break
break
def _limit_task(self, request, bucket, tokens):
bucket.add((request, tokens))
return self._schedule_bucket_request(bucket)
def _limit_post_eta(self, request, bucket, tokens):
self.qos.decrement_eventually()
bucket.add((request, tokens))
return self._schedule_bucket_request(bucket)
def start(self):
blueprint = self.blueprint
while blueprint.state not in STOP_CONDITIONS:
maybe_shutdown()
if self.restart_count:
try:
self._restart_state.step()
except RestartFreqExceeded as exc:
crit('Frequent restarts detected: %r', exc, exc_info=1)
sleep(1)
self.restart_count += 1
if self.app.conf.broker_channel_error_retry:
recoverable_errors = (self.connection_errors + self.channel_errors)
else:
recoverable_errors = self.connection_errors
try:
blueprint.start(self)
except recoverable_errors as exc:
# If we're not retrying connections, we need to properly shutdown or terminate
# the Celery main process instead of abruptly aborting the process without any cleanup.
is_connection_loss_on_startup = self.first_connection_attempt
self.first_connection_attempt = False
connection_retry_type = self._get_connection_retry_type(is_connection_loss_on_startup)
connection_retry = self.app.conf[connection_retry_type]
if not connection_retry:
crit(
f"Retrying to {'establish' if is_connection_loss_on_startup else 're-establish'} "
f"a connection to the message broker after a connection loss has "
f"been disabled (app.conf.{connection_retry_type}=False). Shutting down..."
)
raise WorkerShutdown(1) from exc
if isinstance(exc, OSError) and exc.errno == errno.EMFILE:
crit("Too many open files. Aborting...")
raise WorkerTerminate(1) from exc
maybe_shutdown()
if blueprint.state not in STOP_CONDITIONS:
if self.connection:
self.on_connection_error_after_connected(exc)
else:
self.on_connection_error_before_connected(exc)
self.on_close()
blueprint.restart(self)
def _get_connection_retry_type(self, is_connection_loss_on_startup):
return ('broker_connection_retry_on_startup'
if (is_connection_loss_on_startup
and self.app.conf.broker_connection_retry_on_startup is not None)
else 'broker_connection_retry')
def on_connection_error_before_connected(self, exc):
error(CONNECTION_ERROR, self.conninfo.as_uri(), exc,
'Trying to reconnect...')
def on_connection_error_after_connected(self, exc):
warn(CONNECTION_RETRY, exc_info=True)
try:
self.connection.collect()
except Exception: # pylint: disable=broad-except
pass
if self.app.conf.worker_cancel_long_running_tasks_on_connection_loss:
for request in tuple(active_requests):
if request.task.acks_late and not request.acknowledged:
warn(TERMINATING_TASK_ON_RESTART_AFTER_A_CONNECTION_LOSS,
request)
request.cancel(self.pool)
else:
warnings.warn(CANCEL_TASKS_BY_DEFAULT, CPendingDeprecationWarning)
self.initial_prefetch_count = max(
self.prefetch_multiplier,
self.max_prefetch_count - len(tuple(active_requests)) * self.prefetch_multiplier
)
self._maximum_prefetch_restored = self.initial_prefetch_count == self.max_prefetch_count
if not self._maximum_prefetch_restored:
logger.info(
f"Temporarily reducing the prefetch count to {self.initial_prefetch_count} to avoid over-fetching "
f"since {len(tuple(active_requests))} tasks are currently being processed.\n"
f"The prefetch count will be gradually restored to {self.max_prefetch_count} as the tasks "
"complete processing."
)
def register_with_event_loop(self, hub):
self.blueprint.send_all(
self, 'register_with_event_loop', args=(hub,),
description='Hub.register',
)
def shutdown(self):
self.blueprint.shutdown(self)
def stop(self):
self.blueprint.stop(self)
def on_ready(self):
callback, self.init_callback = self.init_callback, None
if callback:
callback(self)
def loop_args(self):
return (self, self.connection, self.task_consumer,
self.blueprint, self.hub, self.qos, self.amqheartbeat,
self.app.clock, self.amqheartbeat_rate)
def on_decode_error(self, message, exc):
"""Callback called if an error occurs while decoding a message.
Simply logs the error and acknowledges the message so it
doesn't enter a loop.
Arguments:
message (kombu.Message): The message received.
exc (Exception): The exception being handled.
"""
crit(MESSAGE_DECODE_ERROR,
exc, message.content_type, message.content_encoding,
safe_repr(message.headers), dump_body(message, message.body),
exc_info=1)
message.ack()
def on_close(self):
# Clear internal queues to get rid of old messages.
# They can't be acked anyway, as a delivery tag is specific
# to the current channel.
if self.controller and self.controller.semaphore:
self.controller.semaphore.clear()
if self.timer:
self.timer.clear()
for bucket in self.task_buckets.values():
if bucket:
bucket.clear_pending()
for request_id in reserved_requests:
if request_id in requests:
del requests[request_id]
reserved_requests.clear()
if self.pool and self.pool.flush:
self.pool.flush()
def connect(self):
"""Establish the broker connection used for consuming tasks.
Retries establishing the connection if the
:setting:`broker_connection_retry` setting is enabled
"""
conn = self.connection_for_read(heartbeat=self.amqheartbeat)
if self.hub:
conn.transport.register_with_event_loop(conn.connection, self.hub)
return conn
def connection_for_read(self, heartbeat=None):
return self.ensure_connected(
self.app.connection_for_read(heartbeat=heartbeat))
def connection_for_write(self, heartbeat=None):
return self.ensure_connected(
self.app.connection_for_write(heartbeat=heartbeat))
def ensure_connected(self, conn):
# Callback called for each retry while the connection
# can't be established.
def _error_handler(exc, interval, next_step=CONNECTION_RETRY_STEP):
if getattr(conn, 'alt', None) and interval == 0:
next_step = CONNECTION_FAILOVER
next_step = next_step.format(
when=humanize_seconds(interval, 'in', ' '),
retries=int(interval / 2),
max_retries=self.app.conf.broker_connection_max_retries)
error(CONNECTION_ERROR, conn.as_uri(), exc, next_step)
# Remember that the connection is lazy, it won't establish
# until needed.
# TODO: Rely only on broker_connection_retry_on_startup to determine whether connection retries are disabled.
# We will make the switch in Celery 6.0.
retry_disabled = False
if self.app.conf.broker_connection_retry_on_startup is None:
# If broker_connection_retry_on_startup is not set, revert to broker_connection_retry
# to determine whether connection retries are disabled.
retry_disabled = not self.app.conf.broker_connection_retry
warnings.warn(
CPendingDeprecationWarning(
f"The broker_connection_retry configuration setting will no longer determine\n"
f"whether broker connection retries are made during startup in Celery 6.0 and above.\n"
f"If you wish to retain the existing behavior for retrying connections on startup,\n"
f"you should set broker_connection_retry_on_startup to {self.app.conf.broker_connection_retry}.")
)
else:
if self.first_connection_attempt:
retry_disabled = not self.app.conf.broker_connection_retry_on_startup
else:
retry_disabled = not self.app.conf.broker_connection_retry
if retry_disabled:
# Retry disabled, just call connect directly.
conn.connect()
self.first_connection_attempt = False
return conn
conn = conn.ensure_connection(
_error_handler, self.app.conf.broker_connection_max_retries,
callback=maybe_shutdown,
)
self.first_connection_attempt = False
return conn
def _flush_events(self):
if self.event_dispatcher:
self.event_dispatcher.flush()
def on_send_event_buffered(self):
if self.hub:
self.hub._ready.add(self._flush_events)
def add_task_queue(self, queue, exchange=None, exchange_type=None,
routing_key=None, **options):
cset = self.task_consumer
queues = self.app.amqp.queues
# Must use in' here, as __missing__ will automatically
# create queues when :setting:`task_create_missing_queues` is enabled.
# (Issue #1079)
if queue in queues:
q = queues[queue]
else:
exchange = queue if exchange is None else exchange
exchange_type = ('direct' if exchange_type is None
else exchange_type)
q = queues.select_add(queue,
exchange=exchange,
exchange_type=exchange_type,
routing_key=routing_key, **options)
if not cset.consuming_from(queue):
cset.add_queue(q)
cset.consume()
info('Started consuming from %s', queue)
def cancel_task_queue(self, queue):
info('Canceling queue %s', queue)
self.app.amqp.queues.deselect(queue)
self.task_consumer.cancel_by_queue(queue)
def apply_eta_task(self, task):
"""Method called by the timer to apply a task with an ETA/countdown."""
task_reserved(task)
self.on_task_request(task)
self.qos.decrement_eventually()
def _message_report(self, body, message):
return MESSAGE_REPORT.format(dump_body(message, body),
safe_repr(message.content_type),
safe_repr(message.content_encoding),
safe_repr(message.delivery_info),
safe_repr(message.headers))
def on_unknown_message(self, body, message):
warn(UNKNOWN_FORMAT, self._message_report(body, message))
message.reject_log_error(logger, self.connection_errors)
signals.task_rejected.send(sender=self, message=message, exc=None)
def on_unknown_task(self, body, message, exc):
error(UNKNOWN_TASK_ERROR,
exc,
dump_body(message, body),
message.headers,
message.delivery_info,
exc_info=True)
try:
id_, name = message.headers['id'], message.headers['task']
root_id = message.headers.get('root_id')
except KeyError: # proto1
payload = message.payload
id_, name = payload['id'], payload['task']
root_id = None
request = Bunch(
name=name, chord=None, root_id=root_id,
correlation_id=message.properties.get('correlation_id'),
reply_to=message.properties.get('reply_to'),
errbacks=None,
)
message.reject_log_error(logger, self.connection_errors)
self.app.backend.mark_as_failure(
id_, NotRegistered(name), request=request,
)
if self.event_dispatcher:
self.event_dispatcher.send(
'task-failed', uuid=id_,
exception=f'NotRegistered({name!r})',
)
signals.task_unknown.send(
sender=self, message=message, exc=exc, name=name, id=id_,
)
def on_invalid_task(self, body, message, exc):
error(INVALID_TASK_ERROR, exc, dump_body(message, body),
exc_info=True)
message.reject_log_error(logger, self.connection_errors)
signals.task_rejected.send(sender=self, message=message, exc=exc)
def update_strategies(self):
loader = self.app.loader
for name, task in self.app.tasks.items():
self.strategies[name] = task.start_strategy(self.app, self)
task.__trace__ = build_tracer(name, task, loader, self.hostname,
app=self.app)
def create_task_handler(self, promise=promise):
strategies = self.strategies
on_unknown_message = self.on_unknown_message
on_unknown_task = self.on_unknown_task
on_invalid_task = self.on_invalid_task
callbacks = self.on_task_message
call_soon = self.call_soon
def on_task_received(message):
# payload will only be set for v1 protocol, since v2
# will defer deserializing the message body to the pool.
payload = None
try:
type_ = message.headers['task'] # protocol v2
except TypeError:
return on_unknown_message(None, message)
except KeyError:
try:
payload = message.decode()
except Exception as exc: # pylint: disable=broad-except
return self.on_decode_error(message, exc)
try:
type_, payload = payload['task'], payload # protocol v1
except (TypeError, KeyError):
return on_unknown_message(payload, message)
try:
strategy = strategies[type_]
except KeyError as exc:
return on_unknown_task(None, message, exc)
else:
try:
ack_log_error_promise = promise(
call_soon,
(message.ack_log_error,),
on_error=self._restore_prefetch_count_after_connection_restart,
)
reject_log_error_promise = promise(
call_soon,
(message.reject_log_error,),
on_error=self._restore_prefetch_count_after_connection_restart,
)
if (
not self._maximum_prefetch_restored
and self.restart_count > 0
and self._new_prefetch_count <= self.max_prefetch_count
):
ack_log_error_promise.then(self._restore_prefetch_count_after_connection_restart,
on_error=self._restore_prefetch_count_after_connection_restart)
reject_log_error_promise.then(self._restore_prefetch_count_after_connection_restart,
on_error=self._restore_prefetch_count_after_connection_restart)
strategy(
message, payload,
ack_log_error_promise,
reject_log_error_promise,
callbacks,
)
except (InvalidTaskError, ContentDisallowed) as exc:
return on_invalid_task(payload, message, exc)
except DecodeError as exc:
return self.on_decode_error(message, exc)
return on_task_received
def _restore_prefetch_count_after_connection_restart(self, p, *args):
with self.qos._mutex:
if self._maximum_prefetch_restored:
return
new_prefetch_count = min(self.max_prefetch_count, self._new_prefetch_count)
self.qos.value = self.initial_prefetch_count = new_prefetch_count
self.qos.set(self.qos.value)
already_restored = self._maximum_prefetch_restored
self._maximum_prefetch_restored = new_prefetch_count == self.max_prefetch_count
if already_restored is False and self._maximum_prefetch_restored is True:
logger.info(
"Resuming normal operations following a restart.\n"
f"Prefetch count has been restored to the maximum of {self.max_prefetch_count}"
)
@property
def max_prefetch_count(self):
return self.pool.num_processes * self.prefetch_multiplier
@property
def _new_prefetch_count(self):
return self.qos.value + self.prefetch_multiplier
def __repr__(self):
"""``repr(self)``."""
return '<Consumer: {self.hostname} ({state})>'.format(
self=self, state=self.blueprint.human_state(),
)
class Evloop(bootsteps.StartStopStep):
"""Event loop service.
Note:
This is always started last.
"""
label = 'event loop'
last = True
def start(self, c):
self.patch_all(c)
c.loop(*c.loop_args())
def patch_all(self, c):
c.qos._mutex = DummyLock()

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"""Worker Remote Control Bootstep.
``Control`` -> :mod:`celery.worker.pidbox` -> :mod:`kombu.pidbox`.
The actual commands are implemented in :mod:`celery.worker.control`.
"""
from celery import bootsteps
from celery.utils.log import get_logger
from celery.worker import pidbox
from .tasks import Tasks
__all__ = ('Control',)
logger = get_logger(__name__)
class Control(bootsteps.StartStopStep):
"""Remote control command service."""
requires = (Tasks,)
def __init__(self, c, **kwargs):
self.is_green = c.pool is not None and c.pool.is_green
self.box = (pidbox.gPidbox if self.is_green else pidbox.Pidbox)(c)
self.start = self.box.start
self.stop = self.box.stop
self.shutdown = self.box.shutdown
super().__init__(c, **kwargs)
def include_if(self, c):
return (c.app.conf.worker_enable_remote_control and
c.conninfo.supports_exchange_type('fanout'))

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"""Worker Event Dispatcher Bootstep.
``Events`` -> :class:`celery.events.EventDispatcher`.
"""
from kombu.common import ignore_errors
from celery import bootsteps
from .connection import Connection
__all__ = ('Events',)
class Events(bootsteps.StartStopStep):
"""Service used for sending monitoring events."""
requires = (Connection,)
def __init__(self, c,
task_events=True,
without_heartbeat=False,
without_gossip=False,
**kwargs):
self.groups = None if task_events else ['worker']
self.send_events = (
task_events or
not without_gossip or
not without_heartbeat
)
self.enabled = self.send_events
c.event_dispatcher = None
super().__init__(c, **kwargs)
def start(self, c):
# flush events sent while connection was down.
prev = self._close(c)
dis = c.event_dispatcher = c.app.events.Dispatcher(
c.connection_for_write(),
hostname=c.hostname,
enabled=self.send_events,
groups=self.groups,
# we currently only buffer events when the event loop is enabled
# XXX This excludes eventlet/gevent, which should actually buffer.
buffer_group=['task'] if c.hub else None,
on_send_buffered=c.on_send_event_buffered if c.hub else None,
)
if prev:
dis.extend_buffer(prev)
dis.flush()
def stop(self, c):
pass
def _close(self, c):
if c.event_dispatcher:
dispatcher = c.event_dispatcher
# remember changes from remote control commands:
self.groups = dispatcher.groups
# close custom connection
if dispatcher.connection:
ignore_errors(c, dispatcher.connection.close)
ignore_errors(c, dispatcher.close)
c.event_dispatcher = None
return dispatcher
def shutdown(self, c):
self._close(c)

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"""Worker <-> Worker communication Bootstep."""
from collections import defaultdict
from functools import partial
from heapq import heappush
from operator import itemgetter
from kombu import Consumer
from kombu.asynchronous.semaphore import DummyLock
from kombu.exceptions import ContentDisallowed, DecodeError
from celery import bootsteps
from celery.utils.log import get_logger
from celery.utils.objects import Bunch
from .mingle import Mingle
__all__ = ('Gossip',)
logger = get_logger(__name__)
debug, info = logger.debug, logger.info
class Gossip(bootsteps.ConsumerStep):
"""Bootstep consuming events from other workers.
This keeps the logical clock value up to date.
"""
label = 'Gossip'
requires = (Mingle,)
_cons_stamp_fields = itemgetter(
'id', 'clock', 'hostname', 'pid', 'topic', 'action', 'cver',
)
compatible_transports = {'amqp', 'redis'}
def __init__(self, c, without_gossip=False,
interval=5.0, heartbeat_interval=2.0, **kwargs):
self.enabled = not without_gossip and self.compatible_transport(c.app)
self.app = c.app
c.gossip = self
self.Receiver = c.app.events.Receiver
self.hostname = c.hostname
self.full_hostname = '.'.join([self.hostname, str(c.pid)])
self.on = Bunch(
node_join=set(),
node_leave=set(),
node_lost=set(),
)
self.timer = c.timer
if self.enabled:
self.state = c.app.events.State(
on_node_join=self.on_node_join,
on_node_leave=self.on_node_leave,
max_tasks_in_memory=1,
)
if c.hub:
c._mutex = DummyLock()
self.update_state = self.state.event
self.interval = interval
self.heartbeat_interval = heartbeat_interval
self._tref = None
self.consensus_requests = defaultdict(list)
self.consensus_replies = {}
self.event_handlers = {
'worker.elect': self.on_elect,
'worker.elect.ack': self.on_elect_ack,
}
self.clock = c.app.clock
self.election_handlers = {
'task': self.call_task
}
super().__init__(c, **kwargs)
def compatible_transport(self, app):
with app.connection_for_read() as conn:
return conn.transport.driver_type in self.compatible_transports
def election(self, id, topic, action=None):
self.consensus_replies[id] = []
self.dispatcher.send(
'worker-elect',
id=id, topic=topic, action=action, cver=1,
)
def call_task(self, task):
try:
self.app.signature(task).apply_async()
except Exception as exc: # pylint: disable=broad-except
logger.exception('Could not call task: %r', exc)
def on_elect(self, event):
try:
(id_, clock, hostname, pid,
topic, action, _) = self._cons_stamp_fields(event)
except KeyError as exc:
return logger.exception('election request missing field %s', exc)
heappush(
self.consensus_requests[id_],
(clock, f'{hostname}.{pid}', topic, action),
)
self.dispatcher.send('worker-elect-ack', id=id_)
def start(self, c):
super().start(c)
self.dispatcher = c.event_dispatcher
def on_elect_ack(self, event):
id = event['id']
try:
replies = self.consensus_replies[id]
except KeyError:
return # not for us
alive_workers = set(self.state.alive_workers())
replies.append(event['hostname'])
if len(replies) >= len(alive_workers):
_, leader, topic, action = self.clock.sort_heap(
self.consensus_requests[id],
)
if leader == self.full_hostname:
info('I won the election %r', id)
try:
handler = self.election_handlers[topic]
except KeyError:
logger.exception('Unknown election topic %r', topic)
else:
handler(action)
else:
info('node %s elected for %r', leader, id)
self.consensus_requests.pop(id, None)
self.consensus_replies.pop(id, None)
def on_node_join(self, worker):
debug('%s joined the party', worker.hostname)
self._call_handlers(self.on.node_join, worker)
def on_node_leave(self, worker):
debug('%s left', worker.hostname)
self._call_handlers(self.on.node_leave, worker)
def on_node_lost(self, worker):
info('missed heartbeat from %s', worker.hostname)
self._call_handlers(self.on.node_lost, worker)
def _call_handlers(self, handlers, *args, **kwargs):
for handler in handlers:
try:
handler(*args, **kwargs)
except Exception as exc: # pylint: disable=broad-except
logger.exception(
'Ignored error from handler %r: %r', handler, exc)
def register_timer(self):
if self._tref is not None:
self._tref.cancel()
self._tref = self.timer.call_repeatedly(self.interval, self.periodic)
def periodic(self):
workers = self.state.workers
dirty = set()
for worker in workers.values():
if not worker.alive:
dirty.add(worker)
self.on_node_lost(worker)
for worker in dirty:
workers.pop(worker.hostname, None)
def get_consumers(self, channel):
self.register_timer()
ev = self.Receiver(channel, routing_key='worker.#',
queue_ttl=self.heartbeat_interval)
return [Consumer(
channel,
queues=[ev.queue],
on_message=partial(self.on_message, ev.event_from_message),
no_ack=True
)]
def on_message(self, prepare, message):
_type = message.delivery_info['routing_key']
# For redis when `fanout_patterns=False` (See Issue #1882)
if _type.split('.', 1)[0] == 'task':
return
try:
handler = self.event_handlers[_type]
except KeyError:
pass
else:
return handler(message.payload)
# proto2: hostname in header; proto1: in body
hostname = (message.headers.get('hostname') or
message.payload['hostname'])
if hostname != self.hostname:
try:
_, event = prepare(message.payload)
self.update_state(event)
except (DecodeError, ContentDisallowed, TypeError) as exc:
logger.error(exc)
else:
self.clock.forward()

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"""Worker Event Heartbeat Bootstep."""
from celery import bootsteps
from celery.worker import heartbeat
from .events import Events
__all__ = ('Heart',)
class Heart(bootsteps.StartStopStep):
"""Bootstep sending event heartbeats.
This service sends a ``worker-heartbeat`` message every n seconds.
Note:
Not to be confused with AMQP protocol level heartbeats.
"""
requires = (Events,)
def __init__(self, c,
without_heartbeat=False, heartbeat_interval=None, **kwargs):
self.enabled = not without_heartbeat
self.heartbeat_interval = heartbeat_interval
c.heart = None
super().__init__(c, **kwargs)
def start(self, c):
c.heart = heartbeat.Heart(
c.timer, c.event_dispatcher, self.heartbeat_interval,
)
c.heart.start()
def stop(self, c):
c.heart = c.heart and c.heart.stop()
shutdown = stop

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"""Worker <-> Worker Sync at startup (Bootstep)."""
from celery import bootsteps
from celery.utils.log import get_logger
from .events import Events
__all__ = ('Mingle',)
logger = get_logger(__name__)
debug, info, exception = logger.debug, logger.info, logger.exception
class Mingle(bootsteps.StartStopStep):
"""Bootstep syncing state with neighbor workers.
At startup, or upon consumer restart, this will:
- Sync logical clocks.
- Sync revoked tasks.
"""
label = 'Mingle'
requires = (Events,)
compatible_transports = {'amqp', 'redis'}
def __init__(self, c, without_mingle=False, **kwargs):
self.enabled = not without_mingle and self.compatible_transport(c.app)
super().__init__(
c, without_mingle=without_mingle, **kwargs)
def compatible_transport(self, app):
with app.connection_for_read() as conn:
return conn.transport.driver_type in self.compatible_transports
def start(self, c):
self.sync(c)
def sync(self, c):
info('mingle: searching for neighbors')
replies = self.send_hello(c)
if replies:
info('mingle: sync with %s nodes',
len([reply for reply, value in replies.items() if value]))
[self.on_node_reply(c, nodename, reply)
for nodename, reply in replies.items() if reply]
info('mingle: sync complete')
else:
info('mingle: all alone')
def send_hello(self, c):
inspect = c.app.control.inspect(timeout=1.0, connection=c.connection)
our_revoked = c.controller.state.revoked
replies = inspect.hello(c.hostname, our_revoked._data) or {}
replies.pop(c.hostname, None) # delete my own response
return replies
def on_node_reply(self, c, nodename, reply):
debug('mingle: processing reply from %s', nodename)
try:
self.sync_with_node(c, **reply)
except MemoryError:
raise
except Exception as exc: # pylint: disable=broad-except
exception('mingle: sync with %s failed: %r', nodename, exc)
def sync_with_node(self, c, clock=None, revoked=None, **kwargs):
self.on_clock_event(c, clock)
self.on_revoked_received(c, revoked)
def on_clock_event(self, c, clock):
c.app.clock.adjust(clock) if clock else c.app.clock.forward()
def on_revoked_received(self, c, revoked):
if revoked:
c.controller.state.revoked.update(revoked)

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"""Worker Task Consumer Bootstep."""
from kombu.common import QoS, ignore_errors
from celery import bootsteps
from celery.utils.log import get_logger
from .mingle import Mingle
__all__ = ('Tasks',)
logger = get_logger(__name__)
debug = logger.debug
class Tasks(bootsteps.StartStopStep):
"""Bootstep starting the task message consumer."""
requires = (Mingle,)
def __init__(self, c, **kwargs):
c.task_consumer = c.qos = None
super().__init__(c, **kwargs)
def start(self, c):
"""Start task consumer."""
c.update_strategies()
# - RabbitMQ 3.3 completely redefines how basic_qos works...
# This will detect if the new qos semantics is in effect,
# and if so make sure the 'apply_global' flag is set on qos updates.
qos_global = not c.connection.qos_semantics_matches_spec
# set initial prefetch count
c.connection.default_channel.basic_qos(
0, c.initial_prefetch_count, qos_global,
)
c.task_consumer = c.app.amqp.TaskConsumer(
c.connection, on_decode_error=c.on_decode_error,
)
def set_prefetch_count(prefetch_count):
return c.task_consumer.qos(
prefetch_count=prefetch_count,
apply_global=qos_global,
)
c.qos = QoS(set_prefetch_count, c.initial_prefetch_count)
def stop(self, c):
"""Stop task consumer."""
if c.task_consumer:
debug('Canceling task consumer...')
ignore_errors(c, c.task_consumer.cancel)
def shutdown(self, c):
"""Shutdown task consumer."""
if c.task_consumer:
self.stop(c)
debug('Closing consumer channel...')
ignore_errors(c, c.task_consumer.close)
c.task_consumer = None
def info(self, c):
"""Return task consumer info."""
return {'prefetch_count': c.qos.value if c.qos else 'N/A'}