/usr/lib/python3/dist-packages/celery/worker/consumer/gossip.py is in python3-celery 4.1.0-2ubuntu1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 | """Worker <-> Worker communication Bootstep."""
from __future__ import absolute_import, unicode_literals
from collections import defaultdict
from functools import partial
from heapq import heappush
from operator import itemgetter
from kombu import Consumer
from kombu.async.semaphore import DummyLock
from celery import bootsteps
from celery.five import values
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(Gossip, self).__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, '%s.%s' % (hostname, pid), topic, action),
)
self.dispatcher.send('worker-elect-ack', id=id_)
def start(self, c):
super(Gossip, self).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 values(workers):
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:
_, event = prepare(message.payload)
self.update_state(event)
else:
self.clock.forward()
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