debian-celery/celery/events/__init__.py

408 lines
14 KiB
Python

# -*- coding: utf-8 -*-
"""
celery.events
~~~~~~~~~~~~~
Events is a stream of messages sent for certain actions occurring
in the worker (and clients if :setting:`CELERY_SEND_TASK_SENT_EVENT`
is enabled), used for monitoring purposes.
"""
from __future__ import absolute_import
import os
import time
import threading
import warnings
from collections import deque
from contextlib import contextmanager
from copy import copy
from operator import itemgetter
from kombu import Exchange, Queue, Producer
from kombu.connection import maybe_channel
from kombu.mixins import ConsumerMixin
from kombu.utils import cached_property
from celery.app import app_or_default
from celery.utils import anon_nodename, uuid
from celery.utils.functional import dictfilter
from celery.utils.timeutils import adjust_timestamp, utcoffset, maybe_s_to_ms
__all__ = ['Events', 'Event', 'EventDispatcher', 'EventReceiver']
event_exchange = Exchange('celeryev', type='topic')
_TZGETTER = itemgetter('utcoffset', 'timestamp')
W_YAJL = """
anyjson is currently using the yajl library.
This json implementation is broken, it severely truncates floats
so timestamps will not work.
Please uninstall yajl or force anyjson to use a different library.
"""
CLIENT_CLOCK_SKEW = -1
def get_exchange(conn):
ex = copy(event_exchange)
if conn.transport.driver_type == 'redis':
# quick hack for Issue #436
ex.type = 'fanout'
return ex
def Event(type, _fields=None, __dict__=dict, __now__=time.time, **fields):
"""Create an event.
An event is a dictionary, the only required field is ``type``.
A ``timestamp`` field will be set to the current time if not provided.
"""
event = __dict__(_fields, **fields) if _fields else fields
if 'timestamp' not in event:
event.update(timestamp=__now__(), type=type)
else:
event['type'] = type
return event
def group_from(type):
"""Get the group part of an event type name.
E.g.::
>>> group_from('task-sent')
'task'
>>> group_from('custom-my-event')
'custom'
"""
return type.split('-', 1)[0]
class EventDispatcher(object):
"""Dispatches event messages.
:param connection: Connection to the broker.
:keyword hostname: Hostname to identify ourselves as,
by default uses the hostname returned by
:func:`~celery.utils.anon_nodename`.
:keyword groups: List of groups to send events for. :meth:`send` will
ignore send requests to groups not in this list.
If this is :const:`None`, all events will be sent. Example groups
include ``"task"`` and ``"worker"``.
:keyword enabled: Set to :const:`False` to not actually publish any events,
making :meth:`send` a noop operation.
:keyword channel: Can be used instead of `connection` to specify
an exact channel to use when sending events.
:keyword buffer_while_offline: If enabled events will be buffered
while the connection is down. :meth:`flush` must be called
as soon as the connection is re-established.
You need to :meth:`close` this after use.
"""
DISABLED_TRANSPORTS = set(['sql'])
app = None
# set of callbacks to be called when :meth:`enabled`.
on_enabled = None
# set of callbacks to be called when :meth:`disabled`.
on_disabled = None
def __init__(self, connection=None, hostname=None, enabled=True,
channel=None, buffer_while_offline=True, app=None,
serializer=None, groups=None):
self.app = app_or_default(app or self.app)
self.connection = connection
self.channel = channel
self.hostname = hostname or anon_nodename()
self.buffer_while_offline = buffer_while_offline
self.mutex = threading.Lock()
self.producer = None
self._outbound_buffer = deque()
self.serializer = serializer or self.app.conf.CELERY_EVENT_SERIALIZER
self.on_enabled = set()
self.on_disabled = set()
self.groups = set(groups or [])
self.tzoffset = [-time.timezone, -time.altzone]
self.clock = self.app.clock
if not connection and channel:
self.connection = channel.connection.client
self.enabled = enabled
conninfo = self.connection or self.app.connection()
self.exchange = get_exchange(conninfo)
if conninfo.transport.driver_type in self.DISABLED_TRANSPORTS:
self.enabled = False
if self.enabled:
self.enable()
self.headers = {'hostname': self.hostname}
self.pid = os.getpid()
self.warn_if_yajl()
def warn_if_yajl(self):
import anyjson
if anyjson.implementation.name == 'yajl':
warnings.warn(UserWarning(W_YAJL))
def __enter__(self):
return self
def __exit__(self, *exc_info):
self.close()
def enable(self):
self.producer = Producer(self.channel or self.connection,
exchange=self.exchange,
serializer=self.serializer)
self.enabled = True
for callback in self.on_enabled:
callback()
def disable(self):
if self.enabled:
self.enabled = False
self.close()
for callback in self.on_disabled:
callback()
def publish(self, type, fields, producer, retry=False,
retry_policy=None, blind=False, utcoffset=utcoffset,
Event=Event):
"""Publish event using a custom :class:`~kombu.Producer`
instance.
:param type: Event type name, with group separated by dash (`-`).
:param fields: Dictionary of event fields, must be json serializable.
:param producer: :class:`~kombu.Producer` instance to use,
only the ``publish`` method will be called.
:keyword retry: Retry in the event of connection failure.
:keyword retry_policy: Dict of custom retry policy, see
:meth:`~kombu.Connection.ensure`.
:keyword blind: Don't set logical clock value (also do not forward
the internal logical clock).
:keyword Event: Event type used to create event,
defaults to :func:`Event`.
:keyword utcoffset: Function returning the current utcoffset in hours.
"""
with self.mutex:
clock = None if blind else self.clock.forward()
event = Event(type, hostname=self.hostname, utcoffset=utcoffset(),
pid=self.pid, clock=clock, **fields)
exchange = self.exchange
producer.publish(
event,
routing_key=type.replace('-', '.'),
exchange=exchange.name,
retry=retry,
retry_policy=retry_policy,
declare=[exchange],
serializer=self.serializer,
headers=self.headers,
)
def send(self, type, blind=False, **fields):
"""Send event.
:param type: Event type name, with group separated by dash (`-`).
:keyword retry: Retry in the event of connection failure.
:keyword retry_policy: Dict of custom retry policy, see
:meth:`~kombu.Connection.ensure`.
:keyword blind: Don't set logical clock value (also do not forward
the internal logical clock).
:keyword Event: Event type used to create event,
defaults to :func:`Event`.
:keyword utcoffset: Function returning the current utcoffset in hours.
:keyword \*\*fields: Event fields, must be json serializable.
"""
if self.enabled:
groups = self.groups
if groups and group_from(type) not in groups:
return
try:
self.publish(type, fields, self.producer, blind)
except Exception as exc:
if not self.buffer_while_offline:
raise
self._outbound_buffer.append((type, fields, exc))
def flush(self):
"""Flushes the outbound buffer."""
while self._outbound_buffer:
try:
type, fields, _ = self._outbound_buffer.popleft()
except IndexError:
return
self.send(type, **fields)
def extend_buffer(self, other):
"""Copies the outbound buffer of another instance."""
self._outbound_buffer.extend(other._outbound_buffer)
def close(self):
"""Close the event dispatcher."""
self.mutex.locked() and self.mutex.release()
self.producer = None
def _get_publisher(self):
return self.producer
def _set_publisher(self, producer):
self.producer = producer
publisher = property(_get_publisher, _set_publisher) # XXX compat
class EventReceiver(ConsumerMixin):
"""Capture events.
:param connection: Connection to the broker.
:keyword handlers: Event handlers.
:attr:`handlers` is a dict of event types and their handlers,
the special handler `"*"` captures all events that doesn't have a
handler.
"""
app = None
def __init__(self, channel, handlers=None, routing_key='#',
node_id=None, app=None, queue_prefix='celeryev',
accept=None):
self.app = app_or_default(app or self.app)
self.channel = maybe_channel(channel)
self.handlers = {} if handlers is None else handlers
self.routing_key = routing_key
self.node_id = node_id or uuid()
self.queue_prefix = queue_prefix
self.exchange = get_exchange(self.connection or self.app.connection())
self.queue = Queue('.'.join([self.queue_prefix, self.node_id]),
exchange=self.exchange,
routing_key=self.routing_key,
auto_delete=True,
durable=False,
queue_arguments=self._get_queue_arguments())
self.clock = self.app.clock
self.adjust_clock = self.clock.adjust
self.forward_clock = self.clock.forward
if accept is None:
accept = set([self.app.conf.CELERY_EVENT_SERIALIZER, 'json'])
self.accept = accept
def _get_queue_arguments(self):
conf = self.app.conf
return dictfilter({
'x-message-ttl': maybe_s_to_ms(conf.CELERY_EVENT_QUEUE_TTL),
'x-expires': maybe_s_to_ms(conf.CELERY_EVENT_QUEUE_EXPIRES),
})
def process(self, type, event):
"""Process the received event by dispatching it to the appropriate
handler."""
handler = self.handlers.get(type) or self.handlers.get('*')
handler and handler(event)
def get_consumers(self, Consumer, channel):
return [Consumer(queues=[self.queue],
callbacks=[self._receive], no_ack=True,
accept=self.accept)]
def on_consume_ready(self, connection, channel, consumers,
wakeup=True, **kwargs):
if wakeup:
self.wakeup_workers(channel=channel)
def itercapture(self, limit=None, timeout=None, wakeup=True):
return self.consume(limit=limit, timeout=timeout, wakeup=wakeup)
def capture(self, limit=None, timeout=None, wakeup=True):
"""Open up a consumer capturing events.
This has to run in the main process, and it will never
stop unless forced via :exc:`KeyboardInterrupt` or :exc:`SystemExit`.
"""
return list(self.consume(limit=limit, timeout=timeout, wakeup=wakeup))
def wakeup_workers(self, channel=None):
self.app.control.broadcast('heartbeat',
connection=self.connection,
channel=channel)
def event_from_message(self, body, localize=True,
now=time.time, tzfields=_TZGETTER,
adjust_timestamp=adjust_timestamp,
CLIENT_CLOCK_SKEW=CLIENT_CLOCK_SKEW):
type = body['type']
if type == 'task-sent':
# clients never sync so cannot use their clock value
_c = body['clock'] = (self.clock.value or 1) + CLIENT_CLOCK_SKEW
self.adjust_clock(_c)
else:
try:
clock = body['clock']
except KeyError:
body['clock'] = self.forward_clock()
else:
self.adjust_clock(clock)
if localize:
try:
offset, timestamp = tzfields(body)
except KeyError:
pass
else:
body['timestamp'] = adjust_timestamp(timestamp, offset)
body['local_received'] = now()
return type, body
def _receive(self, body, message):
self.process(*self.event_from_message(body))
@property
def connection(self):
return self.channel.connection.client if self.channel else None
class Events(object):
def __init__(self, app=None):
self.app = app
@cached_property
def Receiver(self):
return self.app.subclass_with_self(EventReceiver,
reverse='events.Receiver')
@cached_property
def Dispatcher(self):
return self.app.subclass_with_self(EventDispatcher,
reverse='events.Dispatcher')
@cached_property
def State(self):
return self.app.subclass_with_self('celery.events.state:State',
reverse='events.State')
@contextmanager
def default_dispatcher(self, hostname=None, enabled=True,
buffer_while_offline=False):
with self.app.amqp.producer_pool.acquire(block=True) as prod:
with self.Dispatcher(prod.connection, hostname, enabled,
prod.channel, buffer_while_offline) as d:
yield d