904 lines
31 KiB
Python
904 lines
31 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 OpenStack LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import inspect
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import itertools
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import sys
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import time
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import traceback
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import uuid
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import eventlet
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from eventlet import greenpool
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from eventlet import pools
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import greenlet
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import kombu
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import kombu.entity
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import kombu.messaging
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import kombu.connection
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from nova import context
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from nova import exception
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from nova import flags
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from nova import local
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from nova.rpc import common as rpc_common
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FLAGS = flags.FLAGS
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LOG = rpc_common.LOG
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class ConsumerBase(object):
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"""Consumer base class."""
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def __init__(self, channel, callback, tag, **kwargs):
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"""Declare a queue on an amqp channel.
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'channel' is the amqp channel to use
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'callback' is the callback to call when messages are received
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'tag' is a unique ID for the consumer on the channel
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queue name, exchange name, and other kombu options are
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passed in here as a dictionary.
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"""
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self.callback = callback
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self.tag = str(tag)
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self.kwargs = kwargs
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self.queue = None
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self.reconnect(channel)
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def reconnect(self, channel):
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"""Re-declare the queue after a rabbit reconnect"""
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self.channel = channel
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self.kwargs['channel'] = channel
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self.queue = kombu.entity.Queue(**self.kwargs)
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self.queue.declare()
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def consume(self, *args, **kwargs):
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"""Actually declare the consumer on the amqp channel. This will
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start the flow of messages from the queue. Using the
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Connection.iterconsume() iterator will process the messages,
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calling the appropriate callback.
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If a callback is specified in kwargs, use that. Otherwise,
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use the callback passed during __init__()
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If kwargs['nowait'] is True, then this call will block until
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a message is read.
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Messages will automatically be acked if the callback doesn't
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raise an exception
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"""
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options = {'consumer_tag': self.tag}
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options['nowait'] = kwargs.get('nowait', False)
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callback = kwargs.get('callback', self.callback)
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if not callback:
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raise ValueError("No callback defined")
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def _callback(raw_message):
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message = self.channel.message_to_python(raw_message)
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callback(message.payload)
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message.ack()
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self.queue.consume(*args, callback=_callback, **options)
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def cancel(self):
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"""Cancel the consuming from the queue, if it has started"""
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try:
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self.queue.cancel(self.tag)
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except KeyError, e:
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# NOTE(comstud): Kludge to get around a amqplib bug
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if str(e) != "u'%s'" % self.tag:
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raise
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self.queue = None
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class DirectConsumer(ConsumerBase):
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"""Queue/consumer class for 'direct'"""
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def __init__(self, channel, msg_id, callback, tag, **kwargs):
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"""Init a 'direct' queue.
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'channel' is the amqp channel to use
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'msg_id' is the msg_id to listen on
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'callback' is the callback to call when messages are received
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'tag' is a unique ID for the consumer on the channel
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Other kombu options may be passed
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"""
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# Default options
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options = {'durable': False,
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'auto_delete': True,
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'exclusive': True}
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options.update(kwargs)
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exchange = kombu.entity.Exchange(
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name=msg_id,
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type='direct',
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durable=options['durable'],
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auto_delete=options['auto_delete'])
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super(DirectConsumer, self).__init__(
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channel,
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callback,
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tag,
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name=msg_id,
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exchange=exchange,
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routing_key=msg_id,
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**options)
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class TopicConsumer(ConsumerBase):
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"""Consumer class for 'topic'"""
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def __init__(self, channel, topic, callback, tag, **kwargs):
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"""Init a 'topic' queue.
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'channel' is the amqp channel to use
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'topic' is the topic to listen on
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'callback' is the callback to call when messages are received
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'tag' is a unique ID for the consumer on the channel
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Other kombu options may be passed
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"""
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# Default options
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options = {'durable': FLAGS.rabbit_durable_queues,
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'auto_delete': False,
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'exclusive': False}
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options.update(kwargs)
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exchange = kombu.entity.Exchange(
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name=FLAGS.control_exchange,
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type='topic',
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durable=options['durable'],
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auto_delete=options['auto_delete'])
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super(TopicConsumer, self).__init__(
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channel,
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callback,
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tag,
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name=topic,
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exchange=exchange,
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routing_key=topic,
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**options)
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class FanoutConsumer(ConsumerBase):
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"""Consumer class for 'fanout'"""
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def __init__(self, channel, topic, callback, tag, **kwargs):
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"""Init a 'fanout' queue.
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'channel' is the amqp channel to use
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'topic' is the topic to listen on
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'callback' is the callback to call when messages are received
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'tag' is a unique ID for the consumer on the channel
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Other kombu options may be passed
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"""
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unique = uuid.uuid4().hex
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exchange_name = '%s_fanout' % topic
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queue_name = '%s_fanout_%s' % (topic, unique)
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# Default options
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options = {'durable': False,
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'auto_delete': True,
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'exclusive': True}
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options.update(kwargs)
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exchange = kombu.entity.Exchange(
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name=exchange_name,
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type='fanout',
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durable=options['durable'],
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auto_delete=options['auto_delete'])
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super(FanoutConsumer, self).__init__(
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channel,
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callback,
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tag,
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name=queue_name,
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exchange=exchange,
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routing_key=topic,
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**options)
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class Publisher(object):
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"""Base Publisher class"""
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def __init__(self, channel, exchange_name, routing_key, **kwargs):
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"""Init the Publisher class with the exchange_name, routing_key,
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and other options
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"""
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self.exchange_name = exchange_name
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self.routing_key = routing_key
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self.kwargs = kwargs
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self.reconnect(channel)
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def reconnect(self, channel):
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"""Re-establish the Producer after a rabbit reconnection"""
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self.exchange = kombu.entity.Exchange(name=self.exchange_name,
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**self.kwargs)
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self.producer = kombu.messaging.Producer(exchange=self.exchange,
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channel=channel, routing_key=self.routing_key)
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def send(self, msg):
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"""Send a message"""
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self.producer.publish(msg)
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class DirectPublisher(Publisher):
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"""Publisher class for 'direct'"""
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def __init__(self, channel, msg_id, **kwargs):
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"""init a 'direct' publisher.
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Kombu options may be passed as keyword args to override defaults
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"""
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options = {'durable': False,
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'auto_delete': True,
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'exclusive': True}
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options.update(kwargs)
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super(DirectPublisher, self).__init__(channel,
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msg_id,
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msg_id,
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type='direct',
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**options)
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class TopicPublisher(Publisher):
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"""Publisher class for 'topic'"""
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def __init__(self, channel, topic, **kwargs):
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"""init a 'topic' publisher.
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Kombu options may be passed as keyword args to override defaults
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"""
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options = {'durable': FLAGS.rabbit_durable_queues,
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'auto_delete': False,
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'exclusive': False}
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options.update(kwargs)
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super(TopicPublisher, self).__init__(channel,
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FLAGS.control_exchange,
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topic,
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type='topic',
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**options)
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class FanoutPublisher(Publisher):
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"""Publisher class for 'fanout'"""
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def __init__(self, channel, topic, **kwargs):
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"""init a 'fanout' publisher.
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Kombu options may be passed as keyword args to override defaults
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"""
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options = {'durable': False,
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'auto_delete': True,
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'exclusive': True}
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options.update(kwargs)
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super(FanoutPublisher, self).__init__(channel,
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'%s_fanout' % topic,
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None,
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type='fanout',
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**options)
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class NotifyPublisher(TopicPublisher):
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"""Publisher class for 'notify'"""
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def __init__(self, *args, **kwargs):
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self.durable = kwargs.pop('durable', FLAGS.rabbit_durable_queues)
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super(NotifyPublisher, self).__init__(*args, **kwargs)
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def reconnect(self, channel):
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super(NotifyPublisher, self).reconnect(channel)
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# NOTE(jerdfelt): Normally the consumer would create the queue, but
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# we do this to ensure that messages don't get dropped if the
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# consumer is started after we do
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queue = kombu.entity.Queue(channel=channel,
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exchange=self.exchange,
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durable=self.durable,
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name=self.routing_key,
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routing_key=self.routing_key)
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queue.declare()
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class Connection(object):
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"""Connection object."""
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def __init__(self):
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self.consumers = []
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self.consumer_thread = None
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self.max_retries = FLAGS.rabbit_max_retries
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# Try forever?
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if self.max_retries <= 0:
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self.max_retries = None
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self.interval_start = FLAGS.rabbit_retry_interval
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self.interval_stepping = FLAGS.rabbit_retry_backoff
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# max retry-interval = 30 seconds
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self.interval_max = 30
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self.memory_transport = False
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self.params = dict(hostname=FLAGS.rabbit_host,
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port=FLAGS.rabbit_port,
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userid=FLAGS.rabbit_userid,
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password=FLAGS.rabbit_password,
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virtual_host=FLAGS.rabbit_virtual_host)
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if FLAGS.fake_rabbit:
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self.params['transport'] = 'memory'
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self.memory_transport = True
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else:
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self.memory_transport = False
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self.connection = None
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self.reconnect()
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def _connect(self):
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"""Connect to rabbit. Re-establish any queues that may have
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been declared before if we are reconnecting. Exceptions should
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be handled by the caller.
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"""
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if self.connection:
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LOG.info(_("Reconnecting to AMQP server on "
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"%(hostname)s:%(port)d") % self.params)
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try:
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self.connection.close()
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except self.connection_errors:
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pass
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# Setting this in case the next statement fails, though
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# it shouldn't be doing any network operations, yet.
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self.connection = None
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self.connection = kombu.connection.BrokerConnection(
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**self.params)
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self.connection_errors = self.connection.connection_errors
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if self.memory_transport:
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# Kludge to speed up tests.
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self.connection.transport.polling_interval = 0.0
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self.consumer_num = itertools.count(1)
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self.connection.connect()
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self.channel = self.connection.channel()
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# work around 'memory' transport bug in 1.1.3
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if self.memory_transport:
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self.channel._new_queue('ae.undeliver')
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for consumer in self.consumers:
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consumer.reconnect(self.channel)
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LOG.info(_('Connected to AMQP server on '
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'%(hostname)s:%(port)d' % self.params))
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def reconnect(self):
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"""Handles reconnecting and re-establishing queues.
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Will retry up to self.max_retries number of times.
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self.max_retries = 0 means to retry forever.
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Sleep between tries, starting at self.rabbit_retry_interval
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seconds, backing off self.rabbit_retry_backoff number of seconds
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each attempt.
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"""
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attempt = 0
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while True:
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attempt += 1
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try:
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self._connect()
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return
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except self.connection_errors, e:
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pass
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except Exception, e:
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# NOTE(comstud): Unfortunately it's possible for amqplib
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# to return an error not covered by its transport
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# connection_errors in the case of a timeout waiting for
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# a protocol response. (See paste link in LP888621)
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# So, we check all exceptions for 'timeout' in them
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# and try to reconnect in this case.
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if 'timeout' not in str(e):
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raise
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log_info = {}
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log_info['err_str'] = str(e)
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log_info['max_retries'] = self.max_retries
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log_info.update(self.params)
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if self.max_retries and attempt == self.max_retries:
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LOG.exception(_('Unable to connect to AMQP server on '
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'%(hostname)s:%(port)d after %(max_retries)d '
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'tries: %(err_str)s') % log_info)
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# NOTE(comstud): Copied from original code. There's
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# really no better recourse because if this was a queue we
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# need to consume on, we have no way to consume anymore.
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sys.exit(1)
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if attempt == 1:
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sleep_time = self.rabbit_retry_interval or 1
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elif attempt > 1:
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sleep_time += self.rabbit_retry_backoff
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if self.interval_max:
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sleep_time = min(sleep_time, self.interval_max)
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log_info['sleep_time'] = sleep_time
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LOG.exception(_('AMQP server on %(hostname)s:%(port)d is'
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' unreachable: %(err_str)s. Trying again in '
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'%(sleep_time)d seconds.') % log_info)
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time.sleep(sleep_time)
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def ensure(self, error_callback, method, *args, **kwargs):
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while True:
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try:
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return method(*args, **kwargs)
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except self.connection_errors, e:
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pass
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except Exception, e:
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# NOTE(comstud): Unfortunately it's possible for amqplib
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# to return an error not covered by its transport
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# connection_errors in the case of a timeout waiting for
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# a protocol response. (See paste link in LP888621)
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# So, we check all exceptions for 'timeout' in them
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# and try to reconnect in this case.
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if 'timeout' not in str(e):
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raise
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if error_callback:
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error_callback(e)
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self.reconnect()
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def get_channel(self):
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"""Convenience call for bin/clear_rabbit_queues"""
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return self.channel
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def close(self):
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"""Close/release this connection"""
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self.cancel_consumer_thread()
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self.connection.release()
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self.connection = None
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def reset(self):
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"""Reset a connection so it can be used again"""
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self.cancel_consumer_thread()
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self.channel.close()
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self.channel = self.connection.channel()
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# work around 'memory' transport bug in 1.1.3
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if self.memory_transport:
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self.channel._new_queue('ae.undeliver')
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self.consumers = []
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def declare_consumer(self, consumer_cls, topic, callback):
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"""Create a Consumer using the class that was passed in and
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add it to our list of consumers
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"""
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def _connect_error(exc):
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log_info = {'topic': topic, 'err_str': str(exc)}
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LOG.error(_("Failed to declare consumer for topic '%(topic)s': "
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"%(err_str)s") % log_info)
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def _declare_consumer():
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consumer = consumer_cls(self.channel, topic, callback,
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self.consumer_num.next())
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self.consumers.append(consumer)
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return consumer
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return self.ensure(_connect_error, _declare_consumer)
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def iterconsume(self, limit=None):
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"""Return an iterator that will consume from all queues/consumers"""
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info = {'do_consume': True}
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def _error_callback(exc):
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LOG.exception(_('Failed to consume message from queue: %s') %
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str(exc))
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info['do_consume'] = True
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def _consume():
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if info['do_consume']:
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queues_head = self.consumers[:-1]
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queues_tail = self.consumers[-1]
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for queue in queues_head:
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queue.consume(nowait=True)
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queues_tail.consume(nowait=False)
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info['do_consume'] = False
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return self.connection.drain_events()
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for iteration in itertools.count(0):
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if limit and iteration >= limit:
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raise StopIteration
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yield self.ensure(_error_callback, _consume)
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def cancel_consumer_thread(self):
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"""Cancel a consumer thread"""
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if self.consumer_thread is not None:
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self.consumer_thread.kill()
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try:
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self.consumer_thread.wait()
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except greenlet.GreenletExit:
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pass
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self.consumer_thread = None
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def publisher_send(self, cls, topic, msg, **kwargs):
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"""Send to a publisher based on the publisher class"""
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def _error_callback(exc):
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log_info = {'topic': topic, 'err_str': str(exc)}
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LOG.exception(_("Failed to publish message to topic "
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"'%(topic)s': %(err_str)s") % log_info)
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def _publish():
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publisher = cls(self.channel, topic, **kwargs)
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publisher.send(msg)
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self.ensure(_error_callback, _publish)
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def declare_direct_consumer(self, topic, callback):
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"""Create a 'direct' queue.
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In nova's use, this is generally a msg_id queue used for
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responses for call/multicall
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"""
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self.declare_consumer(DirectConsumer, topic, callback)
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|
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def declare_topic_consumer(self, topic, callback=None):
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"""Create a 'topic' consumer."""
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self.declare_consumer(TopicConsumer, topic, callback)
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def declare_fanout_consumer(self, topic, callback):
|
|
"""Create a 'fanout' consumer"""
|
|
self.declare_consumer(FanoutConsumer, topic, callback)
|
|
|
|
def direct_send(self, msg_id, msg):
|
|
"""Send a 'direct' message"""
|
|
self.publisher_send(DirectPublisher, msg_id, msg)
|
|
|
|
def topic_send(self, topic, msg):
|
|
"""Send a 'topic' message"""
|
|
self.publisher_send(TopicPublisher, topic, msg)
|
|
|
|
def fanout_send(self, topic, msg):
|
|
"""Send a 'fanout' message"""
|
|
self.publisher_send(FanoutPublisher, topic, msg)
|
|
|
|
def notify_send(self, topic, msg, **kwargs):
|
|
"""Send a notify message on a topic"""
|
|
self.publisher_send(NotifyPublisher, topic, msg, **kwargs)
|
|
|
|
def consume(self, limit=None):
|
|
"""Consume from all queues/consumers"""
|
|
it = self.iterconsume(limit=limit)
|
|
while True:
|
|
try:
|
|
it.next()
|
|
except StopIteration:
|
|
return
|
|
|
|
def consume_in_thread(self):
|
|
"""Consumer from all queues/consumers in a greenthread"""
|
|
def _consumer_thread():
|
|
try:
|
|
self.consume()
|
|
except greenlet.GreenletExit:
|
|
return
|
|
if self.consumer_thread is None:
|
|
self.consumer_thread = eventlet.spawn(_consumer_thread)
|
|
return self.consumer_thread
|
|
|
|
def create_consumer(self, topic, proxy, fanout=False):
|
|
"""Create a consumer that calls a method in a proxy object"""
|
|
if fanout:
|
|
self.declare_fanout_consumer(topic, ProxyCallback(proxy))
|
|
else:
|
|
self.declare_topic_consumer(topic, ProxyCallback(proxy))
|
|
|
|
|
|
class Pool(pools.Pool):
|
|
"""Class that implements a Pool of Connections."""
|
|
|
|
# TODO(comstud): Timeout connections not used in a while
|
|
def create(self):
|
|
LOG.debug('Pool creating new connection')
|
|
return Connection()
|
|
|
|
# Create a ConnectionPool to use for RPC calls. We'll order the
|
|
# pool as a stack (LIFO), so that we can potentially loop through and
|
|
# timeout old unused connections at some point
|
|
ConnectionPool = Pool(
|
|
max_size=FLAGS.rpc_conn_pool_size,
|
|
order_as_stack=True)
|
|
|
|
|
|
class ConnectionContext(rpc_common.Connection):
|
|
"""The class that is actually returned to the caller of
|
|
create_connection(). This is a essentially a wrapper around
|
|
Connection that supports 'with' and can return a new Connection or
|
|
one from a pool. It will also catch when an instance of this class
|
|
is to be deleted so that we can return Connections to the pool on
|
|
exceptions and so forth without making the caller be responsible for
|
|
catching all exceptions and making sure to return a connection to
|
|
the pool.
|
|
"""
|
|
|
|
def __init__(self, pooled=True):
|
|
"""Create a new connection, or get one from the pool"""
|
|
self.connection = None
|
|
if pooled:
|
|
self.connection = ConnectionPool.get()
|
|
else:
|
|
self.connection = Connection()
|
|
self.pooled = pooled
|
|
|
|
def __enter__(self):
|
|
"""with ConnectionContext() should return self"""
|
|
return self
|
|
|
|
def _done(self):
|
|
"""If the connection came from a pool, clean it up and put it back.
|
|
If it did not come from a pool, close it.
|
|
"""
|
|
if self.connection:
|
|
if self.pooled:
|
|
# Reset the connection so it's ready for the next caller
|
|
# to grab from the pool
|
|
self.connection.reset()
|
|
ConnectionPool.put(self.connection)
|
|
else:
|
|
try:
|
|
self.connection.close()
|
|
except Exception:
|
|
# There's apparently a bug in kombu 'memory' transport
|
|
# which causes an assert failure.
|
|
# But, we probably want to ignore all exceptions when
|
|
# trying to close a connection, anyway...
|
|
pass
|
|
self.connection = None
|
|
|
|
def __exit__(self, t, v, tb):
|
|
"""end of 'with' statement. We're done here."""
|
|
self._done()
|
|
|
|
def __del__(self):
|
|
"""Caller is done with this connection. Make sure we cleaned up."""
|
|
self._done()
|
|
|
|
def close(self):
|
|
"""Caller is done with this connection."""
|
|
self._done()
|
|
|
|
def create_consumer(self, topic, proxy, fanout=False):
|
|
self.connection.create_consumer(topic, proxy, fanout)
|
|
|
|
def consume_in_thread(self):
|
|
self.connection.consume_in_thread()
|
|
|
|
def __getattr__(self, key):
|
|
"""Proxy all other calls to the Connection instance"""
|
|
if self.connection:
|
|
return getattr(self.connection, key)
|
|
else:
|
|
raise exception.InvalidRPCConnectionReuse()
|
|
|
|
|
|
class ProxyCallback(object):
|
|
"""Calls methods on a proxy object based on method and args."""
|
|
|
|
def __init__(self, proxy):
|
|
self.proxy = proxy
|
|
self.pool = greenpool.GreenPool(FLAGS.rpc_thread_pool_size)
|
|
|
|
def __call__(self, message_data):
|
|
"""Consumer callback to call a method on a proxy object.
|
|
|
|
Parses the message for validity and fires off a thread to call the
|
|
proxy object method.
|
|
|
|
Message data should be a dictionary with two keys:
|
|
method: string representing the method to call
|
|
args: dictionary of arg: value
|
|
|
|
Example: {'method': 'echo', 'args': {'value': 42}}
|
|
|
|
"""
|
|
# It is important to clear the context here, because at this point
|
|
# the previous context is stored in local.store.context
|
|
if hasattr(local.store, 'context'):
|
|
del local.store.context
|
|
LOG.debug(_('received %s') % message_data)
|
|
ctxt = _unpack_context(message_data)
|
|
method = message_data.get('method')
|
|
args = message_data.get('args', {})
|
|
if not method:
|
|
LOG.warn(_('no method for message: %s') % message_data)
|
|
ctxt.reply(_('No method for message: %s') % message_data)
|
|
return
|
|
self.pool.spawn_n(self._process_data, ctxt, method, args)
|
|
|
|
@exception.wrap_exception()
|
|
def _process_data(self, ctxt, method, args):
|
|
"""Thread that magically looks for a method on the proxy
|
|
object and calls it.
|
|
"""
|
|
|
|
try:
|
|
node_func = getattr(self.proxy, str(method))
|
|
node_args = dict((str(k), v) for k, v in args.iteritems())
|
|
# NOTE(vish): magic is fun!
|
|
rval = node_func(context=ctxt, **node_args)
|
|
# Check if the result was a generator
|
|
if inspect.isgenerator(rval):
|
|
for x in rval:
|
|
ctxt.reply(x, None)
|
|
else:
|
|
ctxt.reply(rval, None)
|
|
# This final None tells multicall that it is done.
|
|
ctxt.reply(ending=True)
|
|
except Exception as e:
|
|
LOG.exception('Exception during message handling')
|
|
ctxt.reply(None, sys.exc_info())
|
|
return
|
|
|
|
|
|
def _unpack_context(msg):
|
|
"""Unpack context from msg."""
|
|
context_dict = {}
|
|
for key in list(msg.keys()):
|
|
# NOTE(vish): Some versions of python don't like unicode keys
|
|
# in kwargs.
|
|
key = str(key)
|
|
if key.startswith('_context_'):
|
|
value = msg.pop(key)
|
|
context_dict[key[9:]] = value
|
|
context_dict['msg_id'] = msg.pop('_msg_id', None)
|
|
ctx = RpcContext.from_dict(context_dict)
|
|
LOG.debug(_('unpacked context: %s'), ctx.to_dict())
|
|
return ctx
|
|
|
|
|
|
def _pack_context(msg, context):
|
|
"""Pack context into msg.
|
|
|
|
Values for message keys need to be less than 255 chars, so we pull
|
|
context out into a bunch of separate keys. If we want to support
|
|
more arguments in rabbit messages, we may want to do the same
|
|
for args at some point.
|
|
|
|
"""
|
|
context_d = dict([('_context_%s' % key, value)
|
|
for (key, value) in context.to_dict().iteritems()])
|
|
msg.update(context_d)
|
|
|
|
|
|
class RpcContext(context.RequestContext):
|
|
"""Context that supports replying to a rpc.call"""
|
|
def __init__(self, *args, **kwargs):
|
|
msg_id = kwargs.pop('msg_id', None)
|
|
self.msg_id = msg_id
|
|
super(RpcContext, self).__init__(*args, **kwargs)
|
|
|
|
def reply(self, reply=None, failure=None, ending=False):
|
|
if self.msg_id:
|
|
msg_reply(self.msg_id, reply, failure, ending)
|
|
if ending:
|
|
self.msg_id = None
|
|
|
|
|
|
class MulticallWaiter(object):
|
|
def __init__(self, connection):
|
|
self._connection = connection
|
|
self._iterator = connection.iterconsume()
|
|
self._result = None
|
|
self._done = False
|
|
self._got_ending = False
|
|
|
|
def done(self):
|
|
if self._done:
|
|
return
|
|
self._done = True
|
|
self._iterator.close()
|
|
self._iterator = None
|
|
self._connection.close()
|
|
|
|
def __call__(self, data):
|
|
"""The consume() callback will call this. Store the result."""
|
|
if data['failure']:
|
|
self._result = rpc_common.RemoteError(*data['failure'])
|
|
elif data.get('ending', False):
|
|
self._got_ending = True
|
|
else:
|
|
self._result = data['result']
|
|
|
|
def __iter__(self):
|
|
"""Return a result until we get a 'None' response from consumer"""
|
|
if self._done:
|
|
raise StopIteration
|
|
while True:
|
|
self._iterator.next()
|
|
if self._got_ending:
|
|
self.done()
|
|
raise StopIteration
|
|
result = self._result
|
|
if isinstance(result, Exception):
|
|
self.done()
|
|
raise result
|
|
yield result
|
|
|
|
|
|
def create_connection(new=True):
|
|
"""Create a connection"""
|
|
return ConnectionContext(pooled=not new)
|
|
|
|
|
|
def multicall(context, topic, msg):
|
|
"""Make a call that returns multiple times."""
|
|
# Can't use 'with' for multicall, as it returns an iterator
|
|
# that will continue to use the connection. When it's done,
|
|
# connection.close() will get called which will put it back into
|
|
# the pool
|
|
LOG.debug(_('Making asynchronous call on %s ...'), topic)
|
|
msg_id = uuid.uuid4().hex
|
|
msg.update({'_msg_id': msg_id})
|
|
LOG.debug(_('MSG_ID is %s') % (msg_id))
|
|
_pack_context(msg, context)
|
|
|
|
conn = ConnectionContext()
|
|
wait_msg = MulticallWaiter(conn)
|
|
conn.declare_direct_consumer(msg_id, wait_msg)
|
|
conn.topic_send(topic, msg)
|
|
return wait_msg
|
|
|
|
|
|
def call(context, topic, msg):
|
|
"""Sends a message on a topic and wait for a response."""
|
|
rv = multicall(context, topic, msg)
|
|
# NOTE(vish): return the last result from the multicall
|
|
rv = list(rv)
|
|
if not rv:
|
|
return
|
|
return rv[-1]
|
|
|
|
|
|
def cast(context, topic, msg):
|
|
"""Sends a message on a topic without waiting for a response."""
|
|
LOG.debug(_('Making asynchronous cast on %s...'), topic)
|
|
_pack_context(msg, context)
|
|
with ConnectionContext() as conn:
|
|
conn.topic_send(topic, msg)
|
|
|
|
|
|
def fanout_cast(context, topic, msg):
|
|
"""Sends a message on a fanout exchange without waiting for a response."""
|
|
LOG.debug(_('Making asynchronous fanout cast...'))
|
|
_pack_context(msg, context)
|
|
with ConnectionContext() as conn:
|
|
conn.fanout_send(topic, msg)
|
|
|
|
|
|
def notify(context, topic, msg):
|
|
"""Sends a notification event on a topic."""
|
|
LOG.debug(_('Sending notification on %s...'), topic)
|
|
_pack_context(msg, context)
|
|
with ConnectionContext() as conn:
|
|
conn.notify_send(topic, msg, durable=True)
|
|
|
|
|
|
def msg_reply(msg_id, reply=None, failure=None, ending=False):
|
|
"""Sends a reply or an error on the channel signified by msg_id.
|
|
|
|
Failure should be a sys.exc_info() tuple.
|
|
|
|
"""
|
|
with ConnectionContext() as conn:
|
|
if failure:
|
|
message = str(failure[1])
|
|
tb = traceback.format_exception(*failure)
|
|
LOG.error(_("Returning exception %s to caller"), message)
|
|
LOG.error(tb)
|
|
failure = (failure[0].__name__, str(failure[1]), tb)
|
|
|
|
try:
|
|
msg = {'result': reply, 'failure': failure}
|
|
except TypeError:
|
|
msg = {'result': dict((k, repr(v))
|
|
for k, v in reply.__dict__.iteritems()),
|
|
'failure': failure}
|
|
if ending:
|
|
msg['ending'] = True
|
|
conn.direct_send(msg_id, msg)
|