507 lines
17 KiB
Python
507 lines
17 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 OpenStack LLC
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# Copyright 2011 - 2012, Red Hat, Inc.
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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 itertools
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import time
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import uuid
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import json
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import logging
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import eventlet
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import greenlet
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import qpid.messaging
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import qpid.messaging.exceptions
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from heat.common import config
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from heat.openstack.common import cfg
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from heat.rpc import amqp as rpc_amqp
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from heat.rpc import common as rpc_common
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LOG = logging.getLogger(__name__)
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class ConsumerBase(object):
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"""Consumer base class."""
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def __init__(self, session, callback, node_name, node_opts,
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link_name, link_opts):
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"""Declare a queue on an amqp session.
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'session' is the amqp session to use
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'callback' is the callback to call when messages are received
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'node_name' is the first part of the Qpid address string, before ';'
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'node_opts' will be applied to the "x-declare" section of "node"
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in the address string.
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'link_name' goes into the "name" field of the "link" in the address
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string
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'link_opts' will be applied to the "x-declare" section of "link"
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in the address string.
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"""
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self.callback = callback
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self.receiver = None
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self.session = None
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addr_opts = {
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"create": "always",
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"node": {
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"type": "topic",
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"x-declare": {
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"durable": True,
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"auto-delete": True,
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},
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},
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"link": {
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"name": link_name,
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"durable": True,
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"x-declare": {
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"durable": False,
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"auto-delete": True,
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"exclusive": False,
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},
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},
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}
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addr_opts["node"]["x-declare"].update(node_opts)
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addr_opts["link"]["x-declare"].update(link_opts)
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self.address = "%s ; %s" % (node_name, json.dumps(addr_opts))
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self.reconnect(session)
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def reconnect(self, session):
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"""Re-declare the receiver after a qpid reconnect"""
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self.session = session
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self.receiver = session.receiver(self.address)
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self.receiver.capacity = 1
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def consume(self):
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"""Fetch the message and pass it to the callback object"""
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message = self.receiver.fetch()
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self.callback(message.content)
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def get_receiver(self):
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return self.receiver
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class DirectConsumer(ConsumerBase):
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"""Queue/consumer class for 'direct'"""
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def __init__(self, session, msg_id, callback):
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"""Init a 'direct' queue.
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'session' is the amqp session 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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"""
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super(DirectConsumer, self).__init__(session, callback,
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"%s/%s" % (msg_id, msg_id),
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{"type": "direct"},
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msg_id,
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{"exclusive": True})
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class TopicConsumer(ConsumerBase):
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"""Consumer class for 'topic'"""
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def __init__(self, session, topic, callback):
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"""Init a 'topic' queue.
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'session' is the amqp session 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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"""
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super(TopicConsumer, self).__init__(session, callback,
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"%s/%s" % (config.FLAGS.control_exchange, topic), {},
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topic, {})
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class FanoutConsumer(ConsumerBase):
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"""Consumer class for 'fanout'"""
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def __init__(self, session, topic, callback):
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"""Init a 'fanout' queue.
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'session' is the amqp session 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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"""
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super(FanoutConsumer, self).__init__(session, callback,
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"%s_fanout" % topic,
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{"durable": False, "type": "fanout"},
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"%s_fanout_%s" % (topic, uuid.uuid4().hex),
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{"exclusive": True})
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class Publisher(object):
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"""Base Publisher class"""
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def __init__(self, session, node_name, node_opts=None):
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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.sender = None
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self.session = session
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addr_opts = {
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"create": "always",
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"node": {
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"type": "topic",
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"x-declare": {
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"durable": False,
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# auto-delete isn't implemented for exchanges in qpid,
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# but put in here anyway
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"auto-delete": True,
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},
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},
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}
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if node_opts:
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addr_opts["node"]["x-declare"].update(node_opts)
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self.address = "%s ; %s" % (node_name, json.dumps(addr_opts))
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self.reconnect(session)
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def reconnect(self, session):
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"""Re-establish the Sender after a reconnection"""
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self.sender = session.sender(self.address)
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def send(self, msg):
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"""Send a message"""
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self.sender.send(msg)
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class DirectPublisher(Publisher):
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"""Publisher class for 'direct'"""
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def __init__(self, session, msg_id):
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"""Init a 'direct' publisher."""
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super(DirectPublisher, self).__init__(session, msg_id,
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{"type": "Direct"})
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class TopicPublisher(Publisher):
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"""Publisher class for 'topic'"""
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def __init__(self, session, topic):
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"""init a 'topic' publisher.
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"""
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super(TopicPublisher, self).__init__(session,
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"%s/%s" % (config.FLAGS.control_exchange, topic))
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class FanoutPublisher(Publisher):
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"""Publisher class for 'fanout'"""
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def __init__(self, session, topic):
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"""init a 'fanout' publisher.
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"""
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super(FanoutPublisher, self).__init__(session,
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"%s_fanout" % topic, {"type": "fanout"})
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class NotifyPublisher(Publisher):
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"""Publisher class for notifications"""
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def __init__(self, session, topic):
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"""init a 'topic' publisher.
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"""
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super(NotifyPublisher, self).__init__(session,
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"%s/%s" % (config.FLAGS.control_exchange, topic),
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{"durable": True})
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class Connection(object):
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"""Connection object."""
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def __init__(self, server_params=None):
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self.session = None
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self.consumers = {}
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self.consumer_thread = None
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if server_params is None:
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server_params = {}
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default_params = dict(hostname=config.FLAGS.qpid_hostname,
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port=config.FLAGS.qpid_port,
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username=config.FLAGS.qpid_username,
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password=config.FLAGS.qpid_password)
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params = server_params
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for key in default_params.keys():
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params.setdefault(key, default_params[key])
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self.broker = params['hostname'] + ":" + str(params['port'])
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# Create the connection - this does not open the connection
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self.connection = qpid.messaging.Connection(self.broker)
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# Check if flags are set and if so set them for the connection
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# before we call open
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self.connection.username = params['username']
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self.connection.password = params['password']
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self.connection.sasl_mechanisms = config.FLAGS.qpid_sasl_mechanisms
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self.connection.reconnect = config.FLAGS.qpid_reconnect
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if config.FLAGS.qpid_reconnect_timeout:
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self.connection.reconnect_timeout = \
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config.FLAGS.qpid_reconnect_timeout
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if config.FLAGS.qpid_reconnect_limit:
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self.connection.reconnect_limit = config.FLAGS.qpid_reconnect_limit
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if config.FLAGS.qpid_reconnect_interval_max:
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self.connection.reconnect_interval_max = (
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config.FLAGS.qpid_reconnect_interval_max)
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if config.FLAGS.qpid_reconnect_interval_min:
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self.connection.reconnect_interval_min = (
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config.FLAGS.qpid_reconnect_interval_min)
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if config.FLAGS.qpid_reconnect_interval:
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self.connection.reconnect_interval = \
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config.FLAGS.qpid_reconnect_interval
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self.connection.hearbeat = config.FLAGS.qpid_heartbeat
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self.connection.protocol = config.FLAGS.qpid_protocol
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self.connection.tcp_nodelay = config.FLAGS.qpid_tcp_nodelay
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# Open is part of reconnect -
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# NOTE(WGH) not sure we need this with the reconnect flags
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self.reconnect()
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def _register_consumer(self, consumer):
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self.consumers[str(consumer.get_receiver())] = consumer
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def _lookup_consumer(self, receiver):
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return self.consumers[str(receiver)]
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def reconnect(self):
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"""Handles reconnecting and re-establishing sessions and queues"""
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if self.connection.opened():
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try:
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self.connection.close()
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except qpid.messaging.exceptions.ConnectionError:
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pass
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while True:
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try:
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self.connection.open()
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except qpid.messaging.exceptions.ConnectionError, e:
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LOG.error(_('Unable to connect to AMQP server: %s ') % e)
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time.sleep(config.FLAGS.qpid_reconnect_interval or 1)
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else:
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break
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LOG.info(_('Connected to AMQP server on %s') % self.broker)
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self.session = self.connection.session()
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for consumer in self.consumers.itervalues():
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consumer.reconnect(self.session)
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if self.consumers:
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LOG.debug(_("Re-established AMQP queues"))
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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 (qpid.messaging.exceptions.Empty,
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qpid.messaging.exceptions.ConnectionError), e:
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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 close(self):
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"""Close/release this connection"""
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self.cancel_consumer_thread()
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self.connection.close()
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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.session.close()
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self.session = self.connection.session()
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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.session, topic, callback)
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self._register_consumer(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, timeout=None):
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"""Return an iterator that will consume from all queues/consumers"""
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def _error_callback(exc):
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if isinstance(exc, qpid.messaging.exceptions.Empty):
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LOG.exception(_('Timed out waiting for RPC response: %s') %
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str(exc))
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raise rpc_common.Timeout()
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else:
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LOG.exception(_('Failed to consume message from queue: %s') %
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str(exc))
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def _consume():
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nxt_receiver = self.session.next_receiver(timeout=timeout)
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try:
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self._lookup_consumer(nxt_receiver).consume()
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except Exception:
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LOG.exception(_("Error processing message. Skipping it."))
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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):
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"""Send to a publisher based on the publisher class"""
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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.exception(_("Failed to publish message to topic "
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"'%(topic)s': %(err_str)s") % log_info)
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def _publisher_send():
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publisher = cls(self.session, topic)
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publisher.send(msg)
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return self.ensure(_connect_error, _publisher_send)
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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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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):
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"""Create a 'fanout' consumer"""
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self.declare_consumer(FanoutConsumer, topic, callback)
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def direct_send(self, msg_id, msg):
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"""Send a 'direct' message"""
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self.publisher_send(DirectPublisher, msg_id, msg)
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def topic_send(self, topic, msg):
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"""Send a 'topic' message"""
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self.publisher_send(TopicPublisher, topic, msg)
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def fanout_send(self, topic, msg):
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"""Send a 'fanout' message"""
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self.publisher_send(FanoutPublisher, topic, msg)
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def notify_send(self, topic, msg, **kwargs):
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"""Send a notify message on a topic"""
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self.publisher_send(NotifyPublisher, topic, msg)
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def consume(self, limit=None):
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"""Consume from all queues/consumers"""
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it = self.iterconsume(limit=limit)
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while True:
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try:
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it.next()
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except StopIteration:
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return
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def consume_in_thread(self):
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"""Consumer from all queues/consumers in a greenthread"""
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def _consumer_thread():
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try:
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self.consume()
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except greenlet.GreenletExit:
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return
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if self.consumer_thread is None:
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self.consumer_thread = eventlet.spawn(_consumer_thread)
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return self.consumer_thread
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def create_consumer(self, topic, proxy, fanout=False):
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"""Create a consumer that calls a method in a proxy object"""
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if fanout:
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consumer = FanoutConsumer(self.session, topic,
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rpc_amqp.ProxyCallback(proxy, Connection.pool))
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else:
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consumer = TopicConsumer(self.session, topic,
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rpc_amqp.ProxyCallback(proxy, Connection.pool))
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self._register_consumer(consumer)
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return consumer
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Connection.pool = rpc_amqp.Pool(connection_cls=Connection)
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def create_connection(new=True):
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"""Create a connection"""
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return rpc_amqp.create_connection(new, Connection.pool)
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def multicall(context, topic, msg, timeout=None):
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"""Make a call that returns multiple times."""
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return rpc_amqp.multicall(context, topic, msg, timeout, Connection.pool)
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def call(context, topic, msg, timeout=None):
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"""Sends a message on a topic and wait for a response."""
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return rpc_amqp.call(context, topic, msg, timeout, Connection.pool)
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def cast(context, topic, msg):
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"""Sends a message on a topic without waiting for a response."""
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return rpc_amqp.cast(context, topic, msg, Connection.pool)
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def fanout_cast(context, topic, msg):
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"""Sends a message on a fanout exchange without waiting for a response."""
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return rpc_amqp.fanout_cast(context, topic, msg, Connection.pool)
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def cast_to_server(context, server_params, topic, msg):
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"""Sends a message on a topic to a specific server."""
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return rpc_amqp.cast_to_server(context, server_params, topic, msg,
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Connection.pool)
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def fanout_cast_to_server(context, server_params, topic, msg):
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"""Sends a message on a fanout exchange to a specific server."""
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return rpc_amqp.fanout_cast_to_server(context, server_params, topic,
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msg, Connection.pool)
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def notify(context, topic, msg):
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"""Sends a notification event on a topic."""
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return rpc_amqp.notify(context, topic, msg, Connection.pool)
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def cleanup():
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return rpc_amqp.cleanup(Connection.pool)
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