OpenStack Orchestration (Heat)
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2011 OpenStack LLC
# Copyright 2011 - 2012, Red Hat, Inc.
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import itertools
import time
import uuid
import json
import logging
import eventlet
import greenlet
import qpid.messaging
import qpid.messaging.exceptions
from heat.common import config
from heat.openstack.common import cfg
from heat.rpc import amqp as rpc_amqp
from heat.rpc import common as rpc_common
LOG = logging.getLogger(__name__)
class ConsumerBase(object):
"""Consumer base class."""
def __init__(self, session, callback, node_name, node_opts,
link_name, link_opts):
"""Declare a queue on an amqp session.
'session' is the amqp session to use
'callback' is the callback to call when messages are received
'node_name' is the first part of the Qpid address string, before ';'
'node_opts' will be applied to the "x-declare" section of "node"
in the address string.
'link_name' goes into the "name" field of the "link" in the address
'link_opts' will be applied to the "x-declare" section of "link"
in the address string.
self.callback = callback
self.receiver = None
self.session = None
addr_opts = {
"create": "always",
"node": {
"type": "topic",
"x-declare": {
"durable": True,
"auto-delete": True,
"link": {
"name": link_name,
"durable": True,
"x-declare": {
"durable": False,
"auto-delete": True,
"exclusive": False,
self.address = "%s ; %s" % (node_name, json.dumps(addr_opts))
def reconnect(self, session):
"""Re-declare the receiver after a qpid reconnect"""
self.session = session
self.receiver = session.receiver(self.address)
self.receiver.capacity = 1
def consume(self):
"""Fetch the message and pass it to the callback object"""
message = self.receiver.fetch()
def get_receiver(self):
return self.receiver
class DirectConsumer(ConsumerBase):
"""Queue/consumer class for 'direct'"""
def __init__(self, session, msg_id, callback):
"""Init a 'direct' queue.
'session' is the amqp session to use
'msg_id' is the msg_id to listen on
'callback' is the callback to call when messages are received
super(DirectConsumer, self).__init__(session, callback,
"%s/%s" % (msg_id, msg_id),
{"type": "direct"},
{"exclusive": True})
class TopicConsumer(ConsumerBase):
"""Consumer class for 'topic'"""
def __init__(self, session, topic, callback):
"""Init a 'topic' queue.
'session' is the amqp session to use
'topic' is the topic to listen on
'callback' is the callback to call when messages are received
super(TopicConsumer, self).__init__(session, callback,
"%s/%s" % (config.FLAGS.control_exchange, topic), {},
topic, {})
class FanoutConsumer(ConsumerBase):
"""Consumer class for 'fanout'"""
def __init__(self, session, topic, callback):
"""Init a 'fanout' queue.
'session' is the amqp session to use
'topic' is the topic to listen on
'callback' is the callback to call when messages are received
super(FanoutConsumer, self).__init__(session, callback,
"%s_fanout" % topic,
{"durable": False, "type": "fanout"},
"%s_fanout_%s" % (topic, uuid.uuid4().hex),
{"exclusive": True})
class Publisher(object):
"""Base Publisher class"""
def __init__(self, session, node_name, node_opts=None):
"""Init the Publisher class with the exchange_name, routing_key,
and other options
self.sender = None
self.session = session
addr_opts = {
"create": "always",
"node": {
"type": "topic",
"x-declare": {
"durable": False,
# auto-delete isn't implemented for exchanges in qpid,
# but put in here anyway
"auto-delete": True,
if node_opts:
self.address = "%s ; %s" % (node_name, json.dumps(addr_opts))
def reconnect(self, session):
"""Re-establish the Sender after a reconnection"""
self.sender = session.sender(self.address)
def send(self, msg):
"""Send a message"""
class DirectPublisher(Publisher):
"""Publisher class for 'direct'"""
def __init__(self, session, msg_id):
"""Init a 'direct' publisher."""
super(DirectPublisher, self).__init__(session, msg_id,
{"type": "Direct"})
class TopicPublisher(Publisher):
"""Publisher class for 'topic'"""
def __init__(self, session, topic):
"""init a 'topic' publisher.
super(TopicPublisher, self).__init__(session,
"%s/%s" % (config.FLAGS.control_exchange, topic))
class FanoutPublisher(Publisher):
"""Publisher class for 'fanout'"""
def __init__(self, session, topic):
"""init a 'fanout' publisher.
super(FanoutPublisher, self).__init__(session,
"%s_fanout" % topic, {"type": "fanout"})
class NotifyPublisher(Publisher):
"""Publisher class for notifications"""
def __init__(self, session, topic):
"""init a 'topic' publisher.
super(NotifyPublisher, self).__init__(session,
"%s/%s" % (config.FLAGS.control_exchange, topic),
{"durable": True})
class Connection(object):
"""Connection object."""
def __init__(self, server_params=None):
self.session = None
self.consumers = {}
self.consumer_thread = None
if server_params is None:
server_params = {}
default_params = dict(hostname=config.FLAGS.qpid_hostname,
params = server_params
for key in default_params.keys():
params.setdefault(key, default_params[key]) = params['hostname'] + ":" + str(params['port'])
# Create the connection - this does not open the connection
self.connection = qpid.messaging.Connection(
# Check if flags are set and if so set them for the connection
# before we call open
self.connection.username = params['username']
self.connection.password = params['password']
self.connection.sasl_mechanisms = config.FLAGS.qpid_sasl_mechanisms
self.connection.reconnect = config.FLAGS.qpid_reconnect
if config.FLAGS.qpid_reconnect_timeout:
self.connection.reconnect_timeout = \
if config.FLAGS.qpid_reconnect_limit:
self.connection.reconnect_limit = config.FLAGS.qpid_reconnect_limit
if config.FLAGS.qpid_reconnect_interval_max:
self.connection.reconnect_interval_max = (
if config.FLAGS.qpid_reconnect_interval_min:
self.connection.reconnect_interval_min = (
if config.FLAGS.qpid_reconnect_interval:
self.connection.reconnect_interval = \
self.connection.hearbeat = config.FLAGS.qpid_heartbeat
self.connection.protocol = config.FLAGS.qpid_protocol
self.connection.tcp_nodelay = config.FLAGS.qpid_tcp_nodelay
# Open is part of reconnect -
# NOTE(WGH) not sure we need this with the reconnect flags
def _register_consumer(self, consumer):
self.consumers[str(consumer.get_receiver())] = consumer
def _lookup_consumer(self, receiver):
return self.consumers[str(receiver)]
def reconnect(self):
"""Handles reconnecting and re-establishing sessions and queues"""
if self.connection.opened():
except qpid.messaging.exceptions.ConnectionError:
while True:
except qpid.messaging.exceptions.ConnectionError, e:
LOG.error(_('Unable to connect to AMQP server: %s ') % e)
time.sleep(config.FLAGS.qpid_reconnect_interval or 1)
break'Connected to AMQP server on %s') %
self.session = self.connection.session()
for consumer in self.consumers.itervalues():
if self.consumers:
LOG.debug(_("Re-established AMQP queues"))
def ensure(self, error_callback, method, *args, **kwargs):
while True:
return method(*args, **kwargs)
except (qpid.messaging.exceptions.Empty,
qpid.messaging.exceptions.ConnectionError), e:
if error_callback:
def close(self):
"""Close/release this connection"""
self.connection = None
def reset(self):
"""Reset a connection so it can be used again"""
self.session = self.connection.session()
self.consumers = {}
def declare_consumer(self, consumer_cls, topic, callback):
"""Create a Consumer using the class that was passed in and
add it to our list of consumers
def _connect_error(exc):
log_info = {'topic': topic, 'err_str': str(exc)}
LOG.error(_("Failed to declare consumer for topic '%(topic)s': "
"%(err_str)s") % log_info)
def _declare_consumer():
consumer = consumer_cls(self.session, topic, callback)
return consumer
return self.ensure(_connect_error, _declare_consumer)
def iterconsume(self, limit=None, timeout=None):
"""Return an iterator that will consume from all queues/consumers"""
def _error_callback(exc):
if isinstance(exc, qpid.messaging.exceptions.Empty):
LOG.exception(_('Timed out waiting for RPC response: %s') %
raise rpc_common.Timeout()
LOG.exception(_('Failed to consume message from queue: %s') %
def _consume():
nxt_receiver = self.session.next_receiver(timeout=timeout)
except Exception:
LOG.exception(_("Error processing message. Skipping it."))
for iteration in itertools.count(0):
if limit and iteration >= limit:
raise StopIteration
yield self.ensure(_error_callback, _consume)
def cancel_consumer_thread(self):
"""Cancel a consumer thread"""
if self.consumer_thread is not None:
except greenlet.GreenletExit:
self.consumer_thread = None
def publisher_send(self, cls, topic, msg):
"""Send to a publisher based on the publisher class"""
def _connect_error(exc):
log_info = {'topic': topic, 'err_str': str(exc)}
LOG.exception(_("Failed to publish message to topic "
"'%(topic)s': %(err_str)s") % log_info)
def _publisher_send():
publisher = cls(self.session, topic)
return self.ensure(_connect_error, _publisher_send)
def declare_direct_consumer(self, topic, callback):
"""Create a 'direct' queue.
In nova's use, this is generally a msg_id queue used for
responses for call/multicall
self.declare_consumer(DirectConsumer, topic, callback)
def declare_topic_consumer(self, topic, callback=None):
"""Create a 'topic' consumer."""
self.declare_consumer(TopicConsumer, topic, callback)
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)
def consume(self, limit=None):
"""Consume from all queues/consumers"""
it = self.iterconsume(limit=limit)
while True:
except StopIteration:
def consume_in_thread(self):
"""Consumer from all queues/consumers in a greenthread"""
def _consumer_thread():
except greenlet.GreenletExit:
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:
consumer = FanoutConsumer(self.session, topic,
rpc_amqp.ProxyCallback(proxy, Connection.pool))
consumer = TopicConsumer(self.session, topic,
rpc_amqp.ProxyCallback(proxy, Connection.pool))
return consumer
Connection.pool = rpc_amqp.Pool(connection_cls=Connection)
def create_connection(new=True):
"""Create a connection"""
return rpc_amqp.create_connection(new, Connection.pool)
def multicall(context, topic, msg, timeout=None):
"""Make a call that returns multiple times."""
return rpc_amqp.multicall(context, topic, msg, timeout, Connection.pool)
def call(context, topic, msg, timeout=None):
"""Sends a message on a topic and wait for a response."""
return, topic, msg, timeout, Connection.pool)
def cast(context, topic, msg):
"""Sends a message on a topic without waiting for a response."""
return rpc_amqp.cast(context, topic, msg, Connection.pool)
def fanout_cast(context, topic, msg):
"""Sends a message on a fanout exchange without waiting for a response."""
return rpc_amqp.fanout_cast(context, topic, msg, Connection.pool)
def cast_to_server(context, server_params, topic, msg):
"""Sends a message on a topic to a specific server."""
return rpc_amqp.cast_to_server(context, server_params, topic, msg,
def fanout_cast_to_server(context, server_params, topic, msg):
"""Sends a message on a fanout exchange to a specific server."""
return rpc_amqp.fanout_cast_to_server(context, server_params, topic,
msg, Connection.pool)
def notify(context, topic, msg):
"""Sends a notification event on a topic."""
return rpc_amqp.notify(context, topic, msg, Connection.pool)
def cleanup():
return rpc_amqp.cleanup(Connection.pool)