# Copyright 2011 OpenStack Foundation # # 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 # # http://www.apache.org/licenses/LICENSE-2.0 # # 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 functools import itertools import socket import ssl import time import uuid import eventlet import greenlet import kombu import kombu.connection import kombu.entity import kombu.messaging from oslo.config import cfg import six from neutron.openstack.common import excutils from neutron.openstack.common.gettextutils import _ from neutron.openstack.common import network_utils from neutron.openstack.common.rpc import amqp as rpc_amqp from neutron.openstack.common.rpc import common as rpc_common from neutron.openstack.common import sslutils kombu_opts = [ cfg.StrOpt('kombu_ssl_version', default='', help='SSL version to use (valid only if SSL enabled). ' 'valid values are TLSv1, SSLv23 and SSLv3. SSLv2 may ' 'be available on some distributions' ), cfg.StrOpt('kombu_ssl_keyfile', default='', help='SSL key file (valid only if SSL enabled)'), cfg.StrOpt('kombu_ssl_certfile', default='', help='SSL cert file (valid only if SSL enabled)'), cfg.StrOpt('kombu_ssl_ca_certs', default='', help=('SSL certification authority file ' '(valid only if SSL enabled)')), cfg.StrOpt('rabbit_host', default='localhost', help='The RabbitMQ broker address where a single node is used'), cfg.IntOpt('rabbit_port', default=5672, help='The RabbitMQ broker port where a single node is used'), cfg.ListOpt('rabbit_hosts', default=['$rabbit_host:$rabbit_port'], help='RabbitMQ HA cluster host:port pairs'), cfg.BoolOpt('rabbit_use_ssl', default=False, help='connect over SSL for RabbitMQ'), cfg.StrOpt('rabbit_userid', default='guest', help='the RabbitMQ userid'), cfg.StrOpt('rabbit_password', default='guest', help='the RabbitMQ password', secret=True), cfg.StrOpt('rabbit_virtual_host', default='/', help='the RabbitMQ virtual host'), cfg.IntOpt('rabbit_retry_interval', default=1, help='how frequently to retry connecting with RabbitMQ'), cfg.IntOpt('rabbit_retry_backoff', default=2, help='how long to backoff for between retries when connecting ' 'to RabbitMQ'), cfg.IntOpt('rabbit_max_retries', default=0, help='maximum retries with trying to connect to RabbitMQ ' '(the default of 0 implies an infinite retry count)'), cfg.BoolOpt('rabbit_ha_queues', default=False, help='use H/A queues in RabbitMQ (x-ha-policy: all).' 'You need to wipe RabbitMQ database when ' 'changing this option.'), ] cfg.CONF.register_opts(kombu_opts) LOG = rpc_common.LOG def _get_queue_arguments(conf): """Construct the arguments for declaring a queue. If the rabbit_ha_queues option is set, we declare a mirrored queue as described here: http://www.rabbitmq.com/ha.html Setting x-ha-policy to all means that the queue will be mirrored to all nodes in the cluster. """ return {'x-ha-policy': 'all'} if conf.rabbit_ha_queues else {} class ConsumerBase(object): """Consumer base class.""" def __init__(self, channel, callback, tag, **kwargs): """Declare a queue on an amqp channel. 'channel' is the amqp channel to use 'callback' is the callback to call when messages are received 'tag' is a unique ID for the consumer on the channel queue name, exchange name, and other kombu options are passed in here as a dictionary. """ self.callback = callback self.tag = str(tag) self.kwargs = kwargs self.queue = None self.ack_on_error = kwargs.get('ack_on_error', True) self.reconnect(channel) def reconnect(self, channel): """Re-declare the queue after a rabbit reconnect.""" self.channel = channel self.kwargs['channel'] = channel self.queue = kombu.entity.Queue(**self.kwargs) self.queue.declare() def _callback_handler(self, message, callback): """Call callback with deserialized message. Messages that are processed without exception are ack'ed. If the message processing generates an exception, it will be ack'ed if ack_on_error=True. Otherwise it will be .requeue()'ed. """ try: msg = rpc_common.deserialize_msg(message.payload) callback(msg) except Exception: if self.ack_on_error: LOG.exception(_("Failed to process message" " ... skipping it.")) message.ack() else: LOG.exception(_("Failed to process message" " ... will requeue.")) message.requeue() else: message.ack() def consume(self, *args, **kwargs): """Actually declare the consumer on the amqp channel. This will start the flow of messages from the queue. Using the Connection.iterconsume() iterator will process the messages, calling the appropriate callback. If a callback is specified in kwargs, use that. Otherwise, use the callback passed during __init__() If kwargs['nowait'] is True, then this call will block until a message is read. """ options = {'consumer_tag': self.tag} options['nowait'] = kwargs.get('nowait', False) callback = kwargs.get('callback', self.callback) if not callback: raise ValueError("No callback defined") def _callback(raw_message): message = self.channel.message_to_python(raw_message) self._callback_handler(message, callback) self.queue.consume(*args, callback=_callback, **options) def cancel(self): """Cancel the consuming from the queue, if it has started.""" try: self.queue.cancel(self.tag) except KeyError as e: # NOTE(comstud): Kludge to get around a amqplib bug if str(e) != "u'%s'" % self.tag: raise self.queue = None class DirectConsumer(ConsumerBase): """Queue/consumer class for 'direct'.""" def __init__(self, conf, channel, msg_id, callback, tag, **kwargs): """Init a 'direct' queue. 'channel' is the amqp channel to use 'msg_id' is the msg_id to listen on 'callback' is the callback to call when messages are received 'tag' is a unique ID for the consumer on the channel Other kombu options may be passed """ # Default options options = {'durable': False, 'queue_arguments': _get_queue_arguments(conf), 'auto_delete': True, 'exclusive': False} options.update(kwargs) exchange = kombu.entity.Exchange(name=msg_id, type='direct', durable=options['durable'], auto_delete=options['auto_delete']) super(DirectConsumer, self).__init__(channel, callback, tag, name=msg_id, exchange=exchange, routing_key=msg_id, **options) class TopicConsumer(ConsumerBase): """Consumer class for 'topic'.""" def __init__(self, conf, channel, topic, callback, tag, name=None, exchange_name=None, **kwargs): """Init a 'topic' queue. :param channel: the amqp channel to use :param topic: the topic to listen on :paramtype topic: str :param callback: the callback to call when messages are received :param tag: a unique ID for the consumer on the channel :param name: optional queue name, defaults to topic :paramtype name: str Other kombu options may be passed as keyword arguments """ # Default options options = {'durable': conf.amqp_durable_queues, 'queue_arguments': _get_queue_arguments(conf), 'auto_delete': conf.amqp_auto_delete, 'exclusive': False} options.update(kwargs) exchange_name = exchange_name or rpc_amqp.get_control_exchange(conf) exchange = kombu.entity.Exchange(name=exchange_name, type='topic', durable=options['durable'], auto_delete=options['auto_delete']) super(TopicConsumer, self).__init__(channel, callback, tag, name=name or topic, exchange=exchange, routing_key=topic, **options) class FanoutConsumer(ConsumerBase): """Consumer class for 'fanout'.""" def __init__(self, conf, channel, topic, callback, tag, **kwargs): """Init a 'fanout' queue. 'channel' is the amqp channel to use 'topic' is the topic to listen on 'callback' is the callback to call when messages are received 'tag' is a unique ID for the consumer on the channel Other kombu options may be passed """ unique = uuid.uuid4().hex exchange_name = '%s_fanout' % topic queue_name = '%s_fanout_%s' % (topic, unique) # Default options options = {'durable': False, 'queue_arguments': _get_queue_arguments(conf), 'auto_delete': True, 'exclusive': False} options.update(kwargs) exchange = kombu.entity.Exchange(name=exchange_name, type='fanout', durable=options['durable'], auto_delete=options['auto_delete']) super(FanoutConsumer, self).__init__(channel, callback, tag, name=queue_name, exchange=exchange, routing_key=topic, **options) class Publisher(object): """Base Publisher class.""" def __init__(self, channel, exchange_name, routing_key, **kwargs): """Init the Publisher class with the exchange_name, routing_key, and other options """ self.exchange_name = exchange_name self.routing_key = routing_key self.kwargs = kwargs self.reconnect(channel) def reconnect(self, channel): """Re-establish the Producer after a rabbit reconnection.""" self.exchange = kombu.entity.Exchange(name=self.exchange_name, **self.kwargs) self.producer = kombu.messaging.Producer(exchange=self.exchange, channel=channel, routing_key=self.routing_key) def send(self, msg, timeout=None): """Send a message.""" if timeout: # # AMQP TTL is in milliseconds when set in the header. # self.producer.publish(msg, headers={'ttl': (timeout * 1000)}) else: self.producer.publish(msg) class DirectPublisher(Publisher): """Publisher class for 'direct'.""" def __init__(self, conf, channel, msg_id, **kwargs): """init a 'direct' publisher. Kombu options may be passed as keyword args to override defaults """ options = {'durable': False, 'auto_delete': True, 'exclusive': False} options.update(kwargs) super(DirectPublisher, self).__init__(channel, msg_id, msg_id, type='direct', **options) class TopicPublisher(Publisher): """Publisher class for 'topic'.""" def __init__(self, conf, channel, topic, **kwargs): """init a 'topic' publisher. Kombu options may be passed as keyword args to override defaults """ options = {'durable': conf.amqp_durable_queues, 'auto_delete': conf.amqp_auto_delete, 'exclusive': False} options.update(kwargs) exchange_name = rpc_amqp.get_control_exchange(conf) super(TopicPublisher, self).__init__(channel, exchange_name, topic, type='topic', **options) class FanoutPublisher(Publisher): """Publisher class for 'fanout'.""" def __init__(self, conf, channel, topic, **kwargs): """init a 'fanout' publisher. Kombu options may be passed as keyword args to override defaults """ options = {'durable': False, 'auto_delete': True, 'exclusive': False} options.update(kwargs) super(FanoutPublisher, self).__init__(channel, '%s_fanout' % topic, None, type='fanout', **options) class NotifyPublisher(TopicPublisher): """Publisher class for 'notify'.""" def __init__(self, conf, channel, topic, **kwargs): self.durable = kwargs.pop('durable', conf.amqp_durable_queues) self.queue_arguments = _get_queue_arguments(conf) super(NotifyPublisher, self).__init__(conf, channel, topic, **kwargs) def reconnect(self, channel): super(NotifyPublisher, self).reconnect(channel) # NOTE(jerdfelt): Normally the consumer would create the queue, but # we do this to ensure that messages don't get dropped if the # consumer is started after we do queue = kombu.entity.Queue(channel=channel, exchange=self.exchange, durable=self.durable, name=self.routing_key, routing_key=self.routing_key, queue_arguments=self.queue_arguments) queue.declare() class Connection(object): """Connection object.""" pool = None def __init__(self, conf, server_params=None): self.consumers = [] self.consumer_thread = None self.proxy_callbacks = [] self.conf = conf self.max_retries = self.conf.rabbit_max_retries # Try forever? if self.max_retries <= 0: self.max_retries = None self.interval_start = self.conf.rabbit_retry_interval self.interval_stepping = self.conf.rabbit_retry_backoff # max retry-interval = 30 seconds self.interval_max = 30 self.memory_transport = False if server_params is None: server_params = {} # Keys to translate from server_params to kombu params server_params_to_kombu_params = {'username': 'userid'} ssl_params = self._fetch_ssl_params() params_list = [] for adr in self.conf.rabbit_hosts: hostname, port = network_utils.parse_host_port( adr, default_port=self.conf.rabbit_port) params = { 'hostname': hostname, 'port': port, 'userid': self.conf.rabbit_userid, 'password': self.conf.rabbit_password, 'virtual_host': self.conf.rabbit_virtual_host, } for sp_key, value in six.iteritems(server_params): p_key = server_params_to_kombu_params.get(sp_key, sp_key) params[p_key] = value if self.conf.fake_rabbit: params['transport'] = 'memory' if self.conf.rabbit_use_ssl: params['ssl'] = ssl_params params_list.append(params) self.params_list = params_list self.memory_transport = self.conf.fake_rabbit self.connection = None self.reconnect() def _fetch_ssl_params(self): """Handles fetching what ssl params should be used for the connection (if any). """ ssl_params = dict() # http://docs.python.org/library/ssl.html - ssl.wrap_socket if self.conf.kombu_ssl_version: ssl_params['ssl_version'] = sslutils.validate_ssl_version( self.conf.kombu_ssl_version) if self.conf.kombu_ssl_keyfile: ssl_params['keyfile'] = self.conf.kombu_ssl_keyfile if self.conf.kombu_ssl_certfile: ssl_params['certfile'] = self.conf.kombu_ssl_certfile if self.conf.kombu_ssl_ca_certs: ssl_params['ca_certs'] = self.conf.kombu_ssl_ca_certs # We might want to allow variations in the # future with this? ssl_params['cert_reqs'] = ssl.CERT_REQUIRED # Return the extended behavior or just have the default behavior return ssl_params or True def _connect(self, params): """Connect to rabbit. Re-establish any queues that may have been declared before if we are reconnecting. Exceptions should be handled by the caller. """ if self.connection: LOG.info(_("Reconnecting to AMQP server on " "%(hostname)s:%(port)d") % params) try: self.connection.release() except self.connection_errors: pass # Setting this in case the next statement fails, though # it shouldn't be doing any network operations, yet. self.connection = None self.connection = kombu.connection.BrokerConnection(**params) self.connection_errors = self.connection.connection_errors if self.memory_transport: # Kludge to speed up tests. self.connection.transport.polling_interval = 0.0 self.consumer_num = itertools.count(1) self.connection.connect() self.channel = self.connection.channel() # work around 'memory' transport bug in 1.1.3 if self.memory_transport: self.channel._new_queue('ae.undeliver') for consumer in self.consumers: consumer.reconnect(self.channel) LOG.info(_('Connected to AMQP server on %(hostname)s:%(port)d') % params) def reconnect(self): """Handles reconnecting and re-establishing queues. Will retry up to self.max_retries number of times. self.max_retries = 0 means to retry forever. Sleep between tries, starting at self.interval_start seconds, backing off self.interval_stepping number of seconds each attempt. """ attempt = 0 while True: params = self.params_list[attempt % len(self.params_list)] attempt += 1 try: self._connect(params) return except (IOError, self.connection_errors) as e: pass except Exception as e: # NOTE(comstud): Unfortunately it's possible for amqplib # to return an error not covered by its transport # connection_errors in the case of a timeout waiting for # a protocol response. (See paste link in LP888621) # So, we check all exceptions for 'timeout' in them # and try to reconnect in this case. if 'timeout' not in str(e): raise log_info = {} log_info['err_str'] = str(e) log_info['max_retries'] = self.max_retries log_info.update(params) if self.max_retries and attempt == self.max_retries: msg = _('Unable to connect to AMQP server on ' '%(hostname)s:%(port)d after %(max_retries)d ' 'tries: %(err_str)s') % log_info LOG.error(msg) raise rpc_common.RPCException(msg) if attempt == 1: sleep_time = self.interval_start or 1 elif attempt > 1: sleep_time += self.interval_stepping if self.interval_max: sleep_time = min(sleep_time, self.interval_max) log_info['sleep_time'] = sleep_time LOG.error(_('AMQP server on %(hostname)s:%(port)d is ' 'unreachable: %(err_str)s. Trying again in ' '%(sleep_time)d seconds.') % log_info) time.sleep(sleep_time) def ensure(self, error_callback, method, *args, **kwargs): while True: try: return method(*args, **kwargs) except (self.connection_errors, socket.timeout, IOError) as e: if error_callback: error_callback(e) except Exception as e: # NOTE(comstud): Unfortunately it's possible for amqplib # to return an error not covered by its transport # connection_errors in the case of a timeout waiting for # a protocol response. (See paste link in LP888621) # So, we check all exceptions for 'timeout' in them # and try to reconnect in this case. if 'timeout' not in str(e): raise if error_callback: error_callback(e) self.reconnect() def get_channel(self): """Convenience call for bin/clear_rabbit_queues.""" return self.channel def close(self): """Close/release this connection.""" self.cancel_consumer_thread() self.wait_on_proxy_callbacks() self.connection.release() self.connection = None def reset(self): """Reset a connection so it can be used again.""" self.cancel_consumer_thread() self.wait_on_proxy_callbacks() self.channel.close() self.channel = self.connection.channel() # work around 'memory' transport bug in 1.1.3 if self.memory_transport: self.channel._new_queue('ae.undeliver') 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.conf, self.channel, topic, callback, six.next(self.consumer_num)) self.consumers.append(consumer) 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.""" info = {'do_consume': True} def _error_callback(exc): if isinstance(exc, socket.timeout): LOG.debug(_('Timed out waiting for RPC response: %s') % str(exc)) raise rpc_common.Timeout() else: LOG.exception(_('Failed to consume message from queue: %s') % str(exc)) info['do_consume'] = True def _consume(): if info['do_consume']: queues_head = self.consumers[:-1] # not fanout. queues_tail = self.consumers[-1] # fanout for queue in queues_head: queue.consume(nowait=True) queues_tail.consume(nowait=False) info['do_consume'] = False return self.connection.drain_events(timeout=timeout) 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: self.consumer_thread.kill() try: self.consumer_thread.wait() except greenlet.GreenletExit: pass self.consumer_thread = None def wait_on_proxy_callbacks(self): """Wait for all proxy callback threads to exit.""" for proxy_cb in self.proxy_callbacks: proxy_cb.wait() def publisher_send(self, cls, topic, msg, timeout=None, **kwargs): """Send to a publisher based on the publisher class.""" def _error_callback(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 _publish(): publisher = cls(self.conf, self.channel, topic, **kwargs) publisher.send(msg, timeout) self.ensure(_error_callback, _publish) 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, queue_name=None, exchange_name=None, ack_on_error=True): """Create a 'topic' consumer.""" self.declare_consumer(functools.partial(TopicConsumer, name=queue_name, exchange_name=exchange_name, ack_on_error=ack_on_error, ), 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, timeout=None): """Send a 'topic' message.""" self.publisher_send(TopicPublisher, topic, msg, timeout) 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, None, **kwargs) def consume(self, limit=None): """Consume from all queues/consumers.""" it = self.iterconsume(limit=limit) while True: try: six.next(it) except StopIteration: return def consume_in_thread(self): """Consumer from all queues/consumers in a greenthread.""" @excutils.forever_retry_uncaught_exceptions 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.""" proxy_cb = rpc_amqp.ProxyCallback( self.conf, proxy, rpc_amqp.get_connection_pool(self.conf, Connection)) self.proxy_callbacks.append(proxy_cb) if fanout: self.declare_fanout_consumer(topic, proxy_cb) else: self.declare_topic_consumer(topic, proxy_cb) def create_worker(self, topic, proxy, pool_name): """Create a worker that calls a method in a proxy object.""" proxy_cb = rpc_amqp.ProxyCallback( self.conf, proxy, rpc_amqp.get_connection_pool(self.conf, Connection)) self.proxy_callbacks.append(proxy_cb) self.declare_topic_consumer(topic, proxy_cb, pool_name) def join_consumer_pool(self, callback, pool_name, topic, exchange_name=None, ack_on_error=True): """Register as a member of a group of consumers for a given topic from the specified exchange. Exactly one member of a given pool will receive each message. A message will be delivered to multiple pools, if more than one is created. """ callback_wrapper = rpc_amqp.CallbackWrapper( conf=self.conf, callback=callback, connection_pool=rpc_amqp.get_connection_pool(self.conf, Connection), wait_for_consumers=not ack_on_error ) self.proxy_callbacks.append(callback_wrapper) self.declare_topic_consumer( queue_name=pool_name, topic=topic, exchange_name=exchange_name, callback=callback_wrapper, ack_on_error=ack_on_error, ) def create_connection(conf, new=True): """Create a connection.""" return rpc_amqp.create_connection( conf, new, rpc_amqp.get_connection_pool(conf, Connection)) def multicall(conf, context, topic, msg, timeout=None): """Make a call that returns multiple times.""" return rpc_amqp.multicall( conf, context, topic, msg, timeout, rpc_amqp.get_connection_pool(conf, Connection)) def call(conf, context, topic, msg, timeout=None): """Sends a message on a topic and wait for a response.""" return rpc_amqp.call( conf, context, topic, msg, timeout, rpc_amqp.get_connection_pool(conf, Connection)) def cast(conf, context, topic, msg): """Sends a message on a topic without waiting for a response.""" return rpc_amqp.cast( conf, context, topic, msg, rpc_amqp.get_connection_pool(conf, Connection)) def fanout_cast(conf, context, topic, msg): """Sends a message on a fanout exchange without waiting for a response.""" return rpc_amqp.fanout_cast( conf, context, topic, msg, rpc_amqp.get_connection_pool(conf, Connection)) def cast_to_server(conf, context, server_params, topic, msg): """Sends a message on a topic to a specific server.""" return rpc_amqp.cast_to_server( conf, context, server_params, topic, msg, rpc_amqp.get_connection_pool(conf, Connection)) def fanout_cast_to_server(conf, context, server_params, topic, msg): """Sends a message on a fanout exchange to a specific server.""" return rpc_amqp.fanout_cast_to_server( conf, context, server_params, topic, msg, rpc_amqp.get_connection_pool(conf, Connection)) def notify(conf, context, topic, msg, envelope): """Sends a notification event on a topic.""" return rpc_amqp.notify( conf, context, topic, msg, rpc_amqp.get_connection_pool(conf, Connection), envelope) def cleanup(): return rpc_amqp.cleanup(Connection.pool)