# vim: tabstop=4 shiftwidth=4 softtabstop=4 # Copyright 2011 OpenStack LLC # # 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 itertools import socket import ssl import sys import time import logging import uuid import eventlet import greenlet import kombu import kombu.entity import kombu.messaging import kombu.connection from reddwarf.common import config from reddwarf.rpc import amqp as rpc_amqp from reddwarf.rpc import common as rpc_common LOG = logging.getLogger(__name__) SSL_VERSION = "SSLv2" 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.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 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. Messages will automatically be acked if the callback doesn't raise an exception """ 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) callback(message.payload) message.ack() 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, 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, 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, 'auto_delete': True, 'exclusive': True} 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, channel, topic, callback, tag, **kwargs): """Init a 'topic' 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 """ # Default options options = {'durable': config.Config.get('rabbit_durable_queues', False), 'auto_delete': False, 'exclusive': False} options.update(kwargs) exchange = kombu.entity.Exchange( name=config.Config.get('control_exchange', 'reddwarf'), type='topic', durable=options['durable'], auto_delete=options['auto_delete']) super(TopicConsumer, self).__init__( channel, callback, tag, name=topic, exchange=exchange, routing_key=topic, **options) class FanoutConsumer(ConsumerBase): """Consumer class for 'fanout'""" def __init__(self, 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, 'auto_delete': True, 'exclusive': True} 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): """Send a message""" self.producer.publish(msg) class DirectPublisher(Publisher): """Publisher class for 'direct'""" def __init__(self, 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': True} 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, channel, topic, **kwargs): """init a 'topic' publisher. Kombu options may be passed as keyword args to override defaults """ options = {'durable': config.Config.get('rabbit_durable_queues', False), 'auto_delete': False, 'exclusive': False} options.update(kwargs) super(TopicPublisher, self).__init__(channel, config.Config.get('control_exchange', 'reddwarf'), topic, type='topic', **options) class FanoutPublisher(Publisher): """Publisher class for 'fanout'""" def __init__(self, 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': True} 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, *args, **kwargs): default = config.Config.get('rabbit_durable_queues', False) self.durable = kwargs.pop('durable', default) super(NotifyPublisher, self).__init__(*args, **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.declare() class Connection(object): """Connection object.""" def __init__(self, server_params=None): self.consumers = [] self.consumer_thread = None self.max_retries = config.Config.get('rabbit_max_retries', 0) # Try forever? if self.max_retries <= 0: self.max_retries = None self.interval_start = config.Config.get('rabbit_retry_interval', 1) self.interval_stepping = config.Config.get('rabbit_retry_backoff', 2) # 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'} params = {} for sp_key, value in server_params.iteritems(): p_key = server_params_to_kombu_params.get(sp_key, sp_key) params[p_key] = value params.setdefault('hostname', config.Config.get('rabbit_host', '127.0.0.1')) params.setdefault('port', config.Config.get('rabbit_port', 5672)) params.setdefault('userid', config.Config.get('rabbit_userid', 'guest')) params.setdefault('password', config.Config.get('rabbit_password', 'guest')) params.setdefault('virtual_host', config.Config.get('rabbit_virtual_host', '/')) self.params = params if config.Config.get('fake_rabbit', False): self.params['transport'] = 'memory' self.memory_transport = True else: self.memory_transport = False if config.Config.get('rabbit_use_ssl', False): self.params['ssl'] = self._fetch_ssl_params() 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 config.Config.get('kombu_ssl_version'): ssl_params['ssl_version'] = config.Config.get('kombu_ssl_version') if config.Config.get('kombu_ssl_keyfile'): ssl_params['keyfile'] = config.Config.get('kombu_ssl_keyfile') if config.Config.get('kombu_ssl_certfile'): ssl_params['certfile'] = config.Config.get('kombu_ssl_certfile') if config.Config.get('kombu_ssl_ca_certs'): ssl_params['ca_certs'] = config.Config.get('kombu_ssl_ca_certs') # We might want to allow variations in the # future with this? ssl_params['cert_reqs'] = ssl.CERT_REQUIRED if not ssl_params: # Just have the default behavior return True else: # Return the extended behavior return ssl_params def _connect(self): """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") % self.params) try: self.connection.close() 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( **self.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') % self.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: attempt += 1 try: self._connect() return except self.connection_errors, e: pass except Exception, 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(self.params) if self.max_retries and attempt == self.max_retries: LOG.exception(_('Unable to connect to AMQP server on ' '%(hostname)s:%(port)d after %(max_retries)d ' 'tries: %(err_str)s') % log_info) # NOTE(comstud): Copied from original code. There's # really no better recourse because if this was a queue we # need to consume on, we have no way to consume anymore. sys.exit(1) 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.exception(_('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), e: pass except Exception, 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.connection.release() self.connection = None def reset(self): """Reset a connection so it can be used again""" self.cancel_consumer_thread() 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.channel, topic, callback, self.consumer_num.next()) 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.exception(_('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] queues_tail = self.consumers[-1] 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 publisher_send(self, cls, topic, msg, **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.channel, topic, **kwargs) LOG.info(_("_publish info%s %s %s %s") % (self.channel, topic, kwargs, publisher)) publisher.send(msg) 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): """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, **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, rpc_amqp.ProxyCallback(proxy, Connection.pool)) else: self.declare_topic_consumer(topic, rpc_amqp.ProxyCallback(proxy, Connection.pool)) 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 rpc_amqp.call(context, 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 cast_with_consumer(context, topic, msg): """Sends a message on a topic without waiting for a response.""" return rpc_amqp.cast_with_consumer(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, Connection.pool) def fanout_cast_to_server(context, server_params, topic, msg): """Sends a message on a fanout exchange to a specific server.""" return rpc_amqp.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)