diff options
Diffstat (limited to 'nova/rpc.py')
| -rw-r--r-- | nova/rpc.py | 152 |
1 files changed, 86 insertions, 66 deletions
diff --git a/nova/rpc.py b/nova/rpc.py index b610cdf9b..2116f22c3 100644 --- a/nova/rpc.py +++ b/nova/rpc.py @@ -16,9 +16,12 @@ # License for the specific language governing permissions and limitations # under the License. -""" -AMQP-based RPC. Queues have consumers and publishers. +"""AMQP-based RPC. + +Queues have consumers and publishers. + No fan-out support yet. + """ import json @@ -40,17 +43,19 @@ from nova import log as logging from nova import utils -FLAGS = flags.FLAGS LOG = logging.getLogger('nova.rpc') + +FLAGS = flags.FLAGS flags.DEFINE_integer('rpc_thread_pool_size', 1024, 'Size of RPC thread pool') class Connection(carrot_connection.BrokerConnection): - """Connection instance object""" + """Connection instance object.""" + @classmethod def instance(cls, new=True): - """Returns the instance""" + """Returns the instance.""" if new or not hasattr(cls, '_instance'): params = dict(hostname=FLAGS.rabbit_host, port=FLAGS.rabbit_port, @@ -71,9 +76,11 @@ class Connection(carrot_connection.BrokerConnection): @classmethod def recreate(cls): - """Recreates the connection instance + """Recreates the connection instance. + + This is necessary to recover from some network errors/disconnects. - This is necessary to recover from some network errors/disconnects""" + """ try: del cls._instance except AttributeError, e: @@ -84,10 +91,12 @@ class Connection(carrot_connection.BrokerConnection): class Consumer(messaging.Consumer): - """Consumer base class + """Consumer base class. + + Contains methods for connecting the fetch method to async loops. - Contains methods for connecting the fetch method to async loops """ + def __init__(self, *args, **kwargs): for i in xrange(FLAGS.rabbit_max_retries): if i > 0: @@ -100,19 +109,18 @@ class Consumer(messaging.Consumer): fl_host = FLAGS.rabbit_host fl_port = FLAGS.rabbit_port fl_intv = FLAGS.rabbit_retry_interval - LOG.error(_("AMQP server on %(fl_host)s:%(fl_port)d is" - " unreachable: %(e)s. Trying again in %(fl_intv)d" - " seconds.") - % locals()) + LOG.error(_('AMQP server on %(fl_host)s:%(fl_port)d is' + ' unreachable: %(e)s. Trying again in %(fl_intv)d' + ' seconds.') % locals()) self.failed_connection = True if self.failed_connection: - LOG.error(_("Unable to connect to AMQP server " - "after %d tries. Shutting down."), + LOG.error(_('Unable to connect to AMQP server ' + 'after %d tries. Shutting down.'), FLAGS.rabbit_max_retries) sys.exit(1) def fetch(self, no_ack=None, auto_ack=None, enable_callbacks=False): - """Wraps the parent fetch with some logic for failed connections""" + """Wraps the parent fetch with some logic for failed connection.""" # TODO(vish): the logic for failed connections and logging should be # refactored into some sort of connection manager object try: @@ -125,14 +133,14 @@ class Consumer(messaging.Consumer): self.declare() super(Consumer, self).fetch(no_ack, auto_ack, enable_callbacks) if self.failed_connection: - LOG.error(_("Reconnected to queue")) + LOG.error(_('Reconnected to queue')) self.failed_connection = False # NOTE(vish): This is catching all errors because we really don't # want exceptions to be logged 10 times a second if some # persistent failure occurs. except Exception, e: # pylint: disable=W0703 if not self.failed_connection: - LOG.exception(_("Failed to fetch message from queue: %s" % e)) + LOG.exception(_('Failed to fetch message from queue: %s' % e)) self.failed_connection = True def attach_to_eventlet(self): @@ -143,8 +151,9 @@ class Consumer(messaging.Consumer): class AdapterConsumer(Consumer): - """Calls methods on a proxy object based on method and args""" - def __init__(self, connection=None, topic="broadcast", proxy=None): + """Calls methods on a proxy object based on method and args.""" + + def __init__(self, connection=None, topic='broadcast', proxy=None): LOG.debug(_('Initing the Adapter Consumer for %s') % topic) self.proxy = proxy self.pool = greenpool.GreenPool(FLAGS.rpc_thread_pool_size) @@ -156,13 +165,14 @@ class AdapterConsumer(Consumer): @exception.wrap_exception def _receive(self, message_data, message): - """Magically looks for a method on the proxy object and calls it + """Magically looks for a method on the proxy object and calls it. 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}} + """ LOG.debug(_('received %s') % message_data) msg_id = message_data.pop('_msg_id', None) @@ -189,22 +199,23 @@ class AdapterConsumer(Consumer): if msg_id: msg_reply(msg_id, rval, None) except Exception as e: - logging.exception("Exception during message handling") + logging.exception('Exception during message handling') if msg_id: msg_reply(msg_id, None, sys.exc_info()) return class Publisher(messaging.Publisher): - """Publisher base class""" + """Publisher base class.""" pass class TopicAdapterConsumer(AdapterConsumer): - """Consumes messages on a specific topic""" - exchange_type = "topic" + """Consumes messages on a specific topic.""" + + exchange_type = 'topic' - def __init__(self, connection=None, topic="broadcast", proxy=None): + def __init__(self, connection=None, topic='broadcast', proxy=None): self.queue = topic self.routing_key = topic self.exchange = FLAGS.control_exchange @@ -214,27 +225,29 @@ class TopicAdapterConsumer(AdapterConsumer): class FanoutAdapterConsumer(AdapterConsumer): - """Consumes messages from a fanout exchange""" - exchange_type = "fanout" + """Consumes messages from a fanout exchange.""" - def __init__(self, connection=None, topic="broadcast", proxy=None): - self.exchange = "%s_fanout" % topic + exchange_type = 'fanout' + + def __init__(self, connection=None, topic='broadcast', proxy=None): + self.exchange = '%s_fanout' % topic self.routing_key = topic unique = uuid.uuid4().hex - self.queue = "%s_fanout_%s" % (topic, unique) + self.queue = '%s_fanout_%s' % (topic, unique) self.durable = False - LOG.info(_("Created '%(exchange)s' fanout exchange " - "with '%(key)s' routing key"), - dict(exchange=self.exchange, key=self.routing_key)) + LOG.info(_('Created "%(exchange)s" fanout exchange ' + 'with "%(key)s" routing key'), + dict(exchange=self.exchange, key=self.routing_key)) super(FanoutAdapterConsumer, self).__init__(connection=connection, topic=topic, proxy=proxy) class TopicPublisher(Publisher): - """Publishes messages on a specific topic""" - exchange_type = "topic" + """Publishes messages on a specific topic.""" + + exchange_type = 'topic' - def __init__(self, connection=None, topic="broadcast"): + def __init__(self, connection=None, topic='broadcast'): self.routing_key = topic self.exchange = FLAGS.control_exchange self.durable = False @@ -243,20 +256,22 @@ class TopicPublisher(Publisher): class FanoutPublisher(Publisher): """Publishes messages to a fanout exchange.""" - exchange_type = "fanout" + + exchange_type = 'fanout' def __init__(self, topic, connection=None): - self.exchange = "%s_fanout" % topic - self.queue = "%s_fanout" % topic + self.exchange = '%s_fanout' % topic + self.queue = '%s_fanout' % topic self.durable = False - LOG.info(_("Creating '%(exchange)s' fanout exchange"), - dict(exchange=self.exchange)) + LOG.info(_('Creating "%(exchange)s" fanout exchange'), + dict(exchange=self.exchange)) super(FanoutPublisher, self).__init__(connection=connection) class DirectConsumer(Consumer): - """Consumes messages directly on a channel specified by msg_id""" - exchange_type = "direct" + """Consumes messages directly on a channel specified by msg_id.""" + + exchange_type = 'direct' def __init__(self, connection=None, msg_id=None): self.queue = msg_id @@ -268,8 +283,9 @@ class DirectConsumer(Consumer): class DirectPublisher(Publisher): - """Publishes messages directly on a channel specified by msg_id""" - exchange_type = "direct" + """Publishes messages directly on a channel specified by msg_id.""" + + exchange_type = 'direct' def __init__(self, connection=None, msg_id=None): self.routing_key = msg_id @@ -279,9 +295,9 @@ class DirectPublisher(Publisher): def msg_reply(msg_id, reply=None, failure=None): - """Sends a reply or an error on the channel signified by msg_id + """Sends a reply or an error on the channel signified by msg_id. - failure should be a sys.exc_info() tuple. + Failure should be a sys.exc_info() tuple. """ if failure: @@ -303,17 +319,20 @@ def msg_reply(msg_id, reply=None, failure=None): class RemoteError(exception.Error): - """Signifies that a remote class has raised an exception + """Signifies that a remote class has raised an exception. Containes a string representation of the type of the original exception, the value of the original exception, and the traceback. These are sent to the parent as a joined string so printing the exception - contains all of the relevent info.""" + contains all of the relevent info. + + """ + def __init__(self, exc_type, value, traceback): self.exc_type = exc_type self.value = value self.traceback = traceback - super(RemoteError, self).__init__("%s %s\n%s" % (exc_type, + super(RemoteError, self).__init__('%s %s\n%s' % (exc_type, value, traceback)) @@ -339,6 +358,7 @@ def _pack_context(msg, context): 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 = dict([('_context_%s' % key, value) for (key, value) in context.to_dict().iteritems()]) @@ -346,11 +366,11 @@ def _pack_context(msg, context): def call(context, topic, msg): - """Sends a message on a topic and wait for a response""" - LOG.debug(_("Making asynchronous call on %s ..."), topic) + """Sends a message on a topic and wait for a response.""" + 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)) + LOG.debug(_('MSG_ID is %s') % (msg_id)) _pack_context(msg, context) class WaitMessage(object): @@ -387,8 +407,8 @@ def call(context, topic, msg): def cast(context, topic, msg): - """Sends a message on a topic without waiting for a response""" - LOG.debug(_("Making asynchronous cast on %s..."), topic) + """Sends a message on a topic without waiting for a response.""" + LOG.debug(_('Making asynchronous cast on %s...'), topic) _pack_context(msg, context) conn = Connection.instance() publisher = TopicPublisher(connection=conn, topic=topic) @@ -397,8 +417,8 @@ def cast(context, 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...")) + """Sends a message on a fanout exchange without waiting for a response.""" + LOG.debug(_('Making asynchronous fanout cast...')) _pack_context(msg, context) conn = Connection.instance() publisher = FanoutPublisher(topic, connection=conn) @@ -407,14 +427,14 @@ def fanout_cast(context, topic, msg): def generic_response(message_data, message): - """Logs a result and exits""" + """Logs a result and exits.""" LOG.debug(_('response %s'), message_data) message.ack() sys.exit(0) def send_message(topic, message, wait=True): - """Sends a message for testing""" + """Sends a message for testing.""" msg_id = uuid.uuid4().hex message.update({'_msg_id': msg_id}) LOG.debug(_('topic is %s'), topic) @@ -425,14 +445,14 @@ def send_message(topic, message, wait=True): queue=msg_id, exchange=msg_id, auto_delete=True, - exchange_type="direct", + exchange_type='direct', routing_key=msg_id) consumer.register_callback(generic_response) publisher = messaging.Publisher(connection=Connection.instance(), exchange=FLAGS.control_exchange, durable=False, - exchange_type="topic", + exchange_type='topic', routing_key=topic) publisher.send(message) publisher.close() @@ -441,8 +461,8 @@ def send_message(topic, message, wait=True): consumer.wait() -if __name__ == "__main__": - # NOTE(vish): you can send messages from the command line using - # topic and a json sting representing a dictionary - # for the method +if __name__ == '__main__': + # You can send messages from the command line using + # topic and a json string representing a dictionary + # for the method send_message(sys.argv[1], json.loads(sys.argv[2])) |