def __init__(self, *args, **kwargs):
max_retries = FLAGS.rabbit_max_retries
sleep_time = FLAGS.rabbit_retry_interval
tries = 0
while True:
tries += 1
if tries > 1:
time.sleep(sleep_time)
# backoff for next retry attempt.. if there is one
sleep_time += FLAGS.rabbit_retry_backoff
if sleep_time > 30:
sleep_time = 30
try:
super(Consumer, self).__init__(*args, **kwargs)
self.failed_connection = False
break
except Exception as e: # Catching all because carrot sucks
self.failed_connection = True
if max_retries > 0 and tries == max_retries:
break
fl_host = FLAGS.rabbit_host
fl_port = FLAGS.rabbit_port
fl_intv = sleep_time
LOG.error(_('AMQP server on %(fl_host)s:%(fl_port)d is'
' unreachable: %(e)s. Trying again in %(fl_intv)d'
' seconds.') % locals())
if self.failed_connection:
LOG.error(_('Unable to connect to AMQP server '
'after %(tries)d tries. Shutting down.') % locals())
sys.exit(1)
def process_data(self, message_data, message):
"""Consumer callback to call a method on a proxy object.
Parses the message for validity and fires off a thread to call the
proxy object method.
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)
# This will be popped off in _unpack_context
msg_id = message_data.get('_msg_id', None)
ctxt = _unpack_context(message_data)
method = message_data.get('method')
args = message_data.get('args', {})
message.ack()
if not method:
# NOTE(vish): we may not want to ack here, but that means that bad
# messages stay in the queue indefinitely, so for now
# we just log the message and send an error string
# back to the caller
LOG.warn(_('no method for message: %s') % message_data)
ctxt.reply(msg_id,
_('No method for message: %s') % message_data)
return
self.pool.spawn_n(self._process_data, ctxt, method, args)
def msg_reply(msg_id, reply=None, failure=None, ending=False):
"""Sends a reply or an error on the channel signified by msg_id.
Failure should be a sys.exc_info() tuple.
"""
if failure:
message = str(failure[1])
tb = traceback.format_exception(*failure)
LOG.error(_("Returning exception %s to caller"), message)
LOG.error(tb)
failure = (failure[0].__name__, str(failure[1]), tb)
with ConnectionPool.item() as conn:
publisher = DirectPublisher(connection=conn, msg_id=msg_id)
try:
msg = {'result': reply, 'failure': failure}
if ending:
msg['ending'] = True
publisher.send(msg)
except TypeError:
msg = {'result': dict((k, repr(v))
for k, v in reply.__dict__.iteritems()),
'failure': failure}
if ending:
msg['ending'] = True
publisher.send(msg)
publisher.close()
def reconnect(self):
"""Handles reconnecting and re-establishing queues"""
if self.connection:
try:
self.connection.close()
except self.connection.connection_errors:
pass
time.sleep(1)
self.connection = kombu.connection.BrokerConnection(**self.params)
if self.memory_transport:
# Kludge to speed up tests.
self.connection.transport.polling_interval = 0.0
self.consumer_num = itertools.count(1)
try:
self.connection.ensure_connection(errback=self.connect_error,
max_retries=self.max_retries,
interval_start=self.interval_start,
interval_step=self.interval_stepping,
interval_max=self.interval_max)
except self.connection.connection_errors, e:
# We should only get here if max_retries is set. We'll go
# ahead and exit in this case.
err_str = str(e)
max_retries = self.max_retries
LOG.error(_('Unable to connect to AMQP server '
'after %(max_retries)d tries: %(err_str)s') % locals())
sys.exit(1)
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)
super(AdapterConsumer, self).__init__(connection=connection,
topic=topic)
self.register_callback(self.process_data)
def fetch(self, no_ack=None, auto_ack=None, enable_callbacks=False):
"""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:
if self.failed_connection:
# NOTE(vish): connection is defined in the parent class, we can
# recreate it as long as we create the backend too
# pylint: disable=W0201
self.connection = Connection.recreate()
self.backend = self.connection.create_backend()
self.declare()
return super(Consumer, self).fetch(no_ack,
auto_ack,
enable_callbacks)
if self.failed_connection:
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))
self.failed_connection = True
def send_message(topic, message, wait=True):
"""Sends a message for testing."""
msg_id = uuid.uuid4().hex
message.update({'_msg_id': msg_id})
LOG.debug(_('topic is %s'), topic)
LOG.debug(_('message %s'), message)
if wait:
consumer = messaging.Consumer(connection=Connection.instance(),
queue=msg_id,
exchange=msg_id,
auto_delete=True,
exchange_type='direct',
routing_key=msg_id)
consumer.register_callback(generic_response)
publisher = messaging.Publisher(connection=Connection.instance(),
exchange=FLAGS.control_exchange,
durable=FLAGS.rabbit_durable_queues,
exchange_type='topic',
routing_key=topic)
publisher.send(message)
publisher.close()
if wait:
consumer.wait()
consumer.close()
def cast(context, topic, msg):
"""Sends a message on a topic without waiting for a response."""
LOG.debug(_('Making asynchronous cast on %s...'), topic)
_pack_context(msg, context)
with ConnectionPool.item() as conn:
publisher = TopicPublisher(connection=conn, topic=topic)
publisher.send(msg)
publisher.close()
def __init__(self, topic, connection=None):
self.exchange = '%s_fanout' % topic
self.queue = '%s_fanout' % topic
self.durable = False
self.auto_delete = True
LOG.info(_('Creating "%(exchange)s" fanout exchange'),
dict(exchange=self.exchange))
super(FanoutPublisher, self).__init__(connection=connection)
def connect_error(self, exc, interval):
"""Callback when there are connection re-tries by kombu"""
info = self.params.copy()
info['intv'] = interval
info['e'] = exc
LOG.error(_('AMQP server on %(hostname)s:%(port)d is'
' unreachable: %(e)s. Trying again in %(intv)d'
' seconds.') % info)
def fanout_cast(context, topic, msg):
"""Sends a message on a fanout exchange without waiting for a response."""
LOG.debug(_('Making asynchronous fanout cast...'))
_pack_context(msg, context)
with ConnectionPool.item() as conn:
publisher = FanoutPublisher(topic, connection=conn)
publisher.send(msg)
publisher.close()
def notify(context, topic, msg):
"""Sends a notification event on a topic."""
LOG.debug(_('Sending notification on %s...'), topic)
_pack_context(msg, context)
with ConnectionPool.item() as conn:
publisher = TopicPublisher(connection=conn, topic=topic,
durable=True)
publisher.send(msg)
publisher.close()
def _unpack_context(msg):
"""Unpack context from msg."""
context_dict = {}
for key in list(msg.keys()):
# NOTE(vish): Some versions of python don't like unicode keys
# in kwargs.
key = str(key)
if key.startswith('_context_'):
value = msg.pop(key)
context_dict[key[9:]] = value
context_dict['msg_id'] = msg.pop('_msg_id', None)
LOG.debug(_('unpacked context: %s'), context_dict)
return RpcContext.from_dict(context_dict)
def publisher_send(self, cls, topic, msg, **kwargs):
"""Send to a publisher based on the publisher class"""
while True:
try:
publisher = cls(self.channel, topic, **kwargs)
publisher.send(msg)
return
except self.connection.connection_errors, e:
LOG.exception(_('Failed to publish message %s' % str(e)))
try:
self.reconnect()
except self.connection.connection_errors, e:
pass
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.durable = False
# Fanout creates unique queue names, so we should auto-remove
# them when done, so they're not left around on restart.
# Also, we're the only one that should be consuming. exclusive
# implies auto_delete, so we'll just set that..
self.exclusive = True
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)
def multicall(context, topic, msg):
"""Make a call that returns multiple times."""
# Can't use 'with' for multicall, as it returns an iterator
# that will continue to use the connection. When it's done,
# connection.close() will get called which will put it back into
# the pool
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))
_pack_context(msg, context)
conn = ConnectionContext()
wait_msg = MulticallWaiter(conn)
conn.declare_direct_consumer(msg_id, wait_msg)
conn.topic_send(topic, msg)
return wait_msg
def iterconsume(self, limit=None):
"""Return an iterator that will consume from all queues/consumers"""
while True:
try:
queues_head = self.consumers[:-1]
queues_tail = self.consumers[-1]
for queue in queues_head:
queue.consume(nowait=True)
queues_tail.consume(nowait=False)
for iteration in itertools.count(0):
if limit and iteration >= limit:
raise StopIteration
yield self.connection.drain_events()
except self.connection.connection_errors, e:
LOG.exception(_('Failed to consume message from queue: '
'%s' % str(e)))
self.reconnect()
def multicall(context, topic, msg):
"""Make a call that returns multiple times."""
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))
_pack_context(msg, context)
con_conn = ConnectionPool.get()
consumer = DirectConsumer(connection=con_conn, msg_id=msg_id)
wait_msg = MulticallWaiter(consumer)
consumer.register_callback(wait_msg)
publisher = TopicPublisher(connection=con_conn, topic=topic)
publisher.send(msg)
publisher.close()
return wait_msg
def wait(self, limit=None):
running = True
while running:
it = self.consumer_set.iterconsume(limit=limit)
if not it:
break
while True:
try:
it.next()
except StopIteration:
return
except greenlet.GreenletExit:
running = False
break
except Exception as e:
LOG.exception(_("Exception while processing consumer"))
self.reconnect()
# Break to outer loop
break
def _process_data(self, ctxt, method, args):
"""Thread that magically looks for a method on the proxy
object and calls it.
"""
try:
node_func = getattr(self.proxy, str(method))
node_args = dict((str(k), v) for k, v in args.iteritems())
# NOTE(vish): magic is fun!
rval = node_func(context=ctxt, **node_args)
# Check if the result was a generator
if inspect.isgenerator(rval):
for x in rval:
ctxt.reply(x, None)
else:
ctxt.reply(rval, None)
# This final None tells multicall that it is done.
ctxt.reply(ending=True)
except Exception as e:
LOG.exception('Exception during message handling')
ctxt.reply(None, sys.exc_info())
return
def __call__(self, message_data):
"""Consumer callback to call a method on a proxy object.
Parses the message for validity and fires off a thread to call the
proxy object method.
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)
ctxt = _unpack_context(message_data)
method = message_data.get('method')
args = message_data.get('args', {})
if not method:
LOG.warn(_('no method for message: %s') % message_data)
ctxt.reply(_('No method for message: %s') % message_data)
return
self.pool.spawn_n(self._process_data, ctxt, method, args)
def create(self):
LOG.debug('Pool creating new connection')
return Connection()
class Connection(object):
"""Connection object."""
def __init__(self):
self.consumers = []
self.consumer_thread = None
self.max_retries = FLAGS.rabbit_max_retries
# Try forever?
if self.max_retries <= 0:
self.max_retries = None
self.interval_start = FLAGS.rabbit_retry_interval
self.interval_stepping = FLAGS.rabbit_retry_backoff
# max retry-interval = 30 seconds
self.interval_max = 30
self.memory_transport = False
self.params = dict(hostname=FLAGS.rabbit_host,
port=FLAGS.rabbit_port,
userid=FLAGS.rabbit_userid,
password=FLAGS.rabbit_password,
virtual_host=FLAGS.rabbit_virtual_host)
if FLAGS.fake_rabbit:
self.params['transport'] = 'memory'
self.memory_transport = True
else:
self.memory_transport = False
self.connection = None
self.reconnect()
def reconnect(self):
"""Handles reconnecting and re-establishing queues"""
if self.connection:
try:
self.connection.close()
except self.connection.connection_errors:
pass
time.sleep(1)
self.connection = kombu.connection.BrokerConnection(**self.params)
if self.memory_transport:
# Kludge to speed up tests.
self.connection.transport.polling_interval = 0.0
self.consumer_num = itertools.count(1)
try:
self.connection.ensure_connection(errback=self.connect_error,
max_retries=self.max_retries,
interval_start=self.interval_start,
interval_step=self.interval_stepping,
interval_max=self.interval_max)
except self.connection.connection_errors, e:
# We should only get here if max_retries is set. We'll go
# ahead and exit in this case.
err_str = str(e)
max_retries = self.max_retries
LOG.error(_('Unable to connect to AMQP server '
'after %(max_retries)d tries: %(err_str)s') % locals())
sys.exit(1)
LOG.info(_('Connected to AMQP server on %(hostname)s:%(port)d' %
self.params))
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)
if self.consumers:
LOG.debug(_("Re-established AMQP queues"))
def fanout_cast(context, topic, msg):
"""Sends a message on a fanout exchange without waiting for a response."""
LOG.debug(_('Making asynchronous fanout cast...'))
_pack_context(msg, context)
with ConnectionContext() as conn:
conn.fanout_send(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)
_pack_context(msg, context)
with ConnectionContext() as conn:
conn.topic_send(topic, msg)
def generic_response(message_data, message):
"""Logs a result and exits."""
LOG.debug(_('response %s'), message_data)
message.ack()
sys.exit(0)
def notify(context, topic, msg):
"""Sends a notification event on a topic."""
LOG.debug(_('Sending notification on %s...'), topic)
_pack_context(msg, context)
with ConnectionContext() as conn:
conn.notify_send(topic, msg, durable=True)
def create(self):
LOG.debug('Pool creating new connection')
return Connection.instance(new=True)
