openstack/oslo.messaging
Code Issues Proposed changes
oslo.messaging/oslo/messaging/_drivers/impl_rabbit.py
Mark McLoughlin c846cf35b8 Add a TransportURL class to the public API 
Nova's cells/rpc_driver.py has some code which allows user of the REST
API to update elements of a cell's transport URL (say, the host name of
the message broker) stored in the database. To achieve this, it has
a parse_transport_url() method which breaks the URL into its constituent
parts and an unparse_transport_url() which re-forms it again after
updating some of its parts.

This is all fine and, since it's fairly specialized, it wouldn't be a
big deal to leave this code in Nova for now ... except the unparse
method looks at CONF.rpc_backend to know what scheme to use in the
returned URL if now backend was specified.

oslo.messaging registers the rpc_backend option, but the ability to
reference any option registered by the library should not be relied upon
by users of the library. Imagine, for instance, if we renamed the option
in future (with backwards compat for old configurations), then this
would mean API breakage.

So, long story short - an API along these lines makes some sense, but
especially since not having it would mean we'd need to add some way to
query the name of the transport driver.

In this commit, we add a simple new TransportURL class:

  >>> url = messaging.TransportURL.parse(cfg.CONF, 'foo:///')
  >>> str(url), url
  ('foo:///', <TransportURL transport='foo'>)
  >>> url.hosts.append(messaging.TransportHost(hostname='localhost'))
  >>> str(url), url
  ('foo://localhost/', <TransportURL transport='foo', hosts=[<TransportHost hostname='localhost'>]>)
  >>> url.transport = None
  >>> str(url), url
  ('kombu://localhost/', <TransportURL transport='kombu', hosts=[<TransportHost hostname='localhost'>]>)
  >>> cfg.CONF.set_override('rpc_backend', 'bar')
  >>> str(url), url
  ('bar://localhost/', <TransportURL transport='bar', hosts=[<TransportHost hostname='localhost'>]>)

The TransportURL.parse() method equates to parse_transport_url() and
TransportURL.__str__() equates to unparse_transport().

The transport drivers are also updated to take a TransportURL as a
required argument, which simplifies the handling of transport URLs in
the drivers.

Change-Id: Ic04173476329858e4a2c2d2707e9d4aeb212d127
2013-08-12 23:30:43 +01:00

887 lines
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# 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 logging
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
from oslo.messaging._drivers import amqp as rpc_amqp
from oslo.messaging._drivers import amqpdriver
from oslo.messaging._drivers import common as rpc_common
from oslo.messaging.openstack.common import excutils
from oslo.messaging.openstack.common import network_utils
from oslo.messaging.openstack.common import sslutils
# FIXME(markmc): remove this
_ = lambda s: s
rabbit_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.'),
# FIXME(markmc): this was toplevel in openstack.common.rpc
cfg.BoolOpt('fake_rabbit',
default=False,
help='If passed, use a fake RabbitMQ provider'),
]
LOG = logging.getLogger(__name__)
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 .reject()'ed.
Rejection is better than waiting for the message to timeout.
Rejected messages are immediately requeued.
"""
ack_msg = False
try:
msg = rpc_common.deserialize_msg(message.payload)
callback(msg)
ack_msg = True
except Exception:
if self.ack_on_error:
ack_msg = True
LOG.exception(_("Failed to process message"
" ... skipping it."))
else:
LOG.exception(_("Failed to process message"
" ... will requeue."))
finally:
if ack_msg:
message.ack()
else:
message.reject()
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 server_params.iteritems():
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.do_consume = 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
if not ssl_params:
# Just have the default behavior
return True
else:
# Return the extended behavior
return ssl_params
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.do_consume = True
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,
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."""
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))
self.do_consume = True
def _consume():
if self.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)
self.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, timeout=None):
"""Consume from all queues/consumers."""
it = self.iterconsume(limit=limit, timeout=timeout)
while True:
try:
it.next()
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),
)
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)
class RabbitDriver(amqpdriver.AMQPDriverBase):
def __init__(self, conf, url, default_exchange=None,
allowed_remote_exmods=[]):
conf.register_opts(rabbit_opts)
conf.register_opts(rpc_amqp.amqp_opts)
connection_pool = rpc_amqp.get_connection_pool(conf, Connection)
super(RabbitDriver, self).__init__(conf, url,
connection_pool,
default_exchange,
allowed_remote_exmods)
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