338 lines
11 KiB
Python
338 lines
11 KiB
Python
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# Copyright 2013 Red Hat, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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__all__ = ['AMQPDriverBase']
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import logging
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import Queue
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import threading
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import uuid
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from oslo import messaging
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from oslo.messaging._drivers import amqp as rpc_amqp
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from oslo.messaging._drivers import base
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from oslo.messaging._drivers import common as rpc_common
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from oslo.messaging import _urls as urls
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LOG = logging.getLogger(__name__)
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class AMQPIncomingMessage(base.IncomingMessage):
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def __init__(self, listener, ctxt, message, msg_id, reply_q):
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super(AMQPIncomingMessage, self).__init__(listener, ctxt, message)
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self.msg_id = msg_id
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self.reply_q = reply_q
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def _send_reply(self, conn, reply=None, failure=None, ending=False):
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if failure:
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failure = rpc_common.serialize_remote_exception(failure)
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# FIXME(markmc): is the reply format really driver specific?
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msg = {'result': reply, 'failure': failure}
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# FIXME(markmc): given that we're not supporting multicall ...
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if ending:
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msg['ending'] = True
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rpc_amqp._add_unique_id(msg)
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# If a reply_q exists, add the msg_id to the reply and pass the
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# reply_q to direct_send() to use it as the response queue.
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# Otherwise use the msg_id for backward compatibilty.
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if self.reply_q:
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msg['_msg_id'] = self.msg_id
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conn.direct_send(self.reply_q, rpc_common.serialize_msg(msg))
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else:
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conn.direct_send(self.msg_id, rpc_common.serialize_msg(msg))
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def reply(self, reply=None, failure=None):
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LOG.info("reply")
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with self.listener.driver._get_connection() as conn:
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self._send_reply(conn, reply, failure)
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self._send_reply(conn, ending=True)
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class AMQPListener(base.Listener):
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def __init__(self, driver, target, conn):
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super(AMQPListener, self).__init__(driver, target)
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self.conn = conn
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self.msg_id_cache = rpc_amqp._MsgIdCache()
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self.incoming = []
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def __call__(self, message):
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# FIXME(markmc): del local.store.context
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# FIXME(markmc): logging isn't driver specific
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rpc_common._safe_log(LOG.debug, 'received %s', message)
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self.msg_id_cache.check_duplicate_message(message)
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ctxt = rpc_amqp.unpack_context(self.conf, message)
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self.incoming.append(AMQPIncomingMessage(self,
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ctxt.to_dict(),
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message,
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ctxt.msg_id,
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ctxt.reply_q))
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def poll(self):
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while True:
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if self.incoming:
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return self.incoming.pop(0)
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self.conn.consume(limit=1)
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class ReplyWaiters(object):
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def __init__(self):
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self._queues = {}
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self._wrn_threshhold = 10
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def get(self, msg_id, timeout):
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try:
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return self._queues[msg_id].get(block=True, timeout=timeout)
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except Queue.Empty:
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raise messaging.MessagingTimeout('Timed out waiting for a reply '
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'to message ID %s' % msg_id)
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def put(self, msg_id, message_data):
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queue = self._queues.get(msg_id)
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if not queue:
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LOG.warn('No calling threads waiting for msg_id : %(msg_id)s'
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', message : %(data)s', {'msg_id': msg_id,
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'data': message_data})
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LOG.warn('_queues: %s' % str(self._queues))
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else:
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queue.put(message_data)
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def wake_all(self, except_id):
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msg_ids = [i for i in self._queues if i != except_id]
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for msg_id in msg_ids:
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self.put(msg_id, None)
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def add(self, msg_id, queue):
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self._queues[msg_id] = queue
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if len(self._queues) > self._wrn_threshhold:
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LOG.warn('Number of call queues is greater than warning '
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'threshhold: %d. There could be a leak.' %
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self._wrn_threshhold)
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self._wrn_threshhold *= 2
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def remove(self, msg_id):
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del self._queues[msg_id]
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class ReplyWaiter(object):
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def __init__(self, conf, reply_q, conn):
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self.conf = conf
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self.conn = conn
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self.reply_q = reply_q
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self.conn_lock = threading.Lock()
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self.incoming = []
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self.msg_id_cache = rpc_amqp._MsgIdCache()
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self.waiters = ReplyWaiters()
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conn.declare_direct_consumer(reply_q, self)
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def __call__(self, message):
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self.incoming.append(message)
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def listen(self, msg_id):
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queue = Queue.Queue()
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self.waiters.add(msg_id, queue)
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def unlisten(self, msg_id):
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self.waiters.remove(msg_id)
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def _process_reply(self, data):
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result = None
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ending = False
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self.msg_id_cache.check_duplicate_message(data)
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if data['failure']:
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failure = data['failure']
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result = rpc_common.deserialize_remote_exception(self.conf,
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failure)
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elif data.get('ending', False):
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ending = True
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else:
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result = data['result']
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return result, ending
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def _poll_connection(self, msg_id, timeout):
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while True:
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while self.incoming:
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message_data = self.incoming.pop(0)
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incoming_msg_id = message_data.pop('_msg_id', None)
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if incoming_msg_id == msg_id:
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return self._process_reply(message_data)
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self.waiters.put(incoming_msg_id, message_data)
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try:
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self.conn.consume(limit=1, timeout=timeout)
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except rpc_common.Timeout:
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raise messaging.MessagingTimeout('Timed out waiting for a '
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'reply to message ID %s'
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% msg_id)
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def _poll_queue(self, msg_id, timeout):
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while True:
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message = self.waiters.get(msg_id, timeout)
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if message is None:
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return None, None, True # lock was released
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reply, ending = self._process_reply(message)
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return reply, ending, False
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def wait(self, msg_id, timeout):
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# NOTE(markmc): multiple threads may call this
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# First thread calls consume, when it gets its reply
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# it wakes up other threads and they call consume
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# If a thread gets a message destined for another
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# thread, it wakes up the other thread
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final_reply = None
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while True:
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if self.conn_lock.acquire(False):
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try:
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while True:
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reply, ending = self._poll_connection(msg_id, timeout)
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if reply:
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final_reply = reply
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elif ending:
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return final_reply
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finally:
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self.conn_lock.release()
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self.waiters.wake_all(msg_id)
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else:
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reply, ending, trylock = self._poll_queue(msg_id, timeout)
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if trylock:
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continue
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if reply:
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final_reply = reply
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elif ending:
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return final_reply
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class AMQPDriverBase(base.BaseDriver):
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def __init__(self, conf, connection_pool, url=None, default_exchange=None):
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super(AMQPDriverBase, self).__init__(conf, url, default_exchange)
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self._default_exchange = urls.exchange_from_url(url, default_exchange)
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# FIXME(markmc): temp hack
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if self._default_exchange:
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self.conf.set_override('control_exchange', self._default_exchange)
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self._connection_pool = connection_pool
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self._reply_q_lock = threading.Lock()
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self._reply_q = None
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self._reply_q_conn = None
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self._waiter = None
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def _get_connection(self, pooled=True):
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return rpc_amqp.ConnectionContext(self.conf,
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self._connection_pool,
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pooled=pooled)
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def _get_reply_q(self):
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with self._reply_q_lock:
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if self._reply_q is not None:
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return self._reply_q
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reply_q = 'reply_' + uuid.uuid4().hex
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conn = self._get_connection(pooled=False)
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self._waiter = ReplyWaiter(self.conf, reply_q, conn)
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self._reply_q = reply_q
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self._reply_q_conn = conn
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return self._reply_q
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def send(self, target, ctxt, message,
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wait_for_reply=None, timeout=None, envelope=False):
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# FIXME(markmc): remove this temporary hack
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class Context(object):
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def __init__(self, d):
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self.d = d
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def to_dict(self):
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return self.d
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context = Context(ctxt)
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msg = message
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msg_id = uuid.uuid4().hex
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msg.update({'_msg_id': msg_id})
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LOG.debug('MSG_ID is %s' % (msg_id))
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rpc_amqp._add_unique_id(msg)
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rpc_amqp.pack_context(msg, context)
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msg.update({'_reply_q': self._get_reply_q()})
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# FIXME(markmc): handle envelope param
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msg = rpc_common.serialize_msg(msg)
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if wait_for_reply:
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self._waiter.listen(msg_id)
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try:
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with self._get_connection() as conn:
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# FIXME(markmc): check that target.topic is set
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if target.fanout:
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conn.fanout_send(target.topic, msg)
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else:
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topic = target.topic
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if target.server:
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topic = '%s.%s' % (target.topic, target.server)
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conn.topic_send(topic, msg, timeout=timeout)
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if wait_for_reply:
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result = self._waiter.wait(msg_id, timeout)
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if isinstance(result, Exception):
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raise result
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return result
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finally:
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if wait_for_reply:
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self._waiter.unlisten(msg_id)
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def listen(self, target):
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# FIXME(markmc): check that topic.target and topic.server is set
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conn = self._get_connection(pooled=False)
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listener = AMQPListener(self, target, conn)
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conn.declare_topic_consumer(target.topic, listener)
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conn.declare_topic_consumer('%s.%s' % (target.topic, target.server),
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listener)
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conn.declare_fanout_consumer(target.topic, listener)
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return listener
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def cleanup(self):
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if self._connection_pool:
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self._connection_pool.empty()
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self._connection_pool = None
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