3067dbd198
The main issue with eventlet.green.zmq is that libzmq as a C-library is completely monkey-patch unfriendly. So any blocking call inside the native library makes calling process stuck. We can't avoid this actually in an absolutely normal situation when a client appears earlier than listener we have all client process get stuck until listener raised. If the listener for example is also blocked awaiting for some other service to appear we have a chain of locks which may occasionally result in a dead-lock. The other situation with Notifier is quite similar. For that reason zmq-broker was restored, but now it serves as an outgoing queue on a client side. Servers remained the same dynamically port-binded. Now all clients can still use green-zmq, but presence of the broker-queue on a host guarantees that green threads will never blocked in a client because all messages will wait their listeners inside the broker queue. The broker process's modules are not monkey-patched, they make use of native threading and native zmq. Possibility to run without broker also remains. The option zmq_use_broker introduced for that reason. Closes-Bug: #1497315 Change-Id: I786b100fd6ee1cf4b99139db0ca044d358d36345
83 lines
2.7 KiB
Python
83 lines
2.7 KiB
Python
# Copyright 2015 Mirantis, 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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import logging
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import os
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from oslo_utils import excutils
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import six
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from stevedore import driver
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import zmq
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from oslo_messaging._drivers.zmq_driver.broker import zmq_queue_proxy
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from oslo_messaging._i18n import _LE, _LI
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LOG = logging.getLogger(__name__)
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class ZmqBroker(object):
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"""Local messaging IPC broker (nodes are still peers).
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The main purpose is to have native zeromq application.
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Benefits of such approach are following:
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1. No risk to block the main thread of the process by unpatched
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native parts of the libzmq (c-library is completely monkey-patch
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unfriendly)
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2. Making use of standard zmq approaches as async pollers,
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devices, queues etc.
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3. Possibility to implement queue persistence not touching existing
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clients (staying in a separate process).
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"""
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def __init__(self, conf):
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super(ZmqBroker, self).__init__()
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self.conf = conf
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self._create_ipc_dirs()
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self.matchmaker = driver.DriverManager(
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'oslo.messaging.zmq.matchmaker',
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self.conf.rpc_zmq_matchmaker,
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).driver(self.conf)
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self.context = zmq.Context()
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self.queue = six.moves.queue.Queue()
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self.proxies = [zmq_queue_proxy.OutgoingQueueProxy(
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conf, self.context, self.queue, self.matchmaker),
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zmq_queue_proxy.IncomingQueueProxy(
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conf, self.context, self.queue)
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]
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def _create_ipc_dirs(self):
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ipc_dir = self.conf.rpc_zmq_ipc_dir
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try:
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os.makedirs("%s/fanout" % ipc_dir)
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except os.error:
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if not os.path.isdir(ipc_dir):
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with excutils.save_and_reraise_exception():
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LOG.error(_LE("Required IPC directory does not exist at"
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" %s"), ipc_dir)
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def start(self):
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for proxy in self.proxies:
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proxy.start()
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def wait(self):
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for proxy in self.proxies:
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proxy.wait()
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def close(self):
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LOG.info(_LI("Broker shutting down ..."))
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for proxy in self.proxies:
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proxy.stop()
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