oslo.messaging/oslo_messaging/_cmd/zmq_broker.py
Oleksii Zamiatin 3067dbd198 Non-blocking outgoing queue was implemented
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
2015-09-28 14:14:53 +03:00

43 lines
1.3 KiB
Python

# Copyright 2015 Mirantis, Inc.
#
# 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 contextlib
import logging
import sys
from oslo_config import cfg
from oslo_messaging._drivers import impl_zmq
from oslo_messaging._drivers.zmq_driver.broker import zmq_broker
from oslo_messaging._executors import impl_pooledexecutor
CONF = cfg.CONF
CONF.register_opts(impl_zmq.zmq_opts)
CONF.register_opts(impl_pooledexecutor._pool_opts)
# TODO(ozamiatin): Move this option assignment to an external config file
# Use efficient zmq poller in real-world deployment
CONF.rpc_zmq_native = True
def main():
CONF(sys.argv[1:], project='oslo')
logging.basicConfig(level=logging.DEBUG)
with contextlib.closing(zmq_broker.ZmqBroker(CONF)) as reactor:
reactor.start()
reactor.wait()
if __name__ == "__main__":
main()