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

oslo_messaging/_cmd/__init__.py

@@ -0,0 +1 @@
+

oslo_messaging/_cmd/zmq_broker.py

@@ -0,0 +1,42 @@
+#    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()

oslo_messaging/_drivers/impl_zmq.py

@@ -80,6 +80,10 @@ zmq_opts = [
                default=1,
                help='The default number of seconds that poll should wait. '
                     'Poll raises timeout exception when timeout expired.'),
+
+    cfg.BoolOpt('zmq_use_broker',
+                default=True,
+                help='Shows whether zmq-messaging uses broker or not.')
 ]
 
 

oslo_messaging/_drivers/zmq_driver/broker/zmq_base_proxy.py

@@ -0,0 +1,53 @@
+#    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 abc
+import logging
+
+import six
+
+from oslo_messaging._drivers.zmq_driver import zmq_async
+
+LOG = logging.getLogger(__name__)
+
+
+@six.add_metaclass(abc.ABCMeta)
+class BaseProxy(object):
+
+    """Base TCP-proxy.
+
+    TCP-proxy redirects messages received by TCP from clients to servers
+    over IPC. Consists of TCP-frontend and IPC-backend objects. Runs
+    in async executor.
+    """
+
+    def __init__(self, conf, context):
+        super(BaseProxy, self).__init__()
+        self.conf = conf
+        self.context = context
+        self.executor = zmq_async.get_executor(self.run,
+                                               zmq_concurrency='native')
+
+    @abc.abstractmethod
+    def run(self):
+        """Main execution point of the proxy"""
+
+    def start(self):
+        self.executor.execute()
+
+    def stop(self):
+        self.executor.stop()
+
+    def wait(self):
+        self.executor.wait()

oslo_messaging/_drivers/zmq_driver/broker/zmq_broker.py

@@ -0,0 +1,82 @@
+#    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 logging
+import os
+
+from oslo_utils import excutils
+import six
+from stevedore import driver
+import zmq
+
+from oslo_messaging._drivers.zmq_driver.broker import zmq_queue_proxy
+from oslo_messaging._i18n import _LE, _LI
+
+
+LOG = logging.getLogger(__name__)
+
+
+class ZmqBroker(object):
+    """Local messaging IPC broker (nodes are still peers).
+       The main purpose is to have native zeromq application.
+       Benefits of such approach are following:
+
+        1. No risk to block the main thread of the process by unpatched
+           native parts of the libzmq (c-library is completely monkey-patch
+           unfriendly)
+        2. Making use of standard zmq approaches as async pollers,
+           devices, queues etc.
+        3. Possibility to implement queue persistence not touching existing
+           clients (staying in a separate process).
+    """
+
+    def __init__(self, conf):
+        super(ZmqBroker, self).__init__()
+        self.conf = conf
+        self._create_ipc_dirs()
+        self.matchmaker = driver.DriverManager(
+            'oslo.messaging.zmq.matchmaker',
+            self.conf.rpc_zmq_matchmaker,
+        ).driver(self.conf)
+
+        self.context = zmq.Context()
+        self.queue = six.moves.queue.Queue()
+        self.proxies = [zmq_queue_proxy.OutgoingQueueProxy(
+            conf, self.context, self.queue, self.matchmaker),
+            zmq_queue_proxy.IncomingQueueProxy(
+                conf, self.context, self.queue)
+        ]
+
+    def _create_ipc_dirs(self):
+        ipc_dir = self.conf.rpc_zmq_ipc_dir
+        try:
+            os.makedirs("%s/fanout" % ipc_dir)
+        except os.error:
+            if not os.path.isdir(ipc_dir):
+                with excutils.save_and_reraise_exception():
+                    LOG.error(_LE("Required IPC directory does not exist at"
+                                  " %s"), ipc_dir)
+
+    def start(self):
+        for proxy in self.proxies:
+            proxy.start()
+
+    def wait(self):
+        for proxy in self.proxies:
+            proxy.wait()
+
+    def close(self):
+        LOG.info(_LI("Broker shutting down ..."))
+        for proxy in self.proxies:
+            proxy.stop()

oslo_messaging/_drivers/zmq_driver/broker/zmq_queue_proxy.py

@@ -0,0 +1,78 @@
+#    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 logging
+
+import six
+import zmq
+
+from oslo_messaging._drivers.zmq_driver.broker import zmq_base_proxy
+from oslo_messaging._drivers.zmq_driver.client.publishers\
+    import zmq_dealer_publisher
+from oslo_messaging._drivers.zmq_driver import zmq_address
+from oslo_messaging._drivers.zmq_driver import zmq_async
+from oslo_messaging._i18n import _LI
+
+LOG = logging.getLogger(__name__)
+
+
+class OutgoingQueueProxy(zmq_base_proxy.BaseProxy):
+
+    def __init__(self, conf, context, queue, matchmaker):
+        super(OutgoingQueueProxy, self).__init__(conf, context)
+        self.queue = queue
+        self.matchmaker = matchmaker
+        self.publisher = zmq_dealer_publisher.DealerPublisher(
+            conf, matchmaker)
+        LOG.info(_LI("Polling at outgoing proxy ..."))
+
+    def run(self):
+        try:
+            request = self.queue.get(timeout=self.conf.rpc_poll_timeout)
+            LOG.info(_LI("Redirecting request %s to TCP publisher ...")
+                     % request)
+            self.publisher.send_request(request)
+        except six.moves.queue.Empty:
+            return
+
+
+class IncomingQueueProxy(zmq_base_proxy.BaseProxy):
+
+    def __init__(self, conf, context, queue):
+        super(IncomingQueueProxy, self).__init__(conf, context)
+        self.poller = zmq_async.get_poller(
+            zmq_concurrency='native')
+
+        self.queue = queue
+
+        self.socket = context.socket(zmq.ROUTER)
+        self.socket.bind(zmq_address.get_broker_address(conf))
+        self.poller.register(self.socket, self.receive_request)
+        LOG.info(_LI("Polling at incoming proxy ..."))
+
+    def run(self):
+        request, socket = self.poller.poll(self.conf.rpc_poll_timeout)
+        if request is None:
+            return
+
+        LOG.info(_LI("Received request and queue it: %s") % str(request))
+
+        self.queue.put(request)
+
+    def receive_request(self, socket):
+        reply_id = socket.recv()
+        assert reply_id is not None, "Valid id expected"
+        empty = socket.recv()
+        assert empty == b'', "Empty delimiter expected"
+        return socket.recv_pyobj()

oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_dealer_publisher.py

@@ -13,7 +13,6 @@
 #    under the License.
 
 import logging
-import uuid
 
 from oslo_messaging._drivers.zmq_driver.client.publishers\
     import zmq_publisher_base
@@ -58,13 +57,8 @@ class DealerPublisher(zmq_publisher_base.PublisherMultisend):
 
     def _send_request(self, socket, request):
 
-        message_id = str(uuid.uuid1())
-
         socket.send(b'', zmq.SNDMORE)
-        socket.send_string(request.msg_type, zmq.SNDMORE)
-        socket.send_string(message_id, zmq.SNDMORE)
-        socket.send_pyobj(request.context, zmq.SNDMORE)
-        socket.send_pyobj(request.message)
+        socket.send_pyobj(request)
 
         LOG.info(_LI("Sending message %(message)s to a target %(target)s")
                  % {"message": request.message,
@@ -75,6 +69,26 @@ class DealerPublisher(zmq_publisher_base.PublisherMultisend):
         super(DealerPublisher, self).cleanup()
 
 
+class DealerPublisherLight(zmq_publisher_base.PublisherBase):
+
+    def __init__(self, conf, address):
+        super(DealerPublisherLight, self).__init__(conf)
+        self.socket = self.zmq_context.socket(zmq.DEALER)
+        self.socket.connect(address)
+
+    def send_request(self, request):
+
+        if request.msg_type == zmq_names.CALL_TYPE:
+            raise zmq_publisher_base.UnsupportedSendPattern(request.msg_type)
+
+        self.socket.send(b'', zmq.SNDMORE)
+        self.socket.send_pyobj(request)
+
+    def cleanup(self):
+        self.socket.setsockopt(zmq.LINGER, 0)
+        self.socket.close()
+
+
 class AcknowledgementReceiver(object):
 
     def __init__(self):

oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_publisher_base.py

@@ -56,7 +56,7 @@ class PublisherBase(object):
     Publisher can send request objects from zmq_request.
     """
 
-    def __init__(self, conf, matchmaker):
+    def __init__(self, conf):
 
         """Construct publisher
 
@@ -65,13 +65,10 @@ class PublisherBase(object):
 
         :param conf: configuration object
         :type conf: oslo_config.CONF
-        :param matchmaker: Name Service interface object
-        :type matchmaker: matchmaker.MatchMakerBase
         """
 
         self.conf = conf
         self.zmq_context = zmq.Context()
-        self.matchmaker = matchmaker
         self.outbound_sockets = {}
         super(PublisherBase, self).__init__()
 
@@ -92,9 +89,7 @@ class PublisherBase(object):
         :param request: Message data and destination container object
         :type request: zmq_request.Request
         """
-        socket.send_string(request.msg_type, zmq.SNDMORE)
-        socket.send_pyobj(request.context, zmq.SNDMORE)
-        socket.send_pyobj(request.message)
+        socket.send_pyobj(request)
 
     def cleanup(self):
         """Cleanup publisher. Close allocated connections."""
@@ -106,8 +101,19 @@ class PublisherBase(object):
 class PublisherMultisend(PublisherBase):
 
     def __init__(self, conf, matchmaker, socket_type):
+
+        """Construct publisher multi-send
+
+        Base class for fanout-sending publishers.
+
+        :param conf: configuration object
+        :type conf: oslo_config.CONF
+        :param matchmaker: Name Service interface object
+        :type matchmaker: matchmaker.MatchMakerBase
+        """
+        super(PublisherMultisend, self).__init__(conf)
         self.socket_type = socket_type
-        super(PublisherMultisend, self).__init__(conf, matchmaker)
+        self.matchmaker = matchmaker
 
     def _check_hosts_connections(self, target):
         #  TODO(ozamiatin): Place for significant optimization
@@ -126,6 +132,7 @@ class PublisherMultisend(PublisherBase):
 
     def _connect_to_host(self, socket, host, target):
         address = zmq_address.get_tcp_direct_address(host)
+        LOG.info(address)
         stype = zmq_names.socket_type_str(self.socket_type)
         try:
             LOG.info(_LI("Connecting %(stype)s to %(address)s for %(target)s")

oslo_messaging/_drivers/zmq_driver/client/publishers/zmq_req_publisher.py

@@ -31,6 +31,10 @@ zmq = zmq_async.import_zmq()
 
 class ReqPublisher(zmq_publisher_base.PublisherBase):
 
+    def __init__(self, conf, matchmaker):
+        super(ReqPublisher, self).__init__(conf)
+        self.matchmaker = matchmaker
+
     def send_request(self, request):
 
         if request.msg_type != zmq_names.CALL_TYPE:

oslo_messaging/_drivers/zmq_driver/client/zmq_client.py

@@ -19,6 +19,7 @@ from oslo_messaging._drivers.zmq_driver.client.publishers\
 from oslo_messaging._drivers.zmq_driver.client.publishers\
     import zmq_req_publisher
 from oslo_messaging._drivers.zmq_driver.client import zmq_request
+from oslo_messaging._drivers.zmq_driver import zmq_address
 from oslo_messaging._drivers.zmq_driver import zmq_async
 
 zmq = zmq_async.import_zmq()
@@ -31,6 +32,12 @@ class ZmqClient(object):
         self.context = zmq.Context()
         self.matchmaker = matchmaker
         self.allowed_remote_exmods = allowed_remote_exmods or []
+
+        self.dealer_publisher = None
+        if self.conf.zmq_use_broker:
+            self.dealer_publisher = zmq_dealer_publisher.DealerPublisherLight(
+                conf, zmq_address.get_broker_address(self.conf))
+        else:
             self.dealer_publisher = zmq_dealer_publisher.DealerPublisher(
                 conf, matchmaker)
 

oslo_messaging/_drivers/zmq_driver/client/zmq_request.py

@@ -14,6 +14,7 @@
 
 import abc
 import logging
+import uuid
 
 import six
 
@@ -61,6 +62,7 @@ class Request(object):
         self.context = context
         self.message = message
         self.retry = retry
+        self.message_id = str(uuid.uuid1())
 
     @abc.abstractproperty
     def msg_type(self):

oslo_messaging/_drivers/zmq_driver/poller/threading_poller.py

@@ -41,7 +41,7 @@ class ThreadingPoller(zmq_poller.ZmqPoller):
         self.poller.register(socket, zmq.POLLIN)
 
     def poll(self, timeout=None):
-        timeout = timeout * 1000  # zmq poller waits milliseconds
+        timeout *= 1000  # zmq poller waits milliseconds
         sockets = None
 
         try:

oslo_messaging/_drivers/zmq_driver/server/consumers/zmq_router_consumer.py

@@ -81,29 +81,22 @@ class RouterConsumer(zmq_consumer_base.SingleSocketConsumer):
             reply_id = socket.recv()
             empty = socket.recv()
             assert empty == b'', 'Bad format: empty delimiter expected'
-            msg_type = socket.recv_string()
-            assert msg_type is not None, 'Bad format: msg type expected'
+            request = socket.recv_pyobj()
 
-            msg_id = None
-            if msg_type != zmq_names.CALL_TYPE:
-                msg_id = socket.recv_string()
-
-            context = socket.recv_pyobj()
-            message = socket.recv_pyobj()
             LOG.info(_LI("Received %(msg_type)s message %(msg)s")
-                     % {"msg_type": msg_type,
-                        "msg": str(message)})
+                     % {"msg_type": request.msg_type,
+                        "msg": str(request.message)})
 
-            if msg_type == zmq_names.CALL_TYPE:
+            if request.msg_type == zmq_names.CALL_TYPE:
                 return zmq_incoming_message.ZmqIncomingRequest(
-                    self.server, context, message, socket, reply_id,
-                    self.poller)
-            elif msg_type in (zmq_names.CAST_TYPES + zmq_names.NOTIFY_TYPES):
+                    self.server, request.context, request.message, socket,
+                    reply_id, self.poller)
+            elif request.msg_type in zmq_names.NON_BLOCKING_TYPES:
                 return RouterIncomingMessage(
-                    self.server, context, message, socket, reply_id,
-                    msg_id, self.poller)
+                    self.server, request.context, request.message, socket,
+                    reply_id, request.message_id, self.poller)
             else:
-                LOG.error(_LE("Unknown message type: %s") % msg_type)
+                LOG.error(_LE("Unknown message type: %s") % request.msg_type)
 
         except zmq.ZMQError as e:
             LOG.error(_LE("Receiving message failed: %s") % str(e))

oslo_messaging/_drivers/zmq_driver/zmq_address.py

@@ -18,8 +18,12 @@ def combine_address(host, port):
 
 
 def get_tcp_direct_address(host):
-    return "tcp://%s" % (host)
+    return "tcp://%s" % str(host)
 
 
 def get_tcp_random_address(conf):
     return "tcp://*"
+
+
+def get_broker_address(conf):
+    return "ipc://%s/zmq-broker" % conf.rpc_zmq_ipc_dir

oslo_messaging/_drivers/zmq_driver/zmq_names.py

@@ -47,6 +47,7 @@ MULTISEND_TYPES = (CAST_FANOUT_TYPE, NOTIFY_FANOUT_TYPE)
 DIRECT_TYPES = (CALL_TYPE, CAST_TYPE, NOTIFY_TYPE)
 CAST_TYPES = (CAST_TYPE, CAST_FANOUT_TYPE)
 NOTIFY_TYPES = (NOTIFY_TYPE, NOTIFY_FANOUT_TYPE)
+NON_BLOCKING_TYPES = CAST_TYPES + NOTIFY_TYPES
 
 
 def socket_type_str(socket_type):

oslo_messaging/tests/drivers/zmq/test_impl_zmq.py

@@ -77,6 +77,7 @@ class ZmqBaseTestCase(test_utils.BaseTestCase):
                   'rpc_zmq_host': '127.0.0.1',
                   'rpc_response_timeout': 5,
                   'rpc_zmq_ipc_dir': self.internal_ipc_dir,
+                  'zmq_use_broker': False,
                   'rpc_zmq_matchmaker': 'dummy'}
         self.config(**kwargs)
 

setup-test-env-zmq.sh

@@ -22,4 +22,6 @@ EOF
 
 redis-server --port $ZMQ_REDIS_PORT &
 
+oslo-messaging-zmq-broker --config-file ${DATADIR}/zmq.conf > ${DATADIR}/zmq-broker.log 2>&1 &
+
 $*

setup.cfg

@@ -22,7 +22,7 @@ packages =
 
 [entry_points]
 console_scripts =
-    oslo-messaging-zmq-receiver = oslo_messaging._cmd.zmq_receiver:main
+    oslo-messaging-zmq-broker = oslo_messaging._cmd.zmq_broker:main
 
 oslo.messaging.drivers =
     rabbit = oslo_messaging._drivers.impl_rabbit:RabbitDriver