90 lines
4.0 KiB
Python
90 lines
4.0 KiB
Python
# Copyright 2015-2016 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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from oslo_messaging._drivers.zmq_driver.client.publishers.dealer \
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import zmq_dealer_publisher_base
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from oslo_messaging._drivers.zmq_driver.client import zmq_receivers
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from oslo_messaging._drivers.zmq_driver.client import zmq_routing_table
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from oslo_messaging._drivers.zmq_driver.client import zmq_senders
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from oslo_messaging._drivers.zmq_driver import zmq_async
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from oslo_messaging._drivers.zmq_driver import zmq_names
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zmq = zmq_async.import_zmq()
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class DealerPublisherDirect(zmq_dealer_publisher_base.DealerPublisherBase):
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"""DEALER-publisher using direct connections.
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Publishing directly to remote services assumes the following:
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- All direct connections are dynamic - so they live per message,
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thus each message send executes the following:
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* Open a new socket
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* Connect to some host got from the RoutingTable
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* Send message(s)
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* Close connection, destroy socket
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- RoutingTable/RoutingTableUpdater implements local cache of
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matchmaker (e.g. Redis) for target resolution to the list of
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available hosts. Cache updates in a background thread.
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- Caching of connections is not appropriate for directly connected
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OS services, because finally it results in a full-mesh of
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connections between services.
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- Yes we lose on performance opening and closing connections
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for each message, but that is done intentionally to implement
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the dynamic connections concept. The key thought here is to
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have minimum number of connected services at the moment.
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- Using the local RoutingTable cache is done to optimise access
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to the matchmaker so we don't call the matchmaker per each message
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"""
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def __init__(self, conf, matchmaker):
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sender = zmq_senders.RequestSenderDirect(conf)
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receiver = zmq_receivers.ReceiverDirect(conf)
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super(DealerPublisherDirect, self).__init__(conf, matchmaker,
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sender, receiver)
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self.routing_table = zmq_routing_table.RoutingTableAdaptor(
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conf, matchmaker, zmq.ROUTER)
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def _get_round_robin_host_connection(self, target, socket):
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host = self.routing_table.get_round_robin_host(target)
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socket.connect_to_host(host)
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def _get_fanout_connection(self, target, socket):
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for host in self.routing_table.get_fanout_hosts(target):
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socket.connect_to_host(host)
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def acquire_connection(self, request):
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socket = self.sockets_manager.get_socket()
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if request.msg_type in zmq_names.DIRECT_TYPES:
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self._get_round_robin_host_connection(request.target, socket)
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elif request.msg_type in zmq_names.MULTISEND_TYPES:
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self._get_fanout_connection(request.target, socket)
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return socket
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def _finally_unregister(self, socket, request):
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super(DealerPublisherDirect, self)._finally_unregister(socket, request)
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self.receiver.unregister_socket(socket)
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def send_request(self, socket, request):
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if request.msg_type in zmq_names.MULTISEND_TYPES:
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for _ in range(socket.connections_count()):
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self.sender.send(socket, request)
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else:
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self.sender.send(socket, request)
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def cleanup(self):
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self.routing_table.cleanup()
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super(DealerPublisherDirect, self).cleanup()
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