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OpenStack Study: matchmaker_ring.py**** CubicPower OpenStack Study ****
# Copyright 2011-2013 Cloudscaling Group, 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. """ The MatchMaker classes should except a Topic or Fanout exchange key and return keys for direct exchanges, per (approximate) AMQP parlance. """ import itertools import json from oslo.config import cfg from neutron.openstack.common.gettextutils import _LW from neutron.openstack.common import log as logging from neutron.openstack.common.rpc import matchmaker as mm matchmaker_opts = [ # Matchmaker ring file cfg.StrOpt('ringfile', deprecated_name='matchmaker_ringfile', deprecated_group='DEFAULT', default='/etc/oslo/matchmaker_ring.json', help='Matchmaker ring file (JSON)'), ] CONF = cfg.CONF CONF.register_opts(matchmaker_opts, 'matchmaker_ring') LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class RingExchange(mm.Exchange): """Match Maker where hosts are loaded from a static JSON formatted file. __init__ takes optional ring dictionary argument, otherwise loads the ringfile from CONF.mathcmaker_ringfile. """
**** CubicPower OpenStack Study **** def __init__(self, ring=None): super(RingExchange, self).__init__() if ring: self.ring = ring else: with open(CONF.matchmaker_ring.ringfile, 'r') as fh: self.ring = json.load(fh) self.ring0 = {} for k in self.ring.keys(): self.ring0[k] = itertools.cycle(self.ring[k])
**** CubicPower OpenStack Study **** def _ring_has(self, key): return key in self.ring0
**** CubicPower OpenStack Study **** class RoundRobinRingExchange(RingExchange): """A Topic Exchange based on a hashmap."""
**** CubicPower OpenStack Study **** def __init__(self, ring=None): super(RoundRobinRingExchange, self).__init__(ring)
**** CubicPower OpenStack Study **** def run(self, key): if not self._ring_has(key): LOG.warn( _LW("No key defining hosts for topic '%s', " "see ringfile") % (key, ) ) return [] host = next(self.ring0[key]) return [(key + '.' + host, host)]
**** CubicPower OpenStack Study **** class FanoutRingExchange(RingExchange): """Fanout Exchange based on a hashmap."""
**** CubicPower OpenStack Study **** def __init__(self, ring=None): super(FanoutRingExchange, self).__init__(ring)
**** CubicPower OpenStack Study **** def run(self, key): # Assume starts with "fanout~", strip it for lookup. nkey = key.split('fanout~')[1:][0] if not self._ring_has(nkey): LOG.warn( _LW("No key defining hosts for topic '%s', " "see ringfile") % (nkey, ) ) return [] return map(lambda x: (key + '.' + x, x), self.ring[nkey])
**** CubicPower OpenStack Study **** class MatchMakerRing(mm.MatchMakerBase): """Match Maker where hosts are loaded from a static hashmap."""
**** CubicPower OpenStack Study **** def __init__(self, ring=None): super(MatchMakerRing, self).__init__() self.add_binding(mm.FanoutBinding(), FanoutRingExchange(ring)) self.add_binding(mm.DirectBinding(), mm.DirectExchange()) self.add_binding(mm.TopicBinding(), RoundRobinRingExchange(ring))
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