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