1958f6e549
When using redis as zmq backend, the keys in redis maybe like follows: "service" "service.host1" "service.host1.host1" "service.host2" "service.host2.host2" "service.host3" "service.host3.host3" If we stopped the service on host1, the key named service.host1 and service.host1.host1 shoule be delete. As the result, the topicexchange message would not sent to host1. But the fact is service.host1 still exsit, and topicexchange message may still sent to host1. To resolve this problem , change the comparison of ttl function from -1 to -2 according to http://redis.io/commands/ttl Change-Id: I5c0af97019fffed6e949eb58d7d60c85f5b08ea1 Closes-Bug:#1417464
146 lines
4.8 KiB
Python
146 lines
4.8 KiB
Python
# Copyright 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 accept 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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from oslo_config import cfg
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from oslo_utils import importutils
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from oslo_messaging._drivers import matchmaker as mm_common
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redis = importutils.try_import('redis')
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matchmaker_redis_opts = [
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cfg.StrOpt('host',
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default='127.0.0.1',
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help='Host to locate redis.'),
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cfg.IntOpt('port',
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default=6379,
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help='Use this port to connect to redis host.'),
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cfg.StrOpt('password',
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help='Password for Redis server (optional).'),
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]
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CONF = cfg.CONF
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opt_group = cfg.OptGroup(name='matchmaker_redis',
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title='Options for Redis-based MatchMaker')
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CONF.register_group(opt_group)
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CONF.register_opts(matchmaker_redis_opts, opt_group)
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class RedisExchange(mm_common.Exchange):
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def __init__(self, matchmaker):
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self.matchmaker = matchmaker
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self.redis = matchmaker.redis
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super(RedisExchange, self).__init__()
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class RedisTopicExchange(RedisExchange):
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"""Exchange where all topic keys are split, sending to second half.
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i.e. "compute.host" sends a message to "compute" running on "host"
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"""
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def run(self, topic):
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while True:
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member_name = self.redis.srandmember(topic)
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if not member_name:
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# If this happens, there are no
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# longer any members.
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break
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if not self.matchmaker.is_alive(topic, member_name):
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continue
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host = member_name.split('.', 1)[1]
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return [(member_name, host)]
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return []
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class RedisFanoutExchange(RedisExchange):
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"""Return a list of all hosts."""
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def run(self, topic):
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topic = topic.split('~', 1)[1]
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hosts = self.redis.smembers(topic)
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good_hosts = filter(
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lambda host: self.matchmaker.is_alive(topic, host), hosts)
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return [(x, x.split('.', 1)[1]) for x in good_hosts]
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class MatchMakerRedis(mm_common.HeartbeatMatchMakerBase):
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"""MatchMaker registering and looking-up hosts with a Redis server."""
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def __init__(self):
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super(MatchMakerRedis, self).__init__()
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if not redis:
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raise ImportError("Failed to import module redis.")
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self.redis = redis.StrictRedis(
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host=CONF.matchmaker_redis.host,
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port=CONF.matchmaker_redis.port,
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password=CONF.matchmaker_redis.password)
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self.add_binding(mm_common.FanoutBinding(), RedisFanoutExchange(self))
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self.add_binding(mm_common.DirectBinding(), mm_common.DirectExchange())
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self.add_binding(mm_common.TopicBinding(), RedisTopicExchange(self))
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def ack_alive(self, key, host):
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topic = "%s.%s" % (key, host)
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if not self.redis.expire(topic, CONF.matchmaker_heartbeat_ttl):
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# If we could not update the expiration, the key
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# might have been pruned. Re-register, creating a new
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# key in Redis.
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self.register(key, host)
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def is_alive(self, topic, host):
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# After redis 2.8, if the specialized key doesn't exist,
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# TTL fuction would return -2. If key exists,
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# but doesn't have expiration associated,
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# TTL func would return -1. For more information,
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# please visit http://redis.io/commands/ttl
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if self.redis.ttl(host) == -2:
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self.expire(topic, host)
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return False
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return True
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def expire(self, topic, host):
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with self.redis.pipeline() as pipe:
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pipe.multi()
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pipe.delete(host)
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pipe.srem(topic, host)
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pipe.execute()
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def backend_register(self, key, key_host):
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with self.redis.pipeline() as pipe:
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pipe.multi()
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pipe.sadd(key, key_host)
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# No value is needed, we just
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# care if it exists. Sets aren't viable
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# because only keys can expire.
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pipe.sadd(key_host, '')
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pipe.execute()
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def backend_unregister(self, key, key_host):
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with self.redis.pipeline() as pipe:
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pipe.multi()
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pipe.srem(key, key_host)
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pipe.delete(key_host)
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pipe.execute()
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