141 lines
4.6 KiB
Python
141 lines
4.6 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(self.host_topic[host], host)
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def is_alive(self, topic, host):
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if self.redis.ttl(host) == -1:
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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.set(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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