101 lines
3.7 KiB
Python
101 lines
3.7 KiB
Python
# Copyright 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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import logging
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import retrying
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import time
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from oslo_messaging._drivers.zmq_driver.matchmaker import zmq_matchmaker_base
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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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from oslo_messaging._i18n import _LW
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zmq = zmq_async.import_zmq()
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LOG = logging.getLogger(__name__)
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class RoutingTable(object):
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"""This class implements local routing-table cache
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taken from matchmaker. Its purpose is to give the next routable
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host id (remote DEALER's id) by request for specific target in
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round-robin fashion.
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"""
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def __init__(self, conf, matchmaker):
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self.conf = conf
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self.matchmaker = matchmaker
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self.routing_table = {}
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self.routable_hosts = {}
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def get_all_hosts(self, target):
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self._update_routing_table(
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target,
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get_hosts=self.matchmaker.get_hosts_fanout,
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get_hosts_retry=self.matchmaker.get_hosts_fanout_retry)
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return self.routable_hosts.get(str(target), [])
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def get_routable_host(self, target):
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self._update_routing_table(
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target,
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get_hosts=self.matchmaker.get_hosts,
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get_hosts_retry=self.matchmaker.get_hosts_retry)
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hosts_for_target = self.routable_hosts.get(str(target))
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if not hosts_for_target:
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# Matchmaker doesn't contain any target
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return None
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host = hosts_for_target.pop(0)
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if not hosts_for_target:
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self._renew_routable_hosts(target)
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return host
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def _is_tm_expired(self, tm):
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return 0 <= self.conf.oslo_messaging_zmq.zmq_target_expire \
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<= time.time() - tm
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def _update_routing_table(self, target, get_hosts, get_hosts_retry):
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routing_record = self.routing_table.get(str(target))
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if routing_record is None:
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self._fetch_hosts(target, get_hosts, get_hosts_retry)
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self._renew_routable_hosts(target)
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elif self._is_tm_expired(routing_record[1]):
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self._fetch_hosts(target, get_hosts, get_hosts_retry)
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def _fetch_hosts(self, target, get_hosts, get_hosts_retry):
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key = str(target)
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if key not in self.routing_table:
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try:
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self.routing_table[key] = (get_hosts_retry(
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target, zmq_names.socket_type_str(zmq.DEALER)),
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time.time())
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except retrying.RetryError:
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LOG.warning(_LW("Matchmaker contains no hosts for target %s")
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% key)
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else:
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try:
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hosts = get_hosts(
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target, zmq_names.socket_type_str(zmq.DEALER))
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self.routing_table[key] = (hosts, time.time())
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except zmq_matchmaker_base.MatchmakerUnavailable:
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LOG.warning(_LW("Matchmaker contains no hosts for target %s")
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% key)
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def _renew_routable_hosts(self, target):
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key = str(target)
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try:
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hosts, _ = self.routing_table[key]
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self.routable_hosts[key] = list(hosts)
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except KeyError:
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self.routable_hosts[key] = []
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