110 lines
4.2 KiB
Python
110 lines
4.2 KiB
Python
# Service heartbeat driver using Memcached
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# Copyright (c) 2013 Akira Yoshiyama <akirayoshiyama at gmail dot com>
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#
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# This is derived from nova/servicegroup/drivers/db.py.
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# Copyright (c) IBM 2012 Pavel Kravchenco <kpavel at il dot ibm dot com>
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# Alexey Roytman <roytman at il dot ibm dot com>
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from oslo.config import cfg
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from nova import conductor
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from nova import context
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from nova.openstack.common import log as logging
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from nova.openstack.common import memorycache
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from nova.openstack.common import timeutils
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from nova.servicegroup import api
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from nova import utils
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CONF = cfg.CONF
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CONF.import_opt('service_down_time', 'nova.service')
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CONF.import_opt('memcached_servers', 'nova.openstack.common.memorycache')
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LOG = logging.getLogger(__name__)
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class MemcachedDriver(api.ServiceGroupDriver):
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def __init__(self, *args, **kwargs):
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test = kwargs.get('test')
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if not CONF.memcached_servers and not test:
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raise RuntimeError(_('memcached_servers not defined'))
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self.mc = memorycache.get_client()
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self.db_allowed = kwargs.get('db_allowed', True)
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self.conductor_api = conductor.API(use_local=self.db_allowed)
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def join(self, member_id, group_id, service=None):
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"""Join the given service with its group."""
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msg = _('Memcached_Driver: join new ServiceGroup member '
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'%(member_id)s to the %(group_id)s group, '
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'service = %(service)s')
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LOG.debug(msg, locals())
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if service is None:
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raise RuntimeError(_('service is a mandatory argument for '
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'Memcached based ServiceGroup driver'))
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report_interval = service.report_interval
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if report_interval:
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pulse = utils.FixedIntervalLoopingCall(self._report_state, service)
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pulse.start(interval=report_interval,
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initial_delay=report_interval)
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return pulse
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def is_up(self, service_ref):
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"""Moved from nova.utils
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Check whether a service is up based on last heartbeat.
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"""
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key = "%(topic)s:%(host)s" % service_ref
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return self.mc.get(str(key)) is not None
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def get_all(self, group_id):
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"""
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Returns ALL members of the given group
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"""
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LOG.debug(_('Memcached_Driver: get_all members of the %s group') %
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group_id)
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rs = []
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ctxt = context.get_admin_context()
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services = self.conductor_api.service_get_all_by_topic(ctxt, group_id)
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for service in services:
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if self.is_up(service):
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rs.append(service['host'])
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return rs
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def _report_state(self, service):
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"""Update the state of this service in the datastore."""
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ctxt = context.get_admin_context()
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try:
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key = "%(topic)s:%(host)s" % service.service_ref
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# memcached has data expiration time capability.
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# set(..., time=CONF.service_down_time) uses it and
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# reduces key-deleting code.
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self.mc.set(str(key),
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timeutils.utcnow(),
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time=CONF.service_down_time)
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# TODO(termie): make this pattern be more elegant.
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if getattr(service, 'model_disconnected', False):
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service.model_disconnected = False
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LOG.error(_('Recovered model server connection!'))
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# TODO(vish): this should probably only catch connection errors
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except Exception: # pylint: disable=W0702
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if not getattr(service, 'model_disconnected', False):
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service.model_disconnected = True
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LOG.exception(_('model server went away'))
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