113 lines
4.2 KiB
Python
113 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 2012 IBM Corp.
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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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import iso8601
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from oslo_log import log as logging
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from oslo_utils import timeutils
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from nova import cache_utils
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import nova.conf
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from nova.i18n import _, _LI, _LW
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from nova.servicegroup import api
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from nova.servicegroup.drivers import base
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CONF = nova.conf.CONF
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LOG = logging.getLogger(__name__)
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class MemcachedDriver(base.Driver):
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def __init__(self, *args, **kwargs):
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self.mc = cache_utils.get_memcached_client(
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expiration_time=CONF.service_down_time)
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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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LOG.debug('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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{'member_id': member_id,
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'group_id': group_id,
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'service': service})
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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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service.tg.add_timer(report_interval, self._report_state,
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api.INITIAL_REPORTING_DELAY, service)
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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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is_up = self.mc.get(str(key)) is not None
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if not is_up:
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LOG.debug('Seems service %s is down', key)
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return is_up
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def updated_time(self, service_ref):
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"""Get the updated time from memcache"""
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key = "%(topic)s:%(host)s" % service_ref
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updated_time_in_mc = self.mc.get(str(key))
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updated_time_in_db = service_ref['updated_at']
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if updated_time_in_mc:
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# Change mc time to offset-aware time
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updated_time_in_mc = \
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updated_time_in_mc.replace(tzinfo=iso8601.UTC)
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# If [DEFAULT]/enable_new_services is set to be false, the
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# ``updated_time_in_db`` will be None, in this case, use
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# ``updated_time_in_mc`` instead.
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if (not updated_time_in_db or
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updated_time_in_db <= updated_time_in_mc):
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return updated_time_in_mc
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return updated_time_in_db
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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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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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# 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.info(
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_LI('Recovered connection to memcache server '
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'for reporting service status.'))
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# TODO(vish): this should probably only catch connection errors
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except Exception:
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if not getattr(service, 'model_disconnected', False):
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service.model_disconnected = True
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LOG.warning(_LW('Lost connection to memcache server '
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'for reporting service status.'))
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