138 lines
4.7 KiB
Python
138 lines
4.7 KiB
Python
# 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_concurrency import lockutils
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from oslo_config import cfg
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from oslo_log import log
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from tooz import coordination
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from ironic_inspector import utils
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CONF = cfg.CONF
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LOG = log.getLogger(__name__)
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COORDINATION_PREFIX = 'ironic_inspector'
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COORDINATION_GROUP_NAME = '.'.join([COORDINATION_PREFIX, 'service_group'])
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LOCK_PREFIX = 'ironic_inspector.'
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class Coordinator(object):
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"""Tooz coordination wrapper."""
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group_name = COORDINATION_GROUP_NAME.encode('ascii')
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lock_prefix = LOCK_PREFIX
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def __init__(self, prefix=None):
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"""Creates a coordinator instance for service coordination.
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:param prefix: The prefix to be part of the member id of the service.
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Different types of services on the same host should use
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different prefix to work properly.
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"""
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self.coordinator = None
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self.started = False
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self.prefix = prefix if prefix else 'default'
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def start(self, heartbeat=True):
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"""Start coordinator.
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:param heartbeat: Whether spawns a new thread to keep heartbeating with
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the tooz backend. Unless there is periodic task to
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do heartbeat manually, it should be always set to
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True.
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"""
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if self.started:
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return
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member_id = '.'.join([COORDINATION_PREFIX, self.prefix,
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CONF.host]).encode('ascii')
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self.coordinator = coordination.get_coordinator(
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CONF.coordination.backend_url, member_id)
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self.coordinator.start(start_heart=heartbeat)
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self.started = True
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LOG.debug('Coordinator started successfully.')
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def stop(self):
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"""Disconnect from coordination backend and stop heartbeat."""
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if self.started:
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try:
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self.coordinator.stop()
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except Exception as e:
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LOG.error('Failed to stop coordinator: %s', e)
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self.coordinator = None
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self.started = False
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LOG.debug('Coordinator stopped successfully')
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def _validate_state(self):
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if not self.started:
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raise utils.Error('Coordinator should be started before '
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'executing coordination actions.')
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def _create_group(self):
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try:
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request = self.coordinator.create_group(self.group_name)
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request.get()
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except coordination.GroupAlreadyExist:
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LOG.debug('Group %s already exists.', self.group_name)
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def join_group(self):
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"""Join service group."""
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self._validate_state()
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try:
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request = self.coordinator.join_group(self.group_name)
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request.get()
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except coordination.GroupNotCreated:
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self._create_group()
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request = self.coordinator.join_group(self.group_name)
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request.get()
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except coordination.MemberAlreadyExist:
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pass
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LOG.debug('Joined group %s', self.group_name)
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def leave_group(self):
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"""Leave service group"""
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self._validate_state()
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try:
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request = self.coordinator.leave_group(self.group_name)
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request.get()
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LOG.debug('Left group %s', self.group_name)
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except coordination.MemberNotJoined:
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LOG.debug('Leaving a non-existing group.')
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def get_members(self):
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"""Get members in the service group."""
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self._validate_state()
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try:
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result = self.coordinator.get_members(self.group_name)
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return result.get()
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except coordination.GroupNotCreated:
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# If the group does not exist, there should be no members in it.
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return set()
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def get_lock(self, uuid):
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"""Get lock for node uuid."""
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self._validate_state()
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lock_name = (self.lock_prefix + uuid).encode('ascii')
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return self.coordinator.get_lock(lock_name)
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_COORDINATOR = None
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@lockutils.synchronized('inspector_coordinator')
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def get_coordinator(prefix=None):
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global _COORDINATOR
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if _COORDINATOR is None:
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_COORDINATOR = Coordinator(prefix=prefix)
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return _COORDINATOR
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