70 lines
2.5 KiB
Python
70 lines
2.5 KiB
Python
# Copyright 2015 VMware, Inc.
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# All Rights Reserved
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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 os
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import traceback
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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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LOG = log.getLogger(__name__)
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class LockManager(object):
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_coordinator = None
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_coordinator_pid = None
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_connect_string = cfg.CONF.locking_coordinator_url
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def __init__(self):
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LOG.debug('LockManager initialized!')
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@staticmethod
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def get_lock(name, **kwargs):
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if cfg.CONF.locking_coordinator_url:
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lck = LockManager._get_lock_distributed(name)
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LOG.debug('Lock %s taken with stack trace %s', name,
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traceback.extract_stack(limit=5))
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return lck
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else:
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# Ensure that external=True
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kwargs['external'] = True
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lck = LockManager._get_lock_local(name, **kwargs)
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LOG.debug('Lock %s taken with stack trace %s', name,
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traceback.extract_stack(limit=5))
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return lck
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@staticmethod
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def _get_lock_local(name, **kwargs):
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return lockutils.lock(name, **kwargs)
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@staticmethod
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def _get_lock_distributed(name):
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if LockManager._coordinator_pid != os.getpid():
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# We should use a per-process coordinator. If PID is different
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# start a new coordinator.
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# While the API workers are spawned, we have to re-initialize
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# a coordinator, so we validate that the PID is still the same.
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LockManager._coordinator_pid = os.getpid()
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LOG.debug('Initialized coordinator with connect string %s',
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LockManager._connect_string)
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LockManager._coordinator = coordination.get_coordinator(
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LockManager._connect_string, 'vmware-neutron-plugin')
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LockManager._coordinator.start()
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LOG.debug('Retrieved lock for %s', name)
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return LockManager._coordinator.get_lock(name)
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