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# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import functools
import itertools
import threading
from oslo_log import log as logging
from designate import objects
LOG = logging.getLogger(__name__)
class ZoneLockLocal(threading.local):
def __init__(self):
super(ZoneLockLocal, self).__init__()
self._held = set()
def hold(self, name):
self._held.add(name)
def release(self, name):
self._held.remove(name)
def has_lock(self, name):
return name in self._held
def extract_zone_id(args, kwargs):
zone_id = None
if 'zone_id' in kwargs:
zone_id = kwargs['zone_id']
elif 'zone' in kwargs:
zone_id = kwargs['zone'].id
elif 'recordset' in kwargs:
zone_id = kwargs['recordset'].zone_id
elif 'record' in kwargs:
zone_id = kwargs['record'].zone_id
if not zone_id:
for arg in itertools.chain(args, kwargs.values()):
if not isinstance(arg, objects.DesignateObject):
continue
if isinstance(arg, objects.Zone):
zone_id = arg.id
if zone_id:
break
elif isinstance(arg, (objects.RecordSet,
objects.Record,
objects.ZoneTransferRequest,
objects.ZoneTransferAccept)):
zone_id = arg.zone_id
if zone_id:
break
if not zone_id and len(args) > 1:
arg = args[1]
if isinstance(arg, str):
zone_id = arg
elif isinstance(zone_id, objects.Zone):
zone_id = arg.id
return zone_id
def synchronized_zone(new_zone=False):
"""Ensures only a single operation is in progress for each zone
A Decorator which ensures only a single operation can be happening
on a single zone at once, within the current designate-central instance
"""
def outer(f):
@functools.wraps(f)
def sync_wrapper(cls, *args, **kwargs):
if new_zone is True:
lock_name = 'create-new-zone'
else:
zone_id = extract_zone_id(args, kwargs)
if zone_id:
lock_name = 'zone-%s' % zone_id
else:
raise Exception('Failed to determine zone id for '
'synchronized operation')
if cls.zone_lock_local.has_lock(lock_name):
return f(cls, *args, **kwargs)
with cls.coordination.get_lock(lock_name):
try:
cls.zone_lock_local.hold(lock_name)
return f(cls, *args, **kwargs)
finally:
cls.zone_lock_local.release(lock_name)
return sync_wrapper
return outer
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