ironic-inspector/ironic_inspector/common/locking.py
Riccardo Pittau 9b1450398c Stop using six library
Since we've dropped support for Python 2.7, it's time to look at
the bright future that Python 3.x will bring and stop forcing
compatibility with older versions.
This patch removes the six library from requirements, not
looking back.

Change-Id: Ic443c7e4d5a5a849c4dc220207f8957e4c90bf53
2019-12-17 09:23:01 +01:00

107 lines
2.6 KiB
Python

# 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 abc
from oslo_concurrency import lockutils
from oslo_config import cfg
from ironic_inspector.common import coordination
CONF = cfg.CONF
_LOCK_TEMPLATE = 'node-%s'
_SEMAPHORES = lockutils.Semaphores()
class BaseLock(object, metaclass=abc.ABCMeta):
@abc.abstractmethod
def acquire(self, blocking=True):
"""Acquire lock."""
@abc.abstractmethod
def release(self):
"""Release lock."""
@abc.abstractmethod
def is_locked(self):
"""Return lock status"""
class InternalLock(BaseLock):
"""Locking mechanism based on threading.Semaphore."""
def __init__(self, uuid):
self._lock = lockutils.internal_lock(_LOCK_TEMPLATE % uuid,
semaphores=_SEMAPHORES)
self._locked = False
def acquire(self, blocking=True):
if not self._locked:
self._locked = self._lock.acquire(blocking=blocking)
return self._locked
def release(self):
if self._locked:
self._lock.release()
self._locked = False
def is_locked(self):
return self._locked
def __enter__(self):
self._lock.acquire()
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self._lock.release()
class ToozLock(BaseLock):
"""Wrapper on tooz locks."""
def __init__(self, lock):
"""Creates a wrapper on the tooz lock.
:param lock: a tooz lock instance.
"""
self._lock = lock
def acquire(self, blocking=True):
if not self._lock.acquired:
self._lock.acquire(blocking=blocking)
return self._lock.acquired
def release(self):
if self._lock.acquired:
self._lock.release()
def is_locked(self):
return self._lock.acquired
def __enter__(self):
self._lock.acquire()
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self._lock.release()
def get_lock(uuid):
if CONF.standalone:
return InternalLock(uuid)
coordinator = coordination.get_coordinator()
lock = coordinator.get_lock(uuid)
return ToozLock(lock)