Hardware introspection daemon for OpenStack Ironic
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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 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)