Source code for ironic_inspector.common.locking

# Licensed under the Apache License, Version 2.0 (the "License");
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#    http://www.apache.org/licenses/LICENSE-2.0
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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()


[docs] class BaseLock(object, metaclass=abc.ABCMeta):
[docs] @abc.abstractmethod def acquire(self, blocking=True): """Acquire lock."""
[docs] @abc.abstractmethod def release(self): """Release lock."""
[docs] @abc.abstractmethod def is_locked(self): """Return lock status"""
[docs] 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
[docs] def acquire(self, blocking=True): if not self._locked: self._locked = self._lock.acquire(blocking=blocking) return self._locked
[docs] def release(self): if self._locked: self._lock.release() self._locked = False
[docs] 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()
[docs] 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
[docs] def acquire(self, blocking=True): if not self._lock.acquired: self._lock.acquire(blocking=blocking) return self._lock.acquired
[docs] def release(self): if self._lock.acquired: self._lock.release()
[docs] 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()
[docs] def get_lock(uuid): if CONF.standalone: return InternalLock(uuid) coordinator = coordination.get_coordinator() lock = coordinator.get_lock(uuid) return ToozLock(lock)