def initial(self, request, *args, **kwargs):
self.lock = None
if request.instance and request.method not in permissions.SAFE_METHODS:
# Make a lock to avoid deadlocks
self.lock = redis.lock(self.model.get_instance_lock_key(
request.instance),
timeout=settings.LOCK_TIMEOUT)
self.lock.acquire()
return super().initial(request, *args, **kwargs)
def __call__(self, *args, **kwargs):
logger = self.get_logger()
lock_key = self.get_lock_key(*args, **kwargs)
lock_expire = self.get_lock_expire(*args, **kwargs)
try:
with redis.lock(lock_key, timeout=lock_expire, blocking_timeout=self.lock_blocking_timeout):
ret = super().__call__(*args, **kwargs)
self.after_lock_released(args, kwargs)
return ret
except LockError:
logger.debug('Already locked.')
return False
def lock(cls, instance_pk):
return redis.lock(cls.LOCK_KEY_TEMPLATE.format(instance_pk=instance_pk),
lock_class=ReentrantLock,
timeout=cls.LOCK_TIMEOUT, sleep=0.01)