def __isFirstExecution(self, taskName, retryCount):
""" Ensures that the task has not been executed before. Meant to be run in a transaction. """
firstExecution = False
keyName = '%s--%s' % (taskName, retryCount)
existingTaskName = _FantasmTaskSemaphore.get_by_key_name(keyName)
if not existingTaskName:
_FantasmTaskSemaphore(key_name=keyName).put()
firstExecution = True
return firstExecution
def txn():
""" lock in transaction to avoid races between Tasks """
entity = _FantasmTaskSemaphore.get_by_key_name(self.semaphoreKey)
if not entity:
_FantasmTaskSemaphore(key_name=self.semaphoreKey, payload=payload).put()
memcache.set(self.semaphoreKey, payload)
return (True, payload)
else:
if entity.payload != payload:
self.logger.critical("Run-once semaphore datastore payload write error.")
memcache.set(self.semaphoreKey, entity.payload) # maybe reduces chance of ejection???
return (False, entity.payload)
def txn():
""" lock in transaction to avoid races between Tasks """
key = db.Key.from_path(_FantasmTaskSemaphore.kind(), self.semaphoreKey, namespace='')
entity = db.get(key)
if not entity:
_FantasmTaskSemaphore(key=key, payload=payload).put()
memcache.set(self.semaphoreKey, payload, namespace=None)
self.logger.debug('Setting run-once semaphore. Semaphore key: "%s", payload: "%s".', self.semaphoreKey, payload)
return (True, payload)
else:
if entity.payload != payload:
self.logger.critical("Run-once semaphore datastore payload write error. Semaphore key: '%s', actual payload: '%s', expected payload: '%s'.", self.semaphoreKey, entity.payload, payload)
memcache.set(self.semaphoreKey, entity.payload, namespace=None) # maybe reduces chance of ejection???
return (False, entity.payload)
def txn():
""" lock in transaction to avoid races between Tasks """
key = db.Key.from_path(_FantasmTaskSemaphore.kind(),
self.semaphoreKey,
namespace='')
entity = db.get(key)
if not entity:
_FantasmTaskSemaphore(key=key, payload=payload).put()
memcache.set(self.semaphoreKey, payload, namespace=None)
self.logger.debug(
'Setting run-once semaphore. Semaphore key: "%s", payload: "%s".',
self.semaphoreKey, payload)
return (True, payload)
else:
if entity.payload != payload:
self.logger.critical(
"Run-once semaphore datastore payload write error. Semaphore key: '%s', actual payload: '%s', expected payload: '%s'.",
self.semaphoreKey, entity.payload, payload)
memcache.set(
self.semaphoreKey, entity.payload,
namespace=None) # maybe reduces chance of ejection???
return (False, entity.payload)