def _handle_for_status(self, event_record: DataRecord) -> Optional[Dict[Any, Any]]:
"""
Take appropriate action based on event_record's status
Parameters
----------
event_record: DataRecord
Returns
-------
Optional[Dict[Any, Any]
Lambda response previously used for this idempotency key, if it has successfully executed already.
Raises
------
AlreadyInProgressError
A lambda execution is already in progress
IdempotencyInconsistentStateError
The persistence store reports inconsistent states across different requests. Retryable.
"""
# This code path will only be triggered if the record becomes expired between the save_inprogress call and here
if event_record.status == STATUS_CONSTANTS["EXPIRED"]:
raise IdempotencyInconsistentStateError("save_inprogress and get_record return inconsistent results.")
if event_record.status == STATUS_CONSTANTS["INPROGRESS"]:
raise IdempotencyAlreadyInProgressError(
f"Execution already in progress with idempotency key: "
f"{self.persistence_store.event_key_jmespath}={event_record.idempotency_key}"
)
return event_record.response_json_as_dict()
def _get_idempotency_record(self) -> DataRecord:
"""
Retrieve the idempotency record from the persistence layer.
Raises
----------
IdempotencyInconsistentStateError
"""
try:
event_record = self.persistence_store.get_record(event=self.event, context=self.context)
except IdempotencyItemNotFoundError:
# This code path will only be triggered if the record is removed between save_inprogress and get_record.
logger.debug(
"An existing idempotency record was deleted before we could retrieve it. Proceeding with lambda "
"handler"
)
raise IdempotencyInconsistentStateError("save_inprogress and get_record return inconsistent results.")
# Allow this exception to bubble up
except IdempotencyValidationError:
raise
# Wrap remaining unhandled exceptions with IdempotencyPersistenceLayerError to ease exception handling for
# clients
except Exception as exc:
raise IdempotencyPersistenceLayerError("Failed to get record from idempotency store") from exc
return event_record