def process_workflow_event(cls, workflow_state, wf_ex_event):
# Append additional workflow context to the event.
event_name = cls.add_context_to_workflow_event(workflow_state, wf_ex_event)
# Check if event is valid.
if event_name not in events.WORKFLOW_EXECUTION_EVENTS:
raise exc.InvalidEvent(event_name)
# Capture current workflow status.
current_workflow_status = workflow_state.status
new_workflow_status = current_workflow_status
# Check if the current workflow status can be transitioned.
if current_workflow_status not in WORKFLOW_STATE_MACHINE_DATA:
raise exc.InvalidWorkflowStatusTransition(current_workflow_status, event_name)
# If the current workflow status can be transitioned and there is no match on the
# event, then there is not status transition.
if event_name not in WORKFLOW_STATE_MACHINE_DATA[current_workflow_status]:
return
new_workflow_status = WORKFLOW_STATE_MACHINE_DATA[current_workflow_status][event_name]
# Assign new workflow status if there is change.
if current_workflow_status != new_workflow_status:
workflow_state.status = new_workflow_status
def request_workflow_status(self, status):
# Record current workflow status.
current_status = self.get_workflow_status()
# Create an event for the request.
wf_ex_event = events.WorkflowExecutionEvent(status)
# Push the event to all the active tasks. The event may trigger status changes to the task.
for task_state in self.workflow_state.get_tasks_by_status(statuses.ACTIVE_STATUSES):
machines.TaskStateMachine.process_event(self.workflow_state, task_state, wf_ex_event)
# Process the workflow status change event.
machines.WorkflowStateMachine.process_event(self.workflow_state, wf_ex_event)
# Get workflow status after event is processed.
updated_status = self.get_workflow_status()
# Ignore if workflow hasn't changed from paused to pausing.
if (status == statuses.PAUSED and
current_status == statuses.PAUSING and
updated_status == statuses.PAUSING):
return
# Ignore if workflow hasn't changed from canceled to canceling.
if (status == statuses.CANCELED and
current_status == statuses.CANCELING and
updated_status == statuses.CANCELING):
return
# Otherwise, if status has not changed as expected, then raise exception.
if status != current_status and current_status == updated_status:
raise exc.InvalidWorkflowStatusTransition(current_status, wf_ex_event.name)
def process_task_event(cls, workflow_state, tk_ex_event):
# Append additional workflow context to the event.
event_name = cls.add_context_to_task_event(workflow_state, tk_ex_event)
# Check if event is valid.
if event_name not in events.TASK_EXECUTION_EVENTS:
raise exc.InvalidEvent(event_name)
# Capture current workflow status.
current_workflow_status = workflow_state.status
new_workflow_status = current_workflow_status
# Check if the current workflow status can be transitioned.
if current_workflow_status not in WORKFLOW_STATE_MACHINE_DATA:
raise exc.InvalidWorkflowStatusTransition(current_workflow_status,
event_name)
# If the current workflow status can be transitioned and there is no match on the
# event, then there is not status transition.
if event_name not in WORKFLOW_STATE_MACHINE_DATA[
current_workflow_status]:
return
new_workflow_status = WORKFLOW_STATE_MACHINE_DATA[
current_workflow_status][event_name]
# Assign new workflow status if there is change.
if current_workflow_status != new_workflow_status:
workflow_state.status = new_workflow_status
# If the final workflow status here is completed, then ensure there is no unreachable
# barrier task(s). A barrier task is unreachable if the workflow is completed but then one
# or more criteria for the task is satisified. In this case, log the task and fail the
# workflow to notify that the execution is incomplete but unable to proceed.
if workflow_state.status in statuses.COMPLETED_STATUSES:
unreachable_barriers = workflow_state.get_unreachable_barriers()
# If there are unreachable barrier tasks, then change workflow status to failed
# and write an error log for each case.
if unreachable_barriers:
workflow_state.status = statuses.FAILED
for entry in unreachable_barriers:
e = exc.UnreachableJoinError(entry["id"], entry["route"])
workflow_state.conductor.log_error(e,
task_id=entry["id"],
route=entry["route"])
def request_workflow_status(self, status):
# Record current workflow status.
current_status = self.get_workflow_status()
# Create an event for the request.
wf_ex_event = events.WorkflowExecutionEvent(status)
# Push the event to all the active tasks. The event may trigger status changes to the task.
for task_state in self.workflow_state.get_tasks_by_status(
statuses.ACTIVE_STATUSES):
machines.TaskStateMachine.process_event(self.workflow_state,
task_state, wf_ex_event)
# Process the workflow status change event.
machines.WorkflowStateMachine.process_event(self.workflow_state,
wf_ex_event)
# Get workflow status after event is processed.
updated_status = self.get_workflow_status()
# If status has not changed as expected, then raise exception.
if status != current_status and current_status == updated_status:
raise exc.InvalidWorkflowStatusTransition(current_status,
wf_ex_event.name)
