How to cancel activity that is invoked asynchronously from the Workflow?

Question

We want to invoke a long-running activity asynchronously and after sometime based on the external signal, would like to cancel that long-running activity.

Async.procedure(activities::longRunningActivity)
// Execute some synchronous activities
Workflow.await(() -> !messageQueue.isEmpty());
if (messageQueue.remove(0) == "something") {
    // Cancel longRunningActivity
}

Currently the only way for an activity to learn about cancellation is through heartbeating. Make sure that your activity heartbeats and doesn't swallow the exception the heartbeat method throws.

Answer 1

Use CancellationScope:

  CancellationScope longRunningCancellationScope =
          Workflow.newCancellationScope(
                  () -> Async.procedure(activities::longRunningActivity));
  longRunningCancellationScope.run();
  // Execute some synchronous activities
  Workflow.await(() -> !messageQueue.isEmpty());
  if (messageQueue.remove(0) == "something") {
      longRunningCancellationScope.cancel();
  }