如何取消从Workflow异步调用的activity？

Question

我们想异步调用一个 long-运行 activity，并在一段时间后根据外部信号取消那个 long-运行 activity。

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

目前 activity 了解取消的唯一方法是通过检测信号。确保您的 activity 心跳并且不会吞下心跳方法抛出的异常。

Answer 1

使用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();
  }