[Axon 3.3.2] Replay Events API, @ResetHandler not called

[Jérôme M.]

Hello,

I'm trying to trigger a replay of the events from a Tracking Processor  ( Axon 3.3.2, Spring Boot 2.0.3)

Here is my configuration  :

@Inject
  public void configure(EventProcessingConfiguration configuration) {
   
    configuration.registerTrackingEventProcessor("foo.test.replay",
        (conf) -> TrackingEventProcessorConfiguration.forParallelProcessing(4));

}

The related Event Handler attached to this processor:

@AllowReplay
@Component
public class Replayer {


  private int count;
 
  @EventHandler
  public void on(DomainEventMessage<?> message, ReplayStatus replayStatus) {
    System.out.println("Thread=" + Thread.currentThread().getId() + ", events replayed=" + ++count);

  }


  @ResetHandler()
  public void onReset() {
    System.out.println("Reset Handler called !");
  }

}

And finally this is how I trigger the replay process :

eventProcessingConfiguration.eventProcessor("foo.test.replay", TrackingEventProcessor.class)
        .ifPresent(eventProcessor -> {

          eventProcessor.shutDown();
          eventProcessor.resetTokens();
          eventProcessor.start();
        });
}

So far, so good, the replay process is working but what I notice is that the onReset() is not called as it should be when I call resetTokens() on the EventProcessor.

After investigating a bit further, I notice that the call of the method annotated with @ResetHandler is triggered by a call to EventHandlerInvoker::performReset. By default, it does nothing.

Now, this interface has three implementations : SimpleEventHandlerInvoker, MultiEventHandlerInvoker, and AbstractSagaManager.

For the SimpleEventHandlerInvoker, the performReset() is correctly implemented, by basically looping over all the EventListener.

But in my case, the Replayer event handler is attached to a MultiEventHandlerInvoker (I don't know why actuallly, but this is part of the Axon internals), which doesn't override the default implementation of performReset().

The obvious solution I have in mind is to implement it and delegate to all embedded EventHandlerInvoker, but before submitting a PR, I would like to validate with you my understanding of the issue.

Is this the right way to use the Replay feature ?

Cheers,

Jerome

[Steven van Beelen]

Hi Jérôme,

Great observation and thanks for pointing out this issue!

If you would be open to creating a PR to adjust the MultiEventHandlerInvoker to override the default behavior, that would be much appreciated.

I would like to point out that the PR should perform the `supportsReset()` call on each `EventHandlerInvoker` prior to performing the `performReset()` call on it.

From the snippet you've shared I assume you are using the Replay functionality as intended by the way.

So no worries in that space so far.

By the way, if a PR doesn't fit in your schedule, an issue documenting this would also be very beneficial to us. :-)

Cheers,

Steven

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[Jérôme M.]

Ok, thanks ! I'll do it this week-end.

Cheers,

Jerome