Kafka manual acknowledge before Spring Boot shutdown

Question

So the question is simple, but I cannot find an answer for quite a while now.

I have manual acknowledgement for my Kafka consumer, and before the application is shutdown I would like to execute some code and then acknowledge to Kafka. So for this I am using the @PreDestroy annotation:

@PreDestroy
private void beforeShutdown() {
    //do some code
    acknowledgement.acknowledge(); //this variable is stored on class level

Now the main problem is that Kafka consumer is shut down BEFORE this executes, therefor the messages don't actually get acknowledged and I receive them again when I start up the app, so I need some kind of workaround or another way to designate this function as the first thing that is called before shutdown. Proof of this can be seen in the log:

Shutting down ExecutorService
Consumer stopped
Shutting down ExecutorService 'taskScheduler'
Shutting down ExecutorService 'applicationTaskExecutor'
EXECUTING MY CODE
[Producer clientId=producer-1] Closing the Kafka producer with timeoutMillis = 30000 ms.

If anyone has a suggestion please tell.

Answer 1

Implement SmartLifeCycle and put the code in stop(). Put the bean in a very high Phase so it is stopped before the container. The containers are in phase Integer.MAX_VALUE - 100 by default so it has to be higher than that.

EDIT

class Listener implements SmartLifecycle { // default phase is last (after the containers for start, before for stop).

    private volatile boolean running;

    @Override
    public void start() {
        this.running = true;
    }

    @Override
    public void stop() {
        this.running = false;
    }

    @Override
    public boolean isRunning() {
        return this.running;
    }

    ...

}