Shutting down Kafka Consumer

Question

I was reading up details of Kafka High level consumer in this link and saw the below statement -

In practice, a more common pattern is to use sleep indefinitely and use a shutdown hook to trigger clean shutdown.

Are there any examples for doing this or pointers which could help?

Answer 1

This will be an example of an infinite loop

public void run() {
    try {
      consumer.subscribe(topics);
      while (true) {
          ConsumerRecords<String, String> records = consumer.poll(Long.MAX_VALUE);
        //do something
      }
    } catch (WakeupException e) {
      // do nothing we are shutting down 
    } finally {
      consumer.close();
    }
  }

  public void shutdown() {
    consumer.wakeup();
  }
}

And this will be your shutdown hook.

@PostConstruct
    private void init(){
        addShutdownHook(); 
    }

 private void addShutdownHook(){
   Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {

            @Override
            public void run() {
                shutdown();
            }
        }));
    }