Spring Kafka listener infinite loop on error

Question

I have Spring Kafka listener initialized as

@Bean
public Map<String, Object> consumerConfig() {
    final HashMap<String, Object> result = new HashMap<>();
    result.put(BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
    result.put(GROUP_ID_CONFIG, groupId);
    result.put(KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    result.put(VALUE_DESERIALIZER_CLASS_CONFIG, MyKafkaJacksonRulesExecutionResultsDeserializer.class);
    return result;
}

@Bean
public ConsumerFactory<Long, MessageResult> consumerFactory() {
    return new DefaultKafkaConsumerFactory<>(consumerConfig());
}

@Bean
public ConcurrentKafkaListenerContainerFactory<Long, MessageResult> kafkaListenerContainerFactory() {
    ConcurrentKafkaListenerContainerFactory<Long, MessageResult> containerFactory = new ConcurrentKafkaListenerContainerFactory<>();
    containerFactory.setConsumerFactory(consumerFactory());
    containerFactory.setConcurrency(KAFKA_LISTENER_THREADS_COUNT);
    containerFactory.getContainerProperties().setPollTimeout(KAFKA_LISTENER_POLL_TIMEOUT);
    containerFactory.getContainerProperties().setAckOnError(true);
    containerFactory.getContainerProperties().setAckMode(RECORD);
    return containerFactory;
}

and used as

@KafkaListener(topics = "${spring.kafka.out-topic}")
public void processSrpResults(MessageResult result) {

deserializer throws an exception during deserialization which causes infinite loop because listener can't fetch messege.

How could I make kafka listener to commit on error?

Answer 1

I created a subclass to the deserializer that was throwing the exception. Then I used that in my configuration as the deserializer. Your processor then has to handle null objects.

public class MyErrorHandlingDeserializer extends ExceptionThrowingDeserializer {

    @Override
    public Object deserialize(String topic, byte[] data) {
        try {
            return super.deserialize(topic, data);
        } catch (Exception e) {
            log.error("Problem deserializing data " + new String(data) + " on topic " + topic, e);
            return null;
        }
    }
}