List Kafka Topics via Spring-Kafka

Question

We would like to list all Kafka topics via spring-kafka to get results similar to the kafka command:

bin/kafka-topics.sh --list --zookeeper localhost:2181

When running the getTopics() method in the service below, we get org.apache.kafka.common.errors.TimeoutException: Timeout expired while fetching topic metadata

Configuration:

@EnableKafka
@Configuration
public class KafkaConfig {
    @Bean
    public ConsumerFactory<String, String> consumerFactory() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:2181");
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, 
            StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, 
            StringDeserializer.class);
        return new DefaultKafkaConsumerFactory<>(props);
}

Service:

@Service
public class TopicServiceKafkaImpl implements TopicService {
    @Autowired
    private ConsumerFactory<String, String> consumerFactory;

    @Override
    public Set<String> getTopics() {
        try (Consumer<String, String> consumer = 
            consumerFactory.createConsumer()) {
            Map<String, List<PartitionInfo>> map = consumer.listTopics();
            return map.keySet();
    }
}

Kafka is up and running and we can send messages from our app to a topic succesfully.

Answer 1

You can list topics like this using Admin Client

    Properties properties = new Properties();
    properties.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");

    AdminClient adminClient = AdminClient.create(properties);

    ListTopicsOptions listTopicsOptions = new ListTopicsOptions();
    listTopicsOptions.listInternal(true);

    System.out.println("topics:" + adminClient.listTopics(listTopicsOptions).names().get());

Answer 2

You are connecting to Zookeeper (2181) instead of Kafka (9092 by default).

The Java kafka clients no longer talk directly to ZK.