使用一组压缩主题中的所有记录的最简单的Spring Kafka@Kafkalistener配置是什么？

Question

@KafkaListener(topicPartitions = @TopicPartition(topic = "compacted",
            partitions = "#{@finder.partitions('compacted')}"),
            partitionOffsets = @PartitionOffset(partition = "*", initialOffset = "0")))
public void listen(@Header(KafkaHeaders.RECEIVED_MESSAGE_KEY) String key, String payload) {
    // process record
}

由于我有几个主题，结果代码非常冗长：

@KafkaListener(topicPartitions = {
        @TopicPartition(
                topic = "${topic1}",
                partitions = "#{@finder.partitions('${topic1}')}",
                partitionOffsets = @PartitionOffset(partition = "*", initialOffset = "0")
        ),
        @TopicPartition(
                topic = "${topic2}",
                partitions = "#{@finder.partitions('${topic2}')}",
                partitionOffsets = @PartitionOffset(partition = "*", initialOffset = "0")
        ),
        // and many more @TopicPartitions...
        @TopicPartition(
                topic = "${topicN}",
                partitions = "#{@finder.partitions('${topicN}')}",
                partitionOffsets = @PartitionOffset(partition = "*", initialOffset = "0")
        )
})
public void listen(@Header(KafkaHeaders.RECEIVED_MESSAGE_KEY) String key, String payload) {
    // process record
}

如何通过配置@kafkalistener注释的topicpartitions属性，使这种重复配置更加简洁？

Answer 1

@kafkalistener目前不可能-请在GitHub上打开一个新的特性问题。

我能想到的唯一工作是从容器工厂以编程方式创建一个侦听器容器，并创建一个侦听器适配器。如果你需要，我可以提供一个例子。

编辑

@SpringBootApplication
public class So64022266Application {

    public static void main(String[] args) {
        SpringApplication.run(So64022266Application.class, args);
    }

    @Bean
    public NewTopic topic1() {
        return TopicBuilder.name("so64022266-1").partitions(10).replicas(1).build();
    }

    @Bean
    public NewTopic topic2() {
        return TopicBuilder.name("so64022266-2").partitions(10).replicas(1).build();
    }

    @Bean
    ConcurrentMessageListenerContainer<String, String> container(@Value("${topics}") String[] topics,
            PartitionFinder finder,
            ConcurrentKafkaListenerContainerFactory<String, String> factory,
            MyListener listener) throws Exception {

        MethodKafkaListenerEndpoint<String, String> endpoint = endpoint(topics, finder, listener);
        ConcurrentMessageListenerContainer<String, String> container = factory.createListenerContainer(endpoint);
        container.getContainerProperties().setGroupId("someGroup");
        return container;
    }

    @Bean
    MethodKafkaListenerEndpoint<String, String> endpoint(String[] topics, PartitionFinder finder,
            MyListener listener) throws NoSuchMethodException {

        MethodKafkaListenerEndpoint<String, String> endpoint = new MethodKafkaListenerEndpoint<>();
        endpoint.setBean(listener);
        endpoint.setMethod(MyListener.class.getDeclaredMethod("listen", String.class, String.class));
        endpoint.setTopicPartitions(Arrays.stream(topics)
            .flatMap(topic -> finder.partitions(topic))
            .toArray(TopicPartitionOffset[]::new));
        endpoint.setMessageHandlerMethodFactory(methodFactory());
        return endpoint;
    }

    @Bean
    DefaultMessageHandlerMethodFactory methodFactory() {
        return new DefaultMessageHandlerMethodFactory();
    }

    @Bean
    public ApplicationRunner runner(KafkaTemplate<String, String> template,
            ConcurrentMessageListenerContainer<String, String> container) {

        return args -> {
            System.out.println(container.getAssignedPartitions());
            template.send("so64022266-1", "key1", "foo");
            template.send("so64022266-2", "key2", "bar");
        };
    }

}

@Component
class MyListener {

    public void listen(@Header(KafkaHeaders.RECEIVED_MESSAGE_KEY) String key, String payload) {
        System.out.println(key + ":" + payload);
    }

}

@Component
class PartitionFinder {

    private final ConsumerFactory<String, String> consumerFactory;

    public PartitionFinder(ConsumerFactory<String, String> consumerFactory) {
        this.consumerFactory = consumerFactory;
    }

    public Stream<TopicPartitionOffset> partitions(String topic) {
        System.out.println("+" + topic + "+");
        try (Consumer<String, String> consumer = consumerFactory.createConsumer()) {
            return consumer.partitionsFor(topic).stream()
                    .map(part -> new TopicPartitionOffset(topic, part.partition(), 0L));
        }
    }

}

topics=so64022266-1, so64022266-2