Spring-Kafka 中的 poll() 和 commitAsync()

Question

我正在尝试在 java 中编写一个 kafka 消费者应用程序 Spring引导平台。早些时候，我用普通 java 编写了代码，但是现在转换为 spring-kafka，因为它可以提供一些优势普通 java。我确实有几个问题想弄明白。

看来我不必在spring-kafka中明确地进行poll()循环它将由@KafkaListener 自动处理？

我设置了enable.auto.commit='false',因为我要做一些在提交偏移量之前进行处理，我怎样才能在中执行 commitAsync() Spring-卡夫卡?

ConsumerConfig.java :

@EnableKafka
@Configuration
public class KafkaConsumerConfig {

    @Value("${app.kafka_brokers}")
    private String KAFKA_BROKERS;

    @Value("${app.topic}")
    private String KAFKA_TOPIC;

    @Value("${app.group_id_config}")
    private String GROUP_ID_CONFIG;

    @Value("${app.schema_registry_url}")
    private String SCHEMA_REGISTRY_URL;

    @Value("${app.offset_reset}")
    private String OFFSET_RESET;

    @Value("${app.max_poll_records}")
    private String MAX_POLL_RECORDS;

    @Value("${app.security.protocol}")
    private String SSL_PROTOCOL;

    @Value("${app.ssl.truststore.password}")
    private String SSL_TRUSTSTORE_SECURE;

    @Value("${app.ssl.keystore.password}")
    private String SSL_KEYSTORE_SECURE;

    @Value("${app.ssl.key.password}")
    private String SSL_KEY_SECURE;

    @Value("${app.ssl.truststore.location}")
    private String SSL_TRUSTSTORE_LOCATION_FILE_NAME;

    @Value("${app.ssl.keystore.location}")
    private String SSL_KEYSTORE_LOCATION_FILE_NAME;

    @Bean
    public ConsumerFactory<String, String> consumerFactory(){

        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,KAFKA_BROKERS);
        props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, OFFSET_RESET);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, KafkaAvroDeserializer.class.getName());
        props.put(ConsumerConfig.GROUP_ID_CONFIG, GROUP_ID_CONFIG);
        props.put(KafkaAvroDeserializerConfig.SCHEMA_REGISTRY_URL_CONFIG, SCHEMA_REGISTRY_URL);
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false");

        props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, SSL_PROTOCOL);
        props.put(SslConfigs.SSL_TRUSTSTORE_LOCATION_CONFIG,SSL_TRUSTSTORE_LOCATION_FILE_NAME);
        props.put(SslConfigs.SSL_TRUSTSTORE_PASSWORD_CONFIG, SSL_TRUSTSTORE_SECURE);
        props.put(SslConfigs.SSL_KEYSTORE_LOCATION_CONFIG,SSL_KEYSTORE_LOCATION_FILE_NAME);
        props.put(SslConfigs.SSL_KEYSTORE_PASSWORD_CONFIG, SSL_KEYSTORE_SECURE);
        props.put(SslConfigs.SSL_KEY_PASSWORD_CONFIG, SSL_KEY_SECURE);

        return new DefaultKafkaConsumerFactory<>(props);

    }

    @Bean
    ConcurrentKafkaListenerContainerFactory<String, String> 
    kafkaListenerContainerFactory() {

      ConcurrentKafkaListenerContainerFactory<String, String> factory =
                            new ConcurrentKafkaListenerContainerFactory<>();
      factory.setConsumerFactory(consumerFactory());
      factory.setConcurrency(3);
      return factory;
  }

}

KafkaConsumer.java :

@Component
public class KafkaConsumer {
    
    @KafkaListener(topics = "topic", groupId = "group")
    public void run(ConsumerRecord<String, GenericRecord> record) {
        
        System.out.println(record);
        
    <-- how to asyncCommit()--> 
    }

}

Answer 1

监听器容器会在监听器正常退出时提交偏移量，具体取决于容器的AckMode 属性； AckMode.BATCH（默认）表示轮询返回的所有记录的偏移量将在所有处理完成后提交，AckMode.RECORD表示每个偏移量将在侦听器退出后立即提交。

sync比。 async 由 syncCommits 容器控制属性。

Answer 2

首先，我建议您使用 Spring kafka 设置的属性和自动配置，而不是创建自己的，因为它遵循 DRY 原则：不要重复自己。

spring:
  kafka:
    bootstrap-servers: ${app.kafka_brokers}
    consumer:
      auto-offset-reset: ${app.offset_reset}
      enable-auto-commit: false   // <---- disable auto committing
    ssl:
      protocol: ${app.security.protocol}
      key-store-location: ${app.ssl.keystore.location}
      key-store-password:  ${app.ssl.keystore.password}
      trust-store-location: ${app.ssl.truststore.location}
      trust-store-password: ${app.ssl.truststore.password}
  // And other properties
    listener:
      ack-mode: manual // This is what you need

AckMode 文档：https://docs.spring.io/spring-kafka/api/org/springframework/kafka/listener/ContainerProperties.AckMode.html

本质上，manual是一个异步确认，而manual_immediate是同步的。

然后在你的 @KafkaListener 组件中你可以注入 org.springframework.kafka.support.Acknowledgment 对象确认你的消息。

@Component
public class KafkaConsumer {
    
    @KafkaListener(topics = "topic", groupId = "group")
    public void run(ConsumerRecord<String, GenericRecord> record, Acknowledgment acknowledgment) {
        
        System.out.println(record);
        
        acknowledgment.acknowledge();
    }

}

这是关于可以注入到 @KafkaListener 方法中的内容的文档：https://docs.spring.io/spring-kafka/reference/html/#message-listeners

Spring-Kafka 中的 poll() 和 commitAsync()

poll() and commitAsync() in Spring-Kafka

apache-kafka

spring-boot

spring-kafka