spring-boot - 如何使用弹簧启动创建 Kafka 消费者侦听器，以防消息被拒绝，在可变时间后重试使用它们

Question

我在 springboot 应用程序中有一个简单的 kafka 消费者监听器，如下所示：

@KafkaListener(topics="mytopic")
public void receive(String message) {
   LOGGER.info("received message='{}'", messge);
}

在某些特定情况下，我想拒绝该消息，但我希望系统在一定时间后再次向我建议；

我能怎么做？

注意：我也想定制kafka配置（不是默认的springboot结构）

Answer 1

请参阅重试交付和有状态重试。

使用所需的重试特性配置侦听器工厂，并（可选）添加一个SeekToCurrentErrorHandler.

Answer 2

我的实现只做你需要的事情：

1) kafka 配置类，它从自定义属性中获取字段并在 5000 毫秒后重试被拒绝的消息（在 kafkaListenerContainerFactory 方法内）：

@Configuration
public class KafkaConfig {

    //...

    @Bean
    public Map<String, Object> consumerConfigs() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);

        if(enableSsl) {
            //configure the following three settings for SSL Encryption
            props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, "SSL");
            props.put(SslConfigs.SSL_TRUSTSTORE_LOCATION_CONFIG, sslTruststoreLocation);
            props.put(SslConfigs.SSL_TRUSTSTORE_PASSWORD_CONFIG,  sslPassword);

            // configure the following three settings for SSL Authentication
            props.put(SslConfigs.SSL_KEYSTORE_LOCATION_CONFIG, sslKeystoreLocation);
            props.put(SslConfigs.SSL_KEYSTORE_PASSWORD_CONFIG, sslPassword);
            props.put(SslConfigs.SSL_KEY_PASSWORD_CONFIG, sslPassword);
        }
        return props;
    }

    @Bean
    public ConsumerFactory<String, String> consumerFactory() {              
        return new DefaultKafkaConsumerFactory<>(consumerConfigs());
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(new DefaultKafkaConsumerFactory<>(consumerConfigs()));

        ContainerProperties containerProperties = factory.getContainerProperties();
        containerProperties.setAckMode(AckMode.MANUAL_IMMEDIATE);

        RetryTemplate retryTemplate = new RetryTemplate();
        factory.setStatefulRetry(false);
        factory.setRetryTemplate(retryTemplate);

        //infinite number of retry attempts
        retryTemplate.setRetryPolicy(new AlwaysRetryPolicy());

        //wait a "waitingTime" time before retrying
        int waitingTime = 5000;
        FixedBackOffPolicy fixedBackOffPolicy = new FixedBackOffPolicy();
        fixedBackOffPolicy.setBackOffPeriod(waitingTime);
        retryTemplate.setBackOffPolicy(fixedBackOffPolicy);

        //or use exponential waiting
        //ExponentialBackOffPolicy expBackoff = new ExponentialBackOffPolicy();
        //expBackoff.setInitialInterval(...);
        //expBackoff.setMaxInterval(...);
        //retryTemplate.setBackOffPolicy(expBackoff);

        return factory;
    }
}

2）消费消息的类：

@Service
public class Consumer {

    private final Logger logger = LoggerFactory.getLogger(Consumer.class);

    //...

    @KafkaListener(topics="${kafka.topics.test}")
    public void consume(String message, Acknowledgment ack) throws IOException {
        if(processMessage) {
            logger.info(String.format("##KAFKA## -> Consumed message -> %s", message)); 
            ack.acknowledge();
        } 
        else { 
            logger.error(String.format("##KAFKA## -> Failed message -> %s", message));  
            throw new IOException("reject message");
        }
    }
}