RabbitMQ死信队列

中间件
rabbitmq
发布日期:   2022-11-20

RabbitMQ死信队列

【MQ中间件】RabbitMQ死信队列

死信队列

“死信”是RabbitMQ中的一种消息机制，当你在消费消息时，如果队列里的消息出现以下情况：

  1. 消息被否定确认，使用 channel.basicNack 或 channel.basicReject ，并且此时requeue 属性被设置为false。
  2. 消息在队列的存活时间超过设置的TTL时间。
  3. 消息队列的消息数量已经超过最大队列长度。

那么该消息将成为“死信”。

“死信”消息会被RabbitMQ进行特殊处理，如果配置了死信队列信息，那么该消息将会被丢进死信队列中，如果没有配置，则该消息将会被丢弃。

如何配置死信队列

通过在channel.queueDeclare 方法中设置x-dead-letter-exchange 参数来为队列添加DLX

args.put (”x-dead-letter-exchange ”,” dlx exchange ”);

也可以为这个DLX 指定路由键，如果没有特殊指定，则使用原队列的路由键：

args.put (”x-dead-letter-routing-key”,”dlx-routing-key”);

配置死信队列呢？其实很简单，大概可以分为以下步骤：

  1. 配置业务队列，绑定到业务交换机上
  2. 为业务队列配置死信交换机和路由key
  3. 为死信交换机配置死信队列

注意，并不是直接声明一个公共的死信队列，然后所以死信消息就自己跑到死信队列里去了。而是为每个需要使用死信的业务队列配置一个死信交换机，这里同一个项目的死信交换机可以共用一个，然后为每个业务队列分配一个单独的路由key。

代码

package com.wql.config;

import org.springframework.amqp.core.*;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.HashMap;
import java.util.Map;

/**
 * @author: wangql
 * @Title: CustomConfigurer
 * @ProjectName: tudou
 * @Description:
 * @date: 2022/1/30 16:32
 */
@Configuration
public class DeadLetterRabbitConfig {

    public static final String BUSINESS_EXCHANGE_NAME = "dead.letter.demo.simple.business.exchange";
    public static final String BUSINESS_QUEUEA_NAME = "dead.letter.demo.simple.business.queuea";
    public static final String BUSINESS_QUEUEB_NAME = "dead.letter.demo.simple.business.queueb";
    public static final String DEAD_LETTER_EXCHANGE = "dead.letter.demo.simple.deadletter.exchange";
    public static final String DEAD_LETTER_QUEUEA_ROUTING_KEY = "dead.letter.demo.simple.deadletter.queuea.routingkey";
    public static final String DEAD_LETTER_QUEUEB_ROUTING_KEY = "dead.letter.demo.simple.deadletter.queueb.routingkey";
    public static final String DEAD_LETTER_QUEUEA_NAME = "dead.letter.demo.simple.deadletter.queuea";
    public static final String DEAD_LETTER_QUEUEB_NAME = "dead.letter.demo.simple.deadletter.queueb";

    // 声明业务Exchange
    @Bean("businessExchange")
    public FanoutExchange businessExchange(){
        return new FanoutExchange(BUSINESS_EXCHANGE_NAME);
    }

    // 声明死信Exchange
    @Bean("deadLetterExchange")
    public DirectExchange deadLetterExchange(){
        return new DirectExchange(DEAD_LETTER_EXCHANGE);
    }

    // 声明业务队列A
    @Bean("businessQueueA")
    public Queue businessQueueA(){
        Map<String, Object> args = new HashMap<>(2);
//       x-dead-letter-exchange    这里声明当前队列绑定的死信交换机
        args.put("x-dead-letter-exchange", DEAD_LETTER_EXCHANGE);
//       x-dead-letter-routing-key  这里声明当前队列的死信路由key
        args.put("x-dead-letter-routing-key", DEAD_LETTER_QUEUEA_ROUTING_KEY);
        return QueueBuilder.durable(BUSINESS_QUEUEA_NAME).withArguments(args).build();
    }

    // 声明业务队列B
    @Bean("businessQueueB")
    public Queue businessQueueB(){
        Map<String, Object> args = new HashMap<>(2);
//       x-dead-letter-exchange    这里声明当前队列绑定的死信交换机
        args.put("x-dead-letter-exchange", DEAD_LETTER_EXCHANGE);
//       x-dead-letter-routing-key  这里声明当前队列的死信路由key
        args.put("x-dead-letter-routing-key", DEAD_LETTER_QUEUEB_ROUTING_KEY);
        return QueueBuilder.durable(BUSINESS_QUEUEB_NAME).withArguments(args).build();
    }

    // 声明死信队列A
    @Bean("deadLetterQueueA")
    public Queue deadLetterQueueA(){
        return new Queue(DEAD_LETTER_QUEUEA_NAME);
    }

    // 声明死信队列B
    @Bean("deadLetterQueueB")
    public Queue deadLetterQueueB(){
        return new Queue(DEAD_LETTER_QUEUEB_NAME);
    }

    // 声明业务队列A绑定关系
    @Bean
    public Binding businessBindingA(@Qualifier("businessQueueA") Queue queue,
                                    @Qualifier("businessExchange") FanoutExchange exchange){
        return BindingBuilder.bind(queue).to(exchange);
    }

    // 声明业务队列B绑定关系
    @Bean
    public Binding businessBindingB(@Qualifier("businessQueueB") Queue queue,
                                    @Qualifier("businessExchange") FanoutExchange exchange){
        return BindingBuilder.bind(queue).to(exchange);
    }

    // 声明死信队列A绑定关系
    @Bean
    public Binding deadLetterBindingA(@Qualifier("deadLetterQueueA") Queue queue,
                                      @Qualifier("deadLetterExchange") DirectExchange exchange){
        return BindingBuilder.bind(queue).to(exchange).with(DEAD_LETTER_QUEUEA_ROUTING_KEY);
    }

    // 声明死信队列B绑定关系
    @Bean
    public Binding deadLetterBindingB(@Qualifier("deadLetterQueueB") Queue queue,
                                      @Qualifier("deadLetterExchange") DirectExchange exchange){
        return BindingBuilder.bind(queue).to(exchange).with(DEAD_LETTER_QUEUEB_ROUTING_KEY);
    }

}

这里声明了两个Exchange，一个是业务Exchange，另一个是死信Exchange，业务Exchange下绑定了两个业务队列，业务队列都配置了同一个死信Exchange，并分别配置了路由key，在死信Exchange下绑定了两个死信队列，设置的路由key分别为业务队列里配置的路由key。

application.yml

default-requeue-rejected属性设置为false。

业务队列消费类：

package com.wql.consumer;


import com.rabbitmq.client.Channel;
import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

import java.io.IOException;

import static com.wql.config.DeadLetterRabbitConfig.BUSINESS_QUEUEA_NAME;
import static com.wql.config.DeadLetterRabbitConfig.BUSINESS_QUEUEB_NAME;

@Slf4j
@Component
public class BusinessMessageReceiver {

    @RabbitListener(queues = BUSINESS_QUEUEA_NAME)
    public void receiveA(Message message, Channel channel) throws IOException {
        String msg = new String(message.getBody());
        log.info("收到业务消息A：{}", msg);
        boolean ack = true;
        Exception exception = null;
        try {
            if (msg.contains("deadletter")){
                throw new RuntimeException("dead letter exception");
            }
        } catch (Exception e){
            ack = false;
            exception = e;
        }
        if (!ack){
            log.error("消息消费发生异常，error msg:{}", exception.getMessage(), exception);
            channel.basicNack(message.getMessageProperties().getDeliveryTag(), false, false);
        } else {
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        }
    }

    @RabbitListener(queues = BUSINESS_QUEUEB_NAME)
    public void receiveB(Message message, Channel channel) throws IOException {
        String msg = new String(message.getBody());
        log.info("收到业务消息A：{}", msg);
        boolean ack = true;
        Exception exception = null;
        try {
            if (msg.contains("deadletter")){
                throw new RuntimeException("dead letter exception");
            }
        } catch (Exception e){
            ack = false;
            exception = e;
        }
        if (!ack){
            log.error("消息消费发生异常，error msg:{}", exception.getMessage(), exception);
            channel.basicNack(message.getMessageProperties().getDeliveryTag(), false, false);
        } else {
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        }
    }
}

死信队列消费类：

package com.wql.consumer;


import com.rabbitmq.client.Channel;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

import java.io.IOException;

import static com.wql.config.DeadLetterRabbitConfig.DEAD_LETTER_QUEUEA_NAME;
import static com.wql.config.DeadLetterRabbitConfig.DEAD_LETTER_QUEUEB_NAME;

@Component
public class DeadLetterMessageReceiver {


    @RabbitListener(queues = DEAD_LETTER_QUEUEA_NAME)
    public void receiveA(Message message, Channel channel) throws IOException {
        System.out.println("收到死信消息A：" + new String(message.getBody()));
        channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
    }

    @RabbitListener(queues = DEAD_LETTER_QUEUEB_NAME)
    public void receiveB(Message message, Channel channel) throws IOException {
        System.out.println("收到死信消息B：" + new String(message.getBody()));
        channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
    }
}

发送死信消息：

@Override
public String sendDeadLetterMessage(String msg) {
    String messageId = String.valueOf(UUID.randomUUID());
    String createTime = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    Map<String, Object> map = new HashMap<>();
    map.put("messageId", messageId);
    map.put("messageData", msg);
    map.put("createTime", createTime);
    rabbitTemplate.convertAndSend(BUSINESS_EXCHANGE_NAME, null, map);
    return "ok";
}

引用

RabbitMQ 如何进行消息可靠投递

Rabbitmq——备份交换机

RabbitMQ重试机制

文章作者: WangQingLei
文章链接: https://qinglei1989.github.io/2022/11/20/middleware-rabbitmq-deadletter/
版权声明: 本博客所有文章除特別声明外，均采用 CC BY 4.0 许可协议。转载请注明来源 WangQingLei !
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