RabbitMQ死信队列延迟交换机

news2024/9/22 9:36:20

RabbitMQ死信队列&延迟交换机

1.什么是死信

死信&死信队列

死信队列的应用：

基于死信队列在队列消息已满的情况下，消息也不会丢失
实现延迟消费的效果。比如：下订单时，有15分钟的付款时间

2. 实现死信队列

2.1 准备Exchange&Queue

package com.llp.rabbitmq.config;

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

/**
 * 死信队列配置
 */
@Configuration
public class DeadLetterConfig {

    public static final String NORMAL_EXCHANGE = "normal-exchange";
    public static final String NORMAL_QUEUE = "normal-queue";
    public static final String NORMAL_ROUTING_KEY = "normal.#";

    public static final String DEAD_EXCHANGE = "dead-exchange";
    public static final String DEAD_QUEUE = "dead-queue";
    public static final String DEAD_ROUTING_KEY = "dead.#";

    @Bean
    public Exchange normalExchange(){
        return ExchangeBuilder.topicExchange(NORMAL_EXCHANGE).build();
    }

    @Bean
    public Queue normalQueue(){
        //普通队列，绑定死信队列
        return QueueBuilder.durable(NORMAL_QUEUE).deadLetterExchange(DEAD_EXCHANGE).deadLetterRoutingKey("dead.abc").build();
    }

    @Bean
    public Binding normalBinding(Queue normalQueue,Exchange normalExchange){
        return BindingBuilder.bind(normalQueue).to(normalExchange).with(NORMAL_ROUTING_KEY).noargs();
    }

    @Bean
    public Exchange deadExchange(){
        return ExchangeBuilder.topicExchange(DEAD_EXCHANGE).build();
    }

    @Bean
    public Queue deadQueue(){
        return QueueBuilder.durable(DEAD_QUEUE).build();
    }

    @Bean
    public Binding deadBinding(Queue deadQueue,Exchange deadExchange){
        return BindingBuilder.bind(deadQueue).to(deadExchange).with(DEAD_ROUTING_KEY).noargs();
    }
}

2.2 实现效果

基于消费者进行reject或者nack实现死信效果

package com.llp.rabbitmq.topic;

import com.llp.rabbitmq.config.DeadLetterConfig;
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;

@Component
public class DeadListener {

    @RabbitListener(queues = DeadLetterConfig.NORMAL_QUEUE)
    public void consume(String msg, Channel channel, Message message) throws IOException {
        System.out.println("接收到normal队列的消息：" + msg);
        //设置消息决绝消费，不需要重新放入到队列中
        channel.basicReject(message.getMessageProperties().getDeliveryTag(),false);
        //或者
        //channel.basicNack(message.getMessageProperties().getDeliveryTag(),false,false);
    }
}

消息的生存时间

给消息设置生存时间

@Test
public void publishExpire(){
    String msg = "dead letter expire";
    rabbitTemplate.convertAndSend(DeadLetterConfig.NORMAL_EXCHANGE, "normal.abc", msg, new MessagePostProcessor() {
        @Override
        public Message postProcessMessage(Message message) throws AmqpException {
            message.getMessageProperties().setExpiration("5000");
            return message;
        }
    });
}

给队列设置消息的生存时间

@Bean
public Queue normalQueue(){
    return QueueBuilder.durable(NORMAL_QUEUE)
            .deadLetterExchange(DEAD_EXCHANGE)
            .deadLetterRoutingKey("dead.abc")
            .ttl(10000)
            .build();
}

设置Queue中的消息最大长度

@Bean
public Queue normalQueue(){
    return QueueBuilder.durable(NORMAL_QUEUE)
            .deadLetterExchange(DEAD_EXCHANGE)
            .deadLetterRoutingKey("dead.abc")
            .maxLength(1)
            .build();
}

只要Queue中已经有一个消息，如果再次发送一个消息，这个消息会变为死信！

3.延迟交换机

下载地址：https://github.com/rabbitmq/rabbitmq-delayed-message-exchange/releases/tag/3.8.9

死信队列实现延迟消费时，如果延迟时间比较复杂，比较多，直接使用死信队列时，需要创建大量的队列还对应不同的时间，可以采用延迟交换机来解决这个问题。

将下载的文件上传到linux服务器并使用如下指令，将文件方到rabbitmq容器的plugins目录下

docker cp rabbitmq_delayed_message_exchange-3.8.9-0199d11c.ez 9da57c5038ba:/opt/rabbitmq/plugins

在rabbitmq容器的/opt/rabbitmq/sbin目录下执行

rabbitmq-plugins enable rabbitmq_delayed_message_exchange

重启容器生效

docker restart 9da57c5038ba

可以看到添加插件后多了一个延迟交换机的选项

构建延迟交换机

package com.llp.rabbitmq.config;

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

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

/**
 * 延迟队列
 */
@Configuration
public class DelayedConfig {

    public static final String DELAYED_EXCHANGE = "delayed-exchange";
    public static final String DELAYED_QUEUE = "delayed-queue";
    public static final String DELAYED_ROUTING_KEY = "delayed.#";

    @Bean
    public Exchange delayedExchange(){
        Map<String, Object> arguments = new HashMap<>();
        arguments.put("x-delayed-type","topic");
        Exchange exchange = new CustomExchange(DELAYED_EXCHANGE,"x-delayed-message",true,false,arguments);
        return exchange;
    }

    @Bean
    public Queue delayedQueue(){
        return QueueBuilder.durable(DELAYED_QUEUE).build();
    }

    @Bean
    public Binding delayedBinding(Queue delayedQueue,Exchange delayedExchange){
        return BindingBuilder.bind(delayedQueue).to(delayedExchange).with(DELAYED_ROUTING_KEY).noargs();
    }
}

发送消息

package com.llp.rabbitmq;

import com.llp.rabbitmq.config.DelayedConfig;
import org.junit.jupiter.api.Test;
import org.springframework.amqp.AmqpException;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessagePostProcessor;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class DelayedPublisherTest {

    @Autowired
    private RabbitTemplate rabbitTemplate;

    @Test
    public void publish(){
        rabbitTemplate.convertAndSend(DelayedConfig.DELAYED_EXCHANGE, "delayed.abc", "xxxx", new MessagePostProcessor() {
            @Override
            public Message postProcessMessage(Message message) throws AmqpException {
                //设置消息指定多少时间被消费，单位毫秒
                message.getMessageProperties().setDelay(30000);
                return message;
            }
        });
    }
}