redis实现延迟队列

冷不防 2022-09-13 04:13 264阅读 0赞

**前言：redis实现延迟队列该怎么做？在这里我分享一下**

### redis实现延迟队列 ###

*   *  一、Redis实现延迟队列
     *  二、redis失效监听事件
     *  三、此种实现面临的问题
     *  四、开发准备
     *  五、基础实现
     *  六、使用redisson实现延迟队列
     *  七、redisson实现延迟队列的原理
     *  八、延迟队列配置
     *  九、疑问解答与加群交流学习

## 一、Redis实现延迟队列 ##

1.  失效监听
2.  redisson实现发布订阅延迟

## 二、redis失效监听事件 ##

集成KeyExpirationEventMessageListener类实现redis失效监听事件

## 三、此种实现面临的问题 ##

1.  redis的失效监听事件会存在一定的时间差，并且当数据量越大时，误差会越大。
2.  redis的失效监听事件会将所有key失效都会通知到onMessage,如果针对一个key，分布式业务的场景下，会出现重复消费的问题。（可以增加分布式锁的实现，但是redisson分布式锁提供了另一种延迟队列的实现方式）

## 四、开发准备 ##

redis需要在服务端开启配置，打开redis服务的配置文件 添加`notify-keyspace-events Ex`

*  相关参数如下：

K：keyspace事件，事件以__keyspace@<db>__为前缀进行发布；        
    E：keyevent事件，事件以__keyevent@<db>__为前缀进行发布；        
    g：一般性的，非特定类型的命令，比如del，expire，rename等；       
    $：字符串特定命令；        
    l：列表特定命令；        
    s：集合特定命令；        
    h：哈希特定命令；        
    z：有序集合特定命令；        
    x：过期事件，当某个键过期并删除时会产生该事件；        
    e：驱逐事件，当某个键因maxmemore策略而被删除时，产生该事件；        
    A：g$lshzxe的别名，因此”AKE”意味着所有事件。

## 五、基础实现 ##

1.  加入依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>

1.  可正常连接存取redis数据之后，创建监听类`RedisKeyExpirationListener`继承`KeyExpirationEventMessageListener`，重写`onMessage`方法。（key失效之后，会发出onMessage方法，之呢个获取失效的key值，不能获取key对应的value值）。

import com.test01.scrm.service.member.api.common.MemberStatusEnum;
    import com.test01.scrm.service.member.provider.service.base.IBaseMemberService;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.data.redis.connection.Message;
    import org.springframework.data.redis.listener.KeyExpirationEventMessageListener;
    import org.springframework.data.redis.listener.RedisMessageListenerContainer;
    import org.springframework.stereotype.Component;
    
    /**
     * @author lwl
     */
    @Component
    @Slf4j
    public class RedisKeyExpirationListener extends KeyExpirationEventMessageListener {
        
        private final IBaseMemberService baseMemberService;
    
    
        private final static String MEMBER_LOCK_ACCOUNT_SUFFIX = ".lock_account";
        private final static String MEMBER_LOCK_ACCOUNT_DOMAIN_SUFFIX = "T";
        private final static String MEMBER_LOCK_ACCOUNT_MEMBER_SUFFIX = "M";
        private final static String MEMBER_REDISSON_LOCK = ".member_lock_redisson";
        private final static int WAIT_TIME = 5;
        private final static int LEASE_TIME = 10;
    
        public RedisKeyExpirationListener(RedisMessageListenerContainer redisMessageListenerContainer, IBaseMemberService baseMemberService) {
        
            super(redisMessageListenerContainer);
            this.baseMemberService = baseMemberService;
        }
    
        @Override
        public void onMessage(Message message, byte[] pattern) {
        
            //获取失效的key
            String expiredKey = message.toString();
            log.info("================================get on message:{}====================", expiredKey);
            if (expiredKey.endsWith(MEMBER_LOCK_ACCOUNT_SUFFIX)) {
        
                log.info("================================on message:{}====================", expiredKey);
                try {
        
                    log.info("=======待解锁账号解锁======expiredKey:{}", expiredKey);
                    String tenantId = expiredKey.substring(expiredKey.indexOf(MEMBER_LOCK_ACCOUNT_DOMAIN_SUFFIX) + 1, expiredKey.indexOf(MEMBER_LOCK_ACCOUNT_MEMBER_SUFFIX));
                    String memberId = expiredKey.substring(expiredKey.indexOf(MEMBER_LOCK_ACCOUNT_MEMBER_SUFFIX) + 1, expiredKey.indexOf(MEMBER_LOCK_ACCOUNT_SUFFIX));
                    baseMemberService.updateAccount(Integer.parseInt(tenantId), Long.parseLong(memberId), MemberStatusEnum.NORMAL.getCode(), null);
                } catch (Exception exception) {
        
                    log.info("auto unlock fail,expired key:{},exception:{}", expiredKey, exception.getMessage());
                }
            }
        }
    }

1.  创建一个配置类`RedisConfig`

/**
     * @author lwl
     */
    @Configuration
    public class RedisConfig {
        
    
        @Value("${redis.dbIndex}")
        private Integer dbIndex;
    
        private final String TOPIC = "__keyevent@" + dbIndex + "__:expired";
        private final RedisConnectionFactory redisConnectionFactory;
    
        public RedisConfig(RedisConnectionFactory redisConnectionFactory) {
        
            this.redisConnectionFactory = redisConnectionFactory;
        }
    
    
        @Bean
        public RedisMessageListenerContainer redisMessageListenerContainer() {
        
            RedisMessageListenerContainer redisMessageListenerContainer = new RedisMessageListenerContainer();
            redisMessageListenerContainer.setConnectionFactory(redisConnectionFactory);
            //keyevent事件，事件以__keyevent@<db>__为前缀进行发布
            //db为redis第几个库 db2...
    //        redisMessageListenerContainer.addMessageListener(redisKeyExpirationListener, new PatternTopic(TOPIC));
            return redisMessageListenerContainer;
        }
    }

## 六、使用redisson实现延迟队列 ##

由于延时队列持久化在redis中，所以机器宕机数据不会异常丢失，机器重启后，会正常消费队列中积累的任务

## 七、redisson实现延迟队列的原理 ##

使用redis的zset有序性，轮询zset中的每个元素，到点后将内容迁移至待消费的队列

## 八、延迟队列配置 ##

package com.test01.scrm.service.member.provider.config.redisson.delay;
    
    import org.redisson.api.RBlockingQueue;
    import org.redisson.api.RDelayedQueue;
    import org.redisson.api.RedissonClient;
    import org.springframework.beans.factory.annotation.Qualifier;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    /**
     * @author lwl
     * redisson延迟队列
     */
    @Configuration
    public class RedissonQueueConfig {
        
    
        private final String queueName = "queue";
    
        @Bean
        public RBlockingQueue<String> rBlockingQueue(@Qualifier("redissonSingle") RedissonClient redissonClient) {
        
            return redissonClient.getBlockingQueue(queueName);
        }
    
        @Bean(name = "rDelayedQueue")
        public RDelayedQueue<String> rDelayedQueue(@Qualifier("redissonSingle") RedissonClient redissonClient,
                                                   @Qualifier("rBlockingQueue") RBlockingQueue<String> blockQueue) {
        
            return redissonClient.getDelayedQueue(blockQueue);
        }
    }

定义队列使用接口

package com.test01.scrm.service.member.provider.config.redisson.delay;
    
    import java.util.concurrent.TimeUnit;
    
    /**
     * @author lwl
     */
    public interface DelayQueue {
        
    
        /**
         * 发布
         *
         * @param object
         * @return
         */
        Boolean offer(Object object);
    
        /**
         * 带延迟功能的队列
         *
         * @param object
         * @param time
         * @param timeUnit
         */
        void offer(Object object, Long time, TimeUnit timeUnit);
    
        void offerAsync(Object object, Long time, TimeUnit timeUnit);
    
        Boolean offerAsync(Object object);
    }

延迟队列实现

package com.test01.scrm.service.member.provider.config.redisson.delay;
    
    import org.redisson.api.RDelayedQueue;
    import org.redisson.api.RFuture;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    import javax.annotation.Resource;
    import java.util.concurrent.ExecutionException;
    import java.util.concurrent.TimeUnit;
    
    /**
     * @author lwl
     */
    @Component
    public class RedissonDelayQueue implements DelayQueue {
        
    
        private static Logger log = LoggerFactory.getLogger(RedissonDelayQueue.class);
    
        @Resource(name = "rDelayedQueue")
        private RDelayedQueue<Object> rDelayedQueue;
    
    
        @Override
        public Boolean offer(Object object) {
        
            return rDelayedQueue.offer(object);
        }
    
        @Override
        public void offer(Object object, Long time, TimeUnit timeUnit) {
        
            rDelayedQueue.offer(object, time, timeUnit);
        }
    
        @Override
        public void offerAsync(Object object, Long time, TimeUnit timeUnit) {
        
            rDelayedQueue.offerAsync(object, time, timeUnit);
        }
    
        @Override
        public Boolean offerAsync(Object object) {
        
            boolean flag = false;
            RFuture<Boolean> rFuture = rDelayedQueue.offerAsync(object);
            try {
        
                flag = rFuture.get();
            } catch (InterruptedException | ExecutionException e) {
        
                log.info("offerAsync exception:{}", e.getMessage());
                e.printStackTrace();
            }
            return flag;
        }
    }

启动一个后台监控线程

package com.test01.scrm.service.member.provider.config.redisson.delay;
    
    import org.redisson.api.RBlockingQueue;
    import org.springframework.stereotype.Component;
    
    import javax.annotation.PostConstruct;
    import javax.annotation.Resource;
    
    /**
     * @author test01
     */
    @Component
    public class RedissonTask {
        
        @Resource(name = "rBlockingQueue")
        private RBlockingQueue<Object> rBlockingQueue;
    
        @PostConstruct
        public void take() {
        
            new Thread(() -> {
        
                while (true) {
        
                    try {
        
                        System.out.println("=========================" + rBlockingQueue.take());
                    } catch (InterruptedException e) {
        
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    }

使用延迟队列发送

package com.test01.scrm.service.member.provider.impl;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.mybatis.spring.annotation.MapperScan;
    import org.redisson.api.RDelayedQueue;
    import org.springframework.boot.test.context.SpringBootTest;
    import org.springframework.test.context.ActiveProfiles;
    import org.springframework.test.context.junit4.SpringRunner;
    
    import javax.annotation.Resource;
    import java.util.concurrent.TimeUnit;
    
    @RunWith(SpringRunner.class)
    @SpringBootTest
    @ActiveProfiles(value = "llh")
    @MapperScan("com.test01.scrm.service.member.provider.mapper")
    public class RDelayQueueTests {
        
    
        @Resource(name = "rDelayedQueue")
        private RDelayedQueue<Object> rDelayedQueue;
    
        @Test
        public void offerAsync() {
        
    
            rDelayedQueue.offerAsync("llh send message", 20, TimeUnit.SECONDS);
        }
    }

## 九、疑问解答与加群交流学习 ##

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