redis实现延迟队列

前言：redis实现延迟队列该怎么做？在这里我分享一下

• • 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

1. 失效监听
2. redisson实现发布订阅延迟

集成KeyExpirationEventMessageListener类实现redis失效监听事件

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）

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@__为前缀进行发布；        
E：keyevent事件，事件以__keyevent@__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。

1. 加入依赖

        org.springframework.boot
        >spring-boot-starter-data-redis

2. 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;


@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());
            }
        }
    }
}

3. 创建一个配置类RedisConfig

@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@__为前缀进行发布
        //db为redis第几个库 db2...
//        redisMessageListenerContainer.addMessageListener(redisKeyExpirationListener, new PatternTopic(TOPIC));
        return redisMessageListenerContainer;
    }
}

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

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

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;


@Configuration
public class RedissonQueueConfig {

    private final String queueName = "queue";

    @Bean
    public RBlockingQueue rBlockingQueue(@Qualifier("redissonSingle") RedissonClient redissonClient) {
        return redissonClient.getBlockingQueue(queueName);
    }

    @Bean(name = "rDelayedQueue")
    public RDelayedQueue rDelayedQueue(@Qualifier("redissonSingle") RedissonClient redissonClient,
                                               @Qualifier("rBlockingQueue") RBlockingQueue 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;


public interface DelayQueue {

    
    Boolean offer(Object object);

    
    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;


@Component
public class RedissonDelayQueue implements DelayQueue {

    private static Logger log = LoggerFactory.getLogger(RedissonDelayQueue.class);

    @Resource(name = "rDelayedQueue")
    private RDelayedQueue