基于Rocket MQ扩展的无限延迟消息队列

亦凉 2024-05-23 20:31 52阅读 0赞

## 基于Rocket MQ扩展的无限延迟消息队列 ##

### 背景: ###

*  Rocket MQ支持的延迟队列时间是固定间隔的, 默认19个等级(包含0等级): 0s, 1s, 5s, 10s, 30s, 1m, 2m, 3m, 4m, 5m, 6m, 7m, 8m, 9m, 10m, 20m, 30m, 1h. 我们的需求是实现用户下单后48小时或72小时给用户发送逼单邮件. 使用默认的延迟消息无法实现该功能, 所以对方案进行了改造.

### 实现原理: ###

*  简单而言, 就是在Rocket [MQ][]延迟队列固定时间间隔的基础上, 通过多次发送延迟消息, 达到任意延时时间组合计算. 通过反射的方式, 实现延迟业务逻辑的调用.
 *  源码如下:
 *      /*
         * Copyright (c) 2020-2030 XXX.Co.Ltd. All Rights Reserved.
         */
        package com.example.xxx.utils;
         
        import com.vevor.bmp.crm.common.constants.MQConstants;
        import lombok.Data;
        import lombok.SneakyThrows;
        import lombok.extern.slf4j.Slf4j;
        import org.apache.rocketmq.spring.annotation.ConsumeMode;
        import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
        import org.apache.rocketmq.spring.core.RocketMQListener;
        import org.apache.rocketmq.spring.core.RocketMQTemplate;
        import org.springframework.messaging.Message;
        import org.springframework.messaging.support.MessageBuilder;
        import org.springframework.stereotype.Component;
         
        import javax.annotation.Resource;
        import java.io.Serializable;
        import java.util.Calendar;
        import java.util.Date;
        import java.util.concurrent.TimeUnit;
         
        /**
         * @version ：1.8.0
         * @description ：基于Rocket MQ的任意延迟时长工具
         * @program ：user-growth
         * @date ：Created in 2023/5/22 3:35 下午
         * @since ：1.8.0
         */
        @Slf4j
        @Component
        @RocketMQMessageListener(consumerGroup = MQConstants.CRM_DELAY_QUEUE_TOPIC_GROUP,
                topic = MQConstants.CRM_DELAY_QUEUE_TOPIC,
                // 消息消费顺序
                consumeMode = ConsumeMode.CONCURRENTLY,
                // 最大消息重复消费次数
                maxReconsumeTimes = 3)
        public class RocketMQDelayQueueUtils implements RocketMQListener<RocketMQDelayQueueUtils.DelayTable<Object>> {
         
            /**
             * Rocket MQ客户端
             */
            @Resource
            private RocketMQTemplate rocketMQTemplate;
         
            /**
             * MQ默认延迟等级
             */
            private static final long[] TIME_DELAY_LEVEL = new long[]{0L, 1000L, 5000L, 10000L,
                    30000L, 60000L, 120000L, 180000L, 240000L, 300000L, 360000L, 420000L,
                    480000L, 540000L, 600000L, 1200000L, 1800000L, 3600000L, 7200000L};
         
            @SneakyThrows
            @Override
            public void onMessage(DelayTable<Object> message) {
                Date endTime = message.getEndTime();
                int delayLevel = getDelayLevel(endTime);
                // 继续延迟
                if (delayLevel != 0) {
                    int currentDelayCount = message.getCurrentDelayCount();
                    currentDelayCount++;
         
                    message.setCurrentDelayCount(currentDelayCount);
                    message.setCurrentDelayLevel(delayLevel);
                    message.setCurrentDelayMillis(TIME_DELAY_LEVEL[delayLevel]);
                    this.sendDelayMessage(message);
                    return;
                }
         
                // 执行业务
                log.info("delay message end! start to process business...");
                Class<? extends DelayMessageHandler> messageHandler = message.getMessageHandler();
                if (messageHandler != null) {
                    DelayMessageHandler delayMessageHandler = messageHandler.newInstance();
                    delayMessageHandler.handle();
                }
            }
         
            /**
             * 延迟消息体
             *
             * @param <E> 消息类型
             */
            @Data
         
            public static class DelayTable<E> implements Serializable {
         
                private static final long serialVersionUID = 2405172041950251807L;
         
                /**
                 * 延迟消息体
                 */
                private E content;
         
                /**
                 * 消息延迟结束时间
                 */
                private Date endTime;
         
                /**
                 * 总延迟毫秒数
                 */
                private long totalDelayTime;
         
                /**
                 * 总延迟时间单位
                 */
                private TimeUnit totalDelayTimeUnit;
         
                /**
                 * 当前延迟次数
                 */
                private int currentDelayCount;
         
                /**
                 * 当前延迟等级
                 */
                private int currentDelayLevel;
         
                /**
                 * 当前延迟毫秒数
                 */
                private long currentDelayMillis;
         
                /**
                 * 延迟处理逻辑
                 */
                private Class<? extends DelayMessageHandler> messageHandler;
            }
         
            /**
             * 发送延迟消息
             *
             * @param message 消息体
             * @param delay 延迟时长
             * @param timeUnit 延迟时间单位
             * @param handler 延迟时间到了之后，需要处理的逻辑
             * @param <E> 延迟消息类型
             */
            public <E> void delay(E message, int delay, TimeUnit timeUnit, Class<? extends DelayMessageHandler> handler) {
                // 把延迟时间转换成时间戳(毫秒)
                long totalDelayMills = timeUnit.toMillis(delay);
         
                // 根据延迟时间计算结束时间
                Calendar instance = Calendar.getInstance();
                instance.add(Calendar.MILLISECOND, (int)totalDelayMills);
                Date endTime = instance.getTime();
         
                // 根据延迟时间匹配延迟等级(delay level)
                int delayLevel = getDelayLevel(endTime);
                long delayMillis = TIME_DELAY_LEVEL[delayLevel];
         
                // 发送消息
                DelayTable<E> delayTable = new DelayTable<>();
                // 全局数据
                delayTable.setContent(message);
                delayTable.setMessageHandler(handler);
                delayTable.setEndTime(endTime);
                delayTable.setTotalDelayTime(delay);
                delayTable.setTotalDelayTimeUnit(timeUnit);
         
                // 当前延迟等级数据
                delayTable.setCurrentDelayCount(1);
                delayTable.setCurrentDelayLevel(delayLevel);
                delayTable.setCurrentDelayMillis(delayMillis);
                this.sendDelayMessage(delayTable);
            }
         
            /**
             * 计算延迟等级
             *
             * @param targetTime 延迟截止时间
             * @return Rocket MQ延迟消息等级
             */
            private static int getDelayLevel(Date targetTime) {
                long currentTime = System.currentTimeMillis();
                long delayMillis = targetTime.getTime() - currentTime;
         
                if (delayMillis <= 0) {
                    // 不延迟，即延迟等级为 0
                    return 0;
                }
         
                // 判断处于哪个延迟等级
                // 0s, 1s, 5s, 10s, 30s, 1m, 2m, 3m, 4m, 5m, 6m, 7m, 8m, 9m, 10m, 20m, 30m, 1h
                for (int i = 1; i <= 18; i++) {
                    long delayLevelTime = TIME_DELAY_LEVEL[i];
                    if (delayMillis < delayLevelTime) {
                        return i - 1;
                    } else if (delayMillis == delayLevelTime) {
                        return i;
                    }
                }
         
                // 最大延迟等级为 18
                return 18;
            }
         
            /**
             * 发送延迟消息
             *
             * @param delayTable 延迟对象，可以循环使用
             */
            @SneakyThrows
            private <E> void sendDelayMessage(DelayTable<E> delayTable) {
                // 消息序列化
                Message<DelayTable<E>> message = MessageBuilder
                                .withPayload(delayTable)
                                .build();
         
                // 设置\发送延迟消息
                int delayLevel = delayTable.getCurrentDelayLevel();
                rocketMQTemplate.syncSend(MQConstants.CRM_DELAY_QUEUE_TOPIC, message
                        , 3000, delayLevel);
         
                log.debug("delay count: {}, delay level: {}, time: {} milliseconds",
                        delayTable.currentDelayCount, delayLevel, TIME_DELAY_LEVEL[delayLevel]);
            }
         
            /**
             * 延迟回调接口
             *
             * 回调逻辑必须实现该接口#hander()方法，在延迟结束后，会通过反射的方式调用该方法
             */
            public interface DelayMessageHandler extends Serializable {
                long serialVersionUID = 2405172041950251807L;
         
                /**
                 * 回调函数
                 */
                void handle();
            }
         
        }

#### 测试代码: ####

*      /*
         * Copyright (c) 2020-2030 Sishun.Co.Ltd. All Rights Reserved.
         */
        package com.vevor.bmp.crm.io.controller;
         
        import com.vevor.bmp.crm.cpm.utils.RocketMQDelayQueueUtils;
        import com.vevor.common.pojo.vo.ResponseResult;
        import lombok.Data;
        import lombok.SneakyThrows;
        import lombok.extern.slf4j.Slf4j;
        import org.redisson.api.RBlockingQueue;
        import org.redisson.api.RedissonClient;
        import org.springframework.web.bind.annotation.GetMapping;
        import org.springframework.web.bind.annotation.RequestParam;
        import org.springframework.web.bind.annotation.RestController;
         
        import javax.annotation.Resource;
        import java.util.concurrent.TimeUnit;
         
        /**
         * @version ：1.8.0
         * @description ：延迟队列测试
         * @program ：user-growth
         * @date ：Created in 2023/5/22 4:54 下午
         * @since ：1.8.0
         */
        @Slf4j
        @RestController
        public class DelayQueueController {
         
            @Resource
            private RocketMQDelayQueueUtils rocketMQDelayQueueUtils;
         
            @GetMapping("/mq/delay")
            @SneakyThrows
            public ResponseResult<String> mqDelay(@RequestParam Integer delay, @RequestParam String task) {
                // 获取延时队列
                rocketMQDelayQueueUtils.delay(task, delay, TimeUnit.SECONDS, CallBack.class);
                return ResponseResult.success();
            }
         
            /**
             * @version ：
             * @description ：
             * @program ：user-growth
             * @date ：Created in 2023/5/23 2:11 下午
             * @since ：
             */
            @Data
            public static class CallBack implements RocketMQDelayQueueUtils.DelayMessageHandler {
         
                /**
                 * 回调函数
                 */
                @Override
                public void handle() {
                    log.info("i am business logical! {}", System.currentTimeMillis());
                }
            }
        }

#### 优缺点: ####

*  优点: 与定时任务框架相比, 通过延迟消息的方式具实时性高、 支持分布式、轻量级、高并发等优点.
 *  缺点: 消息的准确性不可靠, 正常情况下准确性在秒级, 但是当MQ服务出现消息堆积时, 消息的时间就会偏差较大, 所以准确性依赖MQ服务的稳定.

[MQ]: https://so.csdn.net/so/search?q=MQ&spm=1001.2101.3001.7020