使用
依賴設定
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.12.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.homeey</groupId>
<artifactId>redis-delay-queue</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>redis-delay-queue</name>
<description>redis-delay-queue</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- https://mvnrepository.com/artifact/org.redisson/redisson -->
<dependency>
<groupId>org.redisson</groupId>
<artifactId>redisson-spring-boot-starter</artifactId>
<version>3.19.3</version>
</dependency>
<dependency>
<groupId>org.redisson</groupId>
<artifactId>redisson-spring-data-23</artifactId>
<version>3.19.3</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
</project>登入後複製
備註：處理redisson和springboot相容性問題
設定檔
springboot整合redisson有三種方式
詳細的整合查看springboot整合redisson配置
spring:
redis:
database: 0
host: localhost
port: 6379
timeout: 10000
lettuce:
pool:
max-active: 8
max-wait: -1
min-idle: 0
max-idle: 8登入後複製
demo代碼
package com.homeey.redisdelayqueue.delay;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RBlockingQueue;
import org.redisson.api.RDelayedQueue;
import org.redisson.api.RedissonClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
/**
* 明天的你会因今天到的努力而幸运
*
* @author jt4mrg@qq.com
* 23:11 2023-02-19 2023
**/
@Slf4j
@Component
@RequiredArgsConstructor
public class RedissonDelayQueue {
private final RDelayedQueue<String> delayedQueue;
private final RBlockingQueue<String> blockingQueue;
@PostConstruct
public void init() {
ExecutorService executorService = Executors.newFixedThreadPool(1);
executorService.submit(() -> {
while (true) {
try {
String task = blockingQueue.take();
log.info("rev delay task:{}", task);
} catch (Exception e) {
log.error("occur error", e);
}
}
});
}
public void offerTask(String task, long seconds) {
log.info("add delay task:{},delay time:{}s", task, seconds);
delayedQueue.offer(task, seconds, TimeUnit.SECONDS);
}
@Configuration
static class RedissonDelayQueueConfigure {
@Bean
public RBlockingQueue<String> blockingQueue(RedissonClient redissonClient) {
return redissonClient.getBlockingQueue("TOKEN-RENEWAL");
}
@Bean
public RDelayedQueue<String> delayedQueue(RBlockingQueue<String> blockingQueue,
RedissonClient redissonClient) {
return redissonClient.getDelayedQueue(blockingQueue);
}
}
}登入後複製
執行效果
原理分析
#從RedissonDelayedQueue實作中我們看到有四個角色
redisson_delay_queue_timeout:xxx，sorted set資料類型，存放所有延遲任務，按照延遲任務的到期時間戳（提交任務時的時間戳延遲時間）來排序的，所以列表的最前面的第一個元素就是整個延遲隊列中最早要被執行的任務，這個概念很重要
redisson_delay_queue:xxx，list資料型，暫時沒發現什麼用，只是在提交任務時會寫入這裡面，佇列轉移時又會刪除裡面的元素
xxx：list資料型，被稱為目標佇列，這個裡面存放的任務都是已經到了延遲時間的，可以被消費者取得的任務，所以上面demo中的RBlockingQueue的take方法是從這個目標佇列中取得到任務的
redisson_delay_queue_channel:xxx，是一個channel，用來通知客戶端開啟一個延遲任務
佇列建立
#RedissonDelayedQueue延遲佇列建立時，指定了佇列轉移服務，以及實現延遲隊列的四個重要校色的key。核心程式碼是指定佇列轉移任務
QueueTransferTask task = new QueueTransferTask(commandExecutor.getConnectionManager()) {
@Override
protected RFuture<Long> pushTaskAsync() {
return commandExecutor.evalWriteAsync(getRawName(), LongCodec.INSTANCE, RedisCommands.EVAL_LONG,
"local expiredValues = redis.call('zrangebyscore', KEYS[2], 0, ARGV[1], 'limit', 0, ARGV[2]); "//拿到zset中过期的值列表
+ "if #expiredValues > 0 then " //如果有
+ "for i, v in ipairs(expiredValues) do "
+ "local randomId, value = struct.unpack('dLc0', v);"//解构消息，在提交任务时打包的消息
+ "redis.call('rpush', KEYS[1], value);" //放入无前缀的list 队头
+ "redis.call('lrem', KEYS[3], 1, v);"//移除带前缀list 队尾元素
+ "end; "
+ "redis.call('zrem', KEYS[2], unpack(expiredValues));" //移除zset中本次读取的过期元素
+ "end; "
// get startTime from scheduler queue head task
+ "local v = redis.call('zrange', KEYS[2], 0, 0, 'WITHSCORES'); "//取zset最小分值的元素
+ "if v[1] ~= nil then "
+ "return v[2]; " //返回分值，即过期时间
+ "end "
+ "return nil;",
Arrays.asList(getRawName(), timeoutSetName, queueName),
System.currentTimeMillis(), 100);
}
@Override
protected RTopic getTopic() {
return RedissonTopic.createRaw(LongCodec.INSTANCE, commandExecutor, channelName);
}
};登入後複製
生產者
#核心程式碼RedissonDelayedQueue#offerAsync
#
return commandExecutor.evalWriteNoRetryAsync(getRawName(), codec, RedisCommands.EVAL_VOID,
"local value = struct.pack('dLc0', tonumber(ARGV[2]), string.len(ARGV[3]), ARGV[3]);" //打包消息体：消息id，消息长度，消息值
+ "redis.call('zadd', KEYS[2], ARGV[1], value);"//zset中加入消息及其超时分值
+ "redis.call('rpush', KEYS[3], value);" //向带前缀的list中添加消息
// if new object added to queue head when publish its startTime
// to all scheduler workers
+ "local v = redis.call('zrange', KEYS[2], 0, 0); "//取出zset中第一个元素
+ "if v[1] == value then " //如果最快过期的元素就是这次发送的消息
+ "redis.call('publish', KEYS[4], ARGV[1]); " //channel中发布一下超时时间
+ "end;",
Arrays.asList(getRawName(), timeoutSetName, queueName, channelName),
timeout, randomId, encode(e));登入後複製
消費者
消費者最簡單，直接從不帶前綴的list中BLPOP讀取就可以
以上是Redis如何實現延遲隊列的詳細內容。更多資訊請關注PHP中文網其他相關文章！
