Redis가 지연 대기열을 구현하는 방법

<?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>

 QueueTransferTask task = new QueueTransferTask(commandExecutor.getConnectionManager()) {
            
            @Override
            protected RFuture<Long> pushTaskAsync() {
                return commandExecutor.evalWriteAsync(getRawName(), LongCodec.INSTANCE, RedisCommands.EVAL_LONG,
                        "local expiredValues = redis.call(&#39;zrangebyscore&#39;, KEYS[2], 0, ARGV[1], &#39;limit&#39;, 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(&#39;dLc0&#39;, v);"//解构消息，在提交任务时打包的消息
                              + "redis.call(&#39;rpush&#39;, KEYS[1], value);" //放入无前缀的list 队头
                              + "redis.call(&#39;lrem&#39;, KEYS[3], 1, v);"//移除带前缀list 队尾元素
                          + "end; "
                          + "redis.call(&#39;zrem&#39;, 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(&#39;zrange&#39;, KEYS[2], 0, 0, &#39;WITHSCORES&#39;); "//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);
            }
        };

 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));