聊聊redisson的DelayedQueue

序

本文主要研究一下redisson的DelayedQueue

maven

        
            org.redisson
            redisson
            3.8.1
        

实例

    @Test
    public void testDelayedQueue() throws InterruptedException {
        Config config = new Config();
        config.useSingleServer()
                .setAddress("redis://192.168.99.100:6379");
        RedissonClient redisson = Redisson.create(config);
        RBlockingQueue blockingQueue = redisson.getBlockingQueue("dest_queue1");
        RDelayedQueue delayedQueue = redisson.getDelayedQueue(blockingQueue);
        delayedQueue.offer("demo", 10, TimeUnit.SECONDS);
        Assert.assertFalse(blockingQueue.contains("demo"));
        TimeUnit.SECONDS.sleep(15);
        Assert.assertTrue(blockingQueue.contains("demo"));
    }

• 这里使用了两个queue，对delayedQueue的offer操作是直接进入delayedQueue，但是delay是作用在目标队列上，这里就是RBlockingQueue

源码解析

RDelayedQueue.offer

redisson-3.8.1-sources.jar!/org/redisson/RedissonDelayedQueue.java

public class RedissonDelayedQueue extends RedissonExpirable implements RDelayedQueue {

    private final QueueTransferService queueTransferService;
    private final String channelName;
    private final String queueName;
    private final String timeoutSetName;
    
    protected RedissonDelayedQueue(QueueTransferService queueTransferService, Codec codec, final CommandAsyncExecutor commandExecutor, String name) {
        super(codec, commandExecutor, name);
        channelName = prefixName("redisson_delay_queue_channel", getName());
        queueName = prefixName("redisson_delay_queue", getName());
        timeoutSetName = prefixName("redisson_delay_queue_timeout", getName());
        
        //QueueTransferTask task = ......
        
        queueTransferService.schedule(queueName, task);
        
        this.queueTransferService = queueTransferService;
    }

    public void offer(V e, long delay, TimeUnit timeUnit) {
        get(offerAsync(e, delay, timeUnit));
    }
    
    public RFuture offerAsync(V e, long delay, TimeUnit timeUnit) {
        long delayInMs = timeUnit.toMillis(delay);
        long timeout = System.currentTimeMillis() + delayInMs;
     
        long randomId = PlatformDependent.threadLocalRandom().nextLong();
        return commandExecutor.evalWriteAsync(getName(), codec, RedisCommands.EVAL_VOID,
                "local value = struct.pack('dLc0', tonumber(ARGV[2]), string.len(ARGV[3]), ARGV[3]);" 
              + "redis.call('zadd', KEYS[2], ARGV[1], value);"
              + "redis.call('rpush', KEYS[3], value);"
              // if new object added to queue head when publish its startTime 
              // to all scheduler workers 
              + "local v = redis.call('zrange', KEYS[2], 0, 0); "
              + "if v[1] == value then "
                 + "redis.call('publish', KEYS[4], ARGV[1]); "
              + "end;"
                 ,
              Arrays.