StackExchange.Redis

Question

我有以下方法等待 Redis 键的独占锁。这种方法有效，但我想知道是否有没有 for 循环和 Thread.Sleep.

的更好方法

    /// <summary>
    /// wait up to 2 seconds to achieve a lock!  
    /// The lock is good for a maximum of 3 seconds
    /// </summary>
    /// <param name="codeID"></param>
    internal void WaitForSingleUseLock(CodeID codeID)
    {
        var key = _redemptionRepo.SingleUseCodeLockPrefix + codeID.Value;
        var expiration = TimeSpan.FromSeconds(3);
        for (var i = 0; i < 20; i++)
        {
            var lockAchieved = _cacheRepo.LockTake(key, "1", expiration);
            if (lockAchieved)
            {
                break;
            }
            Thread.Sleep(TimeSpan.FromMilliseconds(100));
        }
    }

Answer 1

我唯一可以建议不同的是将 pub/sub 视为侧通道（意思是：另外，而不是替代），用于指示锁可能的时间现在可用 - 即在释放时发布，并使用 sub 释放计时器（通过监视器或异步等待句柄）。

除此之外：没有。 Redis 没有挂起队列的概念。您也许可能使用列表构建一个，但是...

Answer 2

在考虑了@Marc 的评论并与我的团队会面讨论 Task.Delay() 在这种情况下优于 Thread.Sleep() 的好处后，我决定将此作为最终解决方案：

    /// <summary>
    /// wait up to 3 seconds to achieve a lock!  
    /// The lock is good for a maximum of 3 seconds
    /// 
    /// Returns the total amount of time until the lock was taken
    /// </summary>
    internal virtual async Task<TimeSpan> WaitForSingleUseLock(CodeID codeID)
    {
        var key = _redemptionRepo.SingleUseCodeLockPrefix + codeID.Value;
        var totalTime = TimeSpan.Zero;
        var maxTime = TimeSpan.FromSeconds(3);
        var expiration = TimeSpan.FromSeconds(3);
        var sleepTime = TimeSpan.FromMilliseconds(50);
        var lockAchieved = false;

        while (!lockAchieved && totalTime < maxTime)
        {
            lockAchieved = _cacheRepo.LockTake(key, "1", expiration);
            if (lockAchieved)
            {
                continue;
            }
            await Task.Delay(sleepTime);
            totalTime += sleepTime;
        }
        return totalTime;
    }

StackExchange.Redis - 等待锁的最佳方式

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