/// <summary>
/// 增加获取分布式锁请求
/// 主要用于多个线程同时获取同一个couchbase缓存key的加锁数据，将并发转换成队列等待的回调方式处理
/// </summary>
/// <param name="key">couchbase缓存key</param>
/// <param name="getLockTimeOut">获取锁的超时时间，单位：ms</param>
/// <param name="lockTimeOut">持有锁的时间，单位：ms</param>
/// <param name="action">获取到加锁的数据回调事件</param>
/// <param name="cancelToken">等待线程取消通知，用于取消当前线程获取加锁数据操作</param>
private void AddGetWithLockRequest(string key, int getLockTimeOut, int lockTimeOut, Action <IOperationResult <object> > action, CancellationToken cancelToken, string bucketName)
{
ThreadQueue threadQueue;
if (!_keyThreadQueue.TryGetValue(key, out threadQueue))
{
lock (_keyThreadQueueLock)
{
if (!_keyThreadQueue.TryGetValue(key, out threadQueue))
{
threadQueue = new ThreadQueue {
HasProcessThread = false, WaitQueue = new ConcurrentQueue <CanCancelCallback>()
};
var addResult = _keyThreadQueue.TryAdd(key, threadQueue);
Log.Write(string.Format("添加key:({0})的等待队列，状态：{1}", key, addResult), MessageType.Info, GetType());
}
}
}
threadQueue.WaitQueue.Enqueue(new CanCancelCallback {
Callback = action, CancelToken = cancelToken
});
if (!threadQueue.HasProcessThread)
{
lock (threadQueue)
{
if (!threadQueue.HasProcessThread)
{
CreateThreadForCacheKey(key, getLockTimeOut, lockTimeOut, threadQueue, bucketName);
}
}
}
}
/// <summary>
/// 创建一个线程用于处理获取当前Couchbase缓存key的分布式缓存锁的线程队列
/// <para>多个线程需要获取同一个Couchbase缓存key的分布式锁，将这些线程排队，使用一个新线程对这些排队的线程进程处理</para>
/// </summary>
/// <param name="key">couchbase缓存key</param>
/// <param name="getLockTimeOut">获取锁的超时时间，单位：ms</param>
/// <param name="lockTimeOut">持有锁的时间，单位：ms</param>
/// <param name="threadQueue">等待获取当前Couchbase缓存key的分布式缓存锁的线程队列</param>
private void CreateThreadForCacheKey(string key, int getLockTimeOut, int lockTimeOut, ThreadQueue threadQueue, string bucketName)
{
Action action = () =>
{
threadQueue.HasProcessThread = true;
try
{
while (!threadQueue.WaitQueue.IsEmpty)
{
CanCancelCallback queueItem;
if (!threadQueue.WaitQueue.TryDequeue(out queueItem) || queueItem == null || queueItem.Callback == null || queueItem.CancelToken.IsCancellationRequested)
{
Log.Write(string.Format("获取分布式锁的线程被跳过,key：{0}，queueItem 为null:{1}，queueItem.Callback 为null：{2}， queueItem.CancelToken.IsCancellationRequested：{3}",
key, queueItem == null, queueItem == null || queueItem.Callback == null, queueItem == null || queueItem.CancelToken.IsCancellationRequested)
, MessageType.Warn, GetType());
continue;
}
Log.Write(string.Format("处理获取分布式锁，key:{0}", key), MessageType.Debug, GetType());
ProcessGetWithLock(key, getLockTimeOut, lockTimeOut, queueItem, bucketName);
}
}
finally
{
threadQueue.HasProcessThread = false;
}
};
_getCASTaskPool.AddTask(states =>
{
action();
}, null);
}