基于.net的分布式系统限流组件示例详解

class TokenBucketLimitingService: ILimitingService
 {
 private LimitedQueue<object> limitedQueue = null;
 private CancellationTokenSource cancelToken;
 private Task task = null;
 private int maxTPS;
 private int limitSize;
 private object lckObj = new object();
 public TokenBucketLimitingService(int maxTPS, int limitSize)
 {
  this.limitSize = limitSize;
  this.maxTPS = maxTPS;

  if (this.limitSize <= 0)
  this.limitSize = 100;
  if(this.maxTPS <=0)
  this.maxTPS = 1;

  limitedQueue = new LimitedQueue<object>(limitSize);
  for (int i = 0; i < limitSize; i++)
  {
  limitedQueue.Enqueue(new object());
  }
  cancelToken = new CancellationTokenSource();
  task = Task.Factory.StartNew(new Action(TokenProcess), cancelToken.Token);
 }

 /// <summary>
 /// 定时消息令牌
 /// </summary>
 private void TokenProcess()
 {
  int sleep = 1000 / maxTPS;
  if (sleep == 0)
  sleep = 1;

  DateTime start = DateTime.Now;
  while (cancelToken.Token.IsCancellationRequested ==false)
  {
  try
  {
   lock (lckObj)
   {
   limitedQueue.Enqueue(new object());
   }
  }
  catch
  {
  }
  finally
  {
   if (DateTime.Now - start < TimeSpan.FromMilliseconds(sleep))
   {
   int newSleep = sleep - (int)(DateTime.Now - start).TotalMilliseconds;
   if (newSleep > 1)
    Thread.Sleep(newSleep - 1); //做一下时间上的补偿
   }
   start = DateTime.Now;
  }
  }
 }

 public void Dispose()
 {
  cancelToken.Cancel();
 }

 /// <summary>
 /// 请求令牌
 /// </summary>
 /// <returns>true：获取成功，false：获取失败</returns>
 public bool Request()
 {
  if (limitedQueue.Count <= 0)
  return false;
  lock (lckObj)
  {
  if (limitedQueue.Count <= 0)
   return false;

  object data = limitedQueue.Dequeue();
  if (data == null)
   return false;
  }

  return true;
 }
 }

public interface ILimitingService:IDisposable
 {
  /// <summary>
  /// 申请流量处理
  /// </summary>
  /// <returns>true：获取成功，false：获取失败</returns>
  bool Request();
 }

public class LimitingFactory
 {
  /// <summary>
  /// 创建限流服务对象
  /// </summary>
  /// <param name="limitingType">限流模型</param>
  /// <param name="maxQPS">最大QPS</param>
  /// <param name="limitSize">最大可用票据数</param>
  public static ILimitingService Build(LimitingType limitingType = LimitingType.TokenBucket, int maxQPS = 100, int limitSize = 100)
  {
  switch (limitingType)
  {
   case LimitingType.TokenBucket:
   default:
   return new TokenBucketLimitingService(maxQPS, limitSize);
   case LimitingType.LeakageBucket:
   return new LeakageBucketLimitingService(maxQPS, limitSize);
  }
  }
 }

 /// <summary>
 /// 限流模式
 /// </summary>
 public enum LimitingType
 {
  TokenBucket,//令牌桶模式
  LeakageBucket//漏桶模式
 }

public class LimitedQueue<T> : Queue<T>
 {
  private int limit = 0;
  public const string QueueFulled = "TTP-StreamLimiting-1001";

 public int Limit
  {
  get { return limit; }
  set { limit = value; }
  }

 public LimitedQueue()
  : this(0)
  { }

 public LimitedQueue(int limit)
  : base(limit)
  {
  this.Limit = limit;
  }

 public new bool Enqueue(T item)
  {
  if (limit > 0 && this.Count >= this.Limit)
  {
   return false;
  }
  base.Enqueue(item);
  return true;
  }
 }

var service = LimitingFactory.Build(LimitingType.TokenBucket, 500, 200);
while (true)
{
 var result = service.Request();
 //如果返回true，说明可以进行业务处理，否则需要继续等待
 if (result)
 {
  //业务处理......
 }
 else
  Thread.Sleep(1);
}

class LeakageBucketLimitingService: ILimitingService
  {
   private LimitedQueue<object> limitedQueue = null;
   private CancellationTokenSource cancelToken;
   private Task task = null;
   private int maxTPS;
   private int limitSize;
   private object lckObj = new object();
   public LeakageBucketLimitingService(int maxTPS, int limitSize)
   {
    this.limitSize = limitSize;
    this.maxTPS = maxTPS;

   if (this.limitSize <= 0)
     this.limitSize = 100;
    if (this.maxTPS <= 0)
     this.maxTPS = 1;

   limitedQueue = new LimitedQueue<object>(limitSize);
    cancelToken = new CancellationTokenSource();
    task = Task.Factory.StartNew(new Action(TokenProcess), cancelToken.Token);
   }

  private void TokenProcess()
   {
    int sleep = 1000 / maxTPS;
    if (sleep == 0)
     sleep = 1;

   DateTime start = DateTime.Now;
    while (cancelToken.Token.IsCancellationRequested == false)
    {
     try
     {

     if (limitedQueue.Count > 0)
      {
       lock (lckObj)
       {
        if (limitedQueue.Count > 0)
         limitedQueue.Dequeue();
       }
      }
     }
     catch
     {
     }
     finally
     {
      if (DateTime.Now - start < TimeSpan.FromMilliseconds(sleep))
      {
       int newSleep = sleep - (int)(DateTime.Now - start).TotalMilliseconds;
       if (newSleep > 1)
        Thread.Sleep(newSleep - 1); //做一下时间上的补偿
      }
      start = DateTime.Now;
     }
    }
   }

  public void Dispose()
   {
    cancelToken.Cancel();
   }

  public bool Request()
   {
    if (limitedQueue.Count >= limitSize)
     return false;
    lock (lckObj)
    {
     if (limitedQueue.Count >= limitSize)
      return false;

    return limitedQueue.Enqueue(new object());
    }
   }
  }

var service = LimitingFactory.Build(LimitingType.LeakageBucket, 500, 200);
while (true)
{
  var result = service.Request();
  //如果返回true，说明可以进行业务处理，否则需要继续等待
  if (result)
  {
    //业务处理......
  }
  else
   Thread.Sleep(1);
}