public void Throttle_CanPreventConcurrentRequests()
{
// no more than 2 concurrent threads.
ThrottleConfiguration configuration = new ThrottleConfiguration
{
MaxConcurrentThreads = 2
};
Throttle throttle = new Throttle(configuration);
Task[] threads = new Task[5];
ManualResetEvent awaiter = new ManualResetEvent(false);
CancellationTokenSource outerCancellationSource = new CancellationTokenSource(5 * 1000); // 5 seconds
long success = 0;
for (int i = 0; i < threads.Length; i++)
{
int instance = i;
Stopwatch sw = new Stopwatch();
sw.Start();
threads[i] = Task.Run(async() => {
CancellationTokenSource innerCancellationSource = CancellationTokenSource.CreateLinkedTokenSource(
outerCancellationSource.Token,
new CancellationTokenSource(5 * 1000).Token // 5 seconds
);
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] Instance {instance}: thread activated (activateTime: {sw.Elapsed})");
sw.Restart();
awaiter.WaitOne();
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] Instance {instance}: thread started (runTime: {sw.Elapsed})");
try
{
IDisposable lease = await throttle.AcquireLeaseAsync(innerCancellationSource.Token);
using (lease)
{
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] Instance {instance}: acquired lease (threads: {throttle.ActiveThreads}, runTime: {sw.Elapsed})");
await Task.Delay(1000, innerCancellationSource.Token); // do some work
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] Instance {instance}: completed work (runTime: {sw.Elapsed})");
Assert.True(throttle.ActiveThreads <= configuration.MaxConcurrentThreads, $"Instance {instance}: Thread count exceeds max concurrent threads (actual: {throttle.ActiveThreads}, max: {configuration.MaxConcurrentThreads})");
}
long current = Interlocked.Increment(ref success);
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] Instance {instance}: thread complete (runTime: {sw.Elapsed}, success: {current})");
}
catch (Exception ex)
{
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] Instance {instance}: thread failed (runTime: {sw.Elapsed}) {ex}");
throw new Exception("Operation failed", ex);
}
});
}
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] set.....");
awaiter.Set();
Task.WaitAll(threads, outerCancellationSource.Token);
Log.WriteLine($"[{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}] complete.....");
long actual = Interlocked.Read(ref success);
Assert.Equal(threads.Length, actual);
}
