public void BasicLockingLogic_SeemsToWork()
{
// Start one long-running operation and one short-running one.
// Expected behavior is that short one will wait for long one to complete.
using (var semaphore = new SemaphoreSlim(1))
{
int?longCompletedAt = null;
int?shortCompletedAt = null;
var longTask = Task.Run(async() =>
{
Debug.WriteLine("Long entered.");
using (await SemaphoreLock.TakeAsync(semaphore))
{
Debug.WriteLine("Long acquired lock.");
await Task.Delay(5000);
Debug.WriteLine("Long completed.");
longCompletedAt = Environment.TickCount;
}
});
var shortTask = Task.Run(async() =>
{
Debug.WriteLine("Short entered.");
await Task.Delay(500);
Debug.WriteLine("Short starting work.");
using (await SemaphoreLock.TakeAsync(semaphore))
{
Debug.WriteLine("Short acquired lock.");
await Task.Delay(50);
Debug.WriteLine("Short completed.");
shortCompletedAt = Environment.TickCount;
}
});
Task.WaitAll(longTask, shortTask);
Assert.IsTrue(shortCompletedAt.HasValue);
Assert.IsTrue(longCompletedAt.HasValue);
Assert.IsTrue(longCompletedAt.Value < shortCompletedAt.Value);
}
}
private async Task WaitForPredecessorUpdateAsync(CancellationToken cancel)
{
_log.Debug("Will not trigger new probe as it overlaps with existing probe.");
using var readLock = await SemaphoreLock.TakeAsync(_updateLock, cancel);
}
public void LockingLogic_WithTimeout_SeemsToWork()
{
// Start one long-running operation and two short-running ones, where one of the shorts times out on the lock.
using (var semaphore = new SemaphoreSlim(1))
{
int?longCompletedAt = null;
int?short1CompletedAt = null;
int?short2CompletedAt = null;
int?short1TimedOutAt = null;
var longTask = Task.Run(async() =>
{
Debug.WriteLine("Long entered.");
using (await SemaphoreLock.TakeAsync(semaphore))
{
Debug.WriteLine("Long acquired lock.");
await Task.Delay(5000);
Debug.WriteLine("Long completed.");
longCompletedAt = Environment.TickCount;
}
});
var shortTask1 = Task.Run(async() =>
{
Debug.WriteLine("Short1 entered.");
await Task.Delay(500);
Debug.WriteLine("Short1 starting work.");
var lockInstance = await SemaphoreLock.TryTakeAsync(semaphore, TimeSpan.FromSeconds(1));
if (lockInstance == null)
{
Debug.WriteLine("Short1 timed out.");
short1TimedOutAt = Environment.TickCount;
}
else
{
using (lockInstance)
{
Debug.WriteLine("Short1 acquired lock.");
await Task.Delay(50);
Debug.WriteLine("Short1 completed.");
short1CompletedAt = Environment.TickCount;
}
}
});
var shortTask2 = Task.Run(async() =>
{
Debug.WriteLine("Short2 entered.");
await Task.Delay(500);
Debug.WriteLine("Short2 starting work.");
using (await SemaphoreLock.TakeAsync(semaphore))
{
Debug.WriteLine("Short2 acquired lock.");
await Task.Delay(50);
Debug.WriteLine("Short2 completed.");
short2CompletedAt = Environment.TickCount;
}
});
Task.WaitAll(longTask, shortTask1, shortTask2);
Assert.IsFalse(short1CompletedAt.HasValue);
Assert.IsTrue(short1TimedOutAt.HasValue);
Assert.IsTrue(short2CompletedAt.HasValue);
Assert.IsTrue(longCompletedAt.HasValue);
Assert.IsTrue(short1TimedOutAt.Value < longCompletedAt.Value);
Assert.IsTrue(short1TimedOutAt.Value < short2CompletedAt.Value);
Assert.IsTrue(longCompletedAt.Value < short2CompletedAt.Value);
}
}