/// <summary>
/// Assert to find possible deadlocks in code that uses async/await
/// Throws an exception of type <see cref="ConcurrencyException"/> if any errors are found.
/// </summary>
/// <exception cref="ConcurrencyException"></exception>
/// <param name="action">Delegate to execute</param>
/// <param name="shouldEndBeforeMs">Maximum time in which the code should execute, this is used to determine deadlocks.</param>
public static void AssertAsyncDeadlocksOnly(Action action, int shouldEndBeforeMs = 2000)
{
try
{
var cts = new CancellationTokenSource(shouldEndBeforeMs);
ConcurrentRunner.Start(new[] { action }, 1, cts.Token);
}
catch (OperationCanceledException)
{
throw new ConcurrencyException("Possible deadlock detected. Make sure that you do not use .Wait(), .WaitAny(), .WaitAll(), .GetAwaiter().GetResult() or .Result on async methods.");
}
}
/// <summary>
/// Will run the concurrency checker and will output a report if there were any errors.
/// It will throw an exception of type <see cref="ConcurrencyException"/> if any errors are found.
/// </summary>
/// <param name="numberOfConcurrentThreads">Number of concurrent threads to run. The higher the number the more likely a problem will be found.</param>
/// <param name="actions">Actions to execute concurrently</param>
/// <example>ConcurrencyChecker.AssertRun(5, new Action(() => instance.ChangeNameTo("Jane")), new Action(() => instance.ChangeNameTo("Peter")))</example>
/// <returns>Report if failed or null if successful</returns>
public string Run(int numberOfConcurrentThreads, params Action[] actions)
{
if (numberOfConcurrentThreads < actions.Length)
{
throw new ArgumentOutOfRangeException(nameof(numberOfConcurrentThreads), "Number of concurrent threads are less than the number of actions to execute.");
}
_cts = new CancellationTokenSource(5000);
try
{
InitializeMembersToMonitor();
}
catch (OperationCanceledException)
{
return("Initialization failed. This normally happens is you are using a mock framework such as Moq. Please exclude the mock namespace (NSubstitute and Moq is supported out of the box).");
}
_cts = new CancellationTokenSource();
Start(true);
actions.First()();
Stop();
_cts = new CancellationTokenSource(MaxExecutionTimeMs);
try
{
Start();
ConcurrentRunner.Start(actions, numberOfConcurrentThreads, _cts.Token);
Stop();
return(GetReport());
}
catch (OperationCanceledException)
{
return("Possible deadlock detected. Make sure that you do not use .Wait() or .Result on async methods.");
}
}
