is it possible to catch when any Task terminates due exception and log?

Question

Is it possible to catch when any Task terminates due exception and log? I've added CurrentDomain_UnhandledException handling but this doesn't help.

I create tasks using Task.Factory.StartNew() as usual. When somewhere inside such task exception occurs it crashes silently (but it supposed to work forever, i'm also using LongRunning option). So I want to be notified about such behavior.

Ideallly I want to set some option somewhere to be notified when any Task crashes due exception.

If it is not possible then likely I should add something to each Task I create? Of course I can just add big try{} finally{} block inside each Task, but probably there are better solutions?

Answer 1

Assuming you have a Test as Task to run:

static int Test()
{
    throw new Exception();
}

1. First Approach - Process exception in the caller's thread:

   Task<int> task = new Task<int>(Test);
   task.Start();
   
   try
   {
       task.Wait();
   }
   catch (AggregateException ex)
   {
       Console.WriteLine(ex);
   }
   

   Note: The exception will be of type AggregateException. All actual exceptions are available through ex.InnerExceptions property.

2. Second Approach - Process exception in some task's thread:

   Define the ExceptionHandler this way:

   static void ExceptionHandler(Task<int> task)
   {
       var ex = task.Exception;
       Console.WriteLine(ex);
   }
   

   Usage:

   Task<int> task = new Task<int>(Test);
   task.ContinueWith(ExceptionHandler, TaskContinuationOptions.OnlyOnFaulted);
   task.Start();
   

Reference: How to: Handle Exceptions Thrown by Tasks