HttpClient async requests not completing for large batch sent out in a loop

Question

I think I\'ve managed to make a test that shows this problem repeatably, at least on my system. This question relates to HttpClient being used for a bad endpoint (no

Answer 1

Your exception information is being lost in the WhenAll task. Instead of using that, try this:

Task aggregateTask = Task.Factory.ContinueWhenAll(
    Batch,
    TaskExtrasExtensions.PropagateExceptions,
    TaskContinuationOptions.ExecuteSynchronously);

aggregateTask.Wait();

This uses the PropagateExceptions extension method from the Parallel Extensions Extras sample code to ensure that exception information from the tasks in the batch operation are not lost:

/// 
Propagates any exceptions that occurred on the specified tasks.
/// The Task instances whose exceptions are to be propagated.
public static void PropagateExceptions(this Task [] tasks)
{
    if (tasks == null) throw new ArgumentNullException("tasks");
    if (tasks.Any(t => t == null)) throw new ArgumentException("tasks");
    if (tasks.Any(t => !t.IsCompleted)) throw new InvalidOperationException("A task has not completed.");
    Task.WaitAll(tasks);
}