Automatically detect exceptions and set Activity status

[reyang]

Feature Request

Is your feature request related to a problem?

Capturing exception and setting Activity status to ERROR could be a common need. It is a bit annoying to do this all over the places.

Describe the solution you'd like:

I wonder if it would be cool to have a processor that automatically detects exception when an Activity ended, and set the status to ERROR accordingly.

Describe alternatives you've considered.

using System;
using System.Diagnostics;
using System.Runtime.ExceptionServices;
using System.Runtime.InteropServices;
using OpenTelemetry;
using OpenTelemetry.Trace;

class SehDetectionProcessor : BaseProcessor<Activity>
{
    public override void OnEnd(Activity activity)
    {
        if (Marshal.GetExceptionPointers() != IntPtr.Zero)
        {
            activity.SetStatus(Status.Error);
        }
    }
}

class Program
{
    static readonly ActivitySource DemoSource = new ActivitySource("DemoSource");

    static void Main()
    {
        AppDomain.CurrentDomain.UnhandledException += UnhandledExceptionHandler;

        using var tracerProvider = Sdk.CreateTracerProviderBuilder()
            .AddSource("DemoSource")
            .AddProcessor(new SehDetectionProcessor())
            .AddConsoleExporter()
            .Build();

        using (DemoSource.StartActivity("Foo"))
        {
            using (DemoSource.StartActivity("Bar"))
            {
                throw new Exception("Oops!");
            }
        }
    }

    static void UnhandledExceptionHandler(object source, UnhandledExceptionEventArgs args)
    {
        var activity = Activity.Current;

        while (activity != null)
        {
            activity.Dispose(); // TODO: probably check if the activity is already disposed/finished by looking at the end time?
            activity = activity.Parent;
        }
    }
}

[reyang]

@CodeBlanch do you see this useful or crazy?