activity-tracing

name	activity-tracing
description	Guides activity tracing with generated ActivitySources, tags, parent activities, exception status handling, and registration. Use when adding or reviewing OpenTelemetry activity tracing in Bendex flows.

Activity Tracing

• Use activity tracing for user-triggered flows, important domain actions, and cross-component transitions where we need to see call order and inputs.
• Do not add activity tracking to
  • Constructors, destructors
  • HandleCreated events
  • Dispose() methods.
  • Properties (including Get<PropertyName>() or Set<PropertyName>() methods)
  • Methods that are called often, like OnLoad(), OnDraw() or OnMouseMove()
  • *.Designer.cs files
• Prefer activity tracing instead of LogDebug in methods that are traced; remove those debug logs when adding tracing.
• Implementation pattern:
  • Ensure the class has [GenerateActivitySources] and using System.Diagnostics;.
  • Wrap method bodies with using var activity = <Type>ActivitySources.<MethodName>.Create(parentActivity);.
  • Add key inputs via activity?.AddTag("arg.<name>", value);.
  • On exceptions: activity?.AddException(ex); activity?.SetStatus(ActivityStatusCode.Error, ex.Message); then rethrow.
  • If a method has a parent activity, pass it through to downstream calls and to Create(parentActivity).
  • Register the generated activity sources in the module ActivitySources.cs (e.g. add .Concat(<Type>ActivitySources.GetAll()) to the module's GetAll() method).

Example:

[GenerateActivitySources]
public sealed class ExampleService
{
    public void DoWork(int stepIndex, Activity? parentActivity = null)
    {
        using var activity = ExampleServiceActivitySources.DoWork.Create(parentActivity);
        activity?.AddTag("arg.stepIndex", stepIndex);
        try
        {
            // work here
        }
        catch (Exception ex)
        {
            activity?.AddException(ex);
            activity?.SetStatus(ActivityStatusCode.Error, ex.Message);
            throw;
        }
    }
}

Event Handler:

public void OnSomeEvent(object? sender, EventArgs args)
{
    using var activity = ExampleServiceActivitySources.OnSomeEvent.Create();
    try
    {
        // work here
    }
    catch (Exception ex)
    {
        activity?.AddException(ex);
        activity?.SetStatus(ActivityStatusCode.Error, ex.Message);
        throw;
    }
}