ActivitySource returns null Activity when usind AddOpenTelemetry

[andr3marra]

Hello, i am learning how to implement my own traces but i'm not able to make it work with AddOpenTelemetry. Everytime i start and activity if returns null. If i write the same code in a AspNet application, inside a minimal api call the activity returned is not null, looks like i'm missing something here. How can i make the following code work? If i use Sdk.CreateTracerProviderBuilder() it works properly but i want to use DI.

using OpenTelemetry;
using OpenTelemetry.Resources;
using System.Diagnostics;

namespace Sample.DistributedTracing;
class Program {
    public static ActivitySource source = new ActivitySource("Sample.DistributedTracing");
    static async Task Main(string[] args) {

        var builder = Host.CreateApplicationBuilder(args);

        builder.Services.AddOpenTelemetry()
        .WithTracing(tracing => tracing
            .AddSource("Sample.DistributedTracing.*")
        )
        .ConfigureResource(resource => resource
        .AddService("otel-test"))
        .UseOtlpExporter();

        var app = builder.Build();

        await MyClass.DoSomeWork("banana", 8);

        app.Run();
    }
}

public class MyClass {
    public static async Task DoSomeWork(string foo, int bar) {
        using (Activity activity = Program.source.StartActivity("SomeWork")) {
            activity?.AddTag("test", "test");
            await StepOne();
            await StepTwo();
        }
    }

    public static async Task StepOne() {
        await Task.Delay(500);
    }

    public static async Task StepTwo() {
        await Task.Delay(1000);
    }
}

[Kielek]

Blind shot, not tested it:

You are creating activity source as public static ActivitySource source = new ActivitySource("Sample.DistributedTracing"); and registering by .AddSource("Sample.DistributedTracing.*"). Registered activity source name does not match registered regex.

Consider:

.AddSource("Sample.DistributedTracing)