OpenTelemetry: Marten does not create activities

[dvlprx]

Hi community,

I just upgraded to version 7.10 and I can not get otel-activities, to be created.

Question 1

Is it enough to just add "Marten" to the observed sources, to let marten write activities?

This (08.05.2024): https://martendb.io/otel
says, just adding "Marten" as observed tracing-source is enough.

This (09.12.2023): https://event-driven.io/en/set_up_opentelemetry_wtih_event_sourcing_and_marten/
I expect to be the do-it-yourself way, but is not necessary with 7.10, to let marten write activities?

Question 2

Could you please tell me what I am missing :/

OpenTelemetry:

sc.AddOpenTelemetry().WithTracing(tracerBuilder =>
{
    ...
    builder.AddNpgsql();
    builder.AddSource($"Marten");
    ...
}

Marten:

sc.AddMarten(sp =>
{
    ...

    opts.Events.MetadataConfig.CorrelationIdEnabled = true;
    opts.Events.MetadataConfig.CausationIdEnabled = true;

    opts.Policies.ForAllDocuments(x =>
    {
        x.Metadata.CausationId.Enabled = true;
        x.Metadata.CorrelationId.Enabled = true;
    });
}

Question 3

is setting the marten correlation options necessary at all, to let it just write activities (if we don't care about the correlation/causation stuff)

Reproduce

using var a = Tracer.StartActivity(this.VmInstanceId);
await using var session = testSp.GetRequiredService<IDocumentStore>().LightweightSession();
var _ = await session.Events.FetchStreamAsync($"SomeTestStream");

=> this gives me an activity from npgsql with a "received-first-response" event, but it DOES NOT include the db.statement tag

using var a = Tracer.StartActivity(this.VmInstanceId);
await using var session = testSp.GetRequiredService<IDocumentStore>().LightweightSession();
var newEvent = new EventTestMethodInvoked());
var _ = session.Events.Append($"SomeTestStream", newEvent);

=> this gives me NO ACTIVITY at all

Any help, or pointing in the right direction would be very very appreciated ... got stuck on this the whole day.

[jeremydmiller]

@dvlprx Hey, sorry for the lost time on your part, but in the future, can you please ask questions on Discord rather than in GitHub issues?

The IDocumentSession properties actually don't have any connection whatsoever to the open telemetry exporting.

Here's a sample app that is exporting Open Telemetry activities, in this particular case using .NET Aspire, but the fundamentals are the same regardless of Otel tool:

https://github.com/JasperFx/CritterStackSamples/blob/main/MartenWithProjectAspire/EventPublisher/Program.cs

And I'm sorry, but I'm just not signing up to support custom strategies (Oskar's post). Your Tracer.StartActivity() will do zilch unless there's a registered exporter in your app for that particular source.

[dvlprx]

Hi jeremy, thanks you for your quick answer :)

And I'm sorry, but I'm just not signing up to support custom strategie

that's perfectly ok for me - I wouldn't do that too, but in my case this line is irrelevant for the issue, I do have an exporter running, that just prints out all activities (unfiltered without any otel-baseProcessor doing filtering or anything else), so I know there is no activity being exported.

Update

I just switched back to Marten 6.4.0. In that version the first test, that executes the FetchStreamAsync, does add the db.statement tag to the query. But the Events.Append is still not creating any activity at all

[jeremydmiller]

Did you see this first? https://martendb.io/otel.html#event-store-metrics. We don't publish activities for events per se, only tagging events to the connection activity. Like the docs say. And anything to do with db.statement is Npgsql, not Marten.