Custom tags for AspNetCore metrics

[ImoutoChan]

Feature Request

Is there any way to add custom tags for /metrics in OpenTelemetry.Instrumentation.AspNetCore?
I want to add environment and service name.

Describe the solution you'd like:

It would be great to have the ability to enrich default metrics with custom tags. For example, it can look like this:

.AddAspNetCoreInstrumentation(x => x.CustomStaticTags = new Dictionary<string, string>()
{
    ["environment"] = "stage",
    ["application"] = "orders"
})

Describe alternatives you've considered.

The only alternative I see is to copy-paste
MeterProviderBuilderExtensions.cs
AspNetCoreMetrics.cs
HttpInMetricsListener.cs
DiagnosticSourceSubscriber.cs
HttpTagHelper.cs
ListenerHandler.cs

to my project and add a way to customize tags myself.

[Kielek]

Did you have chance to check ResourcesBuilder API?

[ImoutoChan]

@Kielek I tried but I don't see any changes to my metrics:

My configuration:

services.AddOpenTelemetryMetrics(
    builder =>
    {
        builder
            .SetResourceBuilder(
                ResourceBuilder.CreateDefault()
                    .AddService("my-service")
                    .AddAttributes(new[] { new KeyValuePair<string, object>("environment", "test") }))
            .AddMeter("my-service")
            .AddAspNetCoreInstrumentation()
            .AddPrometheusExporter();
    });

Should configured resources be in the tags of produced metrics?

[cijothomas]

If you are using Prometheus, resources are not exported. The spec for prometheus is still evolving, and recently included how to export Resources. But that has not been implemented in .NET yet.

[Kielek]

In https://github.com/open-telemetry/opentelemetry-dotnet-instrumentation in our tests we are using mostly OTLP. It is working as you expected.

Please check: https://github.com/open-telemetry/opentelemetry-dotnet-instrumentation/blob/b4a4120bbd6d76ed6798fa15d4625938ce3b601c/test/IntegrationTests/SmokeTests.cs#L150-L165

[GavinFernando]

I also need to add my custom tags and I tried the options mentioned in this site : https://help.sumologic.com/docs/apm/traces/get-started-transaction-tracing/opentelemetry-instrumentation/java/custom-tags-configuration/

But couldn't get it resolved. Any ideas?

[diseks]

My configuration:

.AddAspNetCoreInstrumentation(x =>
{
    x.Enrich = (string name, HttpContext context, ref TagList tags) 
        => tags.Add("customTag", "customTagValue");
}

[jerviscui]

Is there a solution yet?

[vishweshbankwar]

@ImoutoChan, @jerviscui - Check out https://learn.microsoft.com/en-us/aspnet/core/log-mon/metrics/metrics?view=aspnetcore-8.0#enrich-the-aspnet-core-request-metric

[haris-begluk]

@jerviscui Have you been able to resolve this issue? Is there any workaround in place?

@vishweshbankwar If I'm correct, the only way to enrich the default metrics is by using middleware, right?
Also, is there any chance we could expect this feature soon (as suggested above)?

[cijothomas]

@jerviscui Have you been able to resolve this issue? Is there any workaround in place?

@vishweshbankwar If I'm correct, the only way to enrich the default metrics is by using middleware, right? Also, is there any chance we could expect this feature soon (as suggested above)?

The only way is via the middleware, correct. Given ASP.NET Core is natively instrumented now, it is unlikely that any additions to this package (OTel.Instrumentation.AspNetCore) will be made.