OpenTelemetry.Extensions.Enrichment.Http 1.19.1-beta.1

OpenTelemetry .NET SDK HTTP telemetry enrichment

Contains OpenTelemetry .NET SDK HTTP telemetry enrichment extensions which are used for enrichment of logs, metrics, and traces in outbound HTTP requests.

Introduction

HTTP Telemetry enrichment attaches various types of information to traces generated for outgoing HTTP requests. You can use the HTTP Telemetry enrichment framework to attach any custom information that you would like to be present in traces for outgoing HTTP requests.

With the HTTP Telemetry enrichment framework, you don't need to worry about attaching the information carefully to each telemetry object you touch. Instead, if you implement your enricher class inherited from HttpClientTraceEnricher, it takes care of the details automatically. You simply register your class with the enrichment framework and the enrichment framework will make sure to call the enrichment methods of your class for every outgoing HTTP request in your app.

Traces

Currently this package supports trace enrichment only.

Steps to enable OpenTelemetry.Extensions.Enrichment.Http

Step 1: Install package

Download the OpenTelemetry.Extensions.Enrichment.Http package:

dotnet add package OpenTelemetry.Extensions.Enrichment.Http --prerelease

Step 2: Create enricher class

Create your custom enricher class that inherits from the HttpClientTraceEnricher class and override one or more of the following virtual methods, as needed:

• EnrichWithRequest(in TraceEnrichmentBag bag, HttpRequestMessage request)
• EnrichWithResponse(in TraceEnrichmentBag bag, HttpResponseMessage response)
• EnrichWithException(in TraceEnrichmentBag bag, Exception exception)

Each method receives a TraceEnrichmentBag, the same lightweight readonly struct used by OpenTelemetry.Extensions.Enrichment, which exposes a single Add(string key, object? value) method for adding tags.

internal sealed class MyHttpClientTraceEnricher : HttpClientTraceEnricher
{
    public override void EnrichWithRequest(in TraceEnrichmentBag bag, HttpRequestMessage request)
    {
        if (request.Headers.TryGetValues("x-my-custom-header", out var values))
        {
            bag.Add("http.request.header.x-my-custom-header", string.Join(",", values));
        }
    }

    public override void EnrichWithResponse(in TraceEnrichmentBag bag, HttpResponseMessage response)
    {
        bag.Add("http.response.content-length", response.Content.Headers.ContentLength);
    }

    public override void EnrichWithException(in TraceEnrichmentBag bag, Exception exception)
    {
        bag.Add("exception.source", exception.Source);
    }
}

Optionally, inject other services your enricher class depends on via its constructor, the same way you would with TraceEnricher (see the OpenTelemetry.Extensions.Enrichment README for an example).

Step 3: Register enricher class

Add your custom enricher class to the TracerProviderBuilder by calling the TryAddHttpClientTraceEnricher<T>() method:

using var tracerProvider = Sdk.CreateTracerProviderBuilder()
    .AddHttpClientInstrumentation()
    .TryAddHttpClientTraceEnricher<MyHttpClientTraceEnricher>()
    .AddConsoleExporter()
    .Build();

Alternatively, you can add your custom enricher to the IServiceCollection directly:

var builder = Host.CreateApplicationBuilder(args);

builder.Services.TryAddHttpClientTraceEnricher<MyHttpClientTraceEnricher>();

builder.Services.AddOpenTelemetry()
    .WithTracing(tracing => tracing
        .AddHttpClientInstrumentation()
        .AddConsoleExporter());

var app = builder.Build();

app.Run();

Step 4: Usage

Once registered, the enrichment methods of your class are called automatically for every outgoing HTTP request made through an instrumented HttpClient - no additional code is required at the call site. Issue an outgoing request and the tags added in your enricher will appear on the resulting Activity.