OpenTelemetryBuilder methods:

• ConfigureResource: Registers a callback action to configure the ResourceBuilder for tracing and metric providers.

• WithTracing: Enables tracing and optionally configures the TracerProvider.

• WithMetrics: Enables metrics and optionally configures the MeterProvider.

Usage

The following example shows how to register OpenTelemetry tracing & metrics in an ASP.NET Core host using the OpenTelemetry.Extensions.Hosting extensions.

using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.DependencyInjection;
using OpenTelemetry.Metrics;
using OpenTelemetry.Trace;

var appBuilder = WebApplication.CreateBuilder(args);

appBuilder.Services.AddOpenTelemetry()
    .ConfigureResource(builder => builder.AddService(serviceName: "MyService"))
    .WithTracing(builder => builder.AddConsoleExporter())
    .WithMetrics(builder => builder.AddConsoleExporter());

var app = appBuilder.Build();

app.Run();

A fully functional example can be found here.

Resources

To dynamically add resources at startup from the dependency injection you can provide an IResourceDetector. To make use of it add it to the dependency injection and then you can use the IServiceProvider to add it to OpenTelemetry:

public class MyResourceDetector : IResourceDetector
{
    private readonly IWebHostEnvironment webHostEnvironment;

    public MyResourceDetector(IWebHostEnvironment webHostEnvironment)
    {
        this.webHostEnvironment = webHostEnvironment;
    }

    public Resource Detect()
    {
        return ResourceBuilder.CreateEmpty()
            .AddService(serviceName: this.webHostEnvironment.ApplicationName)
            .AddAttributes(new Dictionary<string, object> { ["host.environment"] = this.webHostEnvironment.EnvironmentName })
            .Build();
    }
}

services.AddSingleton<MyResourceDetector>();

services.AddOpenTelemetry()
    .ConfigureResource(builder =>
        builder.AddDetector(sp => sp.GetRequiredService<MyResourceDetector>()))
    .WithTracing(builder => builder.AddConsoleExporter())
    .WithMetrics(builder => builder.AddConsoleExporter());

Migrating from pre-release versions of OpenTelemetry.Extensions.Hosting

Pre-release versions (all versions prior to 1.4.0) of OpenTelemetry.Extensions.Hosting contained signal-specific methods for configuring tracing and metrics:

• AddOpenTelemetryTracing: Configure OpenTelemetry and register an IHostedService to automatically start tracing services in the supplied IServiceCollection.

• AddOpenTelemetryMetrics: Configure OpenTelemetry and register an IHostedService to automatically start metric services in the supplied IServiceCollection.

These methods were marked obsolete and later removed. You should migrate your code to the new AddOpenTelemetry method documented above. Refer the old and new versions of the example application to assist you in your migration.

Hosted Service Ordering and Telemetry Capture

TBD

References

• OpenTelemetry Project