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OpenTracing instrumentation for .NET Core apps

This repository provides OpenTracing instrumentation for .NET Core based applications. It can be used with any OpenTracing compatible tracer.

IMPORTANT: OpenTracing and OpenCensus have merget to form OpenTelemetry! The OpenTelemetry .NET library can be found at

Supported .NET versions

This project currently only supports apps targeting .NET Core 3.1, .NET 6.0, or .NET 7.0!

This project DOES NOT support the full .NET framework as that uses different instrumentation code.

Supported libraries and frameworks

DiagnosticSource based instrumentation

This project supports any library or framework that uses .NET's DiagnosticSource to instrument its code. It will create a span for every Activity and it will create span.Log calls for all other diagnostic events.

To further improve the tracing output, the library provides enhanced instrumentation (Inject/Extract, tags, configuration options) for the following libraries / frameworks:

  • ASP.NET Core
  • Entity Framework Core
  • System.Net.Http (HttpClient)
  • System.Data.SqlClient
  • Microsoft.Data.SqlClient

Microsoft.Extensions.Logging based instrumentation

This project also adds itself as a logger provider for logging events from the Microsoft.Extensions.Logging system. It will create span.Log calls for each logging event, however it will only create them if there is an active span (ITracer.ActiveSpan).


This project depends on several packages from Microsofts Microsoft.Extensions.* stack (e.g. Dependency Injection, Logging) so its main use case is ASP.NET Core apps and any other Microsoft.Extensions-based console apps.

1. Add the NuGet package OpenTracing.Contrib.NetCore to your project.
2. Add the OpenTracing services to your IServiceCollection via services.AddOpenTracing().

How you do this depends on how you've setup the Microsoft.Extensions.DependencyInjection system in your app.

In ASP.NET Core apps you can add the call to your ConfigureServices method (of your Program.cs file):

public static IWebHost BuildWebHost(string[] args)
    return WebHost.CreateDefaultBuilder(args)
        .ConfigureServices(services =>
            // Enables and automatically starts the instrumentation!
3. Make sure InstrumentationService, which implements IHostedService, is started.

InstrumentationService is responsible for starting and stopping the instrumentation. The service implements IHostedService so it is automatically started in ASP.NET Core, however if you have your own console host, you manually have to call StartAsync and StopAsync.

Note that .NET Core 2.1 greatly simplified this setup by introducing a generic HostBuilder that works similar to the existing WebHostBuilder from ASP.NET Core. Have a look at the TrafficGenerator sample for an example of a HostBuilder based console application.