manual-instrumentation.md

Manually instrument a .NET application

You can build upon the provided tracing functionality by modifying and adding to automatically generated traces. The OpenTelemetry Tracing library for .NET provides and registers an OpenTracing-compatible global tracer you can use.

OpenTracing version 0.12.1 is supported and the provided tracer offers a complete implementation of the OpenTracing API.

The auto-instrumentation provides a base you can build on by adding your own custom instrumentation. By using both instrumentation approaches, you'll be able to present a more detailed representation of the logic and functionality of your application, clients, and framework.

1. Add the OpenTracing dependency to your project:

   <PackageReference Include="OpenTracing" Version="0.12.1" />

2. Obtain the OpenTracing.Util.GlobalTracer instance and create spans that automatically become child spans of any existing spans in the same context:

   using OpenTracing;
   using OpenTracing.Util;
   
   namespace MyProject
   {
       public class MyClass
       {
           public static async void MyMethod()
           {
               // Obtain the automatically registered OpenTracing.Util.GlobalTracer instance
               var tracer = GlobalTracer.Instance;
   
               // Create an active span that will be automatically parented by any existing span in this context
               using (IScope scope = tracer.BuildSpan("MyTracedFunctionality").StartActive(finishSpanOnDispose: true))
               {
                   var span = scope.Span;
                   span.SetTag("MyImportantTag", "MyImportantValue");
                   span.Log("My Important Log Statement");
   
                   var ret = await MyAppFunctionality();
   
                   span.SetTag("FunctionalityReturned", ret.ToString());
               }
           }
       }
   }

Further reading:

• OpenTracing documentation
• OpenTracing terminology