opentelemetry-dotnet/docs/trace/README.md

OpenTelemetry .NET Traces

Best Practices

ActivitySource singleton

ActivitySource SHOULD only be created once and reused throughout the application lifetime. This example shows how ActivitySource is created as a static field and then used in the application. You could also look at this ASP.NET Core example which shows a more Dependency Injection friendly way of doing this by extracting the ActivitySource into a dedicated class called Instrumentation which is then added as a Singleton service.

Manually creating Activities

As shown in the getting started guide, it is very easy to manually create Activity. Due to this, it can be tempting to create too many activities (eg: for each method call). In addition to being expensive, excessive activities can also make trace visualization harder. Instead of manually creating Activity, check if you can leverage instrumentation libraries, such as ASP.NET Core, HttpClient which will not only create and populate Activity with tags(attributes), but also take care of propagating/restoring the context across process boundaries. If the Activity produced by the instrumentation library is missing some information you need, it is generally recommended to enrich the existing Activity with that information, as opposed to creating a new one.

Common issues that lead to missing traces

• The ActivitySource used to create the Activity is not added to the TracerProvider. Use AddSource method to enable the activity from a given ActivitySource.
• TracerProvider is disposed too early. You need to ensure that the TracerProvider instance is kept active for traces to be collected. In a typical application, a single TracerProvider is built at application startup, and is disposed of at application shutdown. For an ASP.NET Core application, use AddOpenTelemetry and WithTraces methods from the OpenTelemetry.Extensions.Hosting package to correctly setup TracerProvider. Here's a sample ASP.NET Core app for reference. For simpler applications such as Console apps, refer to this example.
• TODO: Sampling