Consider 1st class support for SignalR tracing

[BrennanConroy]

Component

OpenTelemetry.Instrumentation.AspNetCore

Is your feature request related to a problem?

In .NET 9, SignalR has added telemetry support which uses the name "Microsoft.AspNetCore.SignalR.Server" on the server-side and "Microsoft.AspNetCore.SignalR.Client" on the client-side. It would be nice if AddAspNetCoreInstrumentation could enable the server-side tracing as SignalR is part of ASP.NET Core.

What is the expected behavior?

Calling tracing.AddAspNetCoreInstrumentation(); sets up SignalR (at least server-side) tracing.

Right now you would need to call tracing.AddSource("Microsoft.AspNetCore.SignalR.Server");. It also looks like there is more logic based on specific activity names

opentelemetry-dotnet-contrib/src/OpenTelemetry.Instrumentation.AspNetCore/Implementation/HttpInListener.cs

Line 21 in 88645a9

internal const string ActivityOperationName = "Microsoft.AspNetCore.Hosting.HttpRequestIn";

Not sure what exactly is done there but there might be more work to be done for listening to SignalR activites too.

Which alternative solutions or features have you considered?

Alternatively, there could be a new AddSignalRInstrumentation() similar to other libraries like AddGrpcCoreInstrumentation().

For the client-side, there might also want to be a separate method for it similar to AddHttpClientInstrumentation.

Additional context

dotnet/aspnetcore#51557 tracks the ASP.NET Core side for SignalR instrumentation and includes cross-linking to relevant PRs and other information.

[JamesNK]

Implementing AddSignalRInstrumentation() might be as simple as calling builder.AddActivitySource("Microsoft.AspNetCore.SignalR.Server") internally.

It would only be supported in .NET 9 and later.