[OpenTelemetry.Instrumentation.AspNetCore] Implement gRPC server instrumentation with use of Interceptor instead or extend ResolveSpanStatusForGrpcStatusCode method

[prybski]

Feature Request

Last time, when migrating to OpenTelemetry in our team we have encountered a problem with experimental instrumentation for gRPC server from this C# project: https://github.com/open-telemetry/opentelemetry-dotnet/tree/main/src/OpenTelemetry.Instrumentation.AspNetCore. The problem is that ActivityStatus is not being set with respect to this semantics for gRPC status codes: https://opentelemetry.io/docs/specs/semconv/rpc/grpc/#grpc-status - below source code of the .ResolveSpanStatusForGrpcStatusCode(...) method is implemented in a way it should be implemented for ActivityKind being Client:

/// <summary>
/// Helper method that populates span properties from RPC status code according
/// to https://github.com/open-telemetry/semantic-conventions/blob/main/docs/rpc/grpc.md#grpc-attributes.
/// </summary>
/// <param name="statusCode">RPC status code.</param>
/// <returns>Resolved span <see cref="Status"/> for the Grpc status code.</returns>
public static ActivityStatusCode ResolveSpanStatusForGrpcStatusCode(int statusCode)
{
    var status = ActivityStatusCode.Error;

    if (typeof(StatusCanonicalCode).IsEnumDefined(statusCode))
    {
        status = ((StatusCanonicalCode)statusCode) switch
        {
            StatusCanonicalCode.Ok => ActivityStatusCode.Unset,
             _ => ActivityStatusCode.Error,
        };
    }

    return status;
}

Describe the solution you'd like:

I think that we would have two possible solutions:

• Implement instrumentation of gRPC server with use of Interceptor, which allows easily handle exceptions and set appropriate ActivityStatus based on the gRPC status code (that is something what we have right now, to have proper mapping between gRPC status code and ActivityStatus)
• Extend .ResolveSpanStatusForGrpcStatusCode(...) method to properly resolve ActivityStatus for ActivityKind being Server based on the gRPC status code (I have linked semantics for ActivityKind being Server earlier).