otelgrpc: Add metrics tests for ServerStreamInterceptors

[MadVikingGod]

Problem Statement

There are two problems discovered in #4322:

1. There are no tests around the metrics produced by a ServerStreamInteceptor
2. Under test, ServerStreamInteceptors don't have peerInfo within the call made. This means that peer info will not show in tests, but does show in actual use.

Proposed Solution

Write a test similar to checkUnaryServerRecords to assert that the produced metrics match

Change the test such that it does have peerInfo within it's context

[fatsheep9146]

@pellared @MadVikingGod

opentelemetry-go-contrib/instrumentation/google.golang.org/grpc/otelgrpc/interceptor.go

Lines 449 to 499 in b39f96e

	func StreamServerInterceptor(opts ...Option) grpc.StreamServerInterceptor {
	cfg := newConfig(opts)
	tracer := cfg.TracerProvider.Tracer(
	instrumentationName,
	trace.WithInstrumentationVersion(Version()),
	)
	return func(
	srv interface{},
	ss grpc.ServerStream,
	info *grpc.StreamServerInfo,
	handler grpc.StreamHandler,
	) error {
	ctx := ss.Context()
	i := &InterceptorInfo{
	StreamServerInfo: info,
	Type: StreamServer,
	}
	if cfg.Filter != nil && !cfg.Filter(i) {
	return handler(srv, wrapServerStream(ctx, ss, cfg))
	}
	ctx = extract(ctx, cfg.Propagators)
	name, attr := spanInfo(info.FullMethod, peerFromCtx(ctx))
	startOpts := append([]trace.SpanStartOption{
	trace.WithSpanKind(trace.SpanKindServer),
	trace.WithAttributes(attr...)},
	cfg.SpanStartOptions...,
	)
	ctx, span := tracer.Start(
	trace.ContextWithRemoteSpanContext(ctx, trace.SpanContextFromContext(ctx)),
	name,
	startOpts...,
	)
	defer span.End()
	err := handler(srv, wrapServerStream(ctx, ss, cfg))
	if err != nil {
	s, _ := status.FromError(err)
	statusCode, msg := serverStatus(s)
	span.SetStatus(statusCode, msg)
	span.SetAttributes(statusCodeAttr(s.Code()))
	} else {
	span.SetAttributes(statusCodeAttr(grpc_codes.OK))
	}
	return err
	}
	}

I found that the ServerStreamInterceptors do not produce metric for now, only ServerUnaryInterceptors support, do we need add metrics support for ServerStreamInterceptors and then add test for it? Or should we directly support metrics in StatsHandler, since interceptors will be deprecated in some day.

[pellared]

I think that we wanted to add tests for metrics emitted by server interceptors.

I propose to leave implementation and just add assertions for metrics emitted by the interceptors. You can consider adding an assertion showing that ServerStreamInterceptors does NOT produce any metrics.

I think adding support for metrics in ServerStreamInterceptors is a waste of our time. I would rather work towards making StatsHandler as good as possible.

@MadVikingGod do you agree?

[MadVikingGod]

I was under the impression that the different Interceptors were being deprecated, if that's the case, then I don't think any functionality should be added.

I think there should be some testing around what metrics (if any) are put out by both the stat's handler and the interceptors, and peer Attributes must be part of that dataset.