grpc-server.go

type server struct {
	api.HelloServiceServer
}

func (s *server) SayHello(ctx context.Context, in *api.HelloRequest) (*api.HelloResponse, error) {
	tracer := otel.GetTracerProvider().Tracer("webserver-grpc")
	_, span := tracer.Start(ctx, "SayHello-span")
	defer span.End()

	fmt.Println(ctx)
	log.Printf("Received: %v\n", in.GetGreeting())
	time.Sleep(50 * time.Millisecond)

	return &api.HelloResponse{Reply: "Hello " + in.Greeting}, nil
}

func main() {
	lis, err := net.Listen("tcp", ":"+os.Getenv("PORT"))
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}

	s := grpc.NewServer(
		grpc.UnaryInterceptor(otelgrpc.UnaryServerInterceptor()),
		grpc.StreamInterceptor(otelgrpc.StreamServerInterceptor()),
	)

	api.RegisterHelloServiceServer(s, &server{})
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}