How is the api implemented in grpc?

Question

I used the official documentation https://grpc.io/docs/languages/go/basics/, but after implementation, questions arose. When I create a TCP server I have to specify host and port (in my case mcrsrv-book:7561). But what if I want to implement another API for GRPC? Do I need to start another server on a new port (e.g. mcrsrv-book:7562)? How is routing and api implemented in grpc?

My server code is:

type routeGuideServer struct {
    pb.UnimplementedRouteGuideServer
    savedFeatures []*pb.Response // read-only after initialized
}

// GetFeature returns the feature at the given point.
func (s *routeGuideServer) GetFeature(ctx context.Context, request *pb.Request) (*pb.Response, error) {

    context := localContext.LocalContext{}
    book := bookRepository.FindOrFailBook(context, int(request.BookId))

    return &pb.Response{
        Name:        book.Name,
        BookId:      int32(book.BookId),
        AuthorId:    int32(book.AuthorId),
        Category:    book.Category,
        Description: "Описание",
    }, nil
}

func newServer() *routeGuideServer {
    s := &routeGuideServer{}
    return s
}

func SomeAction() {
    lis, err := net.Listen("tcp", fmt.Sprintf("mcrsrv-book:7561"))
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    var opts []grpc.ServerOption
    grpcServer := grpc.NewServer(opts...)
    pb.RegisterRouteGuideServer(grpcServer, newServer())
    grpcServer.Serve(lis)
}

I think there should be options other than opening a separate port for each grpc service.

How is the api implemented in grpc?

Answer 1

If you want to use the same address for a different service, you can just re-register the other service before initiating the grpc server.

grpcServer := grpc.NewServer(opts...)
pb.RegisterRouteGuideServer(grpcServer, newServer())

#register other server here with the same 'grpcServer'

grpcServer.Serve(lis)

This stackoverflow thread would probably help as an example of what you want to achieve. The question provided a sample code that I believe align with what you asked.

Access multiple gRPC services over the same connection