Why is that only http or gRPC is able to start up in go application?

Question

I am trying to start http and gRPC service at the same time in a Go application. But to my surprise only http server or gRPC server can start up.

func main() {
    xxhh.Test1()
    xxhh.Test2()

    app := fiber.New()

    app.Get("/", func(c *fiber.Ctx) error {
        return c.SendString("Hello, World !")
    })

    app.Listen(":3000")

    lis, err := net.Listen("tcp", port)
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    s := grpc.NewServer()

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

}

And I also find that if I put the http part at first, then http can start up while gRPC can not. the vice versa is also true

Answer 1

put first part in Goroutines as below

func main() {
xxhh.Test1()
xxhh.Test2()

app := fiber.New()

app.Get("/", func(c *fiber.Ctx) error {
    return c.SendString("Hello, World !")
})

go func() {
    log.Fatal(app.Listen(":3000"))
}()    

lis, err := net.Listen("tcp", port)
if err != nil {
    log.Fatalf("failed to listen: %v", err)
}
s := grpc.NewServer()

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

}