package main import ( "fmt" "net/http" "os" ) func main() { port := os.Getenv("PORT") if port == "" { port = "8000" } http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { fmt.Fprintln(w, "Hello from Go!") }) fmt.Println("Server listening on :" + port) http.ListenAndServe(":"+port, nil) }