app.go

package web

import (
	"net/http"
	"encoding/json"
)

func ServerStart() {
	http.HandleFunc("/", func(res http.ResponseWriter, req *http.Request) {
		buf, err := json.Marshal(map[string]string{"message": "Hello World!"})
		if err != nil {
			res.Write([]byte("Boom!"))
			panic(err)
		}

		res.Header().Set("Content-Type", "application/json")
		res.Write(buf)
	})
	
	http.ListenAndServe(
		":8081",
		nil,
	)
}

cmd-server-server.go

package main

import (
	"fmt"
	
	"github.com/yourname/web"
)

func main() {
	fmt.Println("Starting Server...")
	web.ServerStart()
}