main.go

package main

import (
	"log"
	"net/http"
	"net/http/httputil"
	"net/url"
)

var (
	arrayOfServers = []string{
		"http://127.0.0.1.8000",
		"http://127.0.0.1.8001",
		"http://127.0.0.1.8002",
		"http://127.0.0.1.8003",
		"http://127.0.0.1.8004",
	}
	index = 0
)

func main() {
	http.HandleFunc("/", forwardingServer)
	log.Fatal(":5000", nil)
}
func forwardingServer(res http.ResponseWriter, req *http.Request) {
	url := server()

	rproxy := httputil.NewSingleHostReverseProxy(url)
	rproxy.ServeHTTP(res, req)
}
func server() *url.URL {
	nextIndex := (index + 1) % 5
	url, _ := url.Parse(arrayOfServers[index])
	index = nextIndex
	return url

}

simple server

package main

import (
	"fmt"
	"log"
	"net/http"
	"os"
)

var (
	takingArgs = os.Args[1:]
)

func main() {

	http.HandleFunc("/", simpleServer)
	log.Fatal(http.ListenAndServe(takingArgs[0], nil))
}

func simpleServer(res http.ResponseWriter, req *http.Request) {
	fmt.Fprintf(res, "this is server %s", takingArgs[0])
	//fmt.Fprintf(res, "hi")
}

// a='/home/spurge/goNetworks/simpleServerArgs'
// cd $a;

// for i in {1..5}
// do
//    go run main.go ":800$i"
// done