keeps pinging endpoint until response changes

urlChanged.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"time"
)

func fetch(url string) string {
	resp, err := http.Get(url)

	if err != nil {
		log.Fatalf("error: %s", err)
		os.Exit(2)
	}

	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	body2 := string(body)

	return body2
}

func main() {
	if len(os.Args) != 2 {
		log.Fatalf("Syntax is: %s <url>", "urlChanged")
		os.Exit(1)
	}

	url := os.Args[1]
	deltaT := 2
	t := 0

	firstCall := true

	var oldBody = ""
	var newBody string

	for {
		newBody = fetch(url)

		if firstCall {
			fmt.Println("Got it!")
			firstCall = false
		} else if oldBody != newBody {
			fmt.Printf("%d: changed!\n", t)
			break
		} else {
			fmt.Printf("%d: the same...\n", t)
		}
		oldBody = newBody
		time.Sleep(time.Second * time.Duration(deltaT))
		t += deltaT
	}

}