Pruebas de retry POST request in GoLang

main.go

package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"net/http"
	"time"
)

/*

El proyecto https://httpbin.org sirve para hacer pruebas de request !

Para simular un timbrado que demora,
usaremos la ruta delay con el metodo POST

https://httpbin.org/#/Dynamic_data/post_delay__delay_


*/

func tryPost(url string, body string) (int, []byte, error) {

	req, err := http.NewRequest(http.MethodPost, url, bytes.NewBuffer([]byte(body)))
	if err != nil {
		return 0, nil, err
	}
	req.Header.Add("Content-Type", "application/json")
	client := &http.Client{
		Timeout: time.Second * 5,
	}
	fmt.Printf("Voy a Esperar 5 segundos ... probando %s\n", url)
	resp, err := client.Do(req)
	if err != nil {
		return 0, nil, err
	}
	defer resp.Body.Close()
	respbody, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return 0, nil, err
	}
	return resp.StatusCode, respbody, nil
}

func main() {
	url := "https://httpbin.org/delay/"
	body := `{"message": "hello Mr Server, this is me !"}`

	codestatus := 0
	var respbytes []byte
	var err error

	for i := 6; i > 0; i-- {
		requrl := fmt.Sprintf("%s%d", url, i)
		codestatus, respbytes, err = tryPost(requrl, body)
		if err == nil {
			break
		}
		fmt.Printf("Falla %v\n\n", err)
	}
	fmt.Printf("%d %s\n", codestatus, string(respbytes))
}