Simulate an HTTP request with success or failure using retry logic - algorithm

Question

I want to simulate a re-try option with http like:
first two http attempts with error (using some faulty urls)
the third with success (with valid url)
This is a bit tricky any idea how to do it? I try with loop on the doSomething method with different url but it doesn't make the point,
which is for example, retry at least 3 times until you get http 200, (success) any idea how could I simulate it?
maybe run in loop on following...
www.stackoverflow.com2
www.stackoverflow.com1
www.stackoverflow.com
https://play.golang.org/p/dblPh1T0XBu
package main
import (
`fmt`
`log`
"net/http"
`time`
`github.com/cenkalti/backoff/v4`
)
func main() {
b := backoff.NewExponentialBackOff()
b.MaxElapsedTime = 3 * time.Second
retryable := func() error {
val, err := doSomething("https://www.google.com1")
if err != nil {
return err
}
fmt.Println(val)
return nil
}
notify := func(err error, t time.Duration) {
log.Printf("error: %v happened at time: %v", err, t)
}
err := backoff.RetryNotify(retryable, b, notify)
if err != nil {
fmt.Errorf("error after retrying: %v", err)
}
}
func doSomething(url string) (int, error) {
res, e := http.Get(url)
if e != nil {
fmt.Println("error occurred: ", e)
return 500, e
}
return res.StatusCode, nil
}
The idea on the comment below is part of the problem, I need to use the http calls
https://play.golang.org/p/FTR7J2r-QB7
package main
import (
`fmt`
`log`
`time`
`github.com/cenkalti/backoff/v4`
)
func main() {
b := backoff.NewExponentialBackOff()
b.MaxElapsedTime = 3 * time.Second
retrybuilder := func (count int) func() error {
return func() error {
var succeed bool
count -= 1
if count == 0 {
succeed = true
}
val, err := doSomething(succeed)
if err != nil {
fmt.Println("response: ", val)
}
return err
}
}
notify := func(err error, t time.Duration) {
log.Printf("error: %v happened at time: %v", err, t)
}
err := backoff.RetryNotify(retrybuilder(3), b, notify)
if err != nil {
fmt.Printf("error after retrying: %v", err)
}
}
func doSomething(succeed bool) (int, error) {
if !succeed {
return 500, fmt.Errorf("E_SIMULATED: sim error")
}
return 200, nil
}