backoff.go

package main

import "time"

func backoff(retries int, callback func() error) error {
	var err error
	delay := time.Millisecond
	for {
		err = callback()
		if err == nil {
			break
		}
		if retries == 0 {
			break
		}
		retries--
		delay <<= 1 // multiply previous delay by 2
		time.Sleep(delay)
	}
	return err
}