Go: Simple retry function

retry.go

func retry(attempts int, sleep time.Duration, fn func() error) error {
	if err := fn(); err != nil {
		if s, ok := err.(stop); ok {
			// Return the original error for later checking
			return s.error
		}
 
		if attempts--; attempts > 0 {
			time.Sleep(sleep)
			return retry(attempts, 2*sleep, fn)
		}
		return err
	}
	return nil
}
 
type stop struct {
	error
}

After coding few years in node.js, I have indent allergy.
I would rather write something like:

func retry(attempts int, sleep time.Duration, fn func() error) error {
	err := fn()
	if err == nil {
		return nil
	}
	if s, ok := err.(stop); ok {
		// Return the original error for later checking
		return s.error
	}
	if attempts--; attempts > 0 {
		time.Sleep(sleep)
		return retry(attempts, 2*sleep, fn)
	}
	return err
}

Good point! I like that version as well... However, the if err != nil with a bottom return nil is a such a pattern in the Go world, the if err == nil sometimes throws me off when reading code.

Blog post here: https://upgear.io/blog/simple-golang-retry-function/