Function parseRetryAfter

docker/docker_client.go:506–528

parseRetryAfter determines the delay required by the "Retry-After" header in res and returns it, silently falling back to fallbackDelay if the header is missing or invalid.

(res *http.Response, fallbackDelay time.Duration)

// parseRetryAfter determines the delay required by the "Retry-After" header in res and returns it,
// silently falling back to fallbackDelay if the header is missing or invalid.
func parseRetryAfter(res *http.Response, fallbackDelay time.Duration) time.Duration {
	after := res.Header.Get("Retry-After")
	if after == "" {
		return fallbackDelay
	}
	logrus.Debugf("Detected 'Retry-After' header %q", after)
	// First, check if we have a numerical value.
	if num, err := strconv.ParseInt(after, 10, 64); err == nil {
		return time.Duration(num) * time.Second
	}
	// Second, check if we have an HTTP date.
	if t, err := http.ParseTime(after); err == nil {
		// If the delta between the date and now is positive, use it.
		delta := time.Until(t)
		if delta > 0 {
			return delta
		}
		logrus.Debugf("Retry-After date in the past, ignoring it")
		return fallbackDelay
	}
	logrus.Debugf("Invalid Retry-After format, ignoring it")
	return fallbackDelay
}

// makeRequestToResolvedURL creates and executes a http.Request with the specified parameters, adding authentication and TLS options for the Docker client.
// streamLen, if not -1, specifies the length of the data expected on stream.