Method forwardUncached

cmd/cache-proxy/proxy.go:702–772

forwardUncached forwards a request to the origin without caching. Used for HEAD and other non-GET methods that shouldn't consume cache space. Logs symmetrically with HandleProxy's GET path so a non-2xx PUT/POST (e.g. an S3 501 on a parquet write) is visible in Loki — without this, the non-cached pa

(w http.ResponseWriter, r *http.Request)

	case <-timer.C:
		return true
	}
}

func isRetriableOriginFetchError(err error) bool {
	if err == nil {
		return false
	}
	var oe *originStatusError
	if errors.As(err, &oe) {
		switch oe.status {
		case http.StatusRequestTimeout,
			http.StatusTooManyRequests,
			http.StatusInternalServerError,
			http.StatusBadGateway,
			http.StatusServiceUnavailable,
			http.StatusGatewayTimeout:
			return true
		default:
			return false
		}
	}
	if errors.Is(err, context.Canceled) {
		return false
	}
	if errors.Is(err, context.DeadlineExceeded) {
		return true
	}
	var netErr net.Error
	if errors.As(err, &netErr) && netErr.Timeout() {
		return true
	}
	msg := strings.ToLower(err.Error())
	return strings.Contains(msg, "connection reset by peer") ||
		strings.Contains(msg, "connection refused") ||
		strings.Contains(msg, "unexpected eof") ||
		strings.Contains(msg, "timeout")
}

func originFetchOutcome(err error) string {
	if err == nil {
		return "success"
	}
	var oe *originStatusError
	if errors.As(err, &oe) {
		return "http_error"
	}
	if errors.Is(err, context.Canceled) {
		return "canceled"
	}
	if errors.Is(err, context.DeadlineExceeded) {
		return "timeout"
	}
	var netErr net.Error
	if errors.As(err, &netErr) && netErr.Timeout() {
		return "timeout"
	}
	return "error"
}