fix

valhalla.go

@@ -50,7 +50,7 @@ func (v *ValhallaRouting) Route(locations []orb.Point) (route *Route, err error)
 		return nil, err
 	}
 
-	if len(resp.Directions.Routes) < 1 {
+	if resp.Directions == nil || resp.Directions.Routes == nil || len(resp.Directions.Routes) < 1 {
 		return nil, errors.New("no routes returnes by valhalla")
 	}