log JSON response if httpStatus >= 400

weed/server/common.go

@@ -46,6 +46,12 @@ func writeJson(w http.ResponseWriter, r *http.Request, httpStatus int, obj inter
 	if err != nil {
 		return
 	}
+
+	if httpStatus >= 400 {
+		glog.V(0).Infof("response method:%s URL:%s with httpStatus:%d and JSON:%s",
+			r.Method, r.URL.String(), httpStatus, string(bytes))
+	}
+
 	callback := r.FormValue("callback")
 	if callback == "" {
 		w.Header().Set("Content-Type", "application/json")