flask_app: 增加错误返回

Signed-off-by: binren <zhangbr@elab-plus.com>

flask_app.py

@@ -92,10 +92,12 @@ def tag_tree():
 @app.route('/update_data', methods=['GET', 'POST'])
 def update_data():
     message = None
+    global mvp
     try:
         mvp = Mvp()
         message = mvp.update_data()
     except Exception as e:
+        message['error'] = str(e)
         return json.dumps(message, ensure_ascii=False)
     finally:
         mvp.close()