code: def get_qcos_client(self, app_uri):
          
  
          client = self.qcos_clients.get(app_uri)
          if (client is None):
              client = self.create_qcos_client(app_uri)
              self.qcos_clients[app_uri] = client
  
          return client
docs: 获得资源管理客户端
          缓存，但不是线程安全的