我们部署的应用程序引擎Symfony应用程序无法连接到同一项目上的SQL gcp SQL postgres实例 . 错误是:

An exception occured in driver: SQLSTATE[08006] [7] could not connect 
to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?

我已经设置了 'unix_socket' => '/cloudsql/hireplicity:us-central1:$mydbinstance . 我按照https://cloud.google.com/community/tutorials/run-symfony-on-appengine-flexible中的步骤进行操作