I have tried the following code:
MySQLdb.connect(host='xxx', port=3306, user='yyy')
But I get the following error:
(2005, "Unknown MySQL server host ...
I have tried to remove all firewall restrictions on the external MySQL instance, as a test. I am able to connect to the instance from my developing machine.
I believe this should be possible now that the App Engine supports sockets, or am I wrong?