How to write robust, large scale TCP server in python?

How to write robust, large scale TCP server in python?

I'm searching for a tutorial or more info on how to write robust TCP
server (with some custom app-protocol) in python that will be able to
maintain several connections to TCP clients.
Each TCP client will send some data to server and server will enter this
data in local mysql database. After some predefined period of inactivity,
server will close connection to each client.
Is there any simple example or documentation that I could start ? Any
frameworks for writing such type of web application that could let me
start quickly ?
Thanks in advance, regards, Bulek.