building an online judge to evaluate Python programs

[Jabba Laci]

Hi,

In our school I have an introductory Python course. I have collected a
large list of exercises for the students and I would like them to be
able to test their solutions with an online judge (
http://en.wikipedia.org/wiki/Online_judge ). At the moment I have a
very simple web application that is similar to Project Euler: you
provide the ID of the exercise and the output of the program, and it
tells you if it's correct or not. However, it can only be used with
programs that produce an output (usually a short string or a number).

In the next step I would like to do the following. The user can upload
his/her script, and the system tests it with various inputs and tells
you if it's OK or not (like checkio.org for instance). How to get
started with this?

There are several questions:
* What is someone sends an infinite loop? There should be a time limit.
* What is someone sends a malicious code? The script should be run in a sandbox.

All tips are appreciated.

Thanks,

Laszlo