Let's say I'm running a hosted service that wishes to allow plugins written by third-party clients.
Perhaps a gaming service provider that provides infrastructure but allows clients to develop their own game referees. Or, a coding competition site that allows coders to submit code to be run as their solution to some coding problem.
How would you harden/lock-down/sandbox this user code from doing potential harm to the server that intends to run it?
How would you monitor and restrict resource usage (CPU, memory mostly)?
This is a good start for Python but I'm wondering if anyone here has more specific experiences they can share regardless of language (Python, Lua, Ruby, etc.).
Lua has the best sandboxing and watchdogging that I've seen to date. My host language is Python. Thus, I've decided to go with Lunatic Python.