A supervised owner for a long-lived session.

A session lives as long as the struct that refers to it, so something has to hold on to it. This server does exactly that and nothing else:

children = [
  {Rupyex.Server, name: MyApp.Python, init: "import json"}
]

Supervisor.start_link(children, strategy: :one_for_one)

{:ok, 3} = Rupyex.Server.eval(MyApp.Python, "1 + 2")

Python code does not run inside this process: session/1 hands the session back and the caller talks to the interpreter thread directly, so one slow snippet cannot make the server a bottleneck. When calling in a tight loop, fetch the session once and pass it to Rupyex yourself.