madeleine-rack is a Rack middleware that uses Madeleine to provide data persistence to web applications.
It does this by intercepting and storing all web requests, so that the application's state can later be restored by automatically re-playing the requests.
It supports the basic Rack specification, with a few work-arounds for specific web servers, etc.
Add something like this to your config.ru file:
use Madeleine::Rack::Middleware, "some_storage"
Then use something Rack-based (e.g. rackup) to start the application.
You will find your persistent system root in
Thread.current[:_madeleine_system]
from within your application.