That specifies a self-contained servlet 'application' that will map requests to servlets in module 'thisapp'. Try reloading the page a couple of times to see the visit counter increase. Sessions are automatically created by the setting of a cookie, and are saved and loaded automatically using the standard library module 'pickle'. On my laptop, with Apache, this set-up can handle about 10 requests per second, which is already enough to serve more than 800,000 requests per day. I tried adding a hundred or so postgres DB queries to my test servlet and still got about 5 requests per second.
Sessions have a configurable idle timeout, which defaults to one hour.
What doesn't work Plenty of things need more work. In particular, the current handling of response headers and cookies needs work. That work will get done pretty soon, and contributions are welcome. There's no fancy logging support yet. Later there will be a completely standalone web server application similar to Apache Tomcat.