session_scratch.py

import bottle
from beaker.middleware import SessionMiddleware

session_opts = {
    "session.type": "memory",
    "session.auto": True,
    "session.cookie_expires": 300,
}
app = SessionMiddleware(bottle.app(), session_opts)


@bottle.route("/test")
def test():
    s = bottle.request.environ.get("beaker.session")
    s["test"] = s.get("test", 0) + 1
    s.save()
    return f'Test counter {s.get("test")}'


bottle.run(app=app)