dev.ini

session.framework = beaker
session.key = SessionID
session.type = file
session.data_dir = %(here)s/data/ssessions/data
session.lock_dir = %(here)s/data/ssessions/lock
session.secret = 123

init.py

from pyramid.config import Configurator

import pyramid_beaker


def main(global_config, **settings):
    """ This function returns a Pyramid WSGI application.
    """
    config = Configurator(settings=settings)
    config.include('pyramid_chameleon')
    config.add_static_view('static', 'static', cache_max_age=3600)

    config.add_route('home', '/')
    config.add_route('session_iterate', '/iterate')

    config.include('pyramid_beaker')

    config.scan()
    return config.make_wsgi_app()

views.py

from pyramid.view import view_config
from pyramid.httpexceptions import HTTPFound

@view_config(route_name='home', renderer='templates/mytemplate.pt')
def my_view(request):
    return {'project': 'MyProject'}


@view_config(route_name='session_iterate', renderer='templates/mytemplate.pt')
def session_iterate(request):
    print "~=" * 80

    if 'i' not in request.session:
        print "new session!"
        request.session['i'] = 0
    else:
        print "existing session! increment"
        request.session['i'] += 1
        if request.session['i'] >= 2 :
            print "i <=2 -- invalidte session"
            request.session.invalidate()

    print "session -"
    print request.session.id
    print request.session
    print "cookies -"
    print request.cookies
    print "response -"
    print request.response.__dict__

    return {'project': 'MyProject'}