python - Flask and Web.py both hang on atexit -

i have simple flask app:

from flask import flask import prolog_handler p  app = flask(__name__) app.debug = false  @app.route('/') def hello():     rule in p.rules:         print rule     return 'hello'  if __name__ == '__main__':     app.run(host='0.0.0.0', port=8080) 

the prolog_handler module starts session triplestore , loads rules. has atexit function ends session , prints message "closing...". start server bash prompt python myapp.py. whenever hit ctrl-c stop server, nothing happens. don't returned bash prompt, , don't see "closing..." message printed. tried web.py same results.

the prolog_handler literally simple this:

tstore = openprologsession() rules = ...  def cleanup():     print "closing..."     tstore.endsession()  atexit.register(cleanup) 

so why difficult perform atexit task?

ps: if comment out stuff opening prolog session , ending it, , leave part prints message "closing..." see "closing..." message when hit ctrl-c , returned bash prompt. works expected. what's point of atexit if can't useful it?

this may not perfect answer tried use following flask:

# these functions should called when tear down application app.teardown_functions = []  def teardown_applications():      func in app.teardown_functions:        print('calling teardown function %s' % func.__name__)         func()  app.teardown_functions.append(function_tocall_at_exit) 

this seems work me. tend use gevent flask applications

if __name__ == '__main__':     gevent.signal(signal.sigint, teardown_applications)     http_server = wsgiserver(('', 5000), app)     http_server.serve_forever() 

this works me.

some of module imports:

from flask import flask gevent.wsgi import wsgiserver import gevent import signal  gevent import monkey monkey.patch_all()