tornado-custom-options.py

import tornado.ioloop
import tornado.web

# http://www.tornadoweb.org/en/stable/options.html
from tornado.options import parse_command_line, define, options

define("port", default=8888)
define("debug", default=False)

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")


handlers = [
    (r"/", MainHandler),
]

if __name__ == "__main__":
    parse_command_line()
    
    # debug=True will enable tornado debug mode
    # http://www.tornadoweb.org/en/stable/overview.html#debug-mode
    application = tornado.web.Application(handlers, debug=options.debug)
    application.listen(options.port)
    
    tornado.ioloop.IOLoop.instance().start()