A tornado web service that self-calls itself periodically

gistfile1.txt

import tornado.ioloop
import tornado.web
import pandas as pd
import requests
import os

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        print('handler', pd.Timestamp.utcnow())
        self.write(str(self.request.headers.get('Authorization')))

def callback():
    print('callback', pd.Timestamp.utcnow())
    r = requests.get('http://localhost:9999/')
    assert r.ok

if __name__ == "__main__":
    if os.fork():
        app = tornado.web.Application([
            (r"/", MainHandler),
            ])
        app.listen(9999)
        tornado.ioloop.IOLoop.current().start()
    else:
        tornado.ioloop.PeriodicCallback(callback, 2000).start()
        tornado.ioloop.IOLoop.instance().start()