app.yaml

runtime: python27
api_version: 1
threadsafe: true

handlers:
- url: /.*
  script: main.app

appengine_config.py

# appengine_config.py
from google.appengine.ext import vendor

# Add any libraries install in the "lib" folder.
vendor.add('lib')

cron.yaml

cron:
    - description: "regular job"
      url: /watch
      schedule: every 1 hours

main.py

import webapp2

from google.cloud import pubsub


class WatchPage(webapp2.RequestHandler):
    def get(self):
        pubsub_client = pubsub.Client()
        topic = pubsub_client.topic('timer-topic')

        message_id = topic.publish('ping'.encode('utf-8'))
        self.response.write(message_id)



app = webapp2.WSGIApplication([
    ('/watch', WatchPage),
], debug=True)