Question

I’m trying to initiate a dynamic backend using a cron task, however after I deploy I don’t see the new cron task under the cron tab and also I don’t see any instances of backends under my backend tab. What am I doing wrong?

EDIT: Now the cron job runs properly (after I changed the schedule to “every 1 minutes”. However the backend refuses to run. The cron tab says on time Failed. Maybe I need to define some handler in my app.yaml or something like that?

EDIT2: After using appcfg to update the backends list I can see the backend I defined under backends tab. Now I just have to wait and see if it works (does anybody know of a way to make a get request to the backend with the browser? I don’t want to wait an hour just to see if it’s running (the cron task runs every hour now).

My code

My cron.yaml file:

cron:
- description: crawler backend activation
  url: /crawl
  target: crawler
  schedule: every minute

My backends.yaml file:

backends:
- name: crawler
  class: B1
  instances: 1
  start: crawler.application
  options: dynamic

My backend handler crawl.py:

import logging
import webapp2 as webapp

class Handler(webapp.RequestHandler):
    logging.debug('crawler started')



application = webapp.WSGIApplication([('/crawl', Handler)])

Answer 1

I see a couple of problems with your code. First, your startup handler is called crawl.py, but your backends.yaml refers to crawler.py. Second, the startup handler specified in backends.yaml only specifies the handler file for the start request – all other requests, such as those created by cron, go through app.yaml and are routed to handlers like regular requests.