Is it possible to start a timer in google app engi

Question

For instance, check a status every 30 seconds or poll a web service periodically ?

Answer 1

Yes, you can use the task queue. A task can be configured to run at custom intervals and can perform pretty much any action.

Answer 2

App Engine Cron Service allows you to configure regularly scheduled tasks that operate at defined times or regular intervals

A cron.yaml file in the root directory of your application (alongside app.yaml) configures scheduled tasks for your Python application.
For example:

- description: Webservice polling
  url: /tasks/pollawebservice
  schedule: every 30 minutes

The url field specifies a URL in your application that will be invoked by the Cron Service.