13.2. Scheduled Tasks

Applications do work in response to external stimuli: user requests, incoming email and XMPP messages, HTTP requests sent by a script on your computer. And while task queues can be used to trigger events across a period of time, a task must be enqueued by application code before anything happens.

Sometimes you want an application to do something “on its own.” For instance, an app may need to send nightly email reports of the day’s activity, or fetch new headlines from a news service. For this purpose, App Engine lets you specify a schedule of tasks to perform on a regular basis. In the App Engine API, scheduled tasks are also known as “cron jobs,” named after a similar feature in the Unix operating system.