The Cron Log

The following is an example of a request originating from a cron:

It’s easy to tell this request originates from cron because (1) the originating IP is (which is a reserved IP; cron requests come only from that address) and (2) the queue name is listed as cron .

Capitalization In Cron Scheduling

A note on cron: schedules must be recorded in all lowercase letters. The following picture shows an application upload failure because the S in Saturday is capitalized in cron.

However the all lowercase version schedule: every saturday 9:00 works.

A Simple Cron Declaration

Cron is a service to schedule tasks at predetermined intervals. For example, you could schedule a certain task to run every 10 minutes, or 10 hours, or every Monday. At every interval, App Engine will send a HTTP request to an URL that you specify.

Here’s an example of a cron file:

- description: Description Of Cron
  url: /url
  schedule: every 24 hours
  timezone: America/Chicago

This tells App Engine to run the script located at /url once every 24 hours. You can name other schedules, such as every 10 minutes, or every Monday 9:00 (run every Monday 9 AM).

Cron files are saved as cron.yaml in the root directory of a Go app, or in the /war/WEB-INF folder of a Java application.