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:
cron: - 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.