"Cron is a time-based job scheduler that enables you to schedule jobs (commands) to run periodically at certain times or dates. It is commonly used to automate system maintenance or administration." (src: Wikipedia Cron) After reading this guide, you should be familiar with:
- How to schedule Cron Jobs
Cron Jobs can be scheduled from either the Dashboard or the Boxfile. It's important to note that only certain executables are allowed when using Cron Jobs. See the full list of available executables on Github.
Dashboard
From the Cron tab in your Pagoda Dashboard and click "Add A Job".
Command
Enter your command. Here a few examples to get you started. Files can either be referenced using relative(e.g. app/cache) or absolute(e.g. /var/www/app/cache) paths.
| Purpose | Command |
| Clear Cache | rm /var/www/cache/* |
| Database Migration | php app/db_migration.php |
| Visit URL | wget -q http://example.com/cron/ |
| Visit URL with output | wget -O writable_dir/cron.log http://example.com/cron_script.php |
Read Only File System
Remember that cron commands run in a Read Only File System. Any cron jobs that create files or any output, must create those files in Shared Writable Directories.
If you don't need the output from a cron command it may be simpler to use curl intstead of wget since curl doesn't attempt to create a file by default.
Schedule
Create the schedule you'd like the command to run on. Here are a few examples.
| Interval | Description | Schedule |
| Yearly | Run once a year, midnight, Jan. 1st | 0 0 1 1 * |
| Monthly | Run once a month, midnight, first of month | 0 0 1 * * |
| Weekly | Run once a week, midnight on Sunday | 0 0 * * 0 |
| Daily | Run once a day, midnight | 0 0 * * * |
| Hourly | Run once an hour, beginning of hour | 0 * * * * |
Be aware that there are no Predefined Sheduling Definitions(e.g. @daily, @hourly, etc.) available on Pagoda Box. All schedules must be numeric.
15 Minute Limit
The shortest available cron schedule is every 15 Minutes.
Crons Will Not Run While an App is Sleeping
Idle, unscaled applications are periodically put to sleep on Pagoda Box. If an app is sleeping, cron jobs will not run—automatically or manually. To keep you app from going to sleep, you can either scale any of your components or add caffeine.
Boxfile
If you'd like to configure a cron job using the Boxfile, nest a cron node under the appropriate web component.
YAMLCron Job
Things to Note About Cron Jobs in Your Boxfile
It's important to note that when you remove a Cron Job from your Boxfile, it will not actually remove the Cron Job from your application. This can only be done in your App Dashboard.
Also, if you make an edit to a Cron Job in your Boxfile, it will not edit the existing job, but create a new Cron Job instead. You will need to delete the previous version of your job in your App Dashboard.
Emailing the Output of Your Cron Job
Pagoda Box allows you to specify email addresses to notify when your Cron Job runs. Part of the email will be the actual output of the script or command. You can specify these email addresses in your App Dashboard when creating a new Cron Job or editing an existing job. Adding notification email addresses can not be done in the Boxfile.
