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Cron

Darklang supports scheduled jobs via a Cron component. Use a Cron when you want to schedule something to occur on a timed interval.

Cron Intervals

Cron Basics​

  • Crons run automatically once per interval. (Note: due to the distributed nature of the Darklang platform, it's possible that a Cron may erroneously run more than once per interval.)
  • There is currently no guarantee when within an interval that the Cron will run. Eg, A Cron created at 09:15 and marked as Every 1 hour will run roughly every hours, but there is no guarantee the next run will be at exactly 10:15. We plan to eventually add more fine-grained scheduling.
  • The trace information on Cron will show the most recent 10 times the Cron has run. A Cron never has input data, so the trace will always say No input parameters.
  • To run a Cron on-demand, use the replay button the upper right. Running on-demand does not affect the next scheduled runtime.
  • Crons will not alert you of failures unless you write logic to do so.

FAQ​

Can I set the exact time my Cron will run?​

No, not currently. We plan to eventually support this.

Can I pause a Cron to keep it from running?​

No, not currently. We plan to eventually support this.

Will a Cron ever be executed more than once in parallel?​

Yes, if the cron takes longer to complete than its scheduling interval, multiple executions could overlap and be running in parallel. (See the next question also.)

Does the execution time of my Cron affect its scheduling?​

No. Scheduling happens independently from execution of the Cron's code. Even if execution of a Every 1 min Cron takes 2 minutes to complete, the Cron will still be scheduled every 1 minute.

My Every 1min Cron is not running every minute. Help?​

Please let us know the canvas, Cron name, and approximate time of the problem and we can look into it.

Future Improvements​

  • Granular scheduling, allowing more complex and more precise scheduling (every other hour at 15 minutes past the hour)