Lesson 3: Types of Alarm Feed

Beside the /whisk.system/alarms/interval feed in lesson 2, the alarms provider in Adobe I/O Runtime supports other types of feed.

Firing a trigger once

The /whisk.system/alarms/once feed allows you to fire event once at a specific time. The only required param is date to indicate when the trigger is fired. Optional params are trigger_payload and deleteAfterFire.

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triggers:
  runMeOnce:
    feed: /whisk.system/alarms/once
    inputs: 
      date: YYYY-MM-DDTHH:mm:ss.sssZ
      deleteAfterFire: true
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triggers:
  runMeOnce:
    feed: /whisk.system/alarms/once
    inputs: 
      date: YYYY-MM-DDTHH:mm:ss.sssZ
      deleteAfterFire: true

Please note that YYYY-MM-DDTHH:mm:ss.sssZ is just a format for this field. You are free to update it with the exact date and time you want.

Firing a trigger on a time-based schedule using cron

The /whisk.system/alarms/alarm feed allows you to fire event on a time-based schedule using cron. This is more generic than the interval and once feeds, because you can write crontab to configure the alarm service to trigger at the exact time and interval you want. The only required param is cron, which is a string based on the UNIX crontab syntax that indicates when to fire the trigger in UTC. Optional params are trigger_payload, timezone, startDate and stopDate.

The following example shows a cron schedule at 2am on Sundays in Central Europe Timezone (CET).

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triggers:
  sunday2am:
    feed: /whisk.system/alarms/alarm
    inputs: 
      cron: 0 2 * * 7
      timezone: CET
      startDate: 1601918992704
      stopDate: 1651918992704
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triggers:
  sunday2am:
    feed: /whisk.system/alarms/alarm
    inputs: 
      cron: 0 2 * * 7
      timezone: CET
      startDate: 1601918992704
      stopDate: 1651918992704

Last updated 5/21/2024

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