Skip to content

Latest commit

 

History

History
76 lines (56 loc) · 3.22 KB

prepackages.md

File metadata and controls

76 lines (56 loc) · 3.22 KB
Raw

Pre-installed packages

These are the packages that are pre-installed and available to any I/O Runtime user:

/whisk.system/alarms

You can get details about the content of a package by running this command:

wsk package get --summary /whisk.system/alarms

You can execute any of the actions defined in a shared package by using the fully qualified name. For example:

wsk action invoke /whisk.system/alarms/alarm

Alternatively, you can bind any of this packages to your namespace; see the Packages page. When you bind a package, you can set your own default parameters (if there are any parameters) and run the actions as being local to your namespace.

Using the alarms package

The alarms package can be used to trigger an action(s) for a given interval (once or recurring).This is a three-step process:

  1. Create one or more actions you want to be executed. There is nothing special about these actions, you’d create them just as you would any other action.
  2. Create a trigger and specify the frequency. This is what the Alarms package provides.
  3. Create a rule that links the action(s) to the trigger Every time the trigger is fired, the action(s) is executed.

The alarms package contains:

Entity Type Parameters Description
/whisk.system/alarms package - Alarms utility
/whisk.system/alarms/interval feed minutes, trigger_payload, startDate, stopDate Fire Trigger event on an interval-based schedule
/whisk.system/alarms/once feed date, trigger_payload, deleteAfterFire Fire Trigger event once on a specific date
/whisk.system/alarms/alarm feed cron, trigger_payload, startDate, stopDate Fire Trigger event on a time-based schedule using cron

To create a trigger on an interval-based schedule that will fire every 10 minutes until January 31, 2020 (my-interval is the name of the trigger):

wsk trigger create my-interval \
  --feed /whisk.system/alarms/interval \
  --param minutes 10 \
  --param trigger_payload "{\"name\":\"Vlad\",\"place\":\"Transylvania\"}" \
  --param stopDate "2020-01-31T23:59:00.000Z"

To create a trigger that fires once:

wsk trigger create my-interval \
  --feed /whisk.system/alarms/once \
  --param trigger_payload "{\"name\":\"Vlad\",\"place\":\"Transylvania\"}" \
  --param stopDate "2020-01-31T23:59:00.000Z"
  --param deleteAfterFire "rules"

Finally, to create a trigger that fires on a time-based schedule using cron (it fires every hour):

wsk trigger create my-interval \
  --feed /whisk.system/alarms/alarm \
  --param cron "0 * * * *" \
  --param trigger_payload "{\"name\":\"Vlad\",\"place\":\"Transylvania\"}" \
  --param startDate "2018-10-17" \
  --param stopDate "2019-10-31T23:59:00.000Z"

Here are some examples of how to set various cron values - for more info check this page:

  • * * * * *: The Trigger fires at the top of every minute.
  • 0 * * * *: The Trigger fires at the top of every hour.
  • 0 */2 * * *: The Trigger fires every 2 hours (that is, 02:00:00, 04:00:00, ...).
  • 0 9 8 * *: The Trigger fires at 9:00:00AM (UTC) on the eighth day of every month.