Custom Actions

Produce Custom Action Messages

You can use Custom Actions to enable communication between two Applications on either the same cluster or across different clusters.

Note

To understand the purpose of Custom Actions or view the overall structure of how they work, check out the documentation in the overview page here.

To ensure the Custom Action being sent is handled properly, the app.yaml outputs needs to be declared:

Note

You can choose any name for the type.

This is how the Custom Action Manager chooses which Consumer Application (Executor) will receive the Custom Action object.

custom_actions:
  outputs:
    - type: custom-action-name

The Custom Action Object in the main.py script supports the following attributes :

Attribute	Required	Default Value	Description
resource	required	N/A	The KRNAsset that this Custom Action is meant for.
type	required	N/A	The name of Custom Action.
title	required	N/A	Title of the Custom Action
description	required	N/A	Description details of the Custom Action
expiration_date	required	N/A	Absolute datetime or a timedelta (from now) when the Control Change will expire.
payload	required	N/A	The custom information of the Custom Action that will be required by the Consumer Application
trace_id	optional	N/A	A custom id for tracking the Custom Action status

Example

In this example we will create a Producer Application that will;

1. Package the email details into a Custom Action Object
2. Send the Custom Action object directly to the Consumer Application (Executor) for processing.
3. Package the Custom Action object in a Recommendation and publish the "Recommendation with Custom Action" to the Kelvin UI for approval. (Typically, you would choose either direct sending or publishing with a Recommendation—not both.)

Check out the Consume Custom Actions documentation here to see how to receive this Custom Action in a Consumer Application (Executor).

app.yaml

spec_version: 5.0.0
type: app            # Any app type can handle and/or publish custom actions.

name: hello-app
title: Hello App
description: Lorem ipsum dolor sit amet, consectetur adipiscing elit
version: 1.0.0

custom_actions:
  outputs:
    - type: email

  ...

Publisher Application

import asyncio
from datetime import timedelta, datetime

from kelvin.application import KelvinApp
from kelvin.krn import KRNAsset
from kelvin.message import Recommendation, CustomAction

asset = KRNAsset("air-conditioner-1")

app = KelvinApp()

async def main() -> None:
    asset = KRNAsset("air-conditioner-1")

    ###
    # Directly
    #
    action = CustomAction(resource=asset,
    type="email",
    title="Recommendation to reduce speed",
    description="It is recommended that the speed is reduced",
    expiration_date=datetime.now() + timedelta(hours=1),
    payload={
        "recipient": "operations@example.com",
        "subject": "Recommendation to reduce speed",
        "body": "This is the email body",
    })
    app.publish(action)

    ###
    # Or embedded the Custom Action into a Recommendation   
    #

    rec = Recommendation(resource=asset,
    type="Reduce speed",
    actions=[action],
    )
    app.publish(rec)

if __name__ == "__main__":
    asyncio.run(main())