Documentation

Running an Action

An Action is a fundamental concept in Octant. It is the mechanism allowing Octant to run a command to change the state of the UI or perform some operation against a cluster. Since most Actions are executed upon user interaction with a component, the need to understand an Action is generally only needed by developers and plugin authors.

Anatomy of an Action

Octant uses websockets to communicate between server and client. An Action is a websocket message that is sent from the client to the server. The server expects the message to contain a type to specify the Action and a payload containing data relevant to that particular Action.

{
  "type":"action.octant.dev/setContentPath",
  "payload":{
    "contentPath":"overview/namespace/default",
    "params":{}
  }
}

The above websocket message is an example of how Octant uses Actions to serve content for a given page. When a user navigates to a URL path, it is sent from the client, electron or web browser, where the server will send a response based on the requested content path.

{
  "type":"event.octant.dev/content",
  "data":{},
  "Err":null
}

Then the returned message provides the data to generate the content and provide errors, if any.

Actions in Practice

Most features seen in Octant use Actions. A number of these are not exposed publicly as they perform some operation against the cluster. Examples of such actions can be found here: https://pkg.go. dev/github. com/vmware-tanzu/octant/internal/octant#pkg-constants

Similarly, public Actions are available for consumption and are also used in Octant core.

Many components prompting user interaction in Octant allow binding to an action. For example, a button is used to send some data to the server.

component.NewButton("button",
	action.CreatePayload("action.octant.dev/myAction", map[string]interface{}{
	    "hello": "world"
	})
)

It is the developer’s responsibility to ensure the payload schema is correct in addition to error handling.

Custom Actions in Plugins

If Octant does not provide an Action doing what you want, plugins can create a new action to run some arbitrary code.

The sample plugin provides an example of this by showing the websocket client ID in an application level alert when clicking a button.

This is a powerful feature to integrate Octant with other tools in the ecosystem.