Slack Event Authentication

Slack can be configured to send events on certain actions, e.g. a file has been added or a message has been posted. Another feature of Slack are the slash commands. In both cases a message is getting posted to a confiurable URL. This plugin authenticates the request with the signing secret of the application and in case of a form-encoded request, e.g. slash commands, converts the payload to JSON.

Configuration

Value	Description
secret	Signing Secret for the Slack application. Found in Basic Information of the Slack application.

Example

Slack Webhook Authentication with Signing Secret

direktiv_api: endpoint/v1

allow_anonymous: false
plugins:
  target:
    type: target-flow
    configuration:
        flow: /target.yaml
        content_type: application/json
  auth:
    - type: slack-webhook-auth
      configuration:
        secret: 123MySigningSecret456
methods: 
  - POST
path: /target

Example Slash Command

The following is a simple example of a slash command. The flow fetches the respond_url from the initial request and calls a subflow with the URL as parameter. Because a slash command has to respond immediately the subflow is called with async: true.

Example Flow with Response

direktiv_api: workflow/v1

functions:
- id: response
  type: subflow
  workflow: respond.yaml

states:
- id: start
  type: noop
  transform:
    url: jq(.response_url[0])
  transition: respond
- id: respond
  type: action
  async: true
  action:i

```yaml title="Post Message to Slack to Response URL"
direktiv_api: workflow/v1

functions:
- id: get
  image: gcr.io/direktiv/functions/http-request:1.0
  type: knative-workflow
states:
- id: getter 
  type: action
  log: Requesting jq(.url)
  action:
    function: get
    input: 
      debug: true
      method: "POST"
      url: jq(.url)
      content:
        value:
          text: Hello