Template

Actions used

fetch:template
fs:read
debug:log
fetch:template
fs:read
debug:log

You can check the available actions if you visit /templates/actions.

Walkthrough

You can use this template by registering it from roadie-demo/scaffolder-examples repo

apiVersion: scaffolder.backstage.io/v1beta3
kind: Template
metadata:
  name: debug-template
  title: Debug the nunjucks template
  description: This template will render the provided file and displays it in the scaffolder logs
  owner: group:default/engineering
  type: service

  parameters:
    - title: Document front content
      properties:
        rfcNumber:
          title: rfcNumber
          type: string
        rfcTitle:
          title: RFC Title
          type: string
        abstract:
          title: Document Abstract (optional draft version)
          type: string
          ui:widget: textarea

  steps:
    - id: fetch-template
      action: fetch:template
      input:
        url: https://github.com/roadie-demo/scaffolder-examples/tree/main/debug-template/skeleton
        templateFileExtension: true
        values:
          rfcNumber: ${{ parameters.rfcNumber }}
          rfcTitle: ${{ parameters.rfcTitle }}
          abstract: ${{ parameters.abstract }}

    - id: read-file
      name: Read File
      action: fs:read
      input:
        path: ./template.md

    - id: log-message
      name: Log Message
      action: debug:log
      input:
        message: ${{ steps['read-file'].output.content }}

Breakdown

Parameters

This section configures the frontend for your template. Essentially these values will be provided from the backstage ui to the template.

param

This renders 3 separate input fields for the template. These inputs can be referenced by the steps via their key name inside the properties object.

- title: Document front content
  properties:
    rfcNumber:
      title: rfcNumber
      type: string
    rfcTitle:
      title: RFC Title
      type: string
    abstract:
      title: Document Abstract (optional draft version)
      type: string
      ui:widget: textarea

Steps

fetch-template

Uses the fetch:template. It fetches the template skeleton from the hardcoded URL and puts everything into the docs/rfcs/<rfcnumber> folder. The provided values object will be used to replace the values inside the skeleton template by nunjucks.

- id: fetch-template
  action: fetch:template
  input:
    url: https://github.com/roadie-demo/scaffolder-examples/tree/main/debug-template/skeleton
    templateFileExtension: true
    targetPath: docs/rfcs/${{ parameters.rfcNumber }}
    values:
      rfcNumber: ${{ parameters.rfcNumber }}
      rfcTitle: ${{ parameters.rfcTitle }}
      abstract: ${{ parameters.abstract }}

read-file

Uses the fs:read action. It reads the hard coded ./template.md file’s content into memory.

- id: read-file
  name: Read File
  action: fs:read
  input:
    path: ./template.md

log-message

Uses the debug:log action. It prints out the content of the previously read file to the logs. The steps[id].output is used to access the output of the referenced step.

- id: log-message
  name: Log Message
  action: debug:log
  input:
    listWorkspace: false
    message: ${{ steps['read-file'].output.content }}