Conditionally add fields to steps in backstage scaffolder template

Question

how can I add optional fields to a step based on if user has provided an input parameter? I'm not looking for an entire step to be skipped but only one parameter.

In the following example, I want to add collaborators section in the publish:github step only if the user has selected an additional collaborator from the parameter section.

apiVersion: scaffolder.backstage.io/v1beta3
# https://backstage.io/docs/features/software-catalog/descriptor-format#kind-template
kind: Template
metadata:
  name: example-nodejs-template
  title: Example Node.js Template
  description: An example template for the scaffolder that creates a simple Node.js service
spec:
  owner: user:guest
  type: service

  # These parameters are used to generate the input form in the frontend, and are
  # used to gather input data for the execution of the template.
  parameters:
    - title: Fill in some steps
      required:
        - name
      properties:
        name:
          title: Name
          type: string
          description: Unique name of the component
          ui:autofocus: true
          ui:options:
            rows: 5
        collaborators:
          title: Additional collaborators
          type: string
          description: Github team
          ui:field: EntityPicker
          ui:options:
            orderable: false
            catalogFilter:
              - kind: [Group]
                metadata.annotations.github.com/team-slug: { exists: true }

  # These steps are executed in the scaffolder backend, using data that we gathered
  # via the parameters above.
  steps:

    # Each step executes an action, in this case one templates files into the working directory.
    - id: fetch-base
      name: Fetch Base
      action: fetch:template
      input:
        url: ./content
        values:
          name: ${{ parameters.name }}

    # This step publishes the contents of the working directory to GitHub.
    - id: publish
      name: Publish
      action: publish:github
      input:
        allowedHosts: ["github.com"]
        description: This is the ${{ parameters.name }}.
        repoUrl: github.com?repo=${{ parameters.name }}&owner=manuviswam
        defaultBranch: main
        collaborators:
          - team: ${{ parameters.collaborators }}
            access: admin

    # The final step is to register our new component in the catalog.
    - id: register
      name: Register
      action: catalog:register
      input:
        repoContentsUrl: ${{ steps['publish'].output.repoContentsUrl }}
        catalogInfoPath: '/catalog-info.yaml'

  # Outputs are displayed to the user after a successful execution of the template.
  output:
    links:
      - title: Repository
        url: ${{ steps['publish'].output.remoteUrl }}
      - title: Open in catalog
        icon: catalog
        entityRef: ${{ steps['register'].output.entityRef }}

I've tried to use Nunjucks if condition as follows but it gives me a YAML parsing error

    - id: publish
      name: Publish
      action: publish:github
      input:
        allowedHosts: ["github.com"]
        description: This is the ${{ parameters.name }}.
        repoUrl: github.com?repo=${{ parameters.name }}&owner=manuviswam
        defaultBranch: main
        {% if parameters.collaborators %}
        collaborators:
          - team: ${{ parameters.collaborators }}
            access: admin
        {% endif %}

Conditionally add fields to steps in backstage scaffolder template

0 Answers0