Setup Backstage Templates for Knative Functions

This page describes how to set up Backstage Templates for Knative Functions in OpenShift Serverless, which allow you to create Knative Functions easily in Backstage.

These function templates are provided as examples to help you get started with Knative Functions. You should customize these templates to suit your needs.

Anatomy of a Knative Function Template

A Knative Function template is a YAML file that specifies the structure of a Backstage template. For more information about Backstage templates, see Red Hat Developer Hub documentation.

Knative community provides a Backstage Location where there are multiple templates available. You can use these templates to create Knative Functions in Backstage.

An example of a Knative Function template is as follows, for a Go HTTP function:

apiVersion: scaffolder.backstage.io/v1beta3
kind: Template
metadata:
  name: knative-func-go-http (1)
  title: Create a go http Knative Function application with a CI pipeline (2)
  description: Create a go http Knative Function application with a CI pipeline
  tags:
    - go
    - http
    - knative
    - func
spec:
  owner: knative-authors
  system: knative
  type: service

  parameters: (3)
    - title: Provide information about the new component
      required:
        - orgName
        - repoName
        - owner
        - system
      properties:
        orgName:
          title: Organization Name
          type: string
        repoName:
          title: Repository Name
          type: string
        description:
          title: Description
          type: string
          description: Help others understand what this component is for
        owner:
          title: Owner
          type: string
          ui:field: EntityPicker
          ui:options:
            catalogFilter:
              kind:
                - Group
                - User
        system:
          title: System
          type: string
          ui:field: EntityPicker
          ui:options:
            catalogFilter:
              kind:
                - System
  steps:
    - id: sourceCodeTemplate (4)
      name: Generating the Source Code Component
      action: fetch:template
      input:
        url: ./skeletons/go-http/
        values:
          orgName: ${{ parameters.orgName }}
          repoName: ${{ parameters.repoName }}
          owner: ${{ parameters.owner }}
          system: ${{ parameters.system }}

    - id: catalogTemplate (5)
      name: Generating the Catalog Info Component
      action: fetch:template
      input:
        url: ./catalog-info/
        values:
          orgName: ${{ parameters.orgName }}
          repoName: ${{ parameters.repoName }}
          owner: ${{ parameters.owner }}
          system: ${{ parameters.system }}

    - id: publish (6)
      name: Publishing to the Source Code Repository
      action: publish:github
      input:
        allowedHosts: [ 'github.com' ]
        description: ${{ parameters.description }}
        repoUrl: github.com?owner=${{ parameters.orgName }}&repo=${{ parameters.repoName }}
        defaultBranch: main

    - id: register (7)
      name: Registering the Catalog Info Component
      action: catalog:register
      input:
        repoContentsUrl: ${{ steps.publish.output.repoContentsUrl }}
        catalogInfoPath: /catalog-info.yaml

  output: (8)
    links:
      - title: Open the Source Code Repository
        url: ${{ steps.publish.output.remoteUrl }}
      - title: Open the Catalog Info Component
        icon: catalog
        entityRef: ${{ steps.register.output.entityRef }}
1 The unique name of the template.
2 The title of the template, which is shown to users.
3 The parameters that the user must provide when creating a new component from this template.
4 The first step in the template, which generates the source code for the function. It uses the source code in ./skeletons/go-http/ directory relative to the template location as the code skeleton.
5 This step generates the catalog info for the function. This catalog info is used to register the function in the Backstage catalog.
6 This step publishes the source code to the source code repository. You must have the GitHub integration set up to use this step. See Red Hat Developer Hub documentation for more information.
7 This step registers the function in the Backstage catalog.
8 The output of the template, which includes links to the source code repository and the catalog info component. This output is shown to the user after the template is executed.

For more information about the structure of a Backstage template, see Red Hat Developer Hub documentation.

Add Knative Function Templates to Backstage

To add Knative Function templates to Backstage, you must follow the instructions in the Red Hat Developer Hub documentation.

The Location provided by Knative community is at github.com/knative-extensions/backstage-plugins/blob/main/backstage/templates/location.yaml. You can use this location to add Knative Function templates to Backstage.

Using the templates

  1. Instantiate the template in Backstage.

  2. Clone the repository.

    $ git clone <repository-url>

  3. In the cloned repository, the kn command will be working with the function instance. To learn more about the kn command, see OpenShift Serverless Functions documentation.