Edit the contents of a file

Published on December 28th, 2022

We have scaffolder actions that allow you do a number of “editing” actions on a file:

Proper editing functionality is not well supported by Backstage at the moment though.

Append to a file

Actions used:

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

Example Template

---
apiVersion: scaffolder.backstage.io/v1beta3
kind: Template
metadata:
  name: append-to-file-template
  title: Append To File template example
  description: Template to append content to a file in a repo and raise a PR for the change. NB - This will create a new file if a file does not exist at the path given.
spec:
  owner: roadie
  type: service

  parameters:
    - title: PR Data
      properties:
        repository:
          title: Repository name
          type: string
          description: The name of the repository
        org:
          title: Repository Organisation
          type: string
          description: The Github org that the repository is in
        pr_branch:
          title: PR Branch
          type: string
          description: The new branch to make a pr from
    - title: Append content
      properties:
        path:
          title: Path
          type: string
          description: The path to the file you want to append this content to in the scaffolder workspace
        content:
          title: Text area input
          type: string
          description: Add your new entity
          ui:widget: textarea
          ui:options:
            rows: 10
          ui:help: 'Make sure it is valid by checking the schema at `/tools/entity-preview`'
          ui:placeholder: |
            
            ---
            apiVersion: backstage.io/v1alpha1
              kind: Component
              metadata:
                name: backstage
              spec:
                type: library
                owner: CNCF
                lifecycle: experimental

  steps:
    - id: fetch-repo
      name: Fetch repo
      action: fetch:plain
      input:
        url: https://github.com/${{ parameters.org }}/${{ parameters.repository }}
    - id: append-file
      name: Append To File Or Create New
      action: roadiehq:utils:fs:append
      input:
        path: ${{ parameters.path }}
        content: ${{ parameters.content }}
    - id: publish-pr
      name: Publish PR
      action: publish:github:pull-request
      input:
        repoUrl: github.com?repo=${{ parameters.repository }}&owner=${{ parameters.org }}
        branchName:  ${{ parameters.pr_branch }}
        title: Add entity to ${{ parameters.path }}
        description: PR created from Roadie Backstage scaffolder
    - id: log-message
      name: Log PR URL
      action: debug:log
      input:
        message: 'PR url: ${{ steps["publish-pr"].output.remoteUrl }}'

Merge new json into a file

Actions used:

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

Example Template

---
apiVersion: scaffolder.backstage.io/v1beta3
kind: Template
metadata:
  name: merge-json-template
  title: Merge in Json
  description: Merge in some json to an existing file and open a pull request for it.
spec:
  owner: roadie
  type: service

  parameters:
    properties:
      repository:
        title: Repository name
        type: string
        description: The name of the repository
      org:
        title: Repository Organisation
        type: string
        description: The Github org that the repository is in
      pr_branch:
        title: PR Branch
        type: string
        description: The new branch to make a pr from
      path:
        title: Path
        type: string
        description: The path to the desired new file
      content:
        title: Json
        type: string
        description: Json to merge in
        ui:widget: textarea
        ui:options:
          rows: 10
        ui:placeholder: |
          {"hello": "world"}
  steps:
    - id: log-message
      name: Log PR URL
      action: debug:log
      input:
        message: "Fetching repo from https://github.com/${{ parameters.org }}/${{ parameters.repository }}"
    - id: fetch-repo
      name: Fetch repo
      action: fetch:plain
      input:
        url: "https://github.com/${{ parameters.org }}/${{ parameters.repository }}"
    - id: merge
      name: Merge json
      action: roadiehq:utils:json:merge
      input:
        path: ${{ parameters.path }}
        content: ${{ parameters.content }}
    - id: publish-pr
      name: Publish PR
      action: publish:github:pull-request
      input:
        repoUrl: github.com?repo=${{ parameters.repository }}&owner=${{ parameters.org }}
        branchName: ${{ parameters.pr_branch }}
        title: Merge json into ${{ parameters.path }}
        description: This PR was created by a Roadie Backstage scaffolder task
    - id: log-message
      name: Log PR URL
      action: debug:log
      input:
        message: 'PR url: ${{ steps["publish-pr"].output.remoteUrl }}'

Overwrite a file

Actions used:

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

Example Template

---
apiVersion: scaffolder.backstage.io/v1beta3
kind: Template
metadata:
  name: overwrite-file-template-example
  title: Overwrite file template
  description: Overwrite a file with the given content.
spec:
  owner: roadie
  type: service

  parameters:
    - title: PR Data
      properties:
        repository:
          title: Repository name
          type: string
          description: The name of the repository
        org:
          title: Repository Organisation
          type: string
          description: The Github org that the repository is in
        pr_branch:
          title: PR Branch
          type: string
          description: The new branch to make a pr from
    - title: Overwrite content
      properties:
        path:
          title: Path
          type: string
          description: The path to the file you want to overwrite this content to in the scaffolder workspace
        content:
          title: Text area input
          type: string
          description: New file content
          ui:widget: textarea
          ui:options:
            rows: 20
          ui:help: 'Make sure it is valid by checking the schema at `/tools/entity-preview`'
          ui:placeholder: |
            ---
            apiVersion: backstage.io/v1alpha1
              kind: Component
              metadata:
                name: backstage
              spec:
                type: library
                owner: CNCF
                lifecycle: experimental

  steps:
    - id: fetch-repo
      name: Fetch repo
      action: fetch:plain
      input:
        url: https://github.com/${{ parameters.org }}/${{ parameters.repository }}
    - id: append-file
      name: Overwrite file content
      action: roadiehq:utils:fs:write
      input:
        path: ${{ parameters.path }}
        content: ${{ parameters.content }}
    - id: publish-pr
      name: Publish PR
      action: publish:github:pull-request
      input:
        repoUrl: github.com?repo=${{ parameters.repository }}&owner=${{ parameters.org }}
        branchName:  ${{ parameters.pr_branch }}
        title: Overwrite content for ${{ parameters.path }}
        description: This PR was created by a Roadie Backstage scaffolder task
    - id: log-message
      name: Log PR URL
      action: debug:log
      input:
        message: 'PR url: ${{ steps["publish-pr"].output.remoteUrl }}'