Debug your nunjucks template
Published on October 28th, 2022Template
Actions used
-
fetch:template
-
fs:read
-
debug:log
-
fs:read
You can check the available actions if you visit /create/actions
.
Walkthrough
You can use this template by registering it from RoadieHQ/software-templates 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/RoadieHQ/software-templates/tree/main/scaffolder-templates/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: ${{ steps['read-file'].output.content }}
Breakdown
Parameters
This section configures the frontend for your template. Essentially these values will be provided from the backstage ui to the template.
-
param
This renders 3 separate input fields for the template. These inputs can be referenced by the
steps
via their key name inside the properties object.
- title: Document front content
properties:
rfcNumber:
title: rfcNumber
type: string
rfcTitle:
title: RFC Title
type: string
abstract:
title: Document Abstract (optional draft version)
type: string
ui:widget: textarea
Steps
fetch-template
Uses the fetch:template. It fetches the template skeleton from the hardcoded URL and puts everything into the docs/rfcs/<rfcnumber>
folder.
The provided values object will be used to replace the values inside the skeleton template by nunjucks.
- id: fetch-template
action: fetch:template
input:
url: https://github.com/RoadieHQ/software-templates/tree/main/scaffolder-templates/debug-template/skeleton
templateFileExtension: true
targetPath: docs/rfcs/${{ 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 }}