Awesome

Render Template

GitHub Action to render file based on template and passed variables.

[!NOTE]
This is a Docker-based action and may not work on Windows and MacOS runners.

Inputs

Name	Description	Required
template	Path to template	true
vars	Variables to use in template (in YAML format)	false
vars_path	Path to YAML file with variables	false
result_path	Desired path to result file	false
timezone	Timezone to use in `date` template function	false

You must set at least vars or vars_path.
You may set both of them (vars values will precede over vars_path).

Variables names must be alphanumeric strings (must not contain any hyphens).

There are few template functions available:

date – formats timestamp using Go's time layout.
Example: {{ "2023-05-11T01:42:04Z" | date "2006-01-02" }} will be rendered as 2023-05-11.
You may use timezone input to set timezone for date function (e.g. timezone: "America/New_York").
mdlink – creates markdown link.
Example: {{ "https://github.com" | mdlink "GitHub" }} will be rendered as [GitHub](https://github.com).
number – formats number in English locale.
Example: {{ 1234567890 | number }} will be rendered as 1,234,567,890.
base64 – encodes string to base64.
Example: {{ "hello" | base64 }} will be rendered as aGVsbG8=.
split – splits string by delimiter.
toJSON – converts string to JSON.
Example: {{ "1,2,3" | split "," | toJSON }} will be rendered as ["1","2","3"].

Outputs

Name	Description
result	Rendered file content

Example

kube.template.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .deployment }}
  labels:
    app: {{ .app }}
spec:
  replicas: 3
  selector:
    matchLabels:
      app: {{ .app }}
  template:
    metadata:
      labels:
        app: {{ .app }}
    spec:
      containers:
      - name: {{ .app }}
        image: {{ .image }}
        ports:
        - containerPort: 80

.github/workflows/main.yml

name: main
on:
  push:
    branches:
      - main
env:
  DOCKER_IMAGE: username/image
  DEPLOYMENT_NAME: nginx-deployment
jobs:
  main:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v3

      <...>

      - name: Render template
        id: render_template
        uses: chuhlomin/render-template@v1
        with:
          template: kube.template.yml
          vars: |
            image: ${{ env.DOCKER_IMAGE }}:${{ github.sha }}
            deployment: ${{ env.DEPLOYMENT_NAME }}
            app: nginx

      - name: Deploy
        timeout-minutes: 4
        run: |-
          echo '${{ steps.render_template.outputs.result }}' | kubectl apply -f -
          kubectl rollout status deployment/$DEPLOYMENT_NAME