GitHub Action: envsubst

This GitHub Action substitutes the values of environment variables using envsubst. This Action is provided as a Docker action, so it works only on Linux machines. For more information on types of actions, see the actions documentation

Usage

Prerequisites

Create a workflow .yml file in your .github/workflows directory. An example workflow is available below. For more information, reference the GitHub Help Documentation for Creating a workflow file.

Inputs

• input: Path to the input file
• output: Path to the output file

Example

name: Deploy app to Kubernetes

on:
  push:
    branch:
      - master

jobs:
  deploy:
    name: Deploy app to Kubernetes
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1

      - name: Build and Push Docker image
        run: ./scripts/image
        env:
          IMAGE_TAG: gcr.io/myprj/app:${{ github.sha }}

      - name: Render Deployment YAML
        uses: nowactions/envsubst@v1
        with:
          input: ./deployment.yaml.tmpl
          output: ./deployment.yaml
        env:
          IMAGE_TAG: gcr.io/myprj/app:${{ github.sha }}
          REPLICAS: 3

      - name: Deploy
        run: kubectl apply -f ./deployment.yaml

Development

Release

• Bump up the version in Dockerfile
• Commit the changes
• Run make release