GitHub Actions to build/push a Docker image

https://docs.github.com/en/packages/managing-github-packages-using-github-actions-workflows/publishing-and-installing-a-package-with-github-actions

TL;DR

1. mkdir -p .github/workflows.
2. vim .github/workflows/deploy-image.yml:

   name: Create and publish a Docker image
   
   on:
     push:
       branches: ['main']
   
   env:
     REGISTRY: ghcr.io
     IMAGE_NAME: ${{ github.repository }}
   
   jobs:
     build-and-push-image:
       runs-on: ubuntu-latest
       permissions:
         contents: read
         packages: write
   
       steps:
         - name: Checkout repository
           uses: actions/checkout@v2
   
         - name: Log in to the Container registry
           uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
           with:
             registry: ${{ env.REGISTRY }}
             username: ${{ github.actor }}
             password: ${{ secrets.GITHUB_TOKEN }}
   
         - name: Extract metadata (tags, labels) for Docker
           id: meta
           uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
           with:
             images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
   
         - name: Build and push Docker image
           uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
           with:
             context: .
             push: true
             tags: ${{ steps.meta.outputs.tags }}
             labels: ${{ steps.meta.outputs.labels }}
   

3. Push to the main branch.

Note

• GitHub Actions automatically loads your GitHub token.
  • https://docs.github.com/en/actions/security-guides/automatic-token-authentication
• Deploy location: ghcr.io/atlex00/repo-name:branch-name
• Furthur usage and meaning of each lines: https://docs.github.com/en/actions/learn-github-actions/understanding-github-actions

Run on your own container

From:

runs-on: ubuntu-latest

To:

runs-on: ubuntu-latest
container:
  image: myid/myimage:tag

Service containers

I wanted to test my app in Docker container with a DB instance, so I added service container in the job.

https://docs.github.com/en/actions/using-containerized-services/about-service-containers

runs-on: ubuntu-latest
container:
  image: rust:latest
services:
  mysql:
    image: mysql
    ports:
      - 5432:5432

Inside the main container rust:latest, the domain name of the service container is mysql, the name of service.