A ready-to-use Github action workflow for pushing container images to the registry

In the blog I will present you a ready-to-use Github action workflow
to push container images to the image registry. In modern software development, we depend on
container images a lot. As Github now has its own
container image registry – ghcr.io too,
it becomes easy to build and push images directly to a registry within a single workflow.

Github Action Workflow

Below you see the ready-to-use Github action workflow to push your container
image to the Github container registry ghcr.io:

name: Build and publish the container image

"on":
  push:
    tags:
      - '*'
    branches:
      - 'main'

jobs:
  build-and-push-image:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      -
        name: Checkout repository
        uses: actions/checkout@v2
        with:
          fetch-depth: 0

      -
        name: Get tag
        id: repository
        run: echo  "::set-output name=tag::$(git describe --tags HEAD)"

      -
        name: Set up QEMU
        uses: docker/setup-qemu-action@v1

      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1

      -
        name: Log in to the Container registry
        uses: docker/login-action@v2
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          platforms: linux/amd64,linux/arm64
          push: true
          tags: ghcr.io/${{ github.repository }}:${{ steps.repository.outputs.tag }}

As you can see, it will work on any repository. If you have a git repository for a
container image, just add this workflow.

  • it pushes into the container registry corresponding with the repository
  • it uses git describe --tags HEAD to generate a semver tag for the image
  • it builds a multi-architecture image for amd64 and arm64
  • it runs on every push to the main branch, or tag of a commit

Pretty neat, huh?

install the workflow

To install the workflow, type the following commands:

# add the workflow
$ mkdir -p .github/workflows/
$ curl -sS -L -o .github/workflows/push-to-registry.yaml \
     https://raw.githubusercontent.com/binxio/push-to-registry-gh-action-workflow/main/.github/workflows/push-to-registry.yaml
$ git add .
$ git commit -m 'added push to ghcr.io workflow'

To make a beautiful semantic version release of your image, type:

$ read NEW_SEMVER
$ git tag $NEW_SEMVER
$ git push --tags
$ git push

Checkout the resulting Github action workflow!

Conclusion

With the availability of the Github container image registry,
this simple ready-to-use workflow make Github a one-stop-shop to build and distribute your
container images!

Photo by Jakob Owens on Unsplash

Mark van Holsteijn is a senior software systems architect, and CTO of binx.io. He is passionate about removing waste in the software delivery process and keeping things clear and simple.
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