github_actions_docker_build_push_to_ghcr_workflow.yaml

1name: Create and publish a Docker image
2
3# Configures this workflow to run every time a change is pushed to the branch called `release`.
4on:
5  push:
6    branches: ['release']
7
8# Defines two custom environment variables for the workflow. These are used for the Container registry domain, and a name for the Docker image that this workflow builds.
9env:
10  REGISTRY: ghcr.io
11  IMAGE_NAME: ${{ github.repository }}
12
13# There is a single job in this workflow. It's configured to run on the latest available version of Ubuntu.
14jobs:
15  build-and-push-image:
16    runs-on: ubuntu-latest
17    # Sets the permissions granted to the `GITHUB_TOKEN` for the actions in this job.
18    permissions:
19      contents: read
20      packages: write
21      # 
22    steps:
23      - name: Checkout repository
24        uses: actions/checkout@v4
25
26      # Uses the `docker/login-action` action to log in to the Container registry using the account and password that will publish the packages. Once published, the packages are owned by the account defined here.
27      - name: Log in to the Container registry
28        uses: docker/login-action@65b78e6e13532edd9afa3aa52ac7964289d1a9c1
29        with:
30          registry: ${{ env.REGISTRY }}
31          username: ${{ github.actor }}
32          password: ${{ secrets.GITHUB_TOKEN }}
33
34      # This step uses [docker/metadata-action](https://github.com/docker/metadata-action#about) to extract tags and labels that will be applied to the specified image. The `id` "meta" allows the output of this step to be referenced in a subsequent step. The `images` value provides the base name for the tags and labels.
35      - name: Extract metadata (tags, labels) for Docker
36        id: meta
37        uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
38        with:
39          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
40
41      # This step uses the `docker/build-push-action` action to build the image, based on your repository's `Dockerfile`. If the build succeeds, it pushes the image to GitHub Packages.
42      # It uses the `context` parameter to define the build's context as the set of files located in the specified path. For more information, see "[Usage](https://github.com/docker/build-push-action#usage)" in the README of the `docker/build-push-action` repository.
43      # It uses the `tags` and `labels` parameters to tag and label the image with the output from the "meta" step.
44      - name: Build and push Docker image
45        uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
46        with:
47          context: .
48          push: true
49          tags: ${{ steps.meta.outputs.tags }}
50          labels: ${{ steps.meta.outputs.labels }}