1#
 2name: Create and publish a Docker image
 3
 4# Configures this workflow to run every time a change is pushed to the branch called `main`.
 5on:
 6  push:
 7    branches: ['main']
 8
 9# 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.
10env:
11  REGISTRY: ghcr.io
12  IMAGE_NAME: ${{ github.repository }}
13
14# There is a single job in this workflow. It's configured to run on the latest available version of Ubuntu.
15jobs:
16  build-and-push-image:
17    runs-on: ubuntu-latest
18    # Sets the permissions granted to the `GITHUB_TOKEN` for the actions in this job.
19    permissions:
20      contents: read
21      packages: write
22      # 
23    steps:
24      - name: Checkout repository
25        uses: actions/checkout@v3
26      # Uses the `docker/login-action` action to log in to the Container registry registry using the account and password that will publish the packages. Once published, the packages are scoped to 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      # 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.
34      - name: Extract metadata (tags, labels) for Docker
35        id: meta
36        uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
37        with:
38          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
39      # 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.
40      # 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.
41      # It uses the `tags` and `labels` parameters to tag and label the image with the output from the "meta" step.
42      - name: Build and push Docker image
43        uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
44        with:
45          context: .
46          push: true
47          tags: ${{ steps.meta.outputs.tags }}
48          labels: ${{ steps.meta.outputs.labels }}