build-and-push-image.yml

name: Build and push container image to GHCR

# Run this workflow whenever a Release is published.
on:
    release:
        types: [published]

jobs:
    build-and-push-image:
        runs-on: ubuntu-latest
        steps:
            - name: Checkout branch
              uses: actions/checkout@v4
            - name: Sychronize `VERSION` file with Git tag
              # Get the Git tag name (e.g. "v1.2.3") associated with the GitHub Release,
              # strip away the leading "v", and write the remainder to the `VERSION` file.
              #
              # Note: If the Git tag name doesn't start with a "v" followed by a number,
              #       we just write the entire Git tag name to the `VERSION` file.
              #
              # Note: In bash, `[[ condition ]] && command1 || command2` is a form of if/then/else.
              #       Also, in bash, `${BASH_REMATCH[1]}` contains the first regex capture group.
              #
              run: |
                TAG_NAME='${{ github.ref_name }}'
                [[ "${TAG_NAME}" =~ ^v([0-9].*) ]] && VERSION="${BASH_REMATCH[1]}" || VERSION="${TAG_NAME}"
                echo "${VERSION}" > ./VERSION
            - name: Authenticate with container registry
              uses: docker/login-action@v3
              with:
                  registry: ghcr.io
                  username: ${{ github.actor }}
                  password: ${{ secrets.GITHUB_TOKEN }}
              # Use the `docker/metadata-action` action to extract values that can
              # be incorporated into the tags and labels of the resulting container
              # image. The step's `id` ("meta") can be used in subsequent steps to
              # reference the output of this step.
              # For more info: https://github.com/docker/metadata-action
            - name: Prepare metadata of container image
              id: meta
              uses: docker/metadata-action@v5
              with:
                  images: ghcr.io/microbiomedata/nmdc-aggregator
                  flavor: latest=false
                  tags: type=semver,pattern={{version}}
              # Use the `docker/build-push-action` action to build the image described
              # by the `Dockerfile`. If the build succeeds, push the image to GHCR.
              # It uses the `tags` and `labels` parameters to tag and label the image
              # with the output from the "meta" step above.              
              # For more info: https://github.com/docker/build-push-action#usage.
            - name: Build and push container image
              id: push
              uses: docker/build-push-action@v5
              with:
                  context: .
                  push: true
                  tags: ${{ steps.meta.outputs.tags }}
                  labels: ${{ steps.meta.outputs.labels }}

# References:
# - https://docs.github.com/en/actions/publishing-packages/publishing-docker-images#publishing-images-to-github-packages
# - https://github.com/microbiomedata/nmdc-server/blob/main/.github/workflows/deploy.yml