docker-image.yml

name: Docker Image CI

on:
    push:
        branches:
            - 'main'
    pull_request:
        branches:
            - 'main'

env:
    TEST_CONTAINER_TAG: "ghcr.io/${{github.repository}}:${{github.sha}}"
    RELEASE_CONTAINER_TAG: "ghcr.io/${{github.repository}}:latest"


jobs:
    build_test:
        name: Build Test Container
        runs-on: ubuntu-latest
        steps:
            - name: Login to Registry
              run: >-
                echo "${{ secrets.GITHUB_TOKEN }}"
                | docker login ghcr.io -u $ --password-stdin
            - name: Checkout
              uses: actions/checkout@v4
            - name: Build Test Container
              # in bash, `${ENVIRONMENT_VARIABLE,,}` lowercases whatever is stored in `ENVIRONMENT_VARIABLE`
              run: >-
                docker build
                --pull
                --build-arg CORES="$(nproc)"
                --tag "${TEST_CONTAINER_TAG,,}"
                ${{github.workspace}}
            - name: Push Test Container
              run: >-
                docker push "${TEST_CONTAINER_TAG,,}"
            - name: Push Latest Tag
              if: ${{github.ref_name == 'main'}}
              run: |
                docker pull "${TEST_CONTAINER_TAG,,}"
                docker tag "${TEST_CONTAINER_TAG,,}" "${RELEASE_CONTAINER_TAG,,}"
                docker push "${RELEASE_CONTAINER_TAG,,}"