build.yaml

name: "Build"

on:
  workflow_dispatch:
  push:
    branches:
      - main
    tags:
      - "v[0-9]+.[0-9]+.[0-9]+*"
      # Push events to any matching semantic version tag.
      # For example, 1.10.1 or 2.0.0 or 3.0.0-alpha.

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build-and-push:
    runs-on: ubuntu-latest

    permissions:
      contents: read
      packages: write

    steps:
      - uses: actions/checkout@v4

      - name: Install Nix
        uses: cachix/install-nix-action@v17
        with:
          extra_nix_config: |
            experimental-features = nix-command flakes

      - name: Build Docker image
        run: nix build .#dockerImage

      - name: Load Docker image
        run: docker load -i $(readlink -f result)

      - name: Create Dockerfile
        # This is a trick to get around that there
        # is no way to add labels to an existing image
        # https://stackoverflow.com/a/54598281
        run: |
          echo "FROM principal:latest" > Dockerfile

      - name: Log in to the Container registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata (tags, labels) for Docker
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=sha
            type=ref,event=branch
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=raw,value=latest,enable={{is_default_branch}}

      - name: Build and push Docker image
        uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}