ci.yml

name: Test and publish image

on:
  schedule:
    # Rust tends to make stable releases every six weeks on Thursday 10am
    # Pacific Time. Force a build a few hours later than that (every week) to
    # scoop up the newest stable and beta (including patch releases).
    #
    # This way, even if we don't update the matrix below we should still have
    # images.
    - cron: '0 21 * * THU'
  push:
    branches:
      - main
  pull_request:
    branches:
      - main

# See https://docs.github.com/en/actions/guides/publishing-docker-images for the
# theory, but we do some things differently.

jobs:
  test_image:
    name: Test static linking (using stable Rust)
    runs-on: ubuntu-latest

    steps:
      - name: Check out the repo
        uses: actions/checkout@v2

      # Run some fairly extensive tests to make sure that we actually produce
      # static, working programs.
      - name: Test image
        run: ./test-image

  build_and_push:
    name: Build image & push
    runs-on: ubuntu-latest

    needs:
      - test_image

    strategy:
      matrix:
        # We build multiple versions of the image from the same Dockerfile each
        # time we push. This is different that the standard strategy for
        # maintaining images using GitHub actions, which involves a lot of tags
        # and branches. But since there are new Rust releases far more often
        # than we change this project, it works.
        toolchain:
          - "stable"
          - "beta"
          - "1.57.0"

          # See https://rust-lang.github.io/rustup-components-history/ and choose
          # the newest nightly build that has all the components (except RLS,
          # which is obsolete).
          - "nightly-2021-12-23"

    steps:
      - name: Check out the repo
        uses: actions/checkout@v2

      - name: Login to GitHub Container Registry
        if: ${{ github.event_name != 'pull_request' }}
        uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Log in to Docker Hub
        if: ${{ github.event_name != 'pull_request' }}
        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}

      - name: Build release image
        uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
        with:
          context: .
          push: ${{ github.event_name != 'pull_request' }}
          build-args: |
            TOOLCHAIN=${{ matrix.toolchain }}
          # Use some slightly funky substituations to tag only `stable` as `latest`.
          tags: |
            ghcr.io/emk/rust-musl-builder:${{ matrix.toolchain }}
            ekidd/rust-musl-builder:${{ matrix.toolchain }}
            ${{ matrix.toolchain == 'stable' && 'ghcr.io/emk/rust-musl-builder:latest' || '' }}
            ${{ matrix.toolchain == 'stable' && 'ekidd/rust-musl-builder:latest' || '' }}
          labels: |
            org.opencontainers.image.title=rust-musl-builder
            org.opencontainers.image.description=Tools for statically linked Rust programs using musl-libc
            org.opencontainers.image.url=https://github.com/emk/rust-musl-builder
            org.opencontainers.image.source=https://github.com/emk/rust-musl-builder
            net.randomhacks.rust-musl-builder.toolchain=${{ matrix.toolchain }}