CI.yml

name: CI

on:
  # Following https://github.com/orgs/community/discussions/26276
  # to get builds on PRs and pushes to master but not double
  # builds on PRs.
  push:
    branches:
      - main
  pull_request:
  workflow_dispatch:

env:
  NIX_CONFIG: accept-flake-config = true

jobs:
  check:
    runs-on: nixos

    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 0 # the check script below needs the whole history

      - name: Run checks
        run: nix develop -c ./scripts/check.sh

  build-repo:
    runs-on: nixos

    steps:
      - name: Checkout main 
        uses: actions/checkout@v3
        with:
          ref: main

      - uses: actions/cache@v3
        with:
          path: _cache
          key: 1 # bump to refresh

      - name: Unpack keys
        env:
          KEYS: ${{ secrets.KEYS }}
        run: |
          if [[ -z "$KEYS" ]]; then
            echo "Could not access repository secret keys (PR is coming from a fork?)"
            echo "Generating fresh keys for this run"
            nix develop -c foliage create-keys
          else 
            mkdir _keys
            echo "$KEYS" | base64 -d | tar xvz -C _keys
          fi

      - name: Build repository (main)
        run: |
          nix develop -c foliage build -j 0  --write-metadata
          mv _repo _repo-main
          cp _repo-main/foliage/packages.json packages-old.json

      - name: Checkout tip commit
        uses: actions/checkout@v3
        with:
          clean: false

      - name: Build repository (tip)
        run: |
          nix develop -c foliage build -j 0 --write-metadata
          cp _repo/foliage/packages.json packages-new.json

      - name: Copy static web assets
        run: |
          cp static/index.html _repo
          cp README.md _repo

      # See https://github.com/actions/upload-artifact/issues/36
      - name: Pack repository in a tar archive
        run: tar cf _repo.tar -C _repo .

      # Do this before the check, useful to have the artifact in case the 
      # check fails!
      - name: Upload built repository
        uses: actions/upload-artifact@v3
        with:
          name: built-repo
          path: _repo.tar

      - name: Upload package metadata
        uses: actions/upload-artifact@v3
        with:
          name: package-metadata
          path: |
            packages-old.json
            packages-new.json

      # Note: we use the check script from the tip so we pick up changes 
      # to the script from the PR itself.
      - name: Check new index is an extension of the old index
        run: |
          echo "If this check failed because 'some entries only exist in the old index'"
          echo "then you may need to update your branch.\n"
          echo "If it failed because 'the last old entry is newer than the first new entry'"
          echo "then you may need to update the timestamps in your new packages to be newer than those in main."
          ./scripts/check-archive-extension.sh _repo-main/01-index.tar _repo/01-index.tar

  build-packages:
    runs-on: nixos
    needs:
      - build-repo

    steps:
      - uses: actions/checkout@v3

      - name: Download built repository
        uses: actions/download-artifact@v3
        with:
          name: built-repo

      - name: Unpack built repository
        run: |
          mkdir _repo
          tar xf _repo.tar -C _repo

      - name: Build smoke test packages
        # The > is the "YAML folded string" marker, which replaces 
        # newlines with spaces, since the usual bash idiom of \ 
        # doesn't work for some reason
        run: >
          nix build .#allSmokeTestPackages
          -L 
          --override-input CHaP path:_repo
          --show-trace

  build-new-packages:
    runs-on: nixos

    needs:
      - build-repo

    steps:
      - uses: actions/checkout@v3

      - name: Download built repository
        uses: actions/download-artifact@v3
        with:
          name: built-repo

      - name: Unpack built repository
        run: |
          mkdir _repo
          tar xf _repo.tar -C _repo

      - name: Download package metadata
        uses: actions/download-artifact@v3
        with:
          name: package-metadata
          path: .

      # This is a bit of a hack: to build the newly added packages, we:
      # 1. compute the packages.json that just contains the new pacakge-versions
      # 2. overwrite the built repository's packages.json with the computed one
      # 3. build "all the packages" which now means "the new packages"
      #
      # This avoids us having to do other complicated tricks to make the flake
      # take the set of packages to build as an argument.
      - name: Adjust repository metadata
        run: |
          scripts/compare-package-metadata.sh packages-old.json packages-new.json > packages-diff.json
          echo "Newly added packages:"
          cat packages-diff.json
          mv -f packages-diff.json _repo/foliage/packages.json

      - name: Build all newly added packages
        run: >
          nix build .#allPackages
          -L
          --override-input CHaP path:_repo
          --show-trace

  deploy-check:
    runs-on: nixos

    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    needs: 
      - build-repo

    steps:
      - uses: actions/checkout@v3
        with:
          path: src

      - uses: actions/checkout@v3
        with:
          path: repo
          ref: repo

      - name: Download built repository
        uses: actions/download-artifact@v3
        with:
          name: built-repo

      - name: Unpack built repository
        run: |
          mkdir built-repo
          tar xf _repo.tar -C built-repo

      # This is meaningfully different to the check in 'build': that checks the repository
      # built from main and from the PR tip, but that's not _actually_ the repository
      # deployed in the repo branch. It should be the same, but it can't hurt to check
      # against the thing that's actually deployed before we deploy.
      - name: Check new index is an extension of the old index
        run: |
          ./src/scripts/check-archive-extension.sh repo/01-index.tar built-repo/01-index.tar

  deploy:
    # This job is fine to run on GitHub provided (free) runners.
    runs-on: ubuntu-latest
    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    needs: 
      - check
      - build-repo
      - deploy-check

    concurrency:
      group: "pages"
      cancel-in-progress: true

    # Grant GITHUB_TOKEN the permissions required to make a Pages deployment
    permissions:
      contents: write
      id-token: write
      pages: write

    # Deploy to the github-pages environment
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}

    steps:
      - uses: actions/checkout@v3

      - name: Download built repository
        uses: actions/download-artifact@v3
        with:
          name: built-repo

      - name: Unpack built repository
        run: |
          mkdir _repo
          tar xf _repo.tar -C _repo

      - name: Commit as branch
        run: |
          set -xe

          # see https://github.com/orgs/community/discussions/26560 and https://github.com/actions/checkout/issues/13
          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"

          # Need --force because _repo is gitignore'd
          git add --force _repo
          treeId=$(git write-tree --prefix=_repo)

          # the checkout action doesn't checkout all branches so we fetch
          # the repo branch, if the remote doesn't have it, it's ok we do
          # without
          if git fetch --quiet origin repo; then
            # add commit to branch
            commitId=$(git commit-tree -p origin/repo -m "Update from ${{ github.sha }}" "$treeId")
          else
            # add commit with no parents
            commitId=$(git commit-tree -m "Update from ${{ github.sha }}" "$treeId")
          fi
          git update-ref "refs/heads/repo" "$commitId"
          git push origin repo

      - name: Setup Pages
        uses: actions/configure-pages@v1

      - name: Upload pages artifact
        uses: actions/upload-pages-artifact@v1
        with:
          path: _repo

      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v2