ci.yaml

name: Nix CI
on:
  push:
    # don't run on tags, run on commits
    # https://github.com/orgs/community/discussions/25615
    tags-ignore:
      - "**"
    branches:
      - "**"
  schedule:
    - cron: 0 0 * * *
  pull_request:
  workflow_dispatch:

env:
  # https://stackoverflow.com/a/71158878
  git_pull: git pull --rebase origin ${{ github.head_ref || github.ref_name }}
  pin_nixpkgs: nix registry pin nixpkgs github:NixOS/nixpkgs/807c549feabce7eddbf259dbdcec9e0600a0660d

jobs:
  # Build the action
  # Commit and push the built code
  build:
    name: Build the action
    runs-on: ubuntu-20.04
    permissions:
      contents: write
      actions: write
    steps:
      - uses: actions/checkout@v4
        with:
          submodules: true

      - uses: nixbuild/nix-quick-install-action@v27

      - name: Restore and save Nix store
        uses: ./.
        with:
          primary-key: build-${{ runner.os }}-${{ hashFiles('**/package-lock.json', 'package.json', 'flake.nix', 'flake.lock') }}
          paths: |
            ~/.npm
          # do purge caches
          purge: true
          # purge all versions of the cache
          purge-prefixes: build-${{ runner.os }}-
          # created more than 0 seconds ago relative to the start of the `Post Restore` phase
          purge-created: 0
          # except the version with the `primary-key`, if it exists
          purge-primary-key: never

      # # Uncomment to debug this job
      # - name: Setup tmate session
      #   uses: mxschmitt/action-tmate@v3

      - name: Configure git
        env:
          # required for gh
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          ${{ github.head_ref && format('gh pr checkout {0}', github.event.pull_request.number) || ''}}

          git config --global user.name "github-actions[bot]"
          git config --global user.email "github-actions[bot]@users.noreply.github.com"

      - name: Rebase
        run: ${{ env.git_pull }}

      - name: Install packages & Build the action
        run: nix run .#install

      - name: Update docs
        run: nix run .#write

      - name: Commit & push changes
        run: |
          git add dist
          git commit -m "chore: build the action" || echo "Nothing to commit"
          git add .
          git commit -m "chore: update docs" || echo "Nothing to commit"
          git push

  # Make `individual` caches
  # Restore `individual` or `common` caches
  # Usually, there should be no `individual` caches to restore as they're purged by `merge-similar-caches`
  make-similar-caches:
    name: Make similar caches
    needs: build
    permissions:
      actions: write
    strategy:
      matrix:
        os:
          - macos-11
          - macos-12
          - ubuntu-20.04
          - ubuntu-22.04
        id:
          - 1
          - 2
    runs-on: ${{ matrix.os }}
    steps:
      - name: Checkout this repo
        uses: actions/checkout@v4

      - name: Rebase
        run: ${{ env.git_pull }}

      - uses: nixbuild/nix-quick-install-action@v27

      - name: Restore and save Nix store - ${{ matrix.id }}
        uses: ./.
        with:
          # save a new cache every time `ci.yaml` changes
          primary-key: similar-cache-${{ matrix.os }}-individual-${{ matrix.id }}-${{ hashFiles('.github/workflows/ci.yaml') }}
          # otherwise, restore a common cache if and only if it matches the current `ci.yaml`
          restore-prefixes-first-match: similar-cache-${{ matrix.os }}-common-${{ hashFiles('.github/workflows/ci.yaml') }}
          # do purge caches
          purge: true
          # purge all versions of the cache
          purge-prefixes: similar-cache-${{ matrix.os }}-individual-${{ matrix.id }}-
          # created more than 0 seconds ago relative to the start of the `Post Restore` phase
          purge-created: 0
          # except the version with the `primary-key`, if it exists
          purge-primary-key: never

      - name: Pin nixpkgs
        run: ${{ env.pin_nixpkgs }}

      - name: Install nixpkgs#poetry
        if: ${{ matrix.id == 1 }}
        run: nix profile install nixpkgs#poetry

      - name: Install nixpkgs#nodejs
        if: ${{ matrix.id == 2 }}
        run: nix profile install nixpkgs#nodejs

  # Merge similar `individual` caches
  # Purge `individual` caches and old `common` caches
  # Save new `common` caches
  merge-similar-caches:
    name: Merge similar caches
    needs: make-similar-caches
    permissions:
      actions: write
    strategy:
      matrix:
        os:
          - macos-11
          - macos-12
          - ubuntu-20.04
          - ubuntu-22.04
    runs-on: ${{ matrix.os }}
    steps:
      - name: Checkout this repo
        uses: actions/checkout@v4

      - name: Rebase
        run: ${{ env.git_pull }}

      - uses: nixbuild/nix-quick-install-action@v27

      - name: Restore and save Nix store
        uses: ./.
        with:
          primary-key: similar-cache-${{ matrix.os }}-common-${{ hashFiles('.github/workflows/ci.yaml') }}
          # if no hit, restore current versions of individual caches
          restore-prefixes-all-matches: |
            similar-cache-${{ matrix.os }}-individual-1-${{ hashFiles('.github/workflows/ci.yaml') }}
            similar-cache-${{ matrix.os }}-individual-2-${{ hashFiles('.github/workflows/ci.yaml') }}
          # do purge caches
          purge: true
          # purge old versions of the `common` cache and any versions of individual caches
          purge-prefixes: |
            similar-cache-${{ matrix.os }}-common-
            similar-cache-${{ matrix.os }}-individual-
          # created more than 0 seconds ago relative to the start of the `Post Restore` phase
          purge-created: 0
          # except the version with the `primary-key`, if it exists
          purge-primary-key: never

      - name: Pin nixpkgs
        run: ${{ env.pin_nixpkgs }}

      # Stuff in a profile can survive garbage collection.
      # Therefore, profiles are ignored when restoring a cache.
      # So, the current profile should be the default profile created by nix-quick-install-action.
      # The default profile should contain only nix.
      - name: List profile
        run: nix profile list

      - name: Check that the profile doesn't have anything apart from `nix`
        shell: bash
        run: |
          nix profile list --json \
            | jq '
              .elements 
                | keys 
                | map(select(. != "nix")) 
                | if . != [] then error(.) end
              '

      - name: Install nixpkgs#poetry
        run: nix profile install nixpkgs#poetry

      - name: Install nixpkgs#nodejs
        run: nix profile install nixpkgs#nodejs

      - name: Run poetry
        run: poetry --version

      - name: Run node
        run: node --version

  # Check that the `common` cache is restored correctly
  merge-similar-caches-check:
    name: Merge similar caches
    needs: merge-similar-caches
    permissions:
      actions: write
    strategy:
      matrix:
        os:
          - macos-11
          - macos-12
          - ubuntu-20.04
          - ubuntu-22.04
    runs-on: ${{ matrix.os }}
    steps:
      - name: Checkout this repo
        uses: actions/checkout@v4

      - name: Rebase
        run: ${{ env.git_pull }}

      - uses: nixbuild/nix-quick-install-action@v27

      - name: Restore Nix store
        uses: ./restore
        with:
          primary-key: similar-cache-${{ matrix.os }}-common-${{ hashFiles('.github/workflows/ci.yaml') }}

      - name: Pin nixpkgs
        run: ${{ env.pin_nixpkgs }}

      # Stuff in a profile can survive garbage collection.
      # Therefore, profiles are ignored when restoring a cache.
      # So, the current profile should be the default profile created by nix-quick-install-action.
      # The default profile should contain only nix.
      - name: List profile
        run: nix profile list

      - name: Check that the profile doesn't have anything apart from `nix`
        shell: bash
        run: |
          nix profile list --json \
            | jq '
              .elements 
                | keys 
                | map(select(. != "nix")) 
                | if . != [] then error(.) end
              '

      - name: Install nixpkgs#poetry
        run: nix profile install nixpkgs#poetry

      - name: Install nixpkgs#nodejs
        run: nix profile install nixpkgs#nodejs

      - name: Run poetry
        run: poetry --version

      - name: Run node
        run: node --version

  #
  compare-run-times:
    name: Job with caching
    needs: merge-similar-caches
    permissions:
      actions: write
    strategy:
      matrix:
        do-cache:
          - true
          - false
        os:
          - macos-11
          - macos-12
          - ubuntu-20.04
          - ubuntu-22.04
    runs-on: ${{ matrix.os }}
    steps:
      - name: Checkout this repo
        uses: actions/checkout@v4

      - name: Rebase
        run: ${{ env.git_pull }}

      - uses: nixbuild/nix-quick-install-action@v27

      - name: Restore and save Nix store
        if: ${{ matrix.do-cache }}
        uses: ./.
        with:
          # save a new cache every time ci file changes
          primary-key: cache-${{ matrix.os }}-${{ hashFiles('.github/workflows/ci.yaml') }}
          restore-prefixes-first-match: cache-${{ matrix.os }}-
          # do purge caches
          purge: true
          # purge all versions of the cache
          purge-prefixes: cache-${{ matrix.os }}-
          # created more than 0 seconds ago relative to the start of the `Post Restore` phase
          purge-created: 0
          # except the version with the `primary-key`, if it exists
          purge-primary-key: never
          # and collect garbage in the Nix store until it reaches this size in bytes
          gc-max-store-size: 8000000000

      # Uncomment to debug this job
      # - name: Setup tmate session
      #   uses: mxschmitt/action-tmate@v3

      - name: Show profile
        run: nix profile list

      - name: Pin nixpkgs
        run: ${{ env.pin_nixpkgs }}

      - name: List registry
        run: nix registry list

      - name: Install nixpkgs
        run: nix profile install $(nix flake archive nixpkgs --json | jq -r '.path')

      - name: Show profile
        run: nix profile list

      - name: Install nixpkgs#hello
        run: |
          nix profile install nixpkgs#hello

      - name: Install nixpkgs#cachix
        run: |
          nix profile install nixpkgs#cachix

      - name: Install nixpkgs#nixpkgs-fmt
        run: |
          nix profile install nixpkgs#nixpkgs-fmt

      - name: Install nixpkgs#alejandra
        run: |
          nix profile install nixpkgs#alejandra

      - name: Install nixpkgs#nixd
        run: |
          nix profile install nixpkgs#nixd

      - name: Install nixpkgs#ghc
        run: |
          nix profile install nixpkgs#ghc

      - name: Install nixpkgs#haskell-language-server
        run: |
          nix profile install nixpkgs#haskell-language-server

      - name: Install nixpkgs#purescript
        run: |
          nix profile install nixpkgs#purescript

      - name: Install nixpkgs#nodejs
        run: |
          nix profile install nixpkgs#nodejs

      - name: Show profile
        run: nix profile list