ci.yml

---

name: CI

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

jobs:

  cache-minimal-nix-dependencies:
    name: Cache minimal Nix dependencies

    runs-on: ubuntu-latest
    needs: []

    steps:
      - name: Check out repository code
        uses: actions/checkout@v3.4.0

      - name: Install Nix
        uses: cachix/install-nix-action@v20
        with:
          extra_nix_config: |
            ## Access token to avoid triggering GitHub's rate limiting.
            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

      - name: Setup Nix caches
        uses: cachix/cachix-action@v12
        with:
          name: tweag-cooked-validators
          ## This auth token will give write access to the cache, meaning that
          ## everything that happens in CI will be pushed at the end of the job.
          authToken: '${{ secrets.CACHIX_TWEAG_COOKED_VALIDATORS_AUTH_TOKEN }}'

      - name: Build Nix CI environment
        run: |
          nix develop .#ci --command true

  cache-all-nix-dependencies:
    name: Cache all Nix dependencies

    runs-on: ubuntu-latest
    needs: cache-minimal-nix-dependencies

    steps:
      - name: Check out repository code
        uses: actions/checkout@v3.4.0

      - name: Install Nix
        uses: cachix/install-nix-action@v20
        with:
          extra_nix_config: |
            ## Access token to avoid triggering GitHub's rate limiting.
            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

      - name: Setup Nix caches
        uses: cachix/cachix-action@v12
        with:
          name: tweag-cooked-validators
          ## This auth token will give write access to the cache, meaning that
          ## everything that happens in CI will be pushed at the end of the job.
          authToken: '${{ secrets.CACHIX_TWEAG_COOKED_VALIDATORS_AUTH_TOKEN }}'

      - name: Build all Nix environments
        run: |
          ## REVIEW: There might be a way to just build all the devShells? Also,
          ## we might want to consider building all the package dependencies?
          nix develop .#ci --command true
          nix develop      --command true

  build-and-test:
    name: Build and run tests

    runs-on: ubuntu-latest
    needs: cache-minimal-nix-dependencies

    steps:
      - name: Check out repository code (from PR).
        uses: actions/checkout@v3.4.0

      - name: Install Nix
        uses: cachix/install-nix-action@v20
        with:
          extra_nix_config: |
            ## Access token to avoid triggering GitHub's rate limiting.
            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

      - name: Setup Nix caches
        uses: cachix/cachix-action@v12
        with:
          name: tweag-cooked-validators
          ## No auth token: read only cache.

      ## Example from
      ## https://github.com/actions/cache/blob/ac25611caef967612169ab7e95533cf932c32270/examples.md#haskell---cabal
      - name: Accessing the Cabal cache
        uses: actions/cache@v3
        with:
          path: |
            ~/.cabal/packages
            ~/.cabal/store
            dist-newstyle
          key: ${{ runner.os }}-${{ hashFiles('**/*.cabal', '**/cabal.project', '**/cabal.project.freeze', 'flake.nix', 'flake.lock') }}-build-and-test

      ## Steps below run a certain program and creates two files:
      ## `${proj}-${step}.res` and `${proj}-${step}.out`. The former contains a
      ## string encoding the return code of the tool whereas the latter contains
      ## a human-readable description of what happened.
      ##
      ## The point of this is that we will execute these steps but we "succeed"
      ## iff the build is ok. Another job will then check the resulting files
      ## for their exit codes. This is ugly but it ensures that the `cabal
      ## build` gets cached even if tests fail, which means we save a lot of
      ## time (and CI runner money) in the long run.
      ##
      - name: Build and run tests
        run: |
          nix develop .#ci --command bash -c '
            ## NOTE: `-u` is here to help us avoid making mistakes.
            ##       `-x` is here to help with debugging.
            ##
            ## NOTE: `-o pipefail` is important for the semantics of this
            ## script, because with pipe the result of `cabal build` and `cabal
            ## run tests` through `tee`. Without `-o pipefail`, this succeeds if
            ## and only if the `tee` command succeeds, while with `-o pipefail`
            ## this succeeds if and only if all the commands succeed, which is
            ## what we want.
            set -xuo pipefail

            cabal_build_ok=true

            cabal update

            echo "Running \`cabal build\`"
            cabal_res=0
            cabal build | tee cabal-build.out
            cabal_res=$?
            echo "cabal_build:$cabal_res" > cabal-build.res
            if [ $cabal_res -ne 0 ]; then
              cabal_build_ok=false
            fi

            echo "Running \`cabal run tests\`"
            cabal_res=0
            cabal run tests | tee cabal-test.out
            cabal_res=$?
            echo "run_cabal_test:$cabal_res" > cabal-test.res

            if ! $cabal_build_ok; then
              exit 1
            fi
          '

      - name: Upload build and test outputs
        uses: actions/upload-artifact@v3
        with:
          name: cooked-validators-checks
          path: |
            ./*.out
            ./*.res

  check-result:
    name: Check tests output

    runs-on: ubuntu-latest
    needs: build-and-test

    steps:
      - name: Access build and test outputs
        uses: actions/download-artifact@v3
        with:
          name: cooked-validators-checks

      - name: Check tests output
        run: |
          is_ok=true

          for step in cabal-build cabal-test; do
            echo "!! output from $step"
            cat $step.out
            res=$(cat $step.res | cut -d':' -f2)
            if [ "$res" -ne 0 ]; then
              is_ok=false
            fi
          done

          ## Because there will be a lot of tests, we print a summary of the
          ## results
          echo "Summary of results (1 is failure)"
          cat cabal-build.res cabal-test.res

          if $is_ok; then
            exit 0
          else
            exit 1
          fi

  build-and-deploy-documentation:
    name: Build and deploy documentation

    runs-on: ubuntu-latest
    needs: cache-minimal-nix-dependencies

    steps:
      - name: Check out repository code
        uses: actions/checkout@v3.4.0

      - name: Install Nix
        uses: cachix/install-nix-action@v20
        with:
          extra_nix_config: |
            ## Access token to avoid triggering GitHub's rate limiting.
            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

      - name: Setup Nix caches
        uses: cachix/cachix-action@v12
        with:
          name: tweag-cooked-validators
          ## No auth token: read only cache.

      ## Example from
      ## https://github.com/actions/cache/blob/ac25611caef967612169ab7e95533cf932c32270/examples.md#haskell---cabal
      - name: Accessing the Cabal cache
        uses: actions/cache@v3
        with:
          path: |
            ~/.cabal/packages
            ~/.cabal/store
            dist-newstyle
          key: ${{ runner.os }}-${{ hashFiles('**/*.cabal', '**/cabal.project', '**/cabal.project.freeze', 'flake.nix', 'flake.lock') }}-haddock

      - name: Build documentation
        run: |
          nix develop .#ci --command bash -c '
            ## NOTE: `-e` and `-u` are here to help us avoid making mistakes.
            ##       `-x` is here to help with debugging.
            set -eux

            cabal update

            cabal haddock \
              --haddock-hyperlink-source \
              --haddock-quickjump \
              --haddock-html-location='https://hackage.haskell.org/package/$pkg-$version/docs' \
              cooked-validators

            mkdir -p docs
            cp --force --recursive dist-newstyle/build/*/ghc-*/cooked-validators-*/doc/html/cooked-validators/* docs
          '

      - name: Upload documentation as artifact
        uses: actions/upload-artifact@v3
        with:
          name: documentation
          path: ./docs

      - name: Deploy
        uses: peaceiris/actions-gh-pages@v3
        if: ${{ github.ref == 'refs/heads/main' }}
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: ./docs

  run-and-cache-flake-checks:
    name: Run and cache flake checks

    runs-on: ubuntu-latest
    needs: []

    steps:
      - name: Check out repository code
        uses: actions/checkout@v3.4.0

      - name: Install Nix
        uses: cachix/install-nix-action@v20
        with:
          extra_nix_config: |
            ## Access token to avoid triggering GitHub's rate limiting.
            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

      - name: Setup Nix caches
        uses: cachix/cachix-action@v12
        with:
          name: tweag-cooked-validators
          ## This auth token will give write access to the cache, meaning that
          ## everything that happens in CI will be pushed at the end of the job.
          authToken: '${{ secrets.CACHIX_TWEAG_COOKED_VALIDATORS_AUTH_TOKEN }}'

      - name: Run flake checks
        run: nix flake check --print-build-logs