ci-build-proto.yml

name: "build protobufs"

on:
  push:
    branches:
      - main
      - '*-dev'
  pull_request:
    branches:
      - main
      - '*-dev'
  schedule:
    - cron: "0 0 * * *"

jobs:
  build:

    strategy:
      matrix:
        # We only test on the oldest version we want to support and latest.
        # We trust that things also work for versions in the middle.
        os: [ubuntu-22.04, ubuntu-latest]
        # See Bazelisk README for legal values.
        bazel_version: [7.x, latest]
      # Don't abort other runs when one of them fails, to ease debugging.
      fail-fast: false

    runs-on: ${{ matrix.os }}

    env:
      # This tells Bazelisk (installed as `bazel`) to use specified version.
      # https://github.com/bazelbuild/bazelisk?tab=readme-ov-file#how-does-bazelisk-know-which-bazel-version-to-run
      USE_BAZEL_VERSION: ${{ matrix.bazel_version }}
      CACHE_KEY: ${{ matrix.os }}_bazel-${{ matrix.bazel_version }}

    steps:
    - uses: actions/checkout@v4
      with:
        submodules: recursive

    - name: Mount bazel cache
      uses: actions/cache/restore@v4
      with:
        # See https://docs.bazel.build/versions/master/output_directories.html
        path: "~/.cache/bazel"
        # Create a new cache entry whenever Bazel files change.
        # See https://docs.github.com/en/actions/guides/caching-dependencies-to-speed-up-workflows
        key: ${{ env.CACHE_KEY }}-${{ hashFiles('**/*.bazel*', '**/*.bzl') }}
        restore-keys: |
          ${{ env.CACHE_KEY }}

    - name: Save start time
      uses: josStorer/get-current-time@v2
      id: start-time
      with:
        # Unix timestamp -- seconds since 1970.
        format: X

    - name: Build proto/
      run: cd proto && bazel build //... && bazel test //...

    - name: Build bazel/example/using-bzlmod/
      run: cd bazel/example/using-bzlmod && bazel build //...

    - name: Build bazel/example/using-workspace/
      run: cd bazel/example/using-workspace && bazel build //...
      # This is a legacy example that doesn't work beyond Bazel 7.x.
      if: ${{ env.USE_BAZEL_VERSION == '7.x' }}

    - name: Save end time
      # Always save the end time so we can calculate the build duration.
      if: always()
      uses: josStorer/get-current-time@v2
      id: end-time
      with:
        # Unix timestamp -- seconds since 1970.
        format: X

    - name: Calculate build duration
      # Always calculate the build duration so we can update the cache if needed.
      if: always()
      run: |
        START=${{ steps.start-time.outputs.formattedTime }}
        END=${{ steps.end-time.outputs.formattedTime }}
        DURATION=$(( $END - $START ))
        echo "duration=$DURATION" | tee "$GITHUB_ENV"

    - name: Compress cache
      # Always compress the cache so we can update the cache if needed.
      if: always()
      run: rm -rf $(bazel info repository_cache)

    - name: Save bazel cache
      uses: actions/cache/save@v4
      # Only create a new cache entry if we're on the main branch or the build takes >3mins.
      #
      # NOTE: Even though `always()` evaluates to true, and `true && x == x`,
      # the `always() &&` prefix is not redundant! The call to `always()` has a
      # side effect, which is to override the default behavior of automagically
      # canceling this step if a previous step failed.
      # (Don't blame me, blame GitHub Actions!)
      if: always() && (github.ref_name == 'main' || env.duration > 180)
      with:
        path: "~/.cache/bazel"
        key: ${{ env.CACHE_KEY }}-${{ hashFiles('**/*.bazel*', '**/*.bzl') }}-${{ github.run_id }}