build_cache.yaml

  # What's going here? 😳
  # GitHub action runners share cache only within the same branch or by inheriting from the parent branch (https://stackoverflow.com/a/66632107/368691).
  # i.e. We need a mechanism that would create a shared cache every time that yarn.lock changes.
  # We do this by forcing to cache populating action in every GitHub action runner every time yarn.lock changes.
  # The number 50 comes from the contra-manager maximum number of runners.
  build_cache:
    name: Build cache
    runs-on:
      - self-hosted
      - contra-general-purpose-experimental
    strategy:
      matrix:
        concurrency:
          - 1
          - 2
          - 3
          - 4
          - 5
          - 6
          - 7
          - 8
          - 9
          - 10
          - 11
          - 12
          - 13
          - 14
          - 15
          - 16
          - 17
          - 18
          - 19
          - 20
          - 21
          - 22
          - 23
          - 24
          - 25
          - 26
          - 27
          - 28
          - 29
          - 30
          - 31
          - 32
          - 33
          - 34
          - 35
          - 36
          - 37
          - 38
          - 39
          - 40
          - 41
          - 42
          - 43
          - 44
          - 45
          - 46
          - 47
          - 48
          - 49
          - 50
    steps:
      - run: find . -name . -o -prune -exec rm -rf -- {} +
      - uses: actions/checkout@v2
      - uses: dopplerhq/cli-action@v1
      - name: Load environment variables
        uses: catchco/doppler-environment-loader@v1.0.2
        with:
          doppler-token: ${{ secrets.DOPPLER_TOKEN }}
      - uses: actions/setup-node@v2
        with:
          node-version: '16'
      - name: Setup yarn
        run: npm install -g yarn
      - uses: actions/setup-node@v2
        with:
          node-version: '16'
      - name: Cache node_modules
        id: cache-node-modules
        uses: actions/cache@v2
        with:
          path: node_modules
          key: node_modules-${{ hashFiles('**/yarn.lock') }}  
      - name: Install dependencies
        if: |
          steps.cache-node-modules.outputs.cache-hit != 'true'
        run: |
          yarn config set 'enableGlobalCache' 'true'
          yarn config set 'npmRegistries["//npm.pkg.github.com"].npmAuthToken' "$GITHUB_TOKEN"
          yarn --immutable
          yarn config unset 'npmRegistries["//npm.pkg.github.com"].npmAuthToken'