action.yml

name: Yarn Install
description: Runs yarn install using caching with monorepo support
inputs:
  cache-prefix:
    description: The prefix to use for all cache keys to keep different environments separate
    required: true
  corepack-version:
    description: Version of corepack to use. Defaults to latest
    default: 'latest'
  yarn-install-force:
    description: Whether to force the installation of yarn via corepack
    default: false
outputs:
  cache-hit:
    description: Whether the node_modules cache got an exact cache hit
    value: ${{ steps.cache-modules.outputs.cache-hit }}
  yarn-cache-dir:
    description: The location of the global yarn cache
    value: ${{ steps.yarn-cache.outputs.dir }}
  
runs:
  using: 'composite'
  steps:
    # Cache every node_modules folder inside the monorepo
    - name: cache all node_modules
      id: cache-modules
      uses: actions/cache@v4
      with:
        path: '**/node_modules'
        # We use both yarn.lock and package.json as cache keys to ensure that
        # changes to local monorepo packages bust the cache.
        key: ${{ inputs.cache-prefix }}-node_modules-${{ hashFiles('yarn.lock', '**/package.json') }}
    
    - name: prepare corepack
      shell: bash
      run: |
        if [[ "${{ inputs.yarn-install-force }}" == "true" ]]; then
          npm install --force -g corepack@${{ inputs.corepack-version }}
        else
          npm install -g corepack@${{ inputs.corepack-version }}
        fi
        
        corepack enable
    
    # If we get a cache hit for node_modules, there's no need to bring in the global
    # yarn cache or run yarn install, as all dependencies will be installed already.

    - name: find location of global yarn cache
      id: yarn-cache
      if: steps.cache-modules.outputs.cache-hit != 'true'
      run: echo "dir=$([[ "$(yarn --version)" =~ "1.*" ]] && yarn cache dir || yarn config get cacheFolder)" >> $GITHUB_OUTPUT
      shell: bash

    - name: cache global yarn cache
      uses: actions/cache@v4
      if: steps.cache-modules.outputs.cache-hit != 'true'
      with:
        path: ${{ steps.yarn-cache.outputs.dir }}
        key: ${{ inputs.cache-prefix }}-yarn-${{ hashFiles('yarn.lock') }}
        restore-keys: |
          ${{ inputs.cache-prefix }}-yarn-

    - name: yarn install
      if: steps.cache-modules.outputs.cache-hit != 'true'
      run: '[[ "$(yarn --version)" =~ "1.*" ]] && yarn install --frozen-lockfile || yarn install --immutable'
      shell: bash