How to cache yarn packages in GitHub Actions

Question

I am using GitHub Actions to build my TypeScript project. Everytime I run action I am waiting 3 minutes for all dependencies to get installed.

Is there way to cache

Answer 1

This is a 1-liner cache specifically for Yarn: https://github.com/c-hive/gha-yarn-cache

- uses: actions/checkout@v2
- name: Setup Node.js
  uses: actions/setup-node@v1
  with:
    node-version: 12.x

- uses: c-hive/gha-yarn-cache@v1

- name: Install JS dependencies
  run: yarn install

- name: Test
  run: yarn test

Answer 2

     - name: Get yarn cache directory path
       id: yarn-cache-dir-path
       run: echo "::set-output name=dir::$(yarn cache dir)"

     - uses: actions/cache@v1
       id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
       with:
         path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
         key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
         restore-keys: |
           ${{ runner.os }}-yarn-

The caching code above only caches and restores the yarn cache directory, it doesn't cache the node_modules directory. So if you use this code (@Edric's answer),

- name: Install project dependencies
  if: steps.yarn-cache.outputs.cache-hit != 'true' # Over here!
  run: yarn

node_modules is not created and you will receive dependencies not found errors.

Instead, you can use this:

- name: Install project dependencies
  run: yarn --prefer-offline

This tells yarn to always run but use cached downloads (in the cache directory mentioned above) whenever possible instead of downloading from the server.

---

You can also cache the node_modules directory directly and skip the installation step when the cache is available. This is actually NOT recommended (see comments). Example:

    - name: Get yarn cache directory path
      id: yarn-cache-dir-path
      run: echo "::set-output name=dir::$(yarn cache dir)"
    - name: Cache yarn cache
      uses: actions/cache@v2
      id: cache-yarn-cache
      with:
        path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
        key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
        restore-keys: |
          ${{ runner.os }}-yarn-
    - name: Cache node_modules
      id: cache-node-modules
      uses: actions/cache@v2
      with:
        path: node_modules
        key: ${{ runner.os }}-${{ matrix.node-version }}-nodemodules-${{ hashFiles('**/yarn.lock') }}
        restore-keys: |
          ${{ runner.os }}-${{ matrix.node-version }}-nodemodules-
    - run: yarn
      if: |
        steps.cache-yarn-cache.outputs.cache-hit != 'true' ||
        steps.cache-node-modules.outputs.cache-hit != 'true'

Answer 3

As mentioned in the comment next to the id field for the caching step:

Use this to check for cache-hit (steps.yarn-cache.outputs.cache-hit != 'true')

You're missing a conditional if property that determines whether the step should be run:

- name: Install yarn
  run: npm install -g yarn

- name: Install project dependencies
  if: steps.yarn-cache.outputs.cache-hit != 'true' # Over here!
  run: yarn

P.S. You should probably use the Setup NodeJS GitHub Action that additionally sets up Yarn for you:

- uses: actions/setup-node@v1
  with:
    node-version: '10.x' # The version spec of the version to use.

See the action.yml file for a full list of valid inputs.

---

EDIT: As it turns out, Yarn is included in the list of software installed on the GitHub-hosted Ubuntu 18.04.4 LTS (ubuntu-latest/ubuntu-18.04) runner, so there's no need to include a step to globally install Yarn.