How to zip yarn global folder for reuse in subsequent Google Cloud Build runs

Question

I'm trying to cache my node_module dependencies to speed up my build time, but the zip file that results is empty. With inspiration from THIS response to another question I have the following cloudbuild.yaml.

steps:
  - id: 'download-cached-yarn-dependencies'
    name: gcr.io/cloud-builders/gsutil
    entrypoint: bash
    args:
      - '-c'
      - |
        gsutil cp gs://${PROJECT_ID}_cloudbuild/my-app.cache.tgz build-cache.tgz || exit 0
        tar -zxf build-cache.tgz || exit 0


  - id: install
    name: $_NODE
    entrypoint: 'bash'
    args:
      - '-c'
      - |
        mkdir .yarn-cache
        yarn config set enableGlobalCache true
        yarn config set globalFolder .yarn-cache
        yarn install --immutable

  - id: 'upload-cached-yarn-dependencies'
    name: gcr.io/cloud-builders/gsutil
    entrypoint: bash
    args:
      - '-c'
      - |
        tar -zcvf build-cache.tgz .yarn-cache
        gsutil cp build-cache.tgz gs://${PROJECT_ID}_cloudbuild/my-app.cache.tgz

The only thing that I modified from the previous ANSWER was to add mkdir .yarn-cache to avoid a "Cannot stat: No such file or directory" error.

This build successfully created a my-app.cache.tgz file in my storage bucket, but when unzipped, it is empty.

I also tried to remove the line yarn config set globalFolder .yarn-cache and use the default cache folder /usr/local/share/.config/yarn/global (SOURCE) but this also gave a "Cannot stat: No such file or directory" error.

How can I successfully zip the global folder for reuse in later builds?

Answer 1

I've modified my approach based on THIS answer to another question.

steps:
  # retrieve the cached node_modules from Cloud Storage
  - id: get-cache
    waitFor: ['-']
    name: 'gcr.io/cloud-builders/gsutil'
    # This approach should work for unpacking the local npm package cache.
    script: |
      #!/usr/bin/env bash
      set -Eeuo pipefail
      gsutil -m cp gs://${PROJECT_ID}_cloudbuild/node_modules.cache.tgz  /tmp/build-cache.tgz || echo "Cache archive not found!"
      tar -xzf /tmp/build-cache.tgz || echo "Cache archive not found!"

  # Install dependencies
  - id: install
    waitFor: ['get-cache']
    name: $_NODE
    entrypoint: 'bash'
    args:
      - '-c'
      - |
        yarn install --immutable --frozen-lockfile

  # Zip and upload the node_modules to Cloud Storage
  # - Uncomment to update the cache
  # - comment out to speed up the build
  - id: cache-node-dependencies
    name: 'gcr.io/cloud-builders/gsutil'
    waitFor: ['install']
    script: |
      #!/usr/bin/env bash
      set -Eeuo pipefail
      tar -czf /tmp/cache.tar.gz ./node_modules &&
      gsutil -m cp /tmp/cache.tar.gz gs://${PROJECT_ID}_cloudbuild/node_modules.cache.tgz