Support actions/cache in branch deploy workflow

[aaronccasanova]

Description:

In a recent exploration, I was configuring GitHub actions/cache to optimize subsequent CI builds and realized our /snapit branch deploy workflow is unable to leverage that feature. However, I think there's an opportunity to slightly rework the current implementation and bring us closer to our sub-goal of keeping a majority of work in the GitHub runner.

Current branch deploy workflow:

• User comments /snapit
• Snapit runs changeset version --snapshot snapshot, and
• Force pushes to another branch for Buildkite to take over the build, pack, and upload

Proposed branch deploy workflow:

• User comments /snapit
• Snapit runs changeset version --snapshot snapshot and the existing build_script
• Snapit runs a new pack_script command, and
• Force pushes the packed artifacts to another branch for Buildkite to upload

This update would allow workflows to leverage GitHub actions/cache to only build the changes between runs, and the branch deploy would only be responsible for uploading artifacts. In our case, the branch could essentially be a single .pack dir that, when pushed to, gets uploaded to Cloudsmith.

[aaronccasanova]

Alternatively, we could use a similar pattern to Changesets action custom publishing:

name: Snapit

on:
  issue_comment:
    types:
      - created

jobs:
  snapit:
    name: Snapit
    runs-on: ubuntu-latest
    steps:
      - name: Checkout default branch
        uses: actions/checkout@v4

      - name: Cache turbo build setup
        uses: actions/cache@v4
        with:
          path: .turbo
          key: ${{ runner.os }}-turbo-${{ github.sha }}
          restore-keys: |
            ${{ runner.os }}-turbo-

      - name: Create snapshot version
        uses: Shopify/snapit@main
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          build_script: pnpm turbo run build --cache-dir .turbo
          publish_script: pnpm pack --pack-destination .pack
          branch: snapshot-release

[alex-page]

I really like this. One thing I would suggest with the example is to remove the .pack directory from the branch. We should just push the packed files to . as that will simplify a lot of stuff.