Syncing dev data into previews

By default a preview starts empty (schema from your migrations). To make each preview mirror your dev environment, clone your dev D1 and R2 into the isolated per-PR copies.

      - uses: BitByBit-B3/cf-pr-preview-action@v1
        with:
          worker-prefix: myapp-preview
          db-prefix: myapp-preview
          sync-d1-from: myapp-dev-db        # source D1 name
          sync-r2-from: myapp-dev-bucket    # source R2 bucket name
        env:
          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
          CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
          # R2 S3 credentials (see below)
          R2_ENDPOINT: ${{ secrets.R2_ENDPOINT }}
          R2_ACCESS_KEY_ID: ${{ secrets.R2_DEV_ACCESS_KEY_ID }}
          R2_SECRET_ACCESS_KEY: ${{ secrets.R2_DEV_SECRET_ACCESS_KEY }}

How D1 sync works

1. Full export of the source (dev) D1 — schema and data.
2. Drop the preview D1's existing tables (foreign keys off).
3. Import the dev dump into the preview D1.
4. Apply migrations on top — so any schema changes this PR adds land over the dev snapshot.

A full clone (not data-only) is used on purpose: a dev database frequently drifts ahead of a branch's migration files, and copying rows into a mismatched schema fails. Cloning dev's real schema, then migrating, always works.

D1 allows only one export per database at a time, so the export retries with backoff if a previous export is still in flight.

How R2 sync works

R2 is synced with rclone (Cloudflare S3 provider) from the source bucket into the per-PR bucket.

R2 credentials

The R2 access key and secret must be real R2 S3 API credentials — not the app-runtime values you might keep in wrangler.jsonc vars. Provide them as env/secrets. By default the action reads R2_ENDPOINT, R2_ACCESS_KEY_ID, and R2_SECRET_ACCESS_KEY from the environment (falling back to config vars). Override the names with the r2-*-var inputs.

Large buckets take time to copy on every push — scope sync-r2-from to a bucket whose size is reasonable for per-PR cloning, or omit it and seed R2 in a hook instead.