Purpose

Implement chunked R2-based database export to support any database size (up to 10GB). Uses DO alarms for exports exceeding the 30-second Worker timeout, with breathing intervals to prevent database lock contention. Includes callback URL notifications and new status/download endpoints.

/claim #59

Tasks

• Replace in-memory dump with batched R2 chunked export (1000 rows/batch)
• Implement DO alarm continuation for long-running exports
• Add breathing intervals (2s) between alarm cycles
• Add POST /export/dump with optional callbackUrl param
• Add GET /export/status/:exportId endpoint
• Add GET /export/download/:exportId endpoint
• Add R2 bucket binding to wrangler.toml
• Backwards compatible fallback when R2 is not configured
• Comprehensive test suite (15 tests)

Verify

1. Run pnpm vitest run src/export/chunked-dump.test.ts — 15 tests should pass
2. Run pnpm vitest run — all 166 existing tests still pass
3. Configure R2 bucket, deploy, and hit GET /export/dump on a small DB — should return .sql file directly
4. Hit POST /export/dump?callbackUrl=https://example.com on a large DB — should return 202 with exportId
5. Poll GET /export/status/:exportId — should show progress
6. After completion, GET /export/download/:exportId — should return the .sql file

Before

After

#Short Demo video of changes

https://github.com/user-attachments/assets/7f237412-cba7-4fd5-8832-e29216dd266e