G4 Representative Migration (Go) — Lessons Learned

This document records a representative migration exercise for the pay-theory/limited rate limiter into AppTheory’s TableTheory-backed port.

Representative service example:

• examples/migration/rate-limited-http/README.md

What worked well

• The pay-theory/limited API maps cleanly to AppTheory’s port:
  • github.com/theory-cloud/apptheory/pkg/limited
  • github.com/theory-cloud/apptheory/pkg/limited/middleware
• Import rewrites can be automated safely with a small Go-aware helper:
  • scripts/migrate-from-lift-go.sh (dry-run by default; prints diffs)

Manual steps that remain

• DynamORM → TableTheory: legacy code that initializes DynamoDB via DynamORM must be updated to TableTheory:
  • github.com/pay-theory/dynamorm/... → github.com/theory-cloud/tabletheory
• Logger differences: legacy examples often pass a Zap logger to limited. AppTheory’s port avoids a Zap dependency; use your application logger outside the limiter or attach logging in the middleware layer.
• Table naming: TableTheory binds table name through model metadata; configure it once (recommended via env) before the limiter is first used:
  • APPTHEORY_RATE_LIMIT_TABLE_NAME (default rate-limits)

Follow-up opportunities

• Extend the migration helper to optionally rewrite common DynamORM initialization patterns into TableTheory equivalents (keep it opt-in and diff-based).
• Add a second representative service exercise using Lift runtime + middleware stack once AppTheory’s P0 contract shape is available.