Persist delivery queue across restarts #9
Description
Summary
Back the delivery retry queue with durable storage so pending deliveries survive restarts.
Motivation
The current in-memory queue loses outstanding deliveries on process exit. Persisting queue state would make retry logic resilient to crashes and planned restarts.
Proposed direction
- Store queue state on disk (e.g., in spool directory) or use a lightweight embedded database.
- Ensure enqueue/dequeue flows remain efficient and do not block the main loop.
- Provide migration/upgrade path for existing deployments.
Labels
- feature
- queue