Implement EventStored infrastructure event that notifies subscribers when an event
is successfully persisted. This enables observability and triggers downstream
workflows (caching, metrics, projections) without coupling to application events.
Changes:
- Add EventStored type to event.go containing EventID, ActorID, Version, Timestamp
- Update InMemoryEventStore with optional EventBus and metrics support via builder methods
- Update JetStreamEventStore with optional EventBus and metrics support via builder methods
- Publish EventStored to __internal__ namespace after successful SaveEvent
- EventStored not published if SaveEvent fails (e.g., version conflict)
- EventStored publishing is optional - stores work without EventBus configured
- Metrics are recorded for each EventStored publication
- Add comprehensive test suite covering all acceptance criteria
Meets acceptance criteria:
- EventStored published after SaveEvent succeeds
- EventStored contains EventID, ActorID, Version, Timestamp
- No EventStored published if SaveEvent fails
- EventBus receives EventStored in same operation
- Metrics increment for each EventStored published
Closes#61
Co-Authored-By: Claude Code <noreply@anthropic.com>
- Add ErrVersionConflict error type and VersionConflictError for detailed
conflict information
- Implement version validation in InMemoryEventStore.SaveEvent that rejects
events with version <= current latest version
- Implement version validation in JetStreamEventStore.SaveEvent with version
caching for performance
- Add comprehensive tests for version conflict detection including concurrent
writes to same actor
- Document versioning semantics in EventStore interface and CLAUDE.md
This ensures events have monotonically increasing versions per actor and
provides clear error messages for version conflicts, enabling optimistic
concurrency control patterns.
Closes#6
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Test SaveEvent persists events correctly (single, multiple, multi-actor)
- Test GetEvents retrieves events in insertion order
- Test GetEvents with fromVersion filtering
- Test GetLatestVersion returns correct version
- Test behavior with non-existent actor IDs (returns empty/zero)
- Test concurrent access safety with race detector
- Add mutex protection to InMemoryEventStore for thread safety
Closes#3
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
