Add EventStored internal event published to the EventBus when events are
successfully persisted. This allows observability components (metrics,
projections, audit systems) to react to persisted events without coupling
to application code.
Implementation:
- Add EventTypeEventStored constant to define the event type
- Update InMemoryEventStore with optional EventBroadcaster support
- Add NewInMemoryEventStoreWithBroadcaster constructor
- Update JetStreamEventStore with EventBroadcaster support
- Add NewJetStreamEventStoreWithBroadcaster constructor
- Implement publishEventStored() helper method
- Publish EventStored containing EventID, ActorID, Version, Timestamp
- Only publish on successful SaveEvent (not on version conflicts)
- Automatically recorded in metrics through normal Publish flow
Test coverage:
- EventStored published after successful SaveEvent
- No EventStored published on version conflict
- Multiple EventStored events published in order
- SaveEvent works correctly without broadcaster (nil-safe)
Closes#61
Co-Authored-By: Claude Code <noreply@anthropic.com>
- Fix TOCTOU race condition in SaveEvent by holding the lock throughout entire version validation and publish operation
- Add getLatestVersionLocked helper method to prevent race window where multiple concurrent threads read the same currentVersion
- Fix GetLatestSnapshot to return error when no snapshot exists (not nil), distinguishing "not created" from "error occurred"
- The concurrent version conflict test now passes with exactly 1 success and 49 conflicts instead of 50 successes
These changes ensure thread-safe optimistic concurrency control and consistent error handling semantics.
Co-Authored-By: Claude Code <noreply@anthropic.com>
- Fix thread safety issue in SaveEvent: Lock now only protects cache access. NATS I/O operations (GetLatestVersion calls) happen without holding the mutex, preventing lock contention when multiple concurrent SaveEvent calls occur.
- Improve cache handling: Check cache first with minimal lock hold time. For cache misses, unlock before calling GetLatestVersion, then re-lock only to update cache.
- Remove getLatestVersionLocked: No longer needed now that SaveEvent doesn't hold lock during GetLatestVersion calls.
- Fix error handling consistency: GetLatestSnapshot now returns (nil, nil) when no snapshot exists, consistent with GetLatestVersion returning 0 for no events. Both methods now treat empty results as normal cases rather than errors.
- Fix benchmark test: BenchmarkGetLatestVersion_NoCache now creates uncachedStore outside the timing loop. Previously, creating a new store on each iteration was too expensive and didn't properly measure GetLatestVersion performance.
Co-Authored-By: Claude Code <noreply@anthropic.com>
Closes#127
The GetLatestVersion method previously fetched all events for an actor to find
the maximum version, resulting in O(n) performance. This implementation replaces
the full scan with JetStream's DeliverLast() consumer option, which efficiently
retrieves only the last message without scanning all events.
Performance improvements:
- Uncached lookups: ~1.4ms regardless of event count (constant time)
- Cached lookups: ~630ns (very fast in-memory access)
- Memory usage: Same 557KB allocated regardless of event count
- Works correctly with cache invalidation
The change is backward compatible:
- Cache in getLatestVersionLocked continues to provide O(1) performance
- SaveEvent remains correct with version conflict detection
- All existing tests pass without modification
- Benchmark tests verify O(1) behavior
Co-Authored-By: Claude Code <noreply@anthropic.com>
- Fix cache not repopulated after invalidation: Always update cache with fresh data instead of just deleting on mismatch
- Fix race condition: Hold mutex lock during entire fetch operation to prevent SaveEvent from running between fetch and cache update
- Improve test: Add second GetLatestVersion call to verify cache was properly repopulated after invalidation
Co-Authored-By: Claude Code <noreply@anthropic.com>
Implements cache invalidation on GetLatestVersion when external writers modify the
JetStream stream. The strategy ensures consistency in multi-store scenarios while
maintaining performance for the single-writer case.
Changes:
- Add cache invalidation logic to GetLatestVersion() that detects stale cache
- Document version cache behavior in JetStreamEventStore struct comment
- Add detailed documentation in CLAUDE.md about cache invalidation strategy
- Add TestJetStreamEventStore_CacheInvalidationOnExternalWrite integration test
- Cache is invalidated by deleting entry, forcing fresh fetch on next check
The implementation follows the acceptance criteria by:
1. Documenting the single-writer assumption in code comments
2. Implementing cache invalidation on GetLatestVersion miss
3. Adding comprehensive test for external write scenarios
Closes#126
Co-Authored-By: Claude Code <noreply@anthropic.com>
Add support for optional namespace prefixes on JetStreamEventStore streams
to enable complete namespace isolation at the storage level:
- Add Namespace field to JetStreamConfig
- Add NewJetStreamEventStoreWithNamespace convenience constructor
- Prefix stream names with sanitized namespace when configured
- Add GetNamespace and GetStreamName accessor methods
- Add unit tests for namespace functionality
- Document namespace-scoped stores in CLAUDE.md
The namespace prefix is sanitized (spaces, dots, wildcards converted to
underscores) and prepended to the stream name, ensuring events from one
namespace cannot be read from another namespace's store while maintaining
full backward compatibility for non-namespaced stores.
Closes#19
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add ReplayError and ReplayResult types to capture information about
malformed events encountered during replay. This allows callers to
inspect and handle corrupted data rather than having it silently skipped.
Key changes:
- Add ReplayError type with sequence number, raw data, and underlying error
- Add ReplayResult type containing both successfully parsed events and errors
- Add EventStoreWithErrors interface for stores that can report replay errors
- Implement GetEventsWithErrors on JetStreamEventStore
- Update GetEvents to maintain backward compatibility (still skips malformed)
- Add comprehensive unit tests for the new types
This addresses the issue of silent data loss during event-sourced replay
by giving callers visibility into data quality issues.
Closes#39
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add config structs with sensible defaults for tunable parameters:
- JetStreamConfig for stream retention (1 year) and replica count (1)
- HashRingConfig for virtual nodes per physical node (150)
- ShardConfig for shard count (1024) and replication factor (1)
Each component gets a new WithConfig constructor that accepts custom
configuration, while the original constructors continue to work with
defaults. Zero values in configs fall back to defaults for backward
compatibility.
Closes#38
Co-Authored-By: Claude Opus 4.5 <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>
