gossip_event_sourcing library

Event Sourcing and CQRS library for Dart applications

This library provides the core components for implementing Event Sourcing and Command Query Responsibility Segregation (CQRS) patterns in distributed applications built on the Gossip protocol.

Key components:

EventProcessor: Coordinates event processing to projections
Projection: Base class for read models
ProjectionStore: Interface for persistent projection state storage

Example usage:

// Create a custom projection store implementation
final projectionStore = MyProjectionStore();
await projectionStore.initialize();

// Create event processor
final eventProcessor = EventProcessor(
  projectionStore: projectionStore,
  storeConfig: const ProjectionStoreConfig(),
);

// Create and register your projections
final myProjection = MyProjection();
eventProcessor.registerProjection(myProjection);

// Process events
await eventProcessor.processEvent(event);

Classes

EventProcessor

Coordinates processing of events to update projections. This is the core of the Event Sourcing architecture.

Projection

Base class for all projections (read models). Projections build and maintain UI state from events.

ProjectionStateMetadata

Metadata about a saved projection state (without the actual state data)

ProjectionStateSnapshot

Represents a saved projection state with metadata

ProjectionStore

Interface for storing and loading projection states to avoid replaying all events This is an optional performance optimization for large event stores

ProjectionStoreConfig