Event Driven

Problem: Need complete audit trail of all changes to application state.

Solution: Use an append-only store to record the full series of events that describe actions taken on data in a domain.

When to Use:

• Requiring complete audit trail
• Implementing temporal queries (point-in-time state)
• Supporting event replay and debugging
• Implementing CQRS with eventual consistency

Implementation Considerations:

• Store events in append-only log
• Rebuild current state by replaying events
• Implement event versioning strategy
• Handle event schema evolution
• Consider storage growth over time
• Implement snapshots for performance