event-driven

name	event-driven
description	Event Sourcing, CQRS, Saga patterns, event bus (Kafka, RabbitMQ, AWS EventBridge). Use when implementing event-driven architecture, distributed transactions, or event sourcing.

Event-Driven — Event Sourcing, Saga, CQRS

Architecture événementielle pour découplage et scalabilité.

Patterns

Event Sourcing — Stocker events, pas état (audit, replay)
CQRS — Séparer Read/Write models (projections)
Saga — Transaction distribuée (microservices)
Event Bus — Pub/Sub découplé (Kafka, RabbitMQ)

Event Sourcing

events = [OrderCreated(...), OrderPaid(...), OrderShipped(...)]

def rebuild(events):
    state = {}
    for e in events: state = apply(state, e)
    return state

Saga — Choreography vs Orchestration

Choreography — Events chain services (découplé, debug dur)
Orchestration — Central coordinator (visible, couplé)

Choreo: OrderCreated → Payment → Shipping
Orchestrator: ProcessPayment() → ShipOrder()

Kafka Event Bus

// Producer
producer.send({ topic: 'orders', messages: [{ ... }] });

// Consumer
consumer.run({
  eachMessage: async ({ message }) => {
    (.(message.));
  }
});