Diseño de Sagas basadas en eventos
Diseñe el flujo de una saga de coreografía utilizando eventos para activar acciones en distintos microservicios.
Diseño de Sagas basadas en eventos es una lección gratuita de Microservices Communication Patterns (Saga, Circuit Breaker) en CoddyKit. Esta es la lección 1 de 4. Puedes leer la lección completa abajo gratuitamente — luego la practicas en el navegador con un editor de código integrado y un tutor de IA 24/7. Forma parte de la ruta de aprendizaje de Microservices Communication Patterns (Saga, Circuit Breaker), y tu progreso se sincroniza en la web y la app de CoddyKit. El curso de Microservices Communication Patterns (Saga, Circuit Breaker) incluye 4 lecciones en total.
Partes de esta lección aún no han sido traducidas y se muestran en inglés.
Event-Driven Saga Design
Welcome! In this lesson, we'll learn how to design the flow of a Choreography Saga. This pattern helps manage complex business transactions that span multiple services.
We'll focus on using events as the primary way services communicate and trigger each other's actions.
Choreography Refresher
Remember Choreography Sagas? In this style, services communicate directly by publishing and subscribing to events.
- No central orchestrator: Services react to events from others.
- Decentralized decisions: Each service decides its next step based on the event it receives.
Our Business Scenario
Let's design a saga for an "Online Order Placement" system. This common scenario involves several steps across different microservices:
- Customer places order.
- Inventory is checked and reserved.
- Payment is processed.
- Order is shipped.
Identifying Core Saga Steps
For our "Order Placement" saga, we can break it down into these main steps, each potentially handled by a different service:
- Order Service: Creates the order.
- Inventory Service: Reserves items.
- Payment Service: Processes payment.
- Shipping Service: Schedules shipment.
Events Drive the Flow
In a choreography saga, each step is initiated by an event. When one service completes its task, it publishes an event.
Other services, interested in that event, subscribe to it and react accordingly. This creates a chain reaction.
Kicking Off the Saga
Every saga needs a starting point. For our "Order Placement," the Order Service initiates the process.
When a customer places an order, the Order Service creates it and publishes an OrderCreatedEvent.
Inventory Reacts to Order
The Inventory Service subscribes to OrderCreatedEvent. Upon receiving it, it attempts to reserve the items for the order.
After processing, it publishes either an InventoryReservedEvent or an InventoryFailedEvent.
class OrderCreatedEvent {
String orderId;
String customerId;
// ... item details
}
class InventoryService {
public void handleOrderCreated(OrderCreatedEvent event) {
System.out.println("Inventory Service: Received OrderCreatedEvent for " + event.orderId);
// Logic to reserve items...
boolean success = true; // Assume success for now
if (success) {
System.out.println("Inventory Service: Items reserved. Publishing InventoryReservedEvent.");
// In a real system, publish InventoryReservedEvent
} else {
System.out.println("Inventory Service: Inventory failed. Publishing InventoryFailedEvent.");
// In a real system, publish InventoryFailedEvent
}
}
}
public class Main {
public static void main(String[] args) {
InventoryService inventory = new InventoryService();
OrderCreatedEvent newOrder = new OrderCreatedEvent();
newOrder.orderId = "ORD123";
newOrder.customerId = "CUST456";
inventory.handleOrderCreated(newOrder);
}
}Payment Reacts to Inventory
The Payment Service subscribes to InventoryReservedEvent. This means payment only proceeds if inventory is successfully reserved.
It processes the payment and then publishes either a PaymentProcessedEvent or a PaymentFailedEvent.
Shipping Reacts to Payment
Finally, the Shipping Service subscribes to PaymentProcessedEvent. It schedules the shipment only after payment is confirmed.
It then publishes an OrderShippedEvent to complete the main saga flow.
Planning for Rollbacks
What if a step fails? For example, if payment fails after inventory is reserved? In a choreography saga, we use compensation events.
The Payment Service would publish a PaymentFailedEvent. The Inventory Service would subscribe to this event and publish an InventoryReleasedEvent to undo its previous action.
Saga Flow Check
Consider our Order Placement saga. What is the correct sequence of events if the entire process is successful?
Recap: Designing Event Flows
We've learned how to design a choreography saga by breaking down a business transaction into steps.
- Each step publishes an event to trigger the next.
- We identified the initial event and subsequent events for a successful flow.
- We also briefly considered how compensation events are used to handle failures.
Next, we'll explore how message brokers facilitate this communication!
Preguntas frecuentes
¿La lección «Diseño de Sagas basadas en eventos» es gratis?
Sí — el texto completo de «Diseño de Sagas basadas en eventos» es gratis para leer aquí en la web. Para practicarla de forma interactiva (editor de código integrado y tutor de IA 24/7) y desbloquear el resto del curso de Microservices Communication Patterns (Saga, Circuit Breaker), actualiza a CoddyKit PRO. El curso de Microservices Communication Patterns (Saga, Circuit Breaker) incluye 4 lecciones en total.
¿Qué aprenderé en «Diseño de Sagas basadas en eventos»?
Diseñe el flujo de una saga de coreografía utilizando eventos para activar acciones en distintos microservicios. Practicas Microservices Communication Patterns (Saga, Circuit Breaker) con código real que ejecutas directamente en el navegador, y un tutor de IA 24/7 responde tus preguntas mientras trabajas en la lección.
¿Necesito experiencia previa para empezar Microservices Communication Patterns (Saga, Circuit Breaker)?
No se requiere experiencia previa. Microservices Communication Patterns (Saga, Circuit Breaker) en CoddyKit está estructurado para principiantes hasta estudiantes avanzados, así que puedes empezar aquí o desde el inicio y avanzar a tu ritmo. Esta es la lección 1 de 4.
¿Cuánto tiempo toma la lección «Diseño de Sagas basadas en eventos»?
La mayoría de las lecciones de CoddyKit toman alrededor de 5–10 minutos. Cada una es compacta e interactiva, así que avanzas constantemente y retomas exactamente por donde dejaste en la web y la app.
¿Puedo escribir y ejecutar código en esta lección de Microservices Communication Patterns (Saga, Circuit Breaker)?
Sí. Cada lección de Microservices Communication Patterns (Saga, Circuit Breaker) incluye un editor de código integrado, así que escribes y ejecutas código real directamente en tu navegador y obtienes retroalimentación instantánea de IA — sin configuración local necesaria.
Todas las lecciones de este curso
- Diseño de Sagas basadas en eventos
- Bus de eventos y brokers de mensajes
- Gestión de compensaciones mediante eventos
- Creación de consumidores de eventos idempotentes