Here’s a for a .NET Core microservices architecture: Feature: Distributed Order Processing with Saga Pattern Business Context An e-commerce platform where placing an order involves multiple independent services. Key Capabilities | Capability | Description | |------------|-------------| | Order Creation | User submits order → OrderService creates order in Pending state | | Inventory Reservation | OrderService calls InventoryService to reserve items | | Payment Processing | PaymentService processes charge after successful reservation | | Compensation (Rollback) | If any step fails, previous steps are undone (release inventory, refund payment) | | Order Confirmation | All steps succeed → order marked Confirmed | Tech Stack for This Feature .NET 8 / .NET 9 MassTransit (or Wolverine) → Saga orchestration RabbitMQ / Azure Service Bus → Message broker EF Core + PostgreSQL → Each service has its own DB Polly → Retry & circuit breaker OpenTelemetry → Distributed tracing Microservices Involved | Service | Responsibility | Owns | |---------|---------------|------| | OrderService | Order lifecycle, Saga orchestrator | Orders table | | InventoryService | Stock management | InventoryItems table | | PaymentService | Payment processing | Payments table | | NotificationService | Email/SMS alerts | Notifications table | Sample Message Flow 1. POST /api/orders → OrderSubmitted event 2. Saga starts → ReserveInventory command 3. InventoryService → InventoryReserved event (or Failed) 4. Saga → ProcessPayment command 5. PaymentService → PaymentSucceeded event (or Failed) 6. Saga → ConfirmOrder command + SendNotification Compensation Example (Rollback) If Payment fails after Inventory reservation:
Saga sends: ReleaseInventory command (compensating action) InventoryService releases stock Saga marks order as Failed Saga sends: PaymentFailedNotification ✅ Resilient – No distributed transaction (2PC) needed ✅ Loose coupling – Services only communicate via events/commands ✅ Observable – Each saga step is traceable ✅ Recoverable – Failed sagas can be retried or manually compensated Bonus: Idempotency Each command includes an IdempotencyKey (e.g., orderId+step ) so the same message can be safely reprocessed. Would you like the actual C# code for the Saga orchestrator using MassTransit?
