使用分布式事件实现订单支付库存通知

src/HelloShop.OrderingService/DistributedEvents/EventHandling/OrderPaymentSucceededDistributedEventHandler.cs

@@ -0,0 +1,42 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.OrderingService.DistributedEvents.Events;
+using HelloShop.OrderingService.Entities.Orders;
+using HelloShop.OrderingService.Infrastructure;
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+using Microsoft.EntityFrameworkCore;
+
+namespace HelloShop.OrderingService.DistributedEvents.EventHandling
+{
+    public class OrderPaymentSucceededDistributedEventHandler(OrderingServiceDbContext dbContext, IDistributedEventBus distributedEventBus) : IDistributedEventHandler<OrderPaymentSucceededDistributedEvent>
+    {
+        public async Task HandleAsync(OrderPaymentSucceededDistributedEvent @event)
+        {
+            var strategy = dbContext.Database.CreateExecutionStrategy();
+
+            await strategy.ExecuteAsync(async () =>
+            {
+                await using var transaction = await dbContext.Database.BeginTransactionAsync();
+
+                DbSet<Order> orders = dbContext.Set<Order>();
+
+                Order order = await orders.FindAsync(@event.OrderId) ?? throw new Exception($"Order with id {@event.OrderId} not found");
+
+                await orders.Entry(order).Collection(i => i.OrderItems).LoadAsync();
+
+                order.OrderStatus = OrderStatus.Paid;
+
+                await dbContext.SaveChangesAsync();
+
+                await transaction.CommitAsync();
+
+                var orderStockList = order.OrderItems.Select(orderItem => new OrderStockItem(orderItem.ProductId, orderItem.Units));
+
+                var integrationEvent = new OrderPaidDistributedEvent(order.Id, orderStockList);
+
+                await distributedEventBus.PublishAsync(integrationEvent);
+            });
+        }
+    }
+}

src/HelloShop.OrderingService/DistributedEvents/Events/OrderPaidDistributedEvent.cs

@@ -0,0 +1,9 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+
+namespace HelloShop.OrderingService.DistributedEvents.Events
+{
+    public record OrderPaidDistributedEvent(int OrderId, IEnumerable<OrderStockItem> OrderStockItems) : DistributedEvent;
+}

src/HelloShop.OrderingService/DistributedEvents/Events/OrderPaymentFailedDistributedEvent.cs

@@ -0,0 +1,14 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+
+namespace HelloShop.OrderingService.DistributedEvents.Events
+{
+    public record OrderPaymentFailedDistributedEvent : DistributedEvent
+    {
+        public int OrderId { get; }
+
+        public OrderPaymentFailedDistributedEvent(int orderId) => OrderId = orderId;
+    }
+}

src/HelloShop.OrderingService/DistributedEvents/Events/OrderPaymentSucceededDistributedEvent.cs

@@ -0,0 +1,9 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+
+namespace HelloShop.OrderingService.DistributedEvents.Events
+{
+    public record OrderPaymentSucceededDistributedEvent(int OrderId) : DistributedEvent;
+}

src/HelloShop.OrderingService/Extensions/Extensions.cs

@@ -47,6 +47,7 @@ namespace HelloShop.OrderingService.Extensions
             });
 
             builder.Services.AddHostedService<GracePeriodWorker>();
+            builder.Services.AddHostedService<PaymentWorker>();
         }
 
         public static WebApplication MapApplicationEndpoints(this WebApplication app)

src/HelloShop.OrderingService/Workers/PaymentWorker.cs

@@ -0,0 +1,50 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.OrderingService.DistributedEvents.Events;
+using HelloShop.OrderingService.Entities.Orders;
+using HelloShop.OrderingService.Infrastructure;
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+using Microsoft.EntityFrameworkCore;
+
+namespace HelloShop.OrderingService.Workers
+{
+    public class PaymentWorker(IServiceScopeFactory serviceScopeFactory, ILogger<PaymentWorker> logger) : BackgroundService
+    {
+        protected async override Task ExecuteAsync(CancellationToken stoppingToken)
+        {
+
+            while (!stoppingToken.IsCancellationRequested)
+            {
+                if (logger.IsEnabled(LogLevel.Information))
+                {
+                    logger.LogInformation("{Worker} background task is doing background work.", GetType().Name);
+                }
+
+                using var scope = serviceScopeFactory.CreateAsyncScope();
+                var dbContext = scope.ServiceProvider.GetRequiredService<OrderingServiceDbContext>();
+                var distributedEventBus = scope.ServiceProvider.GetRequiredService<IDistributedEventBus>();
+
+                bool paymentSucceeded = Random.Shared.NextDouble() > 0.3;
+
+                try
+                {
+                    var orders = await dbContext.Set<Order>().Include(o => o.OrderItems).Where(o => o.OrderStatus == OrderStatus.StockConfirmed).ToListAsync(stoppingToken);
+
+                    foreach (var order in orders)
+                    {
+                        DistributedEvent @event = paymentSucceeded ? new OrderPaymentSucceededDistributedEvent(order.Id) : new OrderPaymentFailedDistributedEvent(order.Id);
+
+                        await distributedEventBus.PublishAsync(@event, stoppingToken);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    logger.LogError(ex, "Error occurred executing {Worker} background task.", GetType().Name);
+                }
+
+                await Task.Delay(TimeSpan.FromSeconds(10), stoppingToken);
+            }
+        }
+    }
+}

src/HelloShop.ProductService/DistributedEvents/EventHandling/OrderPaidDistributedEventHandler.cs

@@ -0,0 +1,25 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.ProductService.DistributedEvents.Events;
+using HelloShop.ProductService.Entities.Products;
+using HelloShop.ProductService.Infrastructure;
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+
+namespace HelloShop.ProductService.DistributedEvents.EventHandling
+{
+    public class OrderPaidDistributedEventHandler(ProductServiceDbContext dbContext) : IDistributedEventHandler<OrderPaidDistributedEvent>
+    {
+        public async Task HandleAsync(OrderPaidDistributedEvent @event)
+        {
+            foreach (var orderStockItem in @event.OrderStockItems)
+            {
+                var product = await dbContext.Set<Product>().FindAsync(orderStockItem.ProductId) ?? throw new Exception($"Product with id {orderStockItem.ProductId} not found");
+
+                product.AvailableStock -= orderStockItem.Units;
+            }
+
+            await dbContext.SaveChangesAsync();
+        }
+    }
+}

src/HelloShop.ProductService/DistributedEvents/Events/OrderPaidDistributedEvent.cs

@@ -0,0 +1,9 @@
+// Copyright (c) HelloShop Corporation. All rights reserved.
+// See the license file in the project root for more information.
+
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+
+namespace HelloShop.ProductService.DistributedEvents.Events
+{
+    public record OrderPaidDistributedEvent(int OrderId, IEnumerable<OrderStockItem> OrderStockItems) : DistributedEvent;
+}