使用分布式事件总线异步通信

src/HelloShop.OrderingService/Commands/Orders/CreateOrderCommandHandler.cs

@@ -2,17 +2,19 @@
 // See the license file in the project root for more information.
 
 using AutoMapper;
+using HelloShop.OrderingService.DistributedEvents.Events;
 using HelloShop.OrderingService.Entities.Buyers;
 using HelloShop.OrderingService.Entities.Orders;
 using HelloShop.OrderingService.Infrastructure;
 using HelloShop.OrderingService.LocalEvents;
 using HelloShop.OrderingService.Services;
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
 using MediatR;
 using Microsoft.EntityFrameworkCore;
 
 namespace HelloShop.OrderingService.Commands.Orders
 {
-    public class CreateOrderCommandHandler(IMediator mediator, OrderingServiceDbContext dbContext, IMapper mapper) : IRequestHandler<CreateOrderCommand, bool>
+    public class CreateOrderCommandHandler(IMediator mediator, OrderingServiceDbContext dbContext, IMapper mapper, IDistributedEventBus distributedEventBus) : IRequestHandler<CreateOrderCommand, bool>
     {
         public async Task<bool> Handle(CreateOrderCommand request, CancellationToken cancellationToken)
         {
@@ -45,6 +47,8 @@ namespace HelloShop.OrderingService.Commands.Orders
 
             await mediator.Publish(new OrderStartedLocalEvent(order), cancellationToken);
 
+            await distributedEventBus.PublishAsync(new OrderStartedDistributedEvent(request.UserId), cancellationToken);
+
             return await Task.FromResult(true);
         }
     }

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

@@ -0,0 +1,22 @@
+// 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;
+
+namespace HelloShop.OrderingService.DistributedEvents.EventHandling
+{
+    public class OrderStockConfirmedDistributedEventHandler(OrderingServiceDbContext dbContext) : IDistributedEventHandler<OrderStockConfirmedDistributedEvent>
+    {
+        public async Task HandleAsync(OrderStockConfirmedDistributedEvent @event)
+        {
+            Order order = await dbContext.Set<Order>().FindAsync(@event.OrderId) ?? throw new Exception($"Order with id {@event.OrderId} not found");
+
+            order.OrderStatus = OrderStatus.StockConfirmed;
+
+            await dbContext.SaveChangesAsync();
+        }
+    }
+}

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

@@ -0,0 +1,23 @@
+// 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;
+
+namespace HelloShop.OrderingService.DistributedEvents.EventHandling
+{
+    public class OrderStockRejectedDistributedEventHandler(OrderingServiceDbContext dbContext) : IDistributedEventHandler<OrderStockRejectedDistributedEvent>
+    {
+        public async Task HandleAsync(OrderStockRejectedDistributedEvent @event)
+        {
+            Order order = await dbContext.Set<Order>().FindAsync(@event.OrderId) ?? throw new Exception($"Order with id {@event.OrderId} not found");
+
+            order.OrderStatus = OrderStatus.Cancelled;
+            order.Description = "Product out of stock.";
+
+            await dbContext.SaveChangesAsync();
+        }
+    }
+}

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

@@ -0,0 +1,11 @@
+// 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 OrderAwaitingValidationDistributedEvent(int OrderId, IEnumerable<OrderStockItem> OrderStockItems) : DistributedEvent;
+
+    public record OrderStockItem(int ProductId, int Units);
+}

src/HelloShop.OrderingService/DistributedEvents/Events/OrderStartedDistributedEvent.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 OrderStartedDistributedEvent(int UserId) : DistributedEvent;
+}

src/HelloShop.OrderingService/DistributedEvents/Events/OrderStockConfirmedDistributedEvent.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 OrderStockConfirmedDistributedEvent(int OrderId) : DistributedEvent;
+}

src/HelloShop.OrderingService/DistributedEvents/Events/OrderStockRejectedDistributedEvent.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 OrderStockRejectedDistributedEvent(int OrderId) : DistributedEvent;
+}

src/HelloShop.OrderingService/Extensions/Extensions.cs

@@ -5,6 +5,9 @@ using HelloShop.OrderingService.Behaviors;
 using HelloShop.OrderingService.Constants;
 using HelloShop.OrderingService.Infrastructure;
 using HelloShop.OrderingService.Services;
+using HelloShop.OrderingService.Workers;
+using HelloShop.ServiceDefaults.DistributedEvents.Abstractions;
+using HelloShop.ServiceDefaults.DistributedEvents.DaprBuildingBlocks;
 using HelloShop.ServiceDefaults.Extensions;
 using Microsoft.EntityFrameworkCore;
 using System.Reflection;
@@ -35,11 +38,21 @@ namespace HelloShop.OrderingService.Extensions
             builder.Services.AddModelMapper().AddModelValidator();
 
             builder.Services.AddTransient<ISmsSender, MessageService>().AddTransient<IEmailSender, MessageService>();
+
+            builder.AddDaprDistributedEventBus().AddSubscriptionFromAssembly();
+
+            builder.Services.Configure<HostOptions>(hostOptions =>
+            {
+                hostOptions.BackgroundServiceExceptionBehavior = BackgroundServiceExceptionBehavior.Ignore;
+            });
+
+            builder.Services.AddHostedService<GracePeriodWorker>();
         }
 
         public static WebApplication MapApplicationEndpoints(this WebApplication app)
         {
             app.UseDataSeedingProviders();
+            app.MapDaprDistributedEventBus();
 
             return app;
         }

src/HelloShop.OrderingService/Workers/GracePeriodWorker.cs

@@ -0,0 +1,55 @@
+// 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 GracePeriodWorker(IServiceScopeFactory serviceScopeFactory, ILogger<GracePeriodWorker> 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>();
+
+                DateTimeOffset dateTimeOffset = DateTimeOffset.UtcNow.AddMinutes(-1);
+
+                try
+                {
+                    var orders = await dbContext.Set<Order>().Include(o => o.OrderItems).Where(o => o.OrderStatus == OrderStatus.Submitted && o.OrderDate >= dateTimeOffset).ToListAsync(stoppingToken);
+
+                    foreach (var order in orders)
+                    {
+                        order.OrderStatus = OrderStatus.AwaitingValidation;
+
+                        var orderStockList = order.OrderItems.Select(orderItem => new OrderStockItem(orderItem.ProductId, orderItem.Units));
+
+                        await distributedEventBus.PublishAsync(new OrderAwaitingValidationDistributedEvent(order.Id, orderStockList), stoppingToken);
+
+                        await dbContext.SaveChangesAsync(stoppingToken);
+                    }
+
+                }
+                catch (Exception ex)
+                {
+                    logger.LogError(ex, "Error occurred executing {Worker} background task.", GetType().Name);
+                }
+
+                await Task.Delay(TimeSpan.FromSeconds(10), stoppingToken);
+            }
+        }
+    }
+}