StateMachine instead of compensation

ModularMonolith/Communication/Shop.Communication.UseCases/Emails/Commands/ScheduleEmail/ScheduleEmailCommand.cs

@@ -0,0 +1,13 @@
+using MediatR;
+
+namespace Shop.Communication.UseCases.Emails.Commands.ScheduleEmail
+{
+    internal class ScheduleEmailCommand : IRequest
+    {
+        public string Address { get; set; }
+        public string Subject { get; set; }
+        public string Body { get; set; }
+        public int UserId { get; set; }
+        public int OrderId { get; set; }
+    }
+}

ModularMonolith/Communication/Shop.Communication.UseCases/Emails/Commands/ScheduleEmail/ScheduleEmailCommandHandler.cs

@@ -0,0 +1,30 @@
+using System.Threading;
+using System.Threading.Tasks;
+using AutoMapper;
+using MediatR;
+using Shop.Communication.DataAccess.Interfaces;
+using Shop.Communication.Entities;
+
+namespace Shop.Communication.UseCases.Emails.Commands.ScheduleEmail
+{
+    internal class ScheduleEmailCommandHandler : AsyncRequestHandler<ScheduleEmailCommand>
+    {
+        private readonly ICommunicationDbContext _dbContext;
+        private readonly IMapper _mapper;
+
+        public ScheduleEmailCommandHandler(ICommunicationDbContext dbContext, IMapper mapper)
+        {
+            _dbContext = dbContext;
+            _mapper = mapper;
+        }
+
+        protected override async Task Handle(ScheduleEmailCommand request, CancellationToken cancellationToken)
+        {
+            var email = _mapper.Map<Email>(request);
+
+            _dbContext.Emails.Add(email);
+
+            await _dbContext.SaveChangesAsync(cancellationToken);
+        }
+    }
+}

ModularMonolith/Communication/Shop.Communication.UseCases/Emails/Mappings/EmailsAutoMapperProfile.cs

@@ -1,5 +1,6 @@
 using AutoMapper;
 using Shop.Communication.Entities;
+using Shop.Communication.UseCases.Emails.Commands.ScheduleEmail;
 using Shop.Communication.UseCases.Emails.Dto;
 
 namespace Shop.Communication.UseCases.Emails.Mappings
@@ -9,6 +10,7 @@ internal class EmailsAutoMapperProfile : Profile
         public EmailsAutoMapperProfile()
         {
             CreateMap<Email, EmailDto>();
+            CreateMap<ScheduleEmailCommand, Email>();
         }
     }
 }

ModularMonolith/Communication/Shop.Communication.UseCases/Properties/AssemblyInfo.cs

@@ -2,3 +2,4 @@
 
 [assembly: InternalsVisibleTo("Shop.Communication.Contract.Implementation")]
 [assembly: InternalsVisibleTo("Shop.Communication.Controllers")]
+[assembly: InternalsVisibleTo("Shop.Web")]

ModularMonolith/Order/Shop.Order.Controllers/OrdersController.cs

@@ -2,7 +2,6 @@
 using System.Threading.Tasks;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;
-using Shop.Order.UseCases.Orders.Commands.CreateOrder;
 using Shop.Order.UseCases.Orders.Dto;
 using Shop.Order.UseCases.Orders.Queries.GetOrder;
 
@@ -25,12 +24,5 @@ public async Task<ActionResult<OrderDto>> Get(int id, CancellationToken token)
         {
             return await _mediator.Send(new GetOrderRequest { Id = id }, token);
         }
-
-        // POST api/orders
-        [HttpPost]
-        public async Task<ActionResult<int>> Post([FromBody] CreateOrderDto createOrderDto, CancellationToken token)
-        {
-            return await _mediator.Send(new CreateOrderRequest { CreateOrderDto = createOrderDto }, token);
-        }
     }
 }

ModularMonolith/Order/Shop.Order.UseCases/Orders/Commands/CreateOrder/CreateOrderRequestHandler.cs

@@ -4,7 +4,6 @@
 using AutoMapper;
 using MediatR;
 using Shop.Framework.UseCases.Interfaces.Services;
-using Shop.Order.Contract.Notifications;
 using Shop.Order.DataAccess.Interfaces;
 
 namespace Shop.Order.UseCases.Orders.Commands.CreateOrder
@@ -14,18 +13,15 @@ internal class CreateOrderRequestHandler : IRequestHandler<CreateOrderRequest, i
         private readonly IOrderDbContext _dbContext;
         private readonly IMapper _mapper;
         private readonly ICurrentUserService _currentUserService;
-        private readonly IPublisher _publisher;
 
         public CreateOrderRequestHandler(
             IOrderDbContext dbContext, 
             IMapper mapper, 
-            ICurrentUserService currentUserService,
-            IPublisher publisher)
+            ICurrentUserService currentUserService)
         {
             _dbContext = dbContext;
             _mapper = mapper;
             _currentUserService = currentUserService;
-            _publisher = publisher;
         }
 
         public async Task<int> Handle(CreateOrderRequest request, CancellationToken cancellationToken)
@@ -38,20 +34,6 @@ public async Task<int> Handle(CreateOrderRequest request, CancellationToken canc
 
             await _dbContext.SaveChangesAsync(cancellationToken);
 
-            try
-            {
-                await _publisher.Publish(new OrderCreatedNotification(order.Id, _currentUserService.Id, _currentUserService.Email), cancellationToken);
-            }
-            catch (Exception e) //Compensation
-            {
-                //log exception
-
-                _dbContext.Orders.Remove(order);
-                await _dbContext.SaveChangesAsync(cancellationToken);
-
-                throw;
-            }
-
             return order.Id;
         }
     }

ModularMonolith/Order/Shop.Order.UseCases/Orders/Commands/DeleteOrder/DeleteOrderCommand.cs

@@ -0,0 +1,9 @@
+using MediatR;
+
+namespace Shop.Order.UseCases.Orders.Commands.DeleteOrder
+{
+    internal class DeleteOrderCommand : IRequest
+    {
+        public int Id { get; set; }
+    }
+}

ModularMonolith/Order/Shop.Order.UseCases/Orders/Commands/DeleteOrder/DeleteOrderCommandHandler.cs

@@ -0,0 +1,29 @@
+using System.Threading;
+using System.Threading.Tasks;
+using MediatR;
+using Shop.Framework.UseCases.Interfaces.Exceptions;
+using Shop.Order.DataAccess.Interfaces;
+
+namespace Shop.Order.UseCases.Orders.Commands.DeleteOrder
+{
+    internal class DeleteOrderCommandHandler : AsyncRequestHandler<DeleteOrderCommand>
+    {
+        private readonly IOrderDbContext _dbContext;
+
+        public DeleteOrderCommandHandler(IOrderDbContext dbContext)
+        {
+            _dbContext = dbContext;
+        }
+
+        protected override async Task Handle(DeleteOrderCommand request, CancellationToken cancellationToken)
+        {
+            var order = await _dbContext.Orders.FindAsync(request.Id);
+
+            if (order == null) throw new EntityNotFoundException();
+
+            _dbContext.Orders.Remove(order);
+
+            await _dbContext.SaveChangesAsync(cancellationToken);
+        }
+    }
+}

ModularMonolith/Order/Shop.Order.UseCases/Properties/AssemblyInfo.cs

@@ -1,5 +1,6 @@
 using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("Shop.Order.Controllers")]
+[assembly: InternalsVisibleTo("Shop.Web")]
 
 [assembly: InternalsVisibleTo("Shop.Tests.Unit")]

ModularMonolith/Shop.Tests.Unit/WorkflowTests.cs → ModularMonolith/Shop.Tests.Unit/StateMachineTests.cs

@@ -17,19 +17,17 @@
 using Shop.Communication.UseCases;
 using Shop.Emails.Implementation;
 using Shop.Framework.UseCases.Implementation;
-using Shop.Framework.UseCases.Interfaces.Services;
 using Shop.Order.Contract.Implementation;
 using Shop.Order.DataAccess.MsSql;
 using Shop.Order.UseCases;
-using Shop.Order.UseCases.Orders.Commands.CreateOrder;
 using Shop.Order.UseCases.Orders.Dto;
 using Shop.Utils.Modules;
-using Shop.Web.Utils;
+using Shop.Web.StateMachines;
 using Xunit;
 
 namespace Shop.Tests.Unit
 {
-    public class WorkflowTests
+    public class StateMachineTests
     {
         [Fact]
         public async Task Should_Create_Order_And_Email()
@@ -43,13 +41,15 @@ public async Task Should_Create_Order_And_Email()
 
             var (orderDbContext, communicationDbContext) = await CreateDatabase(connectionString);
 
-            var sender = serviceProvider.GetRequiredService<ISender>();
+            var stateMachine = serviceProvider.GetRequiredService<CreateOrderStateMachine>();
             var dto = new CreateOrderDto { Items = new[] { new OrderItemDto { Count = 1, ProductId = 1 } } };
 
             //act
-            var orderId = await sender.Send(new CreateOrderRequest { CreateOrderDto = dto });
+            var orderId = await stateMachine.RunAsync(dto, CancellationToken.None);
 
             //assert
+            Assert.NotNull(orderId);
+
             var order = await orderDbContext.Orders.FirstOrDefaultAsync(x => x.Id == orderId);
             var email = await communicationDbContext.Emails.FirstOrDefaultAsync(x => x.OrderId == orderId);
 
@@ -79,13 +79,15 @@ public async Task Should_Not_Create_Order_And_Email_On_Error()
 
             var (orderDbContext, communicationDbContext) = await CreateDatabase(connectionString);
 
-            var sender = serviceProvider.GetRequiredService<ISender>();
+            var stateMachine = serviceProvider.GetRequiredService<CreateOrderStateMachine>();
             var dto = new CreateOrderDto { Items = new[] { new OrderItemDto { Count = 1, ProductId = 1 } } };
 
             //act
-            await Assert.ThrowsAsync<Exception>(() => sender.Send(new CreateOrderRequest { CreateOrderDto = dto }));
+            var orderId = await stateMachine.RunAsync(dto, CancellationToken.None);
 
             //assert
+            Assert.Null(orderId);
+
             var ordersCount = await orderDbContext.Orders.CountAsync();
             var emailsCount = await communicationDbContext.Emails.CountAsync();
 
@@ -160,6 +162,8 @@ private ServiceCollection CreateServiceProvider(IConfiguration configuration)
             services.RegisterModule<OrderContractModule>(configuration);
             services.RegisterModule<OrderUseCasesModule>(configuration);
 
+            services.AddScoped<CreateOrderStateMachine>();
+
             return services;
         }
 

ModularMonolith/Shop.Web/Controllers/OrdersController.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using Shop.Order.UseCases.Orders.Dto;
+using Shop.Web.StateMachines;
+
+namespace Shop.Web.Controllers
+{
+    [Route("api/[controller]")]
+    [ApiController]
+    internal class OrdersController : ControllerBase
+    {
+        [HttpPost]
+        public async Task<ActionResult<int>> Post([FromBody] CreateOrderDto createOrderDto, CancellationToken cancellationToken, [FromServices]CreateOrderStateMachine stateMachine)
+        {
+            var orderId = await stateMachine.RunAsync(createOrderDto, cancellationToken);
+            if (orderId == null) throw new Exception("Unable to create order");
+            return orderId;
+        }
+    }
+}

ModularMonolith/Shop.Web/Properties/AssemblyInfo.cs

@@ -0,0 +1,5 @@
+using System.Runtime.CompilerServices;
+
+[assembly: InternalsVisibleTo("Shop.Tests.Unit")]
+
+

ModularMonolith/Shop.Web/Shop.Web.csproj

@@ -9,6 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Appccelerate.StateMachine" Version="5.1.0" />
     <PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="11.0.0" />
     <PackageReference Include="FluentScheduler" Version="5.5.1" />
     <PackageReference Include="MediatR.Extensions.Microsoft.DependencyInjection" Version="10.0.1" />

ModularMonolith/Shop.Web/Startup.cs

@@ -17,6 +17,7 @@
 using Shop.Emails.Implementation;
 using Shop.Framework.UseCases.Implementation;
 using Shop.Utils.Modules;
+using Shop.Web.StateMachines;
 
 namespace Shop.Web
 {
@@ -51,6 +52,8 @@ public void ConfigureServices(IServiceCollection services)
             services.RegisterModule<OrderContractModule>(Configuration);
             services.RegisterModule<OrderUseCasesModule>(Configuration);
 
+            services.AddScoped<CreateOrderStateMachine>();
+
             var sp = services.BuildServiceProvider();
 
             var requests = sp.GetServices<IBaseRequest>();