Prosta architektura dla nieprostego systemu

Prezentacja, którą pokazałem na 4Developers 2015.
Wstęp do CQRSa i krótkie omówienie tego co sprawia, że z zewnątrz wygląda na trudny - jego niezgodności z tradycyjnym podejściem.

Wcześniej znajdowała się tutaj wersja z Software Craftsmanship Silesia z listopada.

Transcript

1. Prosta architektura dla nieprostego systemu Mateusz Stasch
2. Mateusz Stasch @mattstasch http://mattstasch.net
3. CQRS
4. CQRS
5. CQRS jest trudny
6. CQRS jest trudny *
7. CQRS
8. CQRS Implementacja zasady CQS w postaci wzorca architektonicznego*
9. DB Model Business Logic UI DTO DTO ORM
10. DB Domain Model Commands UI DTO DTO ORM Queries
11. DB WRITE Domain Model Commands UI DTO DTO ORM Queries READ Model
12. DB WRITE Domain Model Commands UI DTO DTO ORM Queries SELECT … FROM … WHERE … READ Model
13. READ DB WRITE Domain Model Commands UI DTO DTO Queries SELECT … FROM … WHERE … WRITE DB PROJECTION
14. READ DB WRITE Domain Model Commands UI DTO DTO Queries SELECT … FROM … WHERE … PROJECTION Event Stream
15. CQRS != ES
16. public class UserManager : IUserManager { public UserDetails UpdateUserStatus(...) { // ... return user; } }
17. public class UserManager : IUserManager { public UserDetails UpdateUserStatus(...) { // ... return user; } }
18. RESPONSIBILITY?
20. Manager
22. Command – zmienia stan systemu Query – odczytuje stan systemu
23. public interface IQuery<out TResult> { TResult Execute(); }
24. public interface IQuery<out TResult> { TResult Execute(); } public class QueryDispatcher : IQueryDispatcher { TResult Run<TResult>(IQuery<TResult> query) { using(var tx = session.OpenReadOnlyTransaction()) { return query.Execute(); } } }
25. public interface IQuery<out TResult> { TResult Execute(); } public class QueryDispatcher : IQueryDispatcher { TResult Run<TResult>(IQuery<TResult> query) { using(var tx = session.OpenReadOnlyTransaction()) { return query.Execute(); } } }
26. public interface ICommandHandler<in TCommand> { void Execute(TCommand command); }
27. public interface ICommandHandler<in TCommand> { void Execute(TCommand command); } public class CommandDispatcher : ICommandDispatcher { public void Execute<in TCommand>(TCommand command) { var handler = ResolveCommandHandler<TCommand>(); handler.Execute(command); } }
28. public interface ICommandHandler<in TCommand> { void Execute(TCommand command); } public class CommandDispatcher : ICommandDispatcher { public void Execute<in TCommand>(TCommand command) { var handler = ResolveCommandHandler<TCommand>(); handler.Execute(command); } }
29. Semantyka
30. Ekspresywność kodu Semantyka
31. Ekspresywność kodu Semantyka Single Responsibility
32. using(var tx = session.BeginTransaction()) { try { var user = repository.GetById<UserDetails>(id); user.Status = newStatus; tx.Commit(); return user; } catch { tx.Rollback(); throw; } }
33. public class UserManager : IUserManager { [Transactional] public UserDetails UpdateUserStatus(...) { // ... return user; } }
34. using(var tx = session.BeginTransaction()) { try { var user = repository.GetById<UserDetails>(id); user.Status = newStatus; tx.Commit(); return user; } catch { tx.Rollback(); throw; } }
35. using(var tx = session.BeginTransaction()) { try { var user = repository.GetById<UserDetails>(id); user.Status = newStatus; tx.Commit(); return user; } catch { tx.Rollback(); throw; } }
36. public UpdateUserStatusCommandHandler : ICommandHandler<UpdateUserStatusCommand> { public void Execute(UpdateUserStatusCommand command) { var user = repository.GetById(command.Id); user.Status = command.NewStatus; } }
37. public class CommandDispatcher : ICommandDispatcher { public void Execute<in TCommand>(TCommand command) { var handler = ResolveCommandHandler<TCommand>(); using(var tx = session.OpenTransaction()) { try { handler.Execute(command); tx.Commit(); } catch { tx.Rollback(); throw; } } } }
38. public class TransactionalCommandDispatcherDecorator : ICommandDispatcher { public TransactionalCommandDispatcher(ICommandDispatcher …) {…} public void Execute<in TCommand>(TCommand command) { using(var tx = session.OpenTransaction()) { try { decoratedDispatcher.Execute(command); tx.Commit(); } catch { tx.Rollback(); throw; } } } }
39. Logika biznesowa Infrastruktura
40. Database Infrastructure Domain Business Logic UI
41. Domena
42. Database Infrastructure Domain Querying UI
43. Database Infrastructure Domain Querying UI D e p e n d e n c y I n j e c t i o n IQuery IQueryDispatcher GetUserDetailsQuery
44. Database Infrastructure Domain Querying UI IUserRepository ICommand ICommandHandler ICommandDispatcher D e p e n d e n c y I n j e c t i o n IQuery IQueryDispatcher UpdateStatusCommand(Handler) GetUserDetailsQuery
45. Database Infrastructure Domain Querying UI IUserRepository ICommand ICommandHandler ICommandDispatcher D e p e n d e n c y I n j e c t i o n IQuery IQueryDispatcher UpdateStatusCommand(Handler) CommandDispatcher UserRepository QueryDispatcher GetUserDetailsQuery
46. Domain Infrastructure ICommandDispatcher CommandDispatcher ICommand DeactivateUserCommand IQuery QueryDispatcher IUserRepository UserRepository …
47. using(var tx = session.BeginTransaction()) { try { var user = repository.GetById<UserDetails>(id); user.Status = newStatus; tx.Commit(); return user; } catch { tx.Rollback(); throw; } }
48. public UpdateUserStatusCommandHandler : ICommandHandler<UpdateUserStatusCommand> { // ... public void Execute(UpdateUserStatusCommand command) { var user = repository.GetById(command.Id); user.Status = command.NewStatus; } }
49. public UpdateUserStatusCommandHandler : ICommandHandler<UpdateUserStatusCommand> { // ... public void Execute(UpdateUserStatusCommand command) { var user = repository.GetById(command.Id); user.Status = command.NewStatus; } }
50. Robienie CRUDa w CQRSie jest bezsensowne!
51. Robienie CRUDa w CQRSie jest bezsensowne!
52. public DeactivateUserCommandHandler : ICommandHandler<DeactivateUserCommand> { // ... public void Execute(DeactivateUserCommand command) { var user = repository.GetById(command.Id); user.Deactivate(); } }
53. READ DB WRITE Domain Model Command s UI ORM Queries SELECT … FROM … WHERE … WRITE DB PROJECTION
54. READ DB WRITE Domain Model Command s UI ORM Queries SELECT … FROM … WHERE … WRITE DB PROJECTION
55. READ DB
56. READ DB WRITE DB !=
57. READ DB WRITE DB != Eager Read Derivation
58. READ DB == READ DB READ DB READ DB
59. READ DB WRITE Domain Model Command s UI ORM Queries SELECT … FROM … WHERE … WRITE DB PROJECTION Eventual Consistency
60. DB WRITE Domain Model Command s UI ORM Queries SELECT … FROM … WHERE … READ Model
61. Jak zacząć?
62. Jakiś Framework?
63. Nope!
64. Napisz to sam! To proste!
65. public interface IQuery<out TResult> { TResult Execute(); } public class QueryDispatcher : IQueryDispatcher { TResult Run<out TResult>(IQuery<TResult> query) { using(var tx = session.OpenReadOnlyTransaction()) { return query.Execute(); } } }
66. public interface IQuery<out TResult> { TResult Execute(); } public class QueryDispatcher : IQueryDispatcher { TResult Run<out TResult>(IQuery<TResult> query) { using(var tx = session.OpenReadOnlyTransaction()) { return query.Execute(); } } }
67. public interface ICommandHandler<in TCommand> { void Execute(TCommand command); } public class CommandDispatcher : ICommandDispatcher { public void Execute<in TCommand>(TCommand command) { var handler = ResolveCommandHandler<TCommand>(); handler.Execute(command); } }
68. public class TaskController { public TaskController(TaskManager taskManager) {…} public ActionResult MarkAsFinalized(TaskId taskId) { taskManager.UpdateStatus(taskId, TaskStatuses.Finalized); taskManager.UpdateFinalizationDate(taskId, DateTime.Now); taskManager.UpdateFinalizedBy(taskId, CurrentUser.Id); return Success; } }
69. public class TaskController : Controller { public TaskController(CommandDispatcher commandDispatcher) {…} public ActionResult MarkAsFinalized(TaskId taskId) { var finalizeCommand = new FinalizeTaskCommand(taskId, CurrrentUser.Id); commandDispatcher.Execute(finalizeCommand); return Success; } }
70. public class FinalizeTaskCommand { public FinalizeTaskCommand(TaskId id, UserId finalizingUser) {…} public TaskId Id { get; private set; } public UserId FinalizingUser { get; private set; } }
71. public class FinalizeTaskCommandHandler : ICommandHandler<FinalizeTaskCommand> { public FinalizeTaskCommandHanlder( ITaskRepository repository, IDateTimeProvider dtp ) {…} public void Execute(FinalizeTaskCommand command) { var task = repository.GetById(command.Id); task.Status = TaskStatuses.Done; task.FinalizedAt = dtp.Now(); task.FinalizedBy = command.FinalizingUser; } }
72. public class FinalizeTaskCommandHandler : ICommandHandler<FinalizeTaskCommand> { public FinalizeTaskCommandHanlder( ITaskRepository repository, IDateTimeProvider dtp ) {…} public void Execute(FinalizeTaskCommand command) { var task = repository.GetById(command.Id); task.Finalize(dtp.Now(), command.FinalizingUser); } }
73. Q&A Prosta architektura dla nieprostego systemu Mateusz Stasch
74. Dziękuję za uwagę Prosta architektura dla nieprostego systemu Mateusz Stasch