CQRS and Event Sourcing

Jefersson Nathan (@malukenho)'s talk on #PHPeste about CQRS and Event Sourcing

Transcript

1. CQRS and Event Sourcing
2. MALUKENHO
3. CQRS COMMANDS VALUE OBJECTS ENTITY EVENT SOURCING DOMAIN EVENTS EVENTS STORE AGGREGATE ROOT PROJECTORS LISTENERS
4. DDD CQRS ES Arquitetura Conceitos
6. CQRS
7. WRITE READ
8. CQRS CQS
9. <?php 
 declare(strict_types=1);
 
 final class UserService
 {
 public function enable(Uuid $userId) : void;
 public function disable(Uuid $userId) : void;
 public function fetchAll() : UserCollection;
 } Customer Service
10. <?php declare(strict_types=1);
 
 final class UserWrite
 {
 public function enable(Uuid $userId) : void;
 public function disable(Uuid $userId) : void;
 } <?php declare(strict_types=1);
 
 final class UserRead
 {
 public function fetchAll(Uuid $userId) : UserCollection;
 }
11. WRITE MODEL
12. COMMAND COMMAND BUS COMMAND HANDLER
13. COMMAND
14. COMANDOS SÃO IMPERATIVOS
15. COMANDOS NÃO DEVEM TER RETORNO
16. COMANDOS SÃO VALUE OBJECTS
17. COMANDOS SÃO SERIALIZÁVEIS
18. Register User Command <?php
 
 declare(strict_types=1);
 
 final class RegisterUser
 {
 private $username;
 
 private function __construct(string $username)
 {
 $this->username = $username;
 }
 
 public static function fromUserName(string $username) : self
 {
 return new self($username);
 }
 
 public function username() : string
 {
 return $this->username;
 }
 }
19. COMMAND BUS
20. Simple command bus <?php
 
 declare(strict_types=1);
 
 $commandBus = static function ($command) use ($container) : void {
 $commandClassName = get_class($command);
 
 if (! $container->has($commandClassName)) {
 throw CommandBusException::cannotResolveToCommandHandler($command);
 }
 
 $container->get($commandClassName)($command);
 };

21. COMMAND HANDLER
22. <?php
 
 declare(strict_types=1);
 
 final class RegisterUserHandler
 {
 /**
 * @var UserRepositoryInterface
 */
 private $users;
 
 public function __construct(UserRepositoryInterface $users)
 {
 $this->users = $users;
 }
 
 /**
 * @param RegisterUser $registerUser
 *
 * @return void
 */
 public function __invoke(RegisterUser $registerUser) : void
 {
 $username = $registerUser->username();
 
 $this->users->store(User::registerNew($username, UserId::newUserId()));
 }
 }
23. Register User
 (Command) Command Bus Command Handler
24. All together $commandBus(RegisterUser::fromUserName(
 UserName::fromString('admin')
 ));

25. <?php
 
 declare(strict_types=1);
 
 $app = new \Zend\Expressive\Application();
 
 $app->post(
 
 '/register-user',
 
 function ($request, $response) use ($commandBus) : Response {
 
 $commandBus(RegisterUser::fromUserName(
 
 UserName::fromString($request->getQueryParams()['username'])
 
 ));
 
 
 return $response->withAddedHeader('Location', '/home');
 }
 );
 
 $app->run();
 Middleware
26. VALUE OBJECT
27. $commandBus(RegisterUser::fromUserName(
 UserName::fromString('admin')
 ));
 Where?
28. SELF VALIDATED
29. NAMED CONSTRUCTORS <?php
 
 declare(strict_types=1);
 
 final class Email
 {
 private $email;
 
 private function __construct(string $email)
 { Assert::isValidEmail($email); 
 $this->email = $email;
 }
 
 public static function fromString(string $email) : self
 {
 return new self($email);
 }
 }
30. $commandBus(RegisterUser::fromUserName(
 UserName::fromString('admin')
 ));
 __construct( )
31. new User('malukenho', 5);
32. User::fromNameAndFingersByHand( ’malukenho’, 5 );
33. NAMED CONSTRUCTOR
34. NAMED CONSTRUCTORS <?php
 
 declare(strict_types=1);
 
 final class RegisterUser
 {
 private $username;
 
 private function __construct(string $username)
 {
 $this->username = $username;
 }
 
 public static function fromString(string $username) : self
 {
 return new self($username);
 } public static function fromUser(User $user) : self
 {
 return new self($user->getUsername());
 }
 }
35. ANEMIC DOMAIN
36. ENTITY
37. *IDENTITY
38. UUID
39. UUID 
 Uuid::uuid4(); // 7b733ff1-42d2-4638-b7bd-411997c32b11 Value Object
40. EVITAR INVALID STATE DA ENTIDADE
41. INDEPENDE DE STORAGE
42. #TIPS
43. PERSISTÊNCIA ORM
44. NÃO USE ANNOTATIONS
45. D2.5 IDs __toString();
46. ES EVENT SOURCING
47. WARNING USADO EM CONJUNTO COM CQRS
48. HTTP VERB => COMMAND ROUTER => COMMAND BUS
49. DOMAIN EVENT EVENT BUS LISTENERS / PROJECTORS
50. EVENT STORMING
51. DOMAIN EVENTS
52. EVENTOS JÁ ACONTECERAM
53. Domain Event NewUserWasRegistered::fromUserName(
 UserName::fromString('malukenho')
 ));

54. EVENTOS NÃO PODEM SER DESFEITOS
55. Domain Event UserWasEnabled::fromUserName(...); 
 UserWasDisabled::fromUserName(...);

56. EVENT STORE
57. UUID EVENT PAYLOAD AGGREGATE_ID 1 UserWasCreated {name: “John”, …} 1 2 UserWasActivated {enabled: true} 2 3 UserWasFollowed {name: “Maria”} 1 4 UserWasExcludedBy Administrator {name: “Batman”} 5
58. EVENT STREAM
60. AUDIT LOG
61. Domain Events <?php
 
 declare(strict_types=1);
 
 final class UserWasCreated
 {
 private $userName;
 
 private function __construct(UserName $userName)
 {
 $this->userName = $userName;
 }
 
 public static function fromUserName(UserName $userName) : self
 {
 return new self($userName);
 }
 }
62. AGREGATE ROOT
63. AGGREGATES SÃO ENTIDADES
64. UserName Email USER AGGREGATE CPF Aggregates are Entities that hold other Entities and Value Objects that help keep data consistent. Gender Birthday
65. GARANTEM CONSISTENCIA
66. USER AGGREGATE • User#changeName( ) • User#disable( ) • User#enable( )
67. RECONSTRUINDO ESTADO A PARTIR DO HISTÓRICO DE UM OBJETO
68. Aggregate em uso $userAggregate->enable();
69. Disparando Eventos <?php
 
 declare(strict_types=1);
 
 class User
 {
 public function enable() : void
 {
 $this->recordThat(UserWasEnabled::fromUuid($this->uuid));
 }
 }

70. Changing Aggregate State <?php
 
 declare(strict_types=1);
 
 class User
 {
 public function whenUserWasEnable(UserWasEnabled $event) : void
 {
 $this->enabled = true;
 }
 }

71. Aggregate Root Trigger Events Projectors Event Listeners
72. PROJECTOR
73. Projector Example <?php
 
 declare(strict_types=1);
 
 final class UserWasEnabledProjector
 {
 private $connection;
 
 public function __construct(Connection $connection)
 {
 $this->connection = $connection;
 }
 
 public function __invoke(UserWasEnabled $event) : void
 {
 $this->connection->update(
 'users',
 ['enabled' => true],
 ['user_id' => (string) $event->getUserUuid()]
 );
 }
 }

74. EVENT LISTENERS
75. Event Listeners Example <?php
 
 declare(strict_types=1);
 
 final class UserWasEnabledListener
 {
 private $mailService;
 
 public function __construct(MailService $mailService)
 {
 $this->mailService = $mailService;
 }
 
 public function __invoke(UserWasEnabled $event) : void
 {
 $this->mailService->sendEnabledMail(
 $event->userMail()
 );
 }
 }
76. READ MODEL
77. REPOSITORY
78. HEXAGONAL ARCHITECTURE
79. DELIVERY MECHANISMS
80. <?php
 
 declare(strict_types=1);
 
 $app = new \Zend\Expressive\Application();
 
 $app->post(
 
 '/register-user',
 
 function ($request, $response) use ($commandBus) : Response {
 
 $commandBus(RegisterUser::fromUserName(
 
 UserName::fromString($request->getQueryParams()['username'])
 
 ));
 
 
 return $response->withAddedHeader('Location', '/home');
 }
 );
 
 $app->run();

81. WORKFLOW COMPLETO
82. Command Projectors Event Listeners Middleware Command Handler Aggregate Root
83. PERGUNTAS?
84. THANKS! @malukenho https://joind.in/talk/16a89
85. CREATE TABLE event_stream
 (
 event_id VARCHAR(36) PRIMARY KEY NOT NULL,
 version INTEGER NOT NULL,
 event_name VARCHAR(100) NOT NULL,
 payload TEXT NOT NULL,
 created_at VARCHAR(50) NOT NULL,
 aggregate_id VARCHAR(36) NOT NULL,
 aggregate_type VARCHAR(100) NOT NULL,
 causation_id VARCHAR(36) NOT NULL,
 causation_name VARCHAR(100) NOT NULL
 );