From framework coupled code to #microservices through #DDD /by @codelytv

From framework coupled code to
microservices through DDD modules
MVC, Testing, SOLID, Domain-Driven Design, Microservices
@CodelyTV
@Rafaoe 
@JavierCane#NubeloMeetup - IronHack 25/10/2016

Contents
gOld days The holy grail
of testing
Bigger &
faster
MVC frameworks
to the rescue
Serious
business Recap

Thanks!
@TangeloEng
@UvinumEng@Thatzad

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single.php

! Scripts
◕ index.php
◕ utils.php
◕ helpers.php
◕ include & require_once
The Concept
gOld days

! Have to learn
◕ Mindset
◕ Toolset
◗ PHP – Namespaces y autoloader Composer
◗ PHP – Estilo de código, estándar PSR 2
◗ Generación automática de código con IntelliJ y PhpStorm
◕ Domain
◗ Incomprehensible Finder Kata Refactoring
! All is The Concept
The Concept
gOld days

2. 
MVC frameworks to the rescue

<?php 
 
class ctrl_frontend extends Controller { 
 
function ctrl_frontend() 
{ 
parent::Controller();  
if (!isset($_SESSION)) { 
session_start(); 
} 
} 
 
function index() 
{ 
$this->load-
>model('sobre_nosotros','',TRUE); 
 
THE Controller

$datos['sobreNosotros']=$this-
>sobre_nosotros->getApartados(); 
 
$this->load->view('quienes',
$datos); 
break; 
case 'portfolio':  
$this->load-
>model('proyecto','',TRUE); 
$this->load-
>model('seguimiento_proyecto','',TRUE); 
 
$retorno = $this->proyecto-
>getProyectosPortfolio(); //primero obtengo los
datos de los proyectos 
 
if($retorno!=null){ //si hay
proyectps 
THE Controller

$datos); 
} 
 
private function sesionIniciada(){ 
$this->load->helper('url'); 
redirect('ctrl_backend_admin/
proyectoListar','refresh'); 
} 
 
private function error($msg){ 
$data["tipoError"]=$msg;  
$this->load->view('error',$data); 
} 
} 
 
/* End of file welcome.php */ 
/* Location: ./system/application/controllers/
welcome.php */ 
THE Controller

! Wins
◕ Controller per concept
◕ Isolate views & DB
◕ Active Record discovery
! New
◕ Singletons, singletons everywhere
◕ “Models” & other misconceptions
◕ DB structure defined by ORM
! Still
◕ Highly coupled code
◕ “Software Architecture is for UML people”
The Concept

! Internal doubts
◕ Por qué NO usar getters y setters | Tell don’t ask
◕ Por qué programar sin usar “else” – Cláusulas de guarda
◕ Varios returns en una función: ¿Mal o bien?
◕ Qué son los Code Smells y el Refactoring
◕ Constructores semánticos – Named constructors
The Concept

class CourseController extends FOSRestController 
{ 
public function getCourseAction(Request $request) 
{ 
return $this->getDoctrine() 
->getEntityManager() 
->createQueryBuilder() 
->select('c', 'v') 
->from('AppBundleModelCourse', 'c') 
->where('c.level', '>', $request-
>get('from_level', 0)) 
->getQuery() 
->execute(); 
} 
 
public function getCourseVideosAction($courseId) 
{ 
return $this->getDoctrine() 
Course controller
bit.ly/codelytv-course-ctrl-fw

class Course extends CourseBaseModel 
{ 
public $title; 
public $level; 
 
/** 
* @return mixed 
*/ 
public function getTitle() 
{ 
return $this->title; 
} 
 
/** 
* @param mixed $title 
*/ 
public function setTitle($title) 
{ 
$this->title = $title; 
Course model
bit.ly/codelytv-course-model-anemic

3. 
The holy grail of testing

! Wins
◕ If you don’t test, you’re going to suffer
◕ SOLID at a micro-design scale
! New
◕ Fragile test due to coupled code bases
◕ Test private methods or not?
! Still
◕ Controller per concept
◕ “Models”, singletons & laravel “facades”
The Concept

class CourseControllerTest extends
PHPUnit_Framework_TestCase 
{ 
public function testGetCoursesFilteredByLevel() 
{ 
$fromLevel = 0; 
$request = new Request(['from_level' =>
$fromLevel]); 
 
$container =
Mockery::mock(ContainerInterface::class); 
$doctrine =
Mockery::mock(Registry::class); 
$entityManager =
Mockery::mock(EntityManager::class); 
$queryBuilder =
Mockery::mock(QueryBuilder::class); 
$query =
Course controller test

$controller = new CourseController(); 
$controller->setContainer($container); 
$controllerResult = $controller-
>getCourseAction($request); 
$this->assertEquals( 
[ 
[ 
'title' => 'Codely mola', 
'level' => 2, 
], 
[ 
'title' => 'Aprende a decir
basicamente como Javi', 
'level' => 5, 
], 
], 
$controllerResult 
); 
} 
}
Course controller test
bit.ly/codelytv-course-ctrl-fw-test

! Testing help
◕ Cómo testear código acoplado: Costuras
◕ ¿Puedes ayudarte del #TDD para diseñar software? – Diseños
emergentes
◕ Cómo escuchar a tus test #NaveMisterioCodelyTV
◕ Por qué no usar static
! SOLID
◕ Principio de Responsabilidad Única SRP
◕ Principio de Segregación de Interfaces ISP
◕ Errores comunes al diseñar Interfaces
◕ Principio de Inversión de Dependencias DIP
The Concept

! Wins
◕ Decoupling business logic from framework
◕ Module per concept
◕ Semantics and clean code as something necessary
◕ Ease testing
◕ SOLID at a macro-design scale
◕ DB structure defined by domain
! New
◕ Unlearning process
◕ Deep research aptitude
◕ Theory misinterpretations
The Concept
Serious business

The growth stages of a programmer
1st stage 2nd stage 3rd stage
Knowledge Code complexity
Non scientific source :P : https://www.youtube.com/watch?v=2qYll837a_0

final class VideoController extends Controller 
{ 
private $bus; 
 
public function __construct(CommandBus $bus) 
{ 
$this->bus = $bus; 
} 
 
public function createAction( 
string $id, 
Request $request 
) { 
$command = new CreateVideoCommand( 
$id, 
$request->get('title'), 
$request->get('url'), 
$request->get('course_id') 
Video controller

{ 
$this->bus = $bus; 
} 
 
public function createAction( 
string $id, 
Request $request 
) { 
$command = new CreateVideoCommand( 
$id, 
$request->get('title'), 
$request->get('url'), 
$request->get('course_id') 
); 
 
$this->bus->dispatch($command); 
 
return new HttpCreatedResponse(); 
} 
} 
Video controller
bit.ly/codelytv-video-ctrl

final class CreateVideoCommandHandler implements Command 
{ 
private $creator; 
 
public function __construct(VideoCreator $creator) 
{ 
$this->creator = $creator; 
} 
 
public function __invoke(CreateVideoCommand $command) 
{ 
$id = new VideoId($command->id()); 
$title = new VideoTitle($command->title()); 
$url = new VideoUrl($command->url()); 
$courseId = new CourseId($command->courseId()); 
 
$this->creator->create(
$id,
$title,
$url,
$courseId
Create video command handler
bit.ly/codelytv-video-handler

final class VideoCreator 
{ 
private $repository; 
private $publisher; 
 
public function __construct( 
VideoRepository $repository, 
DomainEventPublisher $publisher 
) { 
$this->repository = $repository; 
$this->publisher = $publisher; 
} 
 
public function create( 
VideoId $id, 
VideoTitle $title, 
VideoUrl $url, 
CourseId $courseId 
Video creator application service

DomainEventPublisher $publisher 
) { 
$this->repository = $repository; 
$this->publisher = $publisher; 
} 
 
public function create( 
VideoId $id, 
VideoUrl $url, 
) { 
$video =
Video::create($id, $title, $url, $courseId); 
 
$this->repository->save($video); 
 
$this->publisher->publish(
$video->pullDomainEvents()
); 
} 
Video creator application service
bit.ly/codelytv-video-as

final class Video extends AggregateRoot 
{ 
private $id; 
private $title; 
private $url; 
private $courseId; 
 
public function __construct( 
VideoId $id, 
VideoUrl $url, 
) 
{ 
$this->id = $id; 
$this->title = $title; 
Video domain model

$this->courseId = $courseId; 
} 
 
public static function create( 
VideoId $id, 
VideoUrl $url, 
) 
{ 
$video =
new self($id, $title, $url, $courseId); 
 
$video->record(
new VideoCreatedDomainEvent($id)
); 
 
return $video; 
} 
Video domain model
bit.ly/codelytv-video-model

final class CreateVideoTest extends VideoModuleUnitTestCase 
{ 
/** @var CreateVideoCommandHandler */ 
private $handler; 
 
protected function setUp() 
{ 
parent::setUp(); 
 
$creator = new VideoCreator( 
$this->repository(), 
$this->domainEventPublisher() 
); 
 
$this->handler =
new CreateVideoCommandHandler($creator); 
} 
 
/** @test */ 
Create video test

public function it_should_create_a_video() 
{ 
$command = CreateVideoCommandStub::random(); 
 
$video = VideoStub::fromRawValues( 
$command->id(), 
$command->title(), 
$command->url(), 
$command->courseId() 
); 
 
$event = VideoCreatedDomainEventStub::fromRawValues( 
$command->id(), 
$command->title(), 
$command->url(), 
$command->courseId() 
); 
 
$this->shouldSaveVideo($video); 
$this->shouldPublishDomainEvents([$event]); 
 
$this->dispatch($command, $this->handler); 
Create video test
bit.ly/codelytv-video-test

! Tips / knowledge we’d like to have had
◕ Caso real de replanteamiento de diseño de Software
◕ Explicar Refactorings de forma didáctica – QWAN Cards
◕ Introducción Arquitectura Hexagonal – DDD
The Concept
Serious business

! Wins:
◕ (SOLID + Software Architecture theory + Testing)
accomplished
◕ Bounded context (even microservices) per concept
◕ More teams
! New:
◕ Accidental complexity (infrastructure, coordination…)
The Concept
Bigger & faster

! There’s no silver bullet approach. All depends on the context, and the
context will evolve.
! Conclusion: The Concept must be easy to promote with context evolutions
◕ From framework to modules:
◗ Decouple from outside infrastructure in order to isolate the domain
◗ Isolate use cases and work on cohesion
◕ From modules to Bounded Context:
◗ Decouple using buses to interact between them
◕ From whatever to Microservices:
◗ You don’t have to promote anything. This is not a change in terms
source code but in terms of infrastructure
The Concept
Recap

Tabla molona
Framework
coupled code
Modules
Bounded
Contexts
Microservices
Learning curve Low Medium High High++
Teams autonomy Low Medium+ High High++
Infrastructure
Shared (&
coupled)
Shared Individual
Individual &
distributed
Code
maintainability/
extensibility
Low— High High+ High++
Infrastructure
complexity
Low Medium Medium High++++
Communication
between them
Coupled Buses Buses Distributed buses
Deploy Shared Shared Shared Isolated
We’re not promoting microservices per se. Due to infrastructure and accidental complexity It could be the worst option actually.

Takeaways
! Unit Testing sucks (and it’s our fault) - José Armesto
! Vídeos sobre SOLID - CodelyTV
! Hexagonal Architecture - Chris Fidao
! Introducción Arquitectura Hexagonal – DDD - CodelyTV
! Domain-Driven Design in PHP - Carlos Buenosvinos, Christian Soronellas
and Keyvan Akbary
! A wave of command buses - Matthias Noback
! How to Avoid Building a Distributed Monolith - Felipe Dornelas
! PHP Barcelona Monthly Talk: DDD Applied & Symfony MPWAR Edition -
Sergi González & Eloi Poch
! Implementing Domain-Driven Design - Vaughn Vernon
! This talk repositories (to be published on github.com/CodelyTV)

Questions?
Thanks!
Contact
@JavierCane
@CodelyTV
@Rafaoe

From framework coupled code to #microservices through #DDD /by @codelytv

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