Modularising the Monolith - Laracon Online Winter 2022

As a product and team grow, you might reach a point where it is hard to scale a monolith application due to different functionalities being tightly coupled in the same codebase with no boundaries.

Microservices have been making waves to solve such problems, however, they would bring their own sets of challenges.

A modular monolith can solve those problems without the drawbacks of microservices. A modular monolith is a system where all of the functionalities live in a single codebase and there are strictly enforced boundaries between different domains.

In this talk, I will walk you through how to modularise a monolith Laravel application based on domain boundaries and how to enforce strict boundaries between different domains.

Transcript

1. RYUTA HAMASAKI @avosalmon
3. Verification Solutions Service Provider >1M Accredified documents 9 markets 3 industries >9M verifications >500 Active issuers A B O U T A C C R E D I F Y
4. Modularising the Monolith Laracon Online Winter 2022
5. SHIP THE PRODUCT TO THE MARKET FIRST
6. BENEFITS OF MONOLITH - Single repository - Single CI/CD pipeline - Single set of infrastructure - Easy to handle DB transactions
7. BIG BALL OF MUD - Tight coupling between functionalities - No domain boundaries - All code is globally accessible - Need to understand the entire codebase
8. MICROSERVICES HTTP HTTP HTTP
9. BENEFITS OF MICROSERVICES - Clear boundaries between services - Deployed independently - Can be scaled independently - Freedom of tech stack
10. CHALLENGES OF MICROSERVICES - Multiple repositories - Multiple CI/CD pipelines - Network overhead - Complex cross-service transactions
11. TECHNICAL DECISIONS ARE ALWAYS TRADE-OFF
12. OUR GOALS - Maximise teams’ productivity - Scalable architecture
13. OUR APPROACH - Modularise the monolith - De fi ne domain boundaries
14. MODULAR MONOLITH Contracts Implementation Tests Contracts Implementation Tests Contracts Implementation Tests Inventory module Order module Payment module
15. MODULAR MONOLITH Contracts Implementation Tests Contracts Implementation Tests Contracts Implementation Tests Inventory module Order module Payment module
16. Contracts Implementation Tests Contracts Implementation Tests Contracts Implementation Tests Inventory service Order module Payment module INCREMENTAL MIGRATION TO MICROSERVICES
17. DISTRIBUTED BIG BALLS OF MUD
18. MICROSERVICES ARE EXPENSIVE TO CHANGE HTTP HTTP HTTP
19. MODULAR MONOLITH IS EASIER TO CHANGE Contracts Implementation Tests Contracts Implementation Tests Contracts Implementation Tests Inventory module Order module Payment module
20. MODULES & TEAM STRUCTURE Order Module Payment Module Shipping Module Campaign Module Auth Module Inventory Module
21. CONS OF MODULAR MONOLITH - Slow tests - More Git rebase - Cannot be scaled independently
22. DEFAULT STRUCTURE
23. MODULAR STRUCTURE
24. MODULAR STRUCTURE
30. <?php use Illuminate\Support\Facades\Route; Route::prefix('order-module') ->middleware(['api', 'auth:sanctum']) ->namespace('Laracon\Order\Application\Http\Controllers') ->group(function () { Route::apiResource('orders', OrderController::class); }); // src/Order/routes.php
31. namespace Laracon\Order\Providers; class OrderServiceProvider extends ServiceProvider { public function boot() { $this->loadRoutesFrom(__DIR__.'/../routes.php'); $this->loadMigrationsFrom(__DIR__.'/../Infrastructure/Database/Migrations'); $this->loadTranslationsFrom(__DIR__.'/../Resources/lang', 'order'); } public function register() { $this->mergeConfigFrom(__DIR__.'/../config/order.php', ‘order'); $this->app->register(AuthServiceProvider::class); $this->app->register(EventServiceProvider::class); $this->app->register(RouteServiceProvider::class); } }
32. namespace Laracon\Order\Providers; class OrderServiceProvider extends ServiceProvider { public function boot() { $this->loadRoutesFrom(__DIR__.'/../routes.php'); $this->loadMigrationsFrom(__DIR__.'/../Infrastructure/Database/Migrations'); $this->loadTranslationsFrom(__DIR__.'/../Resources/lang', 'order'); } public function register() { $this->mergeConfigFrom(__DIR__.'/../config/order.php', ‘order'); $this->app->register(AuthServiceProvider::class); $this->app->register(EventServiceProvider::class); $this->app->register(RouteServiceProvider::class); } }
33. namespace Laracon\Order\Providers; class OrderServiceProvider extends ServiceProvider { public function boot() { $this->loadRoutesFrom(__DIR__.'/../routes.php'); $this->loadMigrationsFrom(__DIR__.'/../Infrastructure/Database/Migrations'); $this->loadTranslationsFrom(__DIR__.'/../Resources/lang', 'order'); } public function register() { $this->mergeConfigFrom(__DIR__.'/../config/order.php', 'order'); $this->app->register(AuthServiceProvider::class); $this->app->register(EventServiceProvider::class); $this->app->register(RouteServiceProvider::class); } }
34. namespace Laracon\Order\Providers; class OrderServiceProvider extends ServiceProvider { public function boot() { $this->loadRoutesFrom(__DIR__.'/../routes.php'); $this->loadMigrationsFrom(__DIR__.'/../Infrastructure/Database/Migrations'); $this->loadTranslationsFrom(__DIR__.'/../Resources/lang', 'order'); } public function register() { $this->mergeConfigFrom(__DIR__.'/../config/order.php', ‘order'); $this->app->register(AuthServiceProvider::class); $this->app->register(EventServiceProvider::class); $this->app->register(RouteServiceProvider::class); } }
35. namespace Laracon\Order\Providers; class OrderServiceProvider extends ServiceProvider { public function boot() { $this->loadRoutesFrom(__DIR__.'/../routes.php'); $this->loadMigrationsFrom(__DIR__.'/../Infrastructure/Database/Migrations'); $this->loadTranslationsFrom(__DIR__.'/../Resources/lang', 'order'); } public function register() { $this->mergeConfigFrom(__DIR__.'/../config/order.php', ‘order'); $this->app->register(AuthServiceProvider::class); $this->app->register(EventServiceProvider::class); $this->app->register(RouteServiceProvider::class); } }
36. namespace Laracon\Order\Providers; class OrderServiceProvider extends ServiceProvider { public function boot() { $this->loadRoutesFrom(__DIR__.'/../routes.php'); $this->loadMigrationsFrom(__DIR__.'/../Infrastructure/Database/Migrations'); $this->loadTranslationsFrom(__DIR__.'/../Resources/lang', 'order'); } public function register() { $this->mergeConfigFrom(__DIR__.'/../config/order.php', ‘order'); $this->app->register(AuthServiceProvider::class); $this->app->register(EventServiceProvider::class); $this->app->register(RouteServiceProvider::class); } }
37. namespace Laracon\Order\Providers; use Illuminate\Foundation\Support\Providers\AuthServiceProvider as ServiceProvider; use Laracon\Order\Application\Policies\OrderPolicy; use Laracon\Order\Domain\Models\Order; class AuthServiceProvider extends ServiceProvider { protected $policies = [ Order::class => OrderPolicy::class, ]; public function boot() { $this->registerPolicies(); } }
38. namespace Laracon\Order\Providers; use Illuminate\Foundation\Support\Providers\EventServiceProvider as ServiceProvider; use Laracon\Order\Domain\Listeners\HandleOrderShipment; use Laracon\Shipping\Contracts\Events\ParcelShipped; class EventServiceProvider extends ServiceProvider { /** * The event listener mappings for the application. * * @var array */ protected $listen = [ ParcelShipped::class => [ HandleOrderShipment::class, ], ]; }
39. namespace Laracon\Order\Providers; use Illuminate\Foundation\Support\Providers\RouteServiceProvider as ServiceProvider; use Illuminate\Support\Facades\Route; use Laracon\Order\Application\Http\Middleware\SomeMiddleware; use Laracon\Order\Domain\Models\Order; class RouteServiceProvider extends ServiceProvider { public function boot() { Route::bind('order', function ($value) { return Order::with('orderLines')->findOrFail($value); }); $this->app[‘router']->aliasMiddleware('do-something', SomeMiddleware::class); } }
40. 'providers' => [ // ... \Laracon\Inventory\Providers\InventoryServiceProvider::class, \Laracon\Order\Providers\OrderServiceProvider::class, \Laracon\Payment\Providers\PaymentServiceProvider::class, \Laracon\Shipping\Providers\ShippingServiceProvider::class, ], // config/app.php
41. { "autoload": { "psr-4": { "App\\": "app/", "Laracon\\": "src/", "Database\\Factories\\": "database/factories/", "Database\\Seeders\\": "database/seeders/" } } } // composer.json
42. { "autoload": { "psr-4": { "App\\": "app/", "Laracon\\": "src/", "Database\\Factories\\": "database/factories/", "Database\\Seeders\\": "database/seeders/" } } } // composer.json
43. COMMUNICATION BETWEEN MODULES
44. COMMUNICATION THROUGH CONTRACT Module A Module B Contract Implementation Downstream Upstream
45. CONTRACT-FIRST DEVELOPMENT - Encapsulates implementation details - Change implementation without changing downstream module - Mock the contract in testing
46. Module A Module B COMMUNICATION WITHOUT CONTRACT Downstream Upstream Implementation
47. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line
48. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line 1. Checkout
49. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line 2. Update inventory 1. Checkout
50. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line 2. Update inventory 3. Process payment 1. Checkout
51. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line 2. Update inventory 3. Process payment 4. Save order 1. Checkout
52. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line 2. Update inventory 3. Process payment 5. Notify warehouse 4. Save order 1. Checkout
53. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
54. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
55. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
56. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
57. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
58. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
59. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
60. class OrderController extends Controller { public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
61. namespace Laracon\Order\Domain\Models; class CartItem extends Model { // ... public function cart(): BelongsTo { return $this->belongsTo(Cart::class); } public function product(): BelongsTo { return $this->belongsTo(Product::class); } }
62. namespace Laracon\Order\Domain\Models; class CartItem extends Model { // ... public function cart(): BelongsTo { return $this->belongsTo(Cart::class); } public function product(): BelongsTo { return $this->belongsTo(Product::class); } }
63. // src/Inventory/Contracts/ProductService.php namespace Laracon\Inventory\Contracts; interface ProductService { /** * Decrement product stock. */ public function decrementStock(int $productId, int $quantity): void; }
64. namespace Laracon\Inventory\Infrastructure\Services; use Laracon\Inventory\Contracts\ProductService as ProductServiceContract; class ProductService implements ProductServiceContract { public function decrementStock(int $productId, int $quantity): void { $product = Product::find($productId); if (!$product) { throw new ProductNotFoundException($productId); } if ($product->stock < $quantity) { throw new OutOfStockException($productId); } if (!$product->is_active) { throw new InactiveProductException($productId); } $product->decrement('stock', $quantity); } }
65. namespace Laracon\Inventory\Infrastructure\Services; use Laracon\Inventory\Contracts\ProductService as ProductServiceContract; class ProductService implements ProductServiceContract { public function decrementStock(int $productId, int $quantity): void { $product = Product::find($productId); if (!$product) { throw new ProductNotFoundException($productId); } if ($product->stock < $quantity) { throw new OutOfStockException($productId); } if (!$product->is_active) { throw new InactiveProductException($productId); } $product->decrement('stock', $quantity); } }
66. namespace Laracon\Inventory\Providers; use Laracon\Inventory\Contracts\ProductService as ProductServiceContract; use Laracon\Inventory\Infrastructure\Services\ProductService; class InventoryServiceProvider extends ServiceProvider { public $bindings = [ ProductServiceContract::class => ProductService::class, ]; // ... }
67. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
68. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $cartItem->product->decrement('stock', $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
69. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $this->productService->decrementStock($cartItem->product_id, $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
70. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $this->productService->decrementStock($cartItem->product_id, $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
71. namespace Laracon\Order\Domain\Models; use Laracon\Inventory\Domain\Models\Product; class Order extends Model { // ... protected $orderLines = []; public function orderLines(): HasMany { return $this->hasMany(OrderLine::class); } public function addOrderLine(Product $product, int $quantity): void { $orderLine = new OrderLine([ 'product_id' => $product->id, 'product_name' => $product->name, 'price' => $product->price, 'quantity' => $quantity, ]); $this->orderLines[] = $orderLine; } }
72. namespace Laracon\Order\Domain\Models; use Laracon\Inventory\Domain\Models\Product; class Order extends Model { // ... protected $orderLines = []; public function orderLines(): HasMany { return $this->hasMany(OrderLine::class); } public function addOrderLine(Product $product, int $quantity): void { $orderLine = new OrderLine([ 'product_id' => $product->id, 'product_name' => $product->name, 'price' => $product->price, 'quantity' => $quantity, ]); $this->orderLines[] = $orderLine; } }
73. DTO = Data Transfer Object - Simple data container class - Transfers data to another module - POPO (Plain Old PHP Object) - Has no behaviour
74. namespace Laracon\Inventory\Contracts\DataTransferObjects; class ProductDto { public function __construct( public readonly int $id, public readonly string $name, public readonly int $price, ) {} }
75. namespace Laracon\Inventory\Contracts; use Laracon\Inventory\Contracts\DataTransferObjects\ProductDto; interface ProductService { /** * Get product by product id. */ public function getProductById(int $productId): ProductDto; }
76. namespace Laracon\Inventory\Infrastructure\Services; use Laracon\Inventory\Contracts\DataTransferObjects\ProductDto; use Laracon\Inventory\Contracts\ProductService as ProductServiceContract; use Laracon\Inventory\Domain\Models\Product; class ProductService implements ProductServiceContract { public function getProductById(int $productId): ProductDto { $product = Product::find($productId); if (!$product) { throw new ProductNotFoundException($productId); } return new ProductDto( $product->id, $product->name, $product->price, ); } }
77. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $this->productService->decrementStock($cartItem->product_id, $cartItem->quantity); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
78. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $this->productService->decrementStock($cartItem->product_id, $cartItem->quantity); $product = $this->productService->getProductById($cartItem->product_id); $order->addOrderLine($cartItem->product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
79. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { $cart->cartItems->each(function (CartItem $cartItem) use ($order) { $this->productService->decrementStock($cartItem->product_id, $cartItem->quantity); $product = $this->productService->getProductById($cartItem->product_id); $order->addOrderLine($product, $cartItem->quantity); }); // ... }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
80. namespace Laracon\Order\Domain\Models; use Laracon\Inventory\Domain\Models\Product; class Order extends Model { // ... protected $orderLines = []; public function addOrderLine(Product $product, int $quantity): void { $orderLine = new OrderLine([ 'product_id' => $product->id, 'product_name' => $product->name, 'price' => $product->price, 'quantity' => $quantity, ]); $this->orderLines[] = $orderLine; } }
81. namespace Laracon\Order\Domain\Models; use Laracon\Inventory\Domain\Models\Product; class Order extends Model { // ... protected $orderLines = []; public function addOrderLine(Product $product, int $quantity): void { $orderLine = new OrderLine([ 'product_id' => $product->id, 'product_name' => $product->name, 'price' => $product->price, 'quantity' => $quantity, ]); $this->orderLines[] = $orderLine; } }
82. namespace Laracon\Order\Domain\Models; use Laracon\Inventory\Contracts\DataTransferObjects\ProductDto; class Order extends Model { // ... protected $orderLines = []; public function addOrderLine(ProductDto $product, int $quantity): void { $orderLine = new OrderLine([ 'product_id' => $product->id, 'product_name' => $product->name, 'price' => $product->price, 'quantity' => $quantity, ]); $this->orderLines[] = $orderLine; } }
83. namespace Laracon\Order\Domain\Models; use Laracon\Inventory\Contracts\DataTransferObjects\ProductDto; class Order extends Model { // ... protected $orderLines = []; public function addOrderLine(ProductDto $product, int $quantity): void { $orderLine = new OrderLine([ 'product_id' => $product->id, 'product_name' => $product->name, 'price' => $product->price, 'quantity' => $quantity, ]); $this->orderLines[] = $orderLine; } }
84. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { // ... $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
85. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct(private ProductService $productService) {} public function store(StoreOrderRequest $request) { $cart = Cart::with('cartItems')->findOrFail($request->cart_id); $order = new Order(['user_id' => $request->user()->id]); try { DB::transaction(function () use ($order, $cart) { // ... $order->checkout(); $stripe = new StripePayment(config(‘services.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
86. namespace Laracon\Payment\Contracts; interface PaymentService { /** * Process payment for the given amount. */ public function charge(int $orderId, int $amount): void; }
87. namespace Laracon\Payment\Infrastructure\Services; use Stripe\StripeClient; use Laracon\Payment\Contracts\PaymentService as PaymentServiceContract; class StripePayment implements PaymentServiceContract { private StripeClient $stripe; public function __construct(string $stripeKey) { $this->stripe = new StripeClient($stripeKey); } public function charge(int $orderId, int $amount): void { $this->stripe->charges->create([ 'amount' => $amount, 'currency' => 'usd', ]); // ... } }
88. namespace Laracon\Payment\Providers; use Illuminate\Support\ServiceProvider; use Laracon\Payment\Contracts\PaymentService as PaymentServiceContract; use Laracon\Payment\Infrastructure\Services\StripePayment; class PaymentServiceProvider extends ServiceProvider { public function register() { $this->app->bind(PaymentServiceContract::class, function ($app) { return new StripePayment(config(‘services.stripe.key')); }); } }
89. use Laracon\Inventory\Contracts\ProductService; class OrderController extends Controller { public function __construct( private ProductService $productService, ) {} public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $stripe = new StripePayment(config('service.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
90. use Laracon\Inventory\Contracts\ProductService; use Laracon\Payment\Contracts\PaymentService; class OrderController extends Controller { public function __construct( private ProductService $productService, private PaymentService $paymentService, ) {} public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $stripe = new StripePayment(config('service.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
91. use Laracon\Inventory\Contracts\ProductService; use Laracon\Payment\Contracts\PaymentService; class OrderController extends Controller { public function __construct( private ProductService $productService, private PaymentService $paymentService, ) {} public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $stripe = new StripePayment(config('service.stripe.key')); $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
92. use Laracon\Inventory\Contracts\ProductService; use Laracon\Payment\Contracts\PaymentService; class OrderController extends Controller { public function __construct( private ProductService $productService, private PaymentService $paymentService, ) {} public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $stripe->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
93. use Laracon\Inventory\Contracts\ProductService; use Laracon\Payment\Contracts\PaymentService; class OrderController extends Controller { public function __construct( private ProductService $productService, private PaymentService $paymentService, ) {} public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $this->paymentService->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
94. namespace Laracon\Payment\Providers; use Illuminate\Support\ServiceProvider; use Laracon\Payment\Contracts\PaymentService as PaymentServiceContract; use Laracon\Payment\Infrastructure\Services\StripePayment; class PaymentServiceProvider extends ServiceProvider { public function register() { $this->app->bind(PaymentServiceContract::class, function ($app) { return new StripePayment(config(‘services.stripe.key')); }); } }
95. namespace Laracon\Payment\Providers; use Illuminate\Support\ServiceProvider; use Laracon\Payment\Contracts\PaymentService as PaymentServiceContract; use Laracon\Payment\Infrastructure\Services\PaddlePayment; class PaymentServiceProvider extends ServiceProvider { public function register() { $this->app->bind(PaymentServiceContract::class, function ($app) { return new PaddlePayment(config(‘services.paddle.key’)); }); } }
96. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line 2. Update inventory 3. Process payment 5. Notify warehouse 4. Save order 1. Checkout
97. Order Inventory Payment Shipping Payment Provider Warehouse System Cart Cart Item Order Order Line OrderFul fi lled Publish Subscribe 2. Update inventory 3. Process payment 4. Save order 1. Checkout
98. class OrderController extends Controller { // ... public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $this->paymentService->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } return new OrderResource($order); } }
99. class OrderController extends Controller { // ... public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $this->paymentService->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } OrderFulfilled::dispatch($order->id); return new OrderResource($order); } }
100. class OrderController extends Controller { // ... public function store(StoreOrderRequest $request) { // ... try { DB::transaction(function () use ($order, $cart) { // ... $this->paymentService->charge($order->id, $order->total_amount); }); } catch (\Exception $e) { abort(Response::HTTP_BAD_REQUEST, trans('order::errors.failed')); } OrderFulfilled::dispatch($order->id); return new OrderResource($order); } }
101. namespace Laracon\Shipping\Providers; use Illuminate\Foundation\Support\Providers\EventServiceProvider as ServiceProvider; use Laracon\Order\Contracts\Events\OrderFulfilled; use Laracon\Shipping\Domain\Listeners\NotifyWarehouse; class EventServiceProvider extends ServiceProvider { protected $listen = [ OrderFulfilled::class => [ NotifyWarehouse::class, ] ]; }
102. namespace Laracon\Shipping\Domain\Listeners; use Laracon\Order\Contracts\Events\OrderFulfilled; class NotifyWarehouse { public function handle(OrderFulfilled $event) { // Notify warehouse system } }
103. TESTING MODULE
104. <phpunit> <testsuites> <testsuite name="Unit"> <directory suffix="Test.php">./src/**/Tests/Unit</directory> </testsuite> <testsuite name="Feature"> <directory suffix="Test.php">./src/**/Tests/Feature</directory> </testsuite> </testsuites> <coverage processUncoveredFiles="true"> <include> <directory suffix=".php">./src</directory> </include> <exclude> <directory suffix="Test.php">./src/**/Tests/*</directory> </exclude> <report> <clover outputFile="coverage/clover.xml"/> </report> </coverage> <!-- ... --> </phpunit>
105. <phpunit> <testsuites> <testsuite name="Unit"> <directory suffix="Test.php">./src/**/Tests/Unit</directory> </testsuite> <testsuite name="Feature"> <directory suffix="Test.php">./src/**/Tests/Feature</directory> </testsuite> </testsuites> <coverage processUncoveredFiles="true"> <include> <directory suffix=".php">./src</directory> </include> <exclude> <directory suffix="Test.php">./src/**/Tests/*</directory> </exclude> <report> <clover outputFile="coverage/clover.xml"/> </report> </coverage> <!-- ... --> </phpunit>
106. <phpunit> <testsuites> <testsuite name="Unit"> <directory suffix="Test.php">./src/**/Tests/Unit</directory> </testsuite> <testsuite name="Feature"> <directory suffix="Test.php">./src/**/Tests/Feature</directory> </testsuite> </testsuites> <coverage processUncoveredFiles="true"> <include> <directory suffix=".php">./src</directory> </include> <exclude> <directory suffix="Test.php">./src/**/Tests/*</directory> </exclude> <report> <clover outputFile="coverage/clover.xml"/> </report> </coverage> <!-- ... --> </phpunit>
107. it('creates a new order', function () { Event::fake(); $user = User::factory()->create(); $cart = Cart::factory()->create(['user_id' => $user->id]); // create some other test data... mock(ProductService::class, function ($mock) use ($product) { $mock->shouldReceive('decrementStock') ->with($product->id, 1) ->once(); $mock->shouldReceive('getProductById') ->with($product->id) ->once() ->andReturn($product); }); mock(PaymentService::class) ->shouldReceive('charge') ->once(); // ...
108. it('creates a new order', function () { Event::fake(); $user = User::factory()->create(); $cart = Cart::factory()->create(['user_id' => $user->id]); // create some other test data... mock(ProductService::class, function ($mock) use ($product) { $mock->shouldReceive('decrementStock') ->with($product->id, 1) ->once(); $mock->shouldReceive('getProductById') ->with($product->id) ->once() ->andReturn($product); }); mock(PaymentService::class) ->shouldReceive('charge') ->once(); // ...
109. it('creates a new order', function () { Event::fake(); $user = User::factory()->create(); $cart = Cart::factory()->create(['user_id' => $user->id]); // create some other test data... mock(ProductService::class, function ($mock) use ($product) { $mock->shouldReceive('decrementStock') ->with($product->id, 1) ->once(); $mock->shouldReceive('getProductById') ->with($product->id) ->once() ->andReturn($product); }); mock(PaymentService::class) ->shouldReceive('charge') ->once(); // ...
110. CROSS-MODULE FOREIGN KEY LEADS TO A TIGHT COUPLING Order module Inventory module Cart Items Products product_id id
111. it('creates a new order', function () { Event::fake(); $user = User::factory()->create(); $cart = Cart::factory()->create(['user_id' => $user->id]); // create some other test data... mock(ProductService::class, function ($mock) use ($product) { $mock->shouldReceive('decrementStock') ->with($product->id, 1) ->once(); $mock->shouldReceive('getProductById') ->with($product->id) ->once() ->andReturn($product); }); mock(PaymentService::class) ->shouldReceive('charge') ->once(); // ...
112. // ... $order = postJson('/order-module/orders', ['cart_id' => $cart->id]) ->assertCreated() ->json('data'); assertDatabaseHas('orders', [ 'id' => $order['id'], ]); Event::assertDispatched(OrderFulfilled::class, $order['id']);
113. HOW CAN WE ENFORCE DOMAIN BOUNDARIES?
114. STATIC ANALYSIS - Deptrac - De fi ne layers based on PHP classes - De fi ne rulesets on layers access - Detect violation of the rulesets - Visualize dependency graph
115. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
116. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
117. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
118. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
119. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
120. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
121. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
122. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
123. parameters: paths: - ./app - ./src layers: - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: App: - Laravel Contract: - Laravel imports: - src/Inventory/deptrac.yaml - src/Order/deptrac.yaml - src/Payment/deptrac.yaml - src/Shipping/deptrac.yaml // deptrac.yaml
124. parameters: paths: - ./src/Order layers: - name: OrderModule collectors: - type: bool must: - type: className regex: Laracon\\Order\\.* must_not: - type: className regex: Laracon\\Order\\Contracts\\.* - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: OrderModule: - App - Contract - Laravel // src/Order/deptrac.yaml
125. parameters: paths: - ./src/Order layers: - name: OrderModule collectors: - type: bool must: - type: className regex: Laracon\\Order\\.* must_not: - type: className regex: Laracon\\Order\\Contracts\\.* - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: OrderModule: - App - Contract - Laravel // src/Order/deptrac.yaml
126. parameters: paths: - ./src/Order layers: - name: OrderModule collectors: - type: bool must: - type: className regex: Laracon\\Order\\.* must_not: - type: className regex: Laracon\\Order\\Contracts\\.* - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: OrderModule: - App - Contract - Laravel // src/Order/deptrac.yaml
127. parameters: paths: - ./src/Order layers: - name: OrderModule collectors: - type: bool must: - type: className regex: Laracon\\Order\\.* must_not: - type: className regex: Laracon\\Order\\Contracts\\.* - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: OrderModule: - App - Contract - Laravel // src/Order/deptrac.yaml
128. parameters: paths: - ./src/Order layers: - name: OrderModule collectors: - type: bool must: - type: className regex: Laracon\\Order\\.* must_not: - type: className regex: Laracon\\Order\\Contracts\\.* - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: OrderModule: - App - Contract - Laravel // src/Order/deptrac.yaml
129. parameters: paths: - ./src/Order layers: - name: OrderModule collectors: - type: bool must: - type: className regex: Laracon\\Order\\.* must_not: - type: className regex: Laracon\\Order\\Contracts\\.* - name: App collectors: - type: className regex: App\\.* - name: Contract collectors: - type: className regex: Laracon\\[^\\]*\\Contracts\\.* - name: Laravel collectors: - type: className regex: (Laravel|Illuminate)\\.* ruleset: OrderModule: - App - Contract - Laravel // src/Order/deptrac.yaml
130. STATIC ANALYSIS IS 
 NOT PERFECT
131. USEFUL LINKS - https://github.com/avosalmon/modular-monolith-laravel - Deconstructing the Monolith: Designing Software that Maximizes Developer Productivity - Under Deconstruction: The State of Shopify’s Monolith - Long live the Monolith! Monolithic Architecture != Big Ball of Mud - Strategic Monoliths and Microservices - Domain-Driven Laravel
132. THANK YOU @avosalmon