Services¶

Services contain business logic and orchestrate use cases.

Location¶

backend/internal/services/
├── user_service.py
├── order_service.py
└── notification_service.py

Structure¶

class OrderService:
    def __init__(self, order_repo, product_repo, payment_service):
        # Inject dependencies
        self.order_repo = order_repo
        self.product_repo = product_repo
        self.payment_service = payment_service

    async def place_order(self, user_id: UUID, items: list) -> Order:
        """
        Use case: Place an order.

        Orchestrates: validation, payment, persistence.
        """
        # 1. Validate items
        products = await self.product_repo.get_by_ids(...)

        # 2. Create order entity
        order = Order(user_id=user_id, items=items)
        order.calculate_total()

        # 3. Process payment
        await self.payment_service.charge(user_id, order.total)

        # 4. Save and return
        return await self.order_repo.save(order)

Rules¶

One service per domain - UserService, OrderService
Inject repositories - Never create them inside
Return domain objects - Not database models

Create with CLI¶

lich make service Order