How would you design a system that adheres to SOLID principles and allows for easy experimentation and prototyping?
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To design a system that adheres to SOLID principles and allows for easy experimentation and prototyping, one approach is to use a modular and layered architecture with well-defined interfaces. Each module should have a clear responsibility and be decoupled from other modules, allowing for easy substitution and testing. Dependency injection can be used to facilitate the substitution of implementations. In addition, feature flags and toggles can be used to enable or disable experimental features without affecting the stability of the system. Here's an example of a layered architecture with interface-based dependencies:
class OrderRepository:
def get_order(self, order_id: int) -> Order:
pass
def save_order(self, order: Order):
pass
class OrderService:
def __init__(self, order_repository: OrderRepository):
self.order_repository = order_repository
def get_order(self, order_id: int) -> Order:
return self.order_repository.get_order(order_id)
def save_order(self, order: Order):
self.order_repository.save_order(order)
class OrderController:
def __init__(self, order_service: OrderService):
self.order_service = order_service
def get_order(self, order_id: int) -> Dict[str, Any]:
order = self.order_service.get_order(order_id)
return {
"id": order.id,
"status": order.status,
"customer_id": order.customer_id
}
In this example, the OrderRepository
interface defines the contract for data persistence, while the OrderService
and OrderController
classes depend on abstractions rather than concrete implementations. This allows for easy substitution of different implementations for testing or experimentation.