clean-architecture-guide

To scaffold a new module in a dotnet modular monolith, create separate Domain, Application, and Infrastructure projects. This structure enforces strict dependency boundaries, keeping domain logic isolated while preparing for Cosmos DB repository patterns and Aspire service wiring.

Clean architecture enforces dependency boundaries by ensuring the Web layer only accesses DTOs and depends on Application, never directly referencing Infrastructure or Domain internals. This unidirectional dependency flow prevents infrastructure concerns from leaking into business logic.

Yes, you can use Cosmos DB repository patterns with Aspire in a clean architecture setup. The Infrastructure layer implements repository interfaces defined in Application, while the AppHost project handles Aspire service registration and dependency injection wiring for the Web project.

The best way to wire Aspire services and DI registration is through the AppHost project. It orchestrates service defaults, registers Cosmos DB dependencies, and configures DI containers for Application and Infrastructure layers, ensuring Web projects receive properly scoped DTOs and use cases.

To plan unit and integration tests for a clean architecture module, use MSTest to cover Domain logic and Application use cases with unit tests, while integration tests validate Infrastructure repository implementations against Cosmos DB and verify Web API endpoints.

Your Web project needs DTO-only access in a clean architecture modular monolith to prevent domain entity corruption and maintain strict layer separation. This ensures presentation concerns remain decoupled from business rules, enforcing boundaries between the Web and Application layers.