At SaM Solutions, we’ve developed a kind of platform that allows you to automate the development and deployment of systems that use Docker. Aliaksandr is a Senior .NET developer at SaM Solutions with 13 years of experience. Being a Microsoft certified engineer, he specializes in web development and has experience in creating desktop and mobile solutions. Aliaksandr is fond of learning new technologies, conducting meetups and teaching newbies at internal company courses.
They are NOT typically CRUD services and are usually standalone services. It’s the outer-most layer, and keeps peripheral concerns like UI and tests. For a Web application, it represents the Web API or Unit Test project. This layer has an implementation of the dependency injection principle so that the application builds a loosely coupled structure and can communicate to the internal layer via interfaces.
Infrastructure.Business
The application follows the onion architecture pattern. It includes adapters for databases, UI, external services like RESTful, etc. It has access to all areas of the API, Domain, and Core, though generally most operations that access the Domain must do so through the API. The exception to this would be something like domain interfaces that contain infrastructure implementations. The Infrastructure layer provides the implementation of the services and interfaces defined by the Domain layer.
Automation — microservices should be deployed and updated automatically and independently from each other. Manual deployment and updating would be challenging because even the smallest project comprises from five to ten microservices, while large systems may comprise up to 500 microservices. Bounded context — each microservice is built around some business function and uses bounded context as a design pattern. In fact, while there are numerous definitions of microservices, there is no single clear and unified definition.
The Onion has Layers
So if tomorrow we want to change EF with any other ORM it will impact Persistence, Application and Presentation layer. Well the notion is Data access layer technology keep changing after almost 3-4 years of life span. Fun Fact – Microsoft themselves recommend this kind of architecture for complex solutions.
- You can now move the EFCore to an Infrastructure Layer.
- That’s quite everything in this simple yet powerful implementation of Onion Architecture in ASP.NET Core.
- This project shouldn’t reference any other projects, even within Domain.
- This approach makes it possible to create a universal business logic that is not tied to anything.
- It just has a few less-than-ideal architecture choices (for long-lived solutions) that prevent me from recommending it as-is.
- Database Independent – Since we have a clean separation of data access, it is quite easy to switch between different database providers.
This separation makes the application more modular and easier to understand. Each layer has a specific responsibility, and there is a clear separation of concerns between the layers. The concept of Separation of Concerns forms the basis of Onion Architecture. It separates the application into layers based on their responsibilities. This makes the application more modular, easier to understand, and maintainable. Software architecture is an essential aspect of any software development project.
The Need to Follow an Architecture
Concepts and technological details are important, but they are secondary. Another important point is reducing complexity by using object-oriented design and design patterns to avoid reinventing the wheel. Onion Architecture is a software architecture pattern that separates the application into layers based on their responsibilities. It follows the Dependency Inversion Principle and is based on the idea of Separation of Concerns. The layers of Onion Architecture include the Domain layer, Application layer, Infrastructure layer, and User Interface layer.
However, the flexibility with technology upgrades doesn’t come handy with tightly coupled systems. The Application layer contains the application-specific logic. It is responsible for coordinating the interaction between the Domain layer, the Infrastructure layer, and the User Interface layer. The Application layer defines the use cases of the application and implements the business logic using the services and interfaces provided by the Domain layer.
Architectural Patterns
In order to access the Database, we introduce a Data Access Layer. This layer usually holds ORMs for ASP.NET to fetch/write to the database. In this article, We will talk about Onion Architecture In ASP.NET Core and its advantages.
The problem here, I think is that while the architecture doesn’t permit the top layer from talking to the domain, the sample project does exactly that, pretty much pulling the guts out. The core domain should not be affected with infrastructure and related dependencies. For example, if you’re using AWS Kinesis and you need to replace it with Kafka streams, the core domain should be not at all affected. If you change from Springboot to Micronaut in Java, Zin to Martini in Golang, WebAPI to Nancy in .NETCore, there should be no change in terms of how you define the core domain. Interactions between domain and persistence will follow a defined standard and will be independent of persistence details. This layer will contain operation-specific orchestration and related logic for the application.
Onion Architecture
This means the core layer is entirely decoupled from the outside world and can be tested independently of other components. The more involved approach is to define compilation modules representing the layers. Its disadvantage is a more complicated build structure and setup of your build tool of choice. On the other side though, having the compiler on your side is very helpful, and prevents the above-mentioned issue.
