At the Global Software Architecture Summit, we discussed many software architecture patterns, so I decided to write an article about it, highlighting the insights of well-known software architects.
What are software architecture patterns?
Software architecture patterns are proven and have a well-structured approach to design. More specifically, an architectural pattern is a set of design decisions that are summarized in practice, have well-defined attributes, and can be reused.
Software development can sometimes be viewed as the process of selecting, customizing, and combining architectural patterns. The software architect must decide which architectural patterns to adopt and how to adapt them to the specific context of the software system.
Mark Richards wrote a book called Software Architecture Patterns, which describes five software architecture patterns: Microkernel Pattern, Microservices Pattern, Layered Architecture Pattern, Event-based Pattern, space-based Pattern.
Five major software architecture patterns
1. Microkernel Pattern
The microkernel architecture pattern is also known as the plug-in pattern. This pattern allows you to add other application functionality as plug-ins to the core application, providing extensibility and separation of functionality.
The microkernel architecture pattern consists of two types of architectural components: core systems and plug-in modules.
- Plug-in modules that provide application functionality and custom processing logic for extensibility, flexibility, and isolation.
- Traditionally, the core system of the microkernel architecture pattern contains only the minimum functionality needed to make the system run.
The best example of the microkernel architecture pattern is the Eclipse IDE. Downloading the basic Eclipse product gives you nothing more than an editor feature. But once you start adding plug-ins, it becomes a highly customizable and useful product.
Advantages:
- Great flexibility and extensibility
- Some plug-ins allow you to add them while the application is running
- Good portability
- Easy to deploy
- Ability to respond quickly to changing environments
- Plug-in modules can be tested separately.
- High performance, because you can customize and simplify your application to include only those features you need.
- Application scenarios
- Take data from different sources, transform it, and output it to applications in different places
- Workflow application
- Task-based applications
2. Microservices Pattern
When you write an application as a set of microservices, you’re really writing multiple applications that work together. Each of these microservices has its own responsibilities and can be developed independently of the other microservices. The only dependency between these microservices is communication. When microservices communicate with each other, you must ensure that the messages they send are backward compatible.
Advantages:
- Each microservice can be written, maintained, and deployed separately
- Easy to extend, because you can extend only the microservices that need to be extended
- It is easier to update and iterate through parts of an application because they are smaller and less coupled to other parts
- Team members are responsive and productive
- Highly maintainable and testable – the microservices pattern allows for rapid and frequent development and deployment
- Deployable independently – its services can be deployed without coordination with other teams
Application Scenarios:
- Small website
- Well-defined enterprise data centers
- A fast-growing business
- Multi-functional development team
3. Layered Architecture Pattern
The most common architectural pattern is the layered architectural pattern. The layered architecture pattern is an N-tier pattern in which software system components are designed in different layers according to their responsibilities.
This is the traditional way most software is designed, and it is independent. This means that all components are interconnected, but not dependent on each other. Each layer of the layered architecture pattern has specific roles and responsibilities within the application. For example, the display layer will be responsible for handling the user interface interaction logic, while the business layer will be responsible for executing specific business rules associated with requests.
One of the powerful features of the layered architecture pattern is the separation of responsibilities between components. Components in a particular layer process only the logic associated with that layer.
Advantages:
- High testability, each layer can be tested separately.
- Highly easy to develop because this pattern is well known and not too complicated to implement, and because most companies develop applications by separating skills layer by layer, this pattern has become the natural choice for most business application development.
- Can be maintained
- It is easy to update a layer individually
Application Scenarios:
- Standard line of business applications that do more than CRUD operations
- New applications that need to be built quickly
- Suitable for less experienced development teams
- Applications that require strict maintainability and testability
4. Event-based Pattern
This is the most common distributed asynchronous architectural pattern for developing highly scalable systems. The architectural pattern consists of a series of components that listen to and process events asynchronously. The event-driven architectural pattern builds a central unit that receives all data and then delegates it to separate modules that handle specific types.
Advantages:
- Easy to adapt to a complex and often chaotic environment
- Elastic scaling
- It is easy to expand when new event types appear
Application Scenarios:
- An asynchronous system with asynchronous data flows
- User interface interaction
5. Space-based Pattern
Spatial based architectural patterns can be specifically used to address scalability and concurrency issues of software systems.
This is a useful software architecture pattern for applications with frequent user visits and occasional high concurrency. This pattern scales by eliminating central database constraints and using a replicated memory-based data grid.
The space-based architectural pattern aims to avoid software system breakdown under high load by splitting processing and storing data across multiple servers.
Advantages:
- Ability to respond quickly to changing environments.
- Although spatial architectural patterns are typically not distributed, they are dynamic, and complex cloud-based tools allow applications to be easily “pushed” to the server, simplifying deployment.
- High performance is achieved through in-memory data access and the caching mechanism built into this pattern.
- High scalability comes from the fact that there is little or no dependency on a centralized database, thus increasing scalability.
Application scenarios
- Applications with large volumes of data, such as user logs
- Low-value data that can occasionally be lost without serious consequences
- Social applications