What is software architecture?
Software architecture is the process of defining the high-level structure and organization of a software system. It involves identifying and selecting the right components, deciding how they will interact with each other, and determining how they should be organized to achieve specific goals. The goal of software architecture is to create a maintainable, scalable, and secure system that meets the needs of users and the organization.
Why do we need software architecture?
A strong architecture provides a solid foundation for building software that meets the needs of users and stakeholders. It ensures that the system meets its functional and non-functional requirements such as performance, security and reliability. With a well-designed architecture, developers can build software that is easy to modify and extend, making it easier to adapt to changing business needs.
Software architecture is also critical to managing complexity. As software systems become more complex, understanding how different components interact with each other becomes challenging. A well-designed architecture provides a high-level view of the system, making it easier to understand its structure and operation. This in turn helps developers identify potential problems and make informed decisions on how to modify the system.
How to document architecture? 4C model.
Context Level
At the highest level, the context level describes the external environment of the system, such as users, other systems, regulations, etc. This level provides a high-level overview of the system’s purpose and relationship to the external world. It helps identify the stakeholders who will interact with the system and the factors that influence its design and development.
Containers level
The next level is the container level, which describes the system’s runtime environment, such as a server, database, or message queue. This level helps identify major technology choices and deployment decisions. It provides an understanding of the physical infrastructure that will support the system and the tools and resources required for deployment and maintenance.
Components level
The third level is the component level, which describes the main functional building blocks of the system. This level helps identify the modules, classes, or functions that make up the system. It provides an understanding of the functionality of a system and the relationships between its different components.
Code level
Finally, the code level is the lowest level and describes the actual code and how it implements the component. This level provides a detailed understanding of how the system works and how its different components interact with each other. For developers who will be working with the code, it is crucial to have a clear understanding of how the code is structured and works.
Using the C4 model, software architects can create diagrams and written documentation describing each level, providing a comprehensive view of the system architecture. This approach helps identify potential issues and trade-offs while promoting scalability, maintainability, and adaptability. By documenting the architecture in this way, developers and stakeholders have a clear, easy-to-understand understanding of the system, making it easier to modify and extend based on business needs.
The following are 12 software architecture styles and designs that software engineers should know.
1. Client-Server
Client-server architecture is a model in which a client (user or application) sends a request to a server, and the server returns the requested data or service. The client and server can be on the same machine or on different machines connected through the network.
The client is responsible for initiating communication with the server and sending requests. The server listens for requests from clients, processes and returns responses.
Advantages of client-server architecture:
- Scalability: Client-server architecture is highly scalable as it allows multiple clients to connect to the same server and share resources.
- Security: Client-server architecture provides better security than other network models because the server can control access to resources and data.
- Reliability: Client-server architecture is very reliable as the server can provide backup and recovery services in case of failure.
2. Layering
This is a common way of designing complex software systems, which breaks the system into layers, each responsible for a specific set of functionality. This approach helps organize code and makes the system easier to maintain and modify over time.
A typical layered architecture consists of three main layers: presentation layer, business logic layer, and data access layer.
Presentation layer : The presentation layer is responsible for displaying information to the user and collecting input. This layer includes the user interface and other components that interact directly with the user. User interface is what users see and interact with, such as buttons, text boxes, and menus. The presentation layer also includes any logic related to the user interface, such as event handlers and validation.
Business logic layer : The business logic layer is responsible for implementing the business rules of the application. This layer contains the code to process and manipulate data, as well as any other application logic. The business logic layer is where the software works its magic. It is where the software performs calculations, makes decisions and performs tasks. It is where the software really does its work.
Data Access Layer : The data access layer is responsible for interacting with databases or other external data sources. This layer contains the code that reads and writes data to the database. The data access layer is key for the software to retrieve data, make changes to the data, and save the changes back to the database. This layer is critical to the functionality of the software as it enables the software to store and retrieve data.
3. Pipes and filters
Pipe and filter architecture is a design pattern that allows software systems to process data by separating processing tasks into independent components. This architecture is particularly helpful for systems that need to process large amounts of data. It improves performance, scalability, and maintainability.
Pipe and filter architecture is based on the concept of pipelines, where data flows through a series of processing steps, each performing a specific task. Each processing step is implemented as an independent component or filter that accepts data as input, performs some operations on the data, and produces output data. The output data is then passed to the next filter in the pipeline.
Filters in a pipeline are independent of each other, meaning they can be developed, tested, and deployed independently. This makes it easy to add new filters to the pipeline or modify existing filters without affecting other parts of the system.
Advantage:
- Scalability: The architecture can scale horizontally by adding more filters to the pipeline, allowing the system to handle larger amounts of data.
- Performance: This architecture can optimize performance by parallelizing data processing across multiple filters.
- Maintainability: The architecture promotes modularity and separation of concerns, making the system easier to maintain and update.
4. Master and slave
Master-slave architecture is a design pattern used in distributed systems in which one node (the master node) controls one or more nodes (the slave nodes) to perform specific tasks. The master node is responsible for distributing workloads to slave nodes and coordinating their activities. Slave nodes do not have the same level of control as the master node and only perform tasks assigned to them by the master node.
Advantages: One of the most important advantages is that it allows efficient distribution of workloads across multiple nodes. This helps reduce the load on any one node and ensures the system can handle large volumes of data and traffic.
Another advantage of using a master-slave architecture is that it provides fault tolerance. If a slave node fails, the master node can redistribute its workload to other slave nodes. This ensures that even if one or more nodes fail, the system can still function properly.
5. Microkernel
Microkernel architecture, also known as pluggable architecture, is a software design pattern that allows developers to build more modular and flexible systems. It separates core system functionality from other functionality, which are implemented in separate modules. The core functions of the system are implemented in the microkernel, which is the most basic core system and only provides the most basic services required to run the system. It’s a plug-and-play concept.
example:
Take an e-commerce website as an example. The microkernel will provide basic services such as handling user authentication, managing user sessions and processing payments. Other features, such as product recommendations, user reviews and social media integration, will be implemented in separate modules.
If the website wants to add a new feature, such as a loyalty program, it can be developed and added as a separate module without affecting the core functionality of the system. This modularity makes it easier to add new features or remove existing features without affecting core system functionality.
Additionally, if a website wants to tailor its system to the specific needs of different users, it can select the required modules for each user. For example, users who frequently purchase electronic products can provide a module that recommends electronic products. On the other hand, users who frequently purchase cosmetics can provide a module for recommending cosmetics.
Finally, if a website wants to expand its system to handle more users or hardware changes, modules can be easily added or removed as needed. This scalability makes it easier to adapt the system to changes in user needs or underlying hardware.
6. Domain-driven design (DDD)
In essence, DDD is a way of thinking about software architecture that emphasizes the domain or problem space of the project. This means that developers focus on the business logic of the software, not just the technical implementation.
In practice, this means developers first understand the domain they are working on and break it down into smaller, more manageable pieces. They then use this understanding to create a domain model, which is a representation of the different entities within the domain and their interactions with each other.
Once a domain model is created, developers can use it to guide the architecture of the rest of the software. This includes the creation of Bounded Contexts, which are areas of software defined by a specific language and context, and Aggregates, which are collections of related entities that are treated as a single unit.
7. Component-based
In software engineering, component-based architecture (CBA) is a software design and development approach that emphasizes reusable software components. The idea of CBA is to make software development more efficient and effective by splitting complex systems into smaller, more manageable components.
What are components?
A software component is a modular, self-contained unit of software that can be reused in different systems. Components typically have well-defined interfaces that specify how other components interact with them. The interface includes information about the component’s inputs, outputs, and behavior.
Components can be classified based on their functionality, such as user interface components, data access components, and business logic components. Each type of component plays a specific role in a software system and can interact with other components through its interfaces.
8. Service-oriented architecture (SOA)
SOA is an architectural style designed to create modular, reusable services that can be easily integrated with other services to create a larger system. In this approach, services expose their functionality through interfaces, which can be accessed by other services or applications.
At its core, SOA is about building software by breaking it into smaller components or modules. This modular approach allows developers to focus on building specific functionality and integrating it with other parts to create a larger system.
Core components of SOA
Service Provider : A service provider is responsible for creating and exposing services for use by the outside world. These services may be used by other services, applications or end users. For example, a payment processing service provider can create and expose a service that allows other applications to process payments.
Service Registry : A service registry is a directory of available services that can be accessed by other services or applications. The service registry provides information about services, such as name, location, and interface. For example, if an application needs to process payments, it can use the service registry to find the payment processing service and access its interface.
Service Requester : The service requester is responsible for consuming the services exposed by the service provider. This can be done by using the service registry to find the appropriate service and then calling its interface. For example, an application can use the service registry to find a payment processing service and then use its interface to process payments.
9. Monomer
Monolithic architecture is a software design style that has been around for decades. It is a way of building an application as a single, cohesive unit, rather than breaking it into individual, smaller components.
In a monolithic architecture, the entire application is built as a single, self-contained unit. All code and dependencies are packaged together so the application can be deployed and run on a single server.
This makes developing and deploying applications easy because everything is in one place. It also makes it easier to scale horizontally by adding more servers.
Advantages of monolithic architecture
One of the biggest advantages of monolithic architecture is its simplicity. Since everything is contained in one unit, there are fewer moving parts to focus on. This makes developing, testing and deploying applications easier.
Another advantage is that monolithic applications are easier to maintain and debug. Since everything is in one place, it’s easier to track down issues and fix them.
Disadvantages of monolithic architecture
One of the biggest disadvantages of a monolithic architecture is that it can be difficult to scale an application vertically. Since everything is running on a single server, the application is limited in the amount of traffic it can handle.
Another disadvantage is that it is difficult to adopt new technologies and languages within a monolithic application. Since everything is packaged together, it’s difficult to update a single component without breaking the entire application.
10. Microservices
Microservices architecture is a software architecture style that builds applications as a set of small, independent services that communicate with each other over a network. Each service focuses on a specific business capability and can be developed, deployed, and scaled independently of other services in the system.
The main idea of microservices architecture is to split a large, monolithic application into smaller, more manageable services. This approach brings many benefits, such as improved scalability, increased flexibility, and faster rollout of new features.
In a microservices architecture, each service can scale independently, making it easier to handle traffic spikes or changes in demand. Developers can also modify or add new services without affecting other parts of the system, speeding up the development process.
Challenges of microservice architecture
While microservices architecture brings many benefits, it also introduces additional complexity. One of the biggest challenges is managing communication between services. Services need to be able to discover each other and communicate efficiently, which can be difficult at scale. In a microservices architecture, load balancing and fault tolerance are also more complex.
Another challenge is ensuring each service has its own data store. In a monolithic application, all data is usually stored in a database. In microservices, each service should have its own data store to ensure that changes to one service do not affect other services in the system. This can lead to increased complexity in data management and synchronization.
Best practices for microservices architecture
To ensure the success of microservices-based systems, developers should follow best practices for designing and implementing microservices. Some of these best practices include:
- Design loosely coupled, highly cohesive services with clear boundaries and well-defined interfaces.
- Use containerization technology such as Docker to package and deploy each service as a separate container. This makes it easy to scale and deploy individual services as needed.
- Implement effective monitoring and management tools to ensure the smooth operation of your system and to quickly detect and resolve issues.
- Use a service mesh, such as Istio, to manage communication and load balancing between services.
- Implement continuous integration and deployment (CI/CD) pipelines to automate testing and deployment of microservices.
11. Event driven
Event-driven architecture (EDA) is a method of designing software systems that enables fast and efficient communication between different components or services. In this paradigm, different software components communicate with each other through events rather than through direct requests or responses.
In event-driven architecture, events are generated by different components of the software system, such as the user interface or backend services. These events are then broadcast to other components of the system, which can subscribe to the events and process them as needed.
For example, consider a simple e-commerce application. When a new order is placed, the order processing service can generate an “order created” event, which is then broadcast to other services such as inventory management, shipping, and billing. Each service can handle events and make updates to its respective systems.
Benefits of being event driven
A key benefit of event-driven architecture is its ability to decouple the different components of a software system. When different components communicate through events rather than direct requests, they have less dependence on each other. This makes it easier to change or update individual components of the system without affecting other parts of the system.
Another benefit of event-driven architecture is scalability. Because events are broadcast to multiple components of the system, large amounts of data and transactions can be processed in parallel. This makes it easier to handle high traffic and demand spikes.
Challenges of event-driven architecture
Although event-driven architecture has many benefits, there are also some challenges. One of the major challenges is managing the complexity of event-driven systems. Because events can be generated and consumed by many different components, tracking and debugging problems that arise can be difficult.
Another challenge is ensuring that events are processed in the correct order. Because events can be generated and processed asynchronously, events may not be processed in the correct order. This can lead to problems such as data inconsistencies or calculation errors.
12. Stream based
As software development becomes more complex and the need for scalability increases, traditional architectures become increasingly inadequate. Stream-based architectures have emerged as a promising alternative, enabling developers to build systems capable of processing large amounts of data in real-time.
At its core, stream-based architecture is based on the principles of event-driven programming. Instead of processing data in batches, stream-based systems process the data generated in real-time. This enables developers to build systems that respond to data changes with minimal latency.
Benefits of stream-based architecture
A key benefit of stream-based architecture is scalability. Since data is processed in real-time, stream-based systems can handle large amounts of data without the need for complex batch processing processes. This makes it possible to build systems that process millions of events per second, ideal for use cases such as sensor data processing, financial transactions, and online advertising.
Another benefit of stream-based architecture is flexibility. Because data is processed in real time, systems can be built that respond to changes in data with minimal latency. This makes it possible to build complex, event-driven systems that can adapt to changing business needs. For example, in an e-commerce platform, a stream-based architecture can be used to track user activities in real time and provide personalized recommendations and promotions based on the user’s browsing and purchase history.
Additionally, stream-based architecture can lead to significant cost savings. Traditional batch processing processes require expensive hardware and complex software infrastructure to manage data processing. Stream-based systems can be built on cheap, general-purpose hardware, making expansion and maintenance easier.
Finally, stream-based architectures are highly fault-tolerant. Because data is processed in real time, it is possible to build systems that can automatically recover from failures without manual intervention. This makes it possible to build systems that operate at scale with high reliability, reducing the risk of data loss or system downtime.
summary
Software architecture is critical to building successful software systems that meet the needs of users and stakeholders. It provides a blueprint for designing and developing software systems, ensuring that the system meets its functional and non-functional requirements, promoting adaptability, and helping to manage complexity. Therefore, it is crucial to invest time and resources at the beginning of a software development project to design a robust architecture. Hope this article can be of some help to you.
