Software Architecture

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Introduction to Software Architecture

Software architecture is the blueprint for system design, detailing how components interact with each other to deliver specific functionality. A well-designed architecture provides solutions to common problems, saves time and effort, and leads to more robust and maintainable systems. Choosing the right software architecture pattern is essential for solving problems efficiently and building systems that can evolve over time.

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Core Architectural Patterns

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1. Layered Architecture

Each layer plays a distinct and clear role within the application context.

Key Characteristics

• Clear separation of concerns: Each layer has a specific responsibility
• Quick development: Great for applications that need to be built rapidly
• Structured organization: Natural code organization by functionality

Trade-offs:

• Source code can become unorganized if proper rules aren’t followed
• Changes may ripple across multiple layers

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2. Microservices Architecture

Break down a large system into smaller and more manageable components. Benefits:

• Fault tolerance built-in
• Independent scaling of components
• Technology flexibility per service
• Team autonomy and ownership

Challenges:

• Increased system complexity
• Distributed system challenges
• Service discovery requirements
• Data consistency concerns

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3. Event-Driven Architecture

Services talk to each other by emitting events that other services may or may not consume. When to Use:

• Real-time data processing
• Asynchronous workflows
• Systems requiring high scalability
• Loosely coupled microservices

Considerations:

• Testing individual components becomes challenging
• Event ordering and consistency
• Debugging distributed flows

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4. Client-Server Architecture

It comprises two main components - clients and servers communicating over a network. Advantages:

• Great for real-time services
• Centralized data management
• Clear separation of concerns

Limitations:

• Servers can become a single point of failure
• Network dependency
• Scalability challenges

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5. Plugin-based Architecture

This pattern consists of two types of components - a core system and plugins. The plugin modules are independent components providing specialized functionality.

Use Cases

Ideal for:

• IDEs (Integrated Development Environments)
• Content management systems
• Applications that need to expand over time

Limitation: Changing the core system is difficult once established.

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6. Hexagonal Architecture

This pattern creates an abstraction layer that protects the core of an application and isolates it from external integrations for better modularity. Also known as ports and adapters architecture. Benefits:

• Better modularity and testability
• Core business logic isolation
• Flexible external integrations

Trade-offs:

• Increased development time
• Steeper learning curve
• More initial complexity

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Design Principles and Acronyms

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SOLID Principles

SOLID principle is essential in object-oriented programming. There are 5 components:

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KISS Principle

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Data and Communication Flow Patterns

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1. Peer-to-Peer

Direct communication between two components without the need for a central coordinator.

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2. API Gateway

Acts as a single entry point for all client requests to the backend services of an application.

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3. Pub-Sub

Decouples the producers of messages (publishers) from the consumers of messages (subscribers) through a message broker.

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4. Request-Response

One of the most fundamental integration patterns, where a client sends a request to a server and waits for a response.

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5. Event Sourcing

Involves storing the state changes of an application as a sequence of events.

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6. ETL (Extract, Transform, Load)

A data integration pattern used to gather data from multiple sources, transform it into a structured format, and load it into a destination database.

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7. Batching

Accumulating data over a period or until a certain threshold is met before processing it as a single group.

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8. Streaming Processing

Allows for the continuous ingestion, processing, and analysis of data streams in real-time.

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9. Orchestration

A central coordinator (orchestrator) manages the interactions between distributed components or services to achieve a workflow or business process.

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Client Architecture Patterns

MVC, MVP, MVVM, and VIPER

Key Differences:

• MVC - The oldest pattern, dating back almost 50 years
• Every pattern has a “view” (V) responsible for displaying content and receiving user input
• Most patterns include a “model” (M) to manage business data
• “Controller,” “presenter,” and “view-model” are translators that mediate between the view and the model
• These translators can be complex to write, so various patterns have been proposed to make them more maintainable

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Best Practices

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Next Steps