architecture-patterns

Architecture Patterns

This skill provides knowledge about common architectural patterns to help design feature implementations. Apply these patterns based on the project's existing architecture and the feature's requirements.

Pattern Selection Guide

Choose patterns based on:

1. Existing architecture - Match what's already in use
2. Team familiarity - Use patterns the team knows
3. Feature requirements - Some patterns fit better for certain features
4. Scale requirements - Consider current and future scale

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Layered Architecture (N-Tier)

When to use: Most web applications, CRUD operations, clear separation of concerns needed

Layers:

┌─────────────────────────┐
│   Presentation Layer    │  UI, API endpoints, controllers
├─────────────────────────┤
│    Application Layer    │  Use cases, orchestration, DTOs
├─────────────────────────┤
│      Domain Layer       │  Business logic, entities, rules
├─────────────────────────┤
│   Infrastructure Layer  │  Database, external services, I/O
└─────────────────────────┘

Key rules:

• Dependencies flow downward only
• Each layer only talks to the layer directly below
• Domain layer has no external dependencies

Implementation tips:

• Use interfaces at layer boundaries
• Keep domain logic in the domain layer, not controllers
• Use DTOs to transfer data between layers

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MVC (Model-View-Controller)

When to use: Web applications with server-rendered views, simple CRUD apps

Components:

User → Controller → Model → Controller → View → User
           ↓           ↑
        Updates      Reads

Model: Data and business logic View: Presentation/UI Controller: Handles input, coordinates model and view

Implementation tips:

• Keep controllers thin - delegate to services
• Models should be framework-agnostic when possible
• Views should have minimal logic

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Repository Pattern

When to use: Data access abstraction, testability, multiple data sources