nw-architecture-patterns

# Architecture Patterns and Methodologies ## C4 Model -- Hierarchical Architecture Visualization Four levels for different audiences: 1. **System Context**: system + users + external systems (stakeholder view) 2. **Containers**: applications, data stores, deployment units (technical overview) 3. **Components**: internal modules within containers (developer view) 4. **Code**: class/module level (optional, often auto-generated) Notation/tooling independent. Reduces communication overhead, shared visual language across stakeholders. ## Hexagonal Architecture (Ports and Adapters) Isolate business logic from infrastructure through ports (interfaces) and adapters (implementations). - **Ports**: technology-agnostic interfaces for external communication - **Primary ports** (driving): REST controllers, CLI handlers, message consumers -- inbound - **Secondary ports** (driven): DB repos, external service clients, filesystem -- outbound - **Adapters**: technology-specific port implementations Benefits: testability (isolated core) | flexibility (swap infrastructure) | technology independence | maintainability Testing: unit tests through driving ports, mock driven ports | integration tests with real infrastructure | acceptance tests end-to-end through primary ports ## Architectural Pattern Selection ### Layered Architecture Horizontal layers with defined dependencies. Use for: traditional enterprise apps, clear separation. Trade-off: familiar but potential overhead, layer couplin...