Hexagonal / Ports and Adapters

Hexagonal architecture keeps application behavior independent from databases, web frameworks, queues, and other runtime devices. The core defines ports; outer adapters implement or invoke them.

src/app/
├── domain/
├── application/
│   └── ports/
├── adapters/
└── interface/

Complete Configuration

deply:
  paths: ["."]
  exclude_files:
    - '.*/\.venv/.*'
    - '.*/tests?/.*'
  layers:
    - name: domain
      collectors:
        - type: directory
          directories: ["src/app/domain"]
    - name: application
      collectors:
        - type: directory
          directories: ["src/app/application"]
    - name: ports
      collectors:
        - type: directory
          directories: ["src/app/application/ports"]
    - name: adapters
      collectors:
        - type: directory
          directories: ["src/app/adapters"]
    - name: interface
      collectors:
        - type: directory
          directories: ["src/app/interface"]
  ruleset:
    domain:
      disallow_layer_dependencies: [application, ports, adapters, interface]
      disallow_external_imports: [django, fastapi, flask, sqlalchemy, requests, httpx]
    application:
      disallow_layer_dependencies: [adapters, interface]
    ports:
      disallow_layer_dependencies: [adapters, interface]
    adapters:
      disallow_layer_dependencies: [interface]

Deply can verify dependency direction and framework isolation. It cannot prove that runtime dependency injection connects every port to the correct adapter.

Validate

deply validate --config=deply.yaml
deply analyze --parallel --config=deply.yaml

Reference: Alistair Cockburn’s original Hexagonal Architecture article.