DDD / Bounded Contexts

Domain-Driven Design uses bounded contexts to keep models and language valid inside explicit business boundaries. Deply can enforce package ownership, not the quality of the domain model or aggregate invariants.

src/app/
├── ordering/{domain,application,infrastructure}/
├── payments/{domain,application,infrastructure}/
└── shared_kernel/

Complete Configuration

deply:
  paths: ["."]
  exclude_files:
    - '.*/\.venv/.*'
    - '.*/tests?/.*'
  layers:
    - name: ordering
      collectors:
        - type: directory
          directories: ["src/app/ordering"]
    - name: payments
      collectors:
        - type: directory
          directories: ["src/app/payments"]
    - name: ordering_domain
      collectors:
        - type: directory
          directories: ["src/app/ordering/domain"]
    - name: payments_domain
      collectors:
        - type: directory
          directories: ["src/app/payments/domain"]
    - name: shared_kernel
      collectors:
        - type: directory
          directories: ["src/app/shared_kernel"]
  ruleset:
    ordering:
      disallow_layer_dependencies: [payments]
    payments:
      disallow_layer_dependencies: [ordering]
    ordering_domain:
      disallow_external_imports: [django, fastapi, flask, sqlalchemy, requests]
    payments_domain:
      disallow_external_imports: [django, fastapi, flask, sqlalchemy, requests]
    shared_kernel:
      disallow_layer_dependencies: [ordering, payments]

An element under ordering/domain belongs to both ordering and ordering_domain; the same applies to payments. Deply checks every membership pair regardless of layer order. Context rules prevent cross-context dependencies, while domain rules isolate business logic from external packages. Create a shared kernel only for stable concepts genuinely shared by both contexts.

Deply cannot verify ubiquitous language, aggregate invariants, context maps, or the organizational ownership implied by a bounded context.

Validate

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

Reference: Domain analysis and bounded contexts.