Deply Rule Presets

Use these presets as starting points, then adapt to the discovered project structure.

Light

Goal: document obvious boundaries and catch accidental direct dependencies.

Use when:

• First Deply adoption.
• Legacy code has unknown coupling.
• User wants low false positives.

Pattern:

• Create layers from existing top-level packages or obvious directories.
• Prefer directory collectors.
• Add only high-confidence disallow_layer_dependencies.
• Exclude tests, migrations, generated files, virtualenvs, build output, and vendored code.
• CI can start as validate-only plus optional non-blocking analysis.

Example:

deply:
  paths:
    - "."
  exclude_files:
    - '.*/\.venv/.*'
    - '.*/tests?/.*'
    - '.*/migrations/.*'
  layers:
    - name: domain
      collectors:
        - type: directory
          directories:
            - "src/app/domain"
    - name: infrastructure
      collectors:
        - type: directory
          directories:
            - "src/app/infrastructure"
  ruleset:
    domain:
      disallow_layer_dependencies:
        - infrastructure

Medium

Goal: enforce normal layered or hexagonal architecture boundaries.

Use when:

• Project has recognizable domain/application/infrastructure/interface layers.
• Team wants CI to block new architecture regressions.

Pattern:

• Layers: domain, application, infrastructure, interface or equivalent project names.
• domain must not depend on application, infrastructure, or interface.
• application must not depend on interface, and usually not directly on infrastructure unless project uses pragmatic service wiring.
• domain disallows framework, ORM, HTTP, queue, cloud SDK, and exchange/client imports.
• application disallows interface frameworks and low-level transport packages unless it owns ports.

Example:

deply:
  paths:
    - "."
  exclude_files:
    - '.*/\.venv/.*'
    - '.*/tests?/.*'
    - '.*/migrations/.*'
  layers:
    - name: domain
      collectors:
        - type: directory
          directories:
            - "src/app/domain"
    - name: application
      collectors:
        - type: directory
          directories:
            - "src/app/application"
    - name: infrastructure
      collectors:
        - type: directory
          directories:
            - "src/app/infrastructure"
    - name: interface
      collectors:
        - type: directory
          directories:
            - "src/app/api"
  ruleset:
    domain:
      disallow_layer_dependencies:
        - application
        - infrastructure
        - interface
      disallow_external_imports:
        - django
        - fastapi
        - flask
        - sqlalchemy
        - requests
    application:
      disallow_layer_dependencies:
        - interface

Strict

Goal: enforce target architecture, not just current layout.

Use when:

• New project.
• Architecture boundaries are already intentional.
• User accepts initial cleanup or ratchet adoption.

Pattern:

• Use explicit architecture layers and framework adapter layers.
• Domain has no framework, persistence, HTTP, queue, cloud, SDK, exchange, or CLI imports.
• Application has no web framework imports and only depends inward.
• Interface/adapters depend inward but not sideways.
• Add naming/decorator/inheritance rules only where the project already follows the convention or user explicitly wants it.
• CI should run validate and analyze.

Strict adoption in legacy repos:

• Do not weaken the rules silently.
• If current violations are accepted temporarily, set --max-violations=N to the exact current count and document that it must only decrease.

Example CI command:

deply validate --config=deply.yaml
deply analyze --parallel --config=deply.yaml --max-violations=0