@appling/codegen-django

Appling code generation extension for Django. It turns an Appling model into a draft Django project managed by uv.

{
  "generate": [
    { "extension": "@appling/codegen-django", "out": "build/shop", "options": { "name": "shop" } }
  ]
}

Requires uv on the PATH. Python and Django (6.1) are installed by uv into the project.

What it generates

| Model | Django | |---|---| | project | uv init, uv add django, django-admin startproject config . | | module | manage.py startapp, added to INSTALLED_APPS; nested modules a.b become the app a_b | | enum | models.TextChoices in <app>/enums.py | | value | TypedDict in <app>/values.py; fields of a value type are stored as JSONField | | entity | a model in <app>/models.py | | field types | CharField, TextField, IntegerField, DecimalField, BooleanField, DateField, DateTimeField, DurationField, FileField, UUIDField; enums as choices; entities as ForeignKey (CASCADE when owned, else PROTECT) or ManyToManyField; lists as JSONField | | unique, ?, default | unique=True, null=True, blank=True, default= | | derived field | a @property with the expression translated to Python | | invariant | CheckConstraint in Meta.constraints when it compares stored fields with constants or other fields | | action | a function in <app>/actions.py, atomic unless consistency eventual: preconditions raise the declared errors, transitions of the state machine check the current state and guard, effects set fields, create rows and send events after commit | | errors | exception classes in <app>/errors.py, with InvalidTransition for state machines | | event | a Django Signal in <app>/events.py | | machine | transitions triggered by an event become signal receivers in <app>/handlers.py, connected in AppConfig.ready | | job | scheduled: a django.tasks task in <app>/jobs.py plus a management command for the scheduler; on an event: a signal receiver | | query | a function in <app>/queries.py returning a queryset with filter and ordering, and the page size | | projection | a REST framework ModelSerializer in <app>/serializers.py; computed fields that follow references become source paths | | external | a typing.Protocol in <app>/externals.py that use cases receive as a parameter | | usecase | a function in <app>/usecases.py calling its steps in order, with try/except for error handlers | | interface rest | REST framework views in <app>/api.py and routes in <app>/api_urls.py under api/: list views for queries with projection, picks and pagination, APIViews for actions; limit becomes a throttle | | page | a server rendered view with its list, detail and form components, posting row actions and forms to a runner view per action | | navigation, messages | the menu of the base template, and labels per language |

| rules | a TestCase per invariant, policy, transition and action with preconditions in <app>/tests.py, one skipped method per case; writing their bodies is a registry task |

Models with projections or interfaces also get Django REST framework. The project ends with manage.py makemigrations, so its migration history starts with the generated models.

appling generate --migrate continues that history: renamed, retyped and removed fields become RenameField, AlterField and RemoveField, renamed and removed entities RenameModel and DeleteModel, a renamed enum value an AlterField with a data migration of the stored values. models.py and enums.py change with them, so makemigrations finds nothing left to guess.

What cannot be translated becomes a registry task: invariants over derived fields or other entities, derived fields and defaults that use actor or other context, policies, roles, guards and effects that cannot be expressed in Python, the client of an external system, scheduling of jobs, use cases from their first await on, authentication and CORS of interfaces.

License

MIT