Django Nova

Typed Django models. Shared Pydantic schemas. Explicit validation boundaries.

Django Nova is a typed, async-oriented toolkit for Django 5. It connects Django models with Pydantic schemas, schema-driven query planning, caching, background tasks, and optional OpenTelemetry tracing.

PyPI · Documentation · Project site · Coverage report · Roadmap

Development status: Beta. This README describes the current development workflow and the reviewed source implementation. Recent source changes may not yet be included in the published PyPI package. Check the changelog and the version you install before adopting an API.

Philosophy

Nova keeps Django's ORM and database semantics while making the boundaries around validation, serialization, and typing explicit.

• Shared schemas: use Pydantic to express data contracts and reusable rules. Django fields, Model.clean(), uniqueness checks, and database constraints retain their own responsibilities.
• Typed boundaries: contain dynamic Django metadata behind focused helpers. Static analysis complements runtime validation; it cannot replace it.
• Schema-selected serialization: serialize the fields required by the selected schema rather than exposing every model attribute.
• Explicit async behavior: support asynchronous workflows without implying that every operation or relation lookup is non-blocking.
• Reproducible evidence: report tests, coverage, and benchmarks as measurements, not as automatic proof of production readiness.

Requirements

The current package manifest declares:

These are dependency bounds, not a claim that every version combination has been tested. Django 6 is outside the declared range.

Installation

For an existing project managed with uv:

uv add django-nova

Or with pip inside an activated virtual environment:

python -m pip install django-nova

Optional integrations are installed explicitly:

uv add 'django-nova[redis]'
uv add 'django-nova[drf]'
uv add 'django-nova[fastapi]'
uv add 'django-nova[graphql]'
uv add 'django-nova[tracing]'
uv add 'django-nova[observability]'

Choose the extras your application needs. tracing supplies the OpenTelemetry API; observability additionally supplies SDK/exporter dependencies. Installing those dependencies does not configure a telemetry exporter. The manifest also provides cache, tasks, and async extras; installing an extra alone does not activate an integration or turn synchronous ORM calls into async operations.

Add Nova and your application to Django settings:

# config/settings.py — extend your existing INSTALLED_APPS.
INSTALLED_APPS = [
    "django.contrib.contenttypes",
    "nova",
    "articles",
]

Keep the other Django applications required by your project. Import model classes only after Django settings and the app registry are initialized.

Quick start

The examples below assume an existing Django project with an articles app. Create it if needed:

uv run python manage.py startapp articles

1. Define a schema and a model

# articles/models.py
from django.db import models
from pydantic import BaseModel, Field

from nova import NovaConfig, NovaModel


class ArticleSchema(BaseModel):
    title: str = Field(min_length=5, max_length=200)
    body: str
    views: int = Field(default=0, ge=0)


class Article(NovaModel):
    title = models.CharField(max_length=200)
    body = models.TextField()
    views = models.IntegerField(default=0)

    _nova_config = NovaConfig(
        pydantic_schema=ArticleSchema,
        strict_validation=True,
        cache_enabled=False,
    )

Django field declarations use assignment (=). Pydantic defines the application contract; Django fields define persistence and field-level rules. Some limits belong at both boundaries. An explicit schema does not rewrite the database model.

2. Create the database table

uv run python manage.py makemigrations articles
uv run python manage.py migrate
uv run python manage.py check
uv run python manage.py shell

3. Save and serialize

Run in the Django shell or an initialized application service:

from articles.models import Article

article = Article(
    title="Hello Nova",
    body="Shared validation with explicit boundaries.",
)
article.save()

payload = article.to_pydantic().model_dump()
assert payload == {
    "title": "Hello Nova",
    "body": "Shared validation with explicit boundaries.",
    "views": 0,
}
assert "id" not in payload  # The explicit schema does not declare it.

4. Handle validation errors

from articles.models import Article
from nova.core.exceptions import NovaValidationError

try:
    Article(title="Hi", body="Too short a title.").save()
except NovaValidationError as exc:
    print(f"Validation failed: {exc}")

For this example, the title fails Pydantic validation before persistence.

Validation contract

NovaModel.save() runs this pipeline before calling Django's save implementation:

Pydantic → Django field validation and conversion → Model.clean()
         → uniqueness checks → constraint checks → database save

• strict_validation=True enables the Pydantic stage.
• strict_validation=False skips that stage; Django validation still runs.
• Successful field.clean() results are assigned back to model attributes before Model.clean() executes.
• Full-model validation is retained when save(update_fields=...) is used.
• QuerySet.update(), bulk_create(), and bulk_update() bypass model save(); they do not acquire its validation contract.
• Database constraints remain necessary. Pre-save checks do not replace database enforcement under concurrent writes.

Automatic schema generation supports mapped Django types, inherited field types, nullable fields, and callable defaults. Decimal digit constraints are transferred to generated schemas. An unknown field falls back to Any, which does not provide specialized type validation.

FileField and ImageField values are serialized as names/paths rather than file contents. Their Django max_length is not transferred to the Pydantic value in the current compiler. Django field validation still applies on the save path.

Query planning and async ORM

For a Nova queryset, .auto() applies a plan derived from the model's schema:

from articles.models import Article

queryset = Article.objects.filter(title__icontains="Nova").auto()
articles = list(queryset)

The selected joins, prefetches, and deferred fields depend on the model/schema. Measure query counts for your actual workload; .auto() is not a universal performance guarantee.

For Nova's additional async queryset helpers, explicitly configure the manager:

from nova.async_orm import AsyncNovaManager

# Inside a NovaModel subclass:
# objects = AsyncNovaManager()

Django's async save API can be used from an async application function:

from articles.models import Article


async def create_article() -> Article:
    article = Article(title="Async Nova", body="Created asynchronously.")
    await article.asave()
    return article

An unloaded nested foreign key may require synchronous SQL during serialization. Do not assume that calling to_pydantic() directly in an async context is safe for every model. Nested M2M and reverse-relation serialization remain separate contracts; see the roadmap.

Background tasks

@nova_task() decorates an async function. Awaiting the decorated call submits work and returns a task ID; it does not await the task's business result. The decorator uses the shared engine returned by get_engine().

import asyncio

from nova import nova_task
from nova.tasks.engine import get_engine


async def main() -> None:
    engine = get_engine()
    completed = asyncio.Event()

    @nova_task(name="demo.greet")
    async def greet(person: str) -> None:
        print(f"Hello, {person}!")
        completed.set()

    await engine.start()
    try:
        task_id = await greet("Nova")
        print(f"Submitted task: {task_id}")
        await asyncio.wait_for(completed.wait(), timeout=10)
    finally:
        await engine.stop()


if __name__ == "__main__":
    asyncio.run(main())

This is an in-process example using the default backend. The event is demo-local synchronization, not a distributed completion mechanism. Start the shared engine in application startup and stop it during shutdown. Backend shutdown behavior, retries, durability, and process recovery must be evaluated for your deployment. Do not submit blocking CPU-intensive work directly to the event loop.

Tracing

Tracing is optional. With no usable tracer, nova_span() yields None. For async operations, keep the awaited work inside the span:

from nova.core.tracing import nova_span


async def fetch_and_measure(fetch):
    with nova_span("article.fetch", component="service"):
        return await fetch()

The current tracing decorators support both ordinary functions and async def:

from nova.core.tracing import trace_task


@trace_task(operation="calculate")
async def calculate_total(prices: list[int]) -> int:
    return sum(prices)

Nova guards its internal telemetry setup, recording, and teardown calls against ordinary exceptions while preserving business results, exceptions, and cancellation. Direct span method calls made by application code are outside that protection. Provider signals derived directly from BaseException are not suppressed. Configure the OpenTelemetry SDK and exporter separately if you want to collect spans.

Development and verification

To work on the repository rather than the published package:

git clone https://github.com/Artem7898/django-nova.git
cd django-nova
uv sync --group dev --all-extras

For an existing checkout containing local changes, run the sync command there; cloning the remote does not include unpublished local fixes. Commit and retain uv.lock for reproducible development environments.

Run static checks and the complete test suite:

uv run pyright src/nova \
&& uv run ruff check . \
&& uv run pytest -q

Pyright uses the repository configuration, including its exclusions and scoped exceptions. A clean run is not a claim that every module has unrestricted strict typing coverage. Application model typing also depends on its own checker and Django stub configuration.

Focused checks:

uv run pytest -q tests/architecture
uv run pytest -q tests/typing/test_django_boundary.py
uv run pytest -q \
  tests/core/test_tracing.py \
  tests/core/test_tracing_async.py \
  tests/core/test_tracing_resilience.py

Check collection when adding or moving tests:

uv run pytest --collect-only -q tests/typing

Place test functions in discoverable test_*.py modules, not package __init__.py files.

Coverage and generated status

uv run pytest -q --cov=src/nova --cov-report=xml:coverage.xml \
&& uv run python scripts/generate_status.py --write \
&& uv run python scripts/generate_status.py --check

Update the README badge using the same coverage snapshot:

uv run python scripts/update_badge.py --write \
&& uv run python scripts/update_badge.py --check

The badge is initially a link to the report, not an invented coverage percentage. The updater replaces its value with the measured percentage from coverage.xml.

The latest local verification reported for the reviewed development changes was 786 tests passed, with clean Pyright and Ruff results; the coverage run and status generation also succeeded. This is a historical development snapshot, not a live CI result or a result independently reproduced for every installation.

STATUS.md distinguishes missing measurements (N/A) from measured 0%. Its overall percentage comes from the XML report's line counters. --check compares the generated report with supplied inputs; it does not prove that the coverage snapshot matches the latest source contents.

Performance

Benchmark model construction and serialization separately:

uv run python scripts/bench.py

Treat this as a local diagnostic, not a universal speed claim. Review the current benchmark script before publishing results; the roadmap tracks improvements to its execution and measurement setup.

Django model construction, Pydantic validation, to_pydantic(), SQL execution, and cache access perform different work. Report Python and dependency versions, hardware, benchmark configuration, repetitions, variability, and raw results. Small differences within measurement noise do not establish that Nova is faster than Django or adds zero overhead.

Scope and limitations

See ROADMAP.md for planned work and STATUS.md for coverage measurements. Neither assigns production readiness from a percentage.

Contributing

Include a minimal reproducer for defects and a regression test for behavior changes. Keep compatibility boundaries explicit, run the checks above, and update documentation when public behavior changes.

• Issue tracker
• Changelog
• Documentation

Author and references

Developed and maintained by Artem Alimpiev.

• ORCID: 0009-0007-6740-7242
• Research references: 10.5281/zenodo.20057443, 10.5281/zenodo.20659647

License

MIT, as declared in the package metadata.