django-ray 0.2.0

Ray-based backend for Django Tasks with distributed execution and database-backed reliability

django-ray

A Ray-based backend for Django Tasks that enables distributed task execution with database-backed reliability.

Why django-ray?

Django projects often need background task execution. While Celery has been the go-to solution for years, Ray offers a more powerful and flexible approach to distributed computing:

• True distributed computing: Ray was built for distributed workloads from the ground up, not just task queues
• Horizontal scaling: Scale from a single machine to thousands of nodes without changing your code
• Resource-aware scheduling: Request specific CPU, GPU, or memory for tasks
• Actor model support: Maintain stateful workers when needed
• Rich ecosystem: Access to Ray's ML libraries, data processing, and more

Despite Ray's capabilities, there was no straightforward way to use it with Django's built-in Tasks framework. django-ray bridges this gap, letting you leverage Ray's distributed computing power while keeping Django's familiar patterns and database-backed reliability.

Overview

django-ray bridges Django's built-in Tasks framework with Ray's distributed computing capabilities, providing:

• Database-backed reliability: Task state is tracked in your Django database, ensuring no tasks are lost
• Multiple execution modes: Sync, local Ray, Ray cluster, or Ray Job API
• Automatic retries: Failed tasks are retried with exponential backoff
• Admin visibility: Monitor and manage tasks through Django admin
• Graceful shutdown: Workers handle signals properly for clean shutdown

Requirements

• Python 3.12+
• Django 6.0+
• Ray 2.53.0+

Installation

pip install django-ray

Or with uv:

uv add django-ray

Quick Start

1. Add django_ray to your INSTALLED_APPS:

INSTALLED_APPS = [
    # ...
    "django_ray",
]

2. Configure django-ray settings:

DJANGO_RAY = {
    "RAY_ADDRESS": "auto",  # Use "ray://host:port" for a remote cluster
    "DEFAULT_CONCURRENCY": 10,
    "MAX_TASK_ATTEMPTS": 3,
}

3. Run migrations:

python manage.py migrate django_ray

4. Start the worker:

# Local Ray (recommended for development)
python manage.py django_ray_worker --queue=default --local

# Connect to Ray cluster
python manage.py django_ray_worker --queue=default --cluster=ray://localhost:10001

# Sync mode (no Ray, for testing)
python manage.py django_ray_worker --queue=default --sync

Worker Execution Modes

Mode	Flag	Description
sync	--sync	Direct execution, no Ray (testing)
local	--local	Local Ray cluster, tasks via @ray.remote
cluster	--cluster=<addr>	Remote Ray cluster, tasks via @ray.remote
ray-job	(default)	Ray Job Submission API (process isolation)

Configuration

Setting	Default	Description
RAY_ADDRESS	None	Must be set at runtime; use "auto" locally or "ray://host:port" for a cluster
DEFAULT_CONCURRENCY	10	Max concurrent tasks per worker
MAX_TASK_ATTEMPTS	3	Max retry attempts
RETRY_BACKOFF_SECONDS	60	Base backoff for retries
RETRY_EXCEPTION_DENYLIST	[]	Exception types that skip auto-retry
STUCK_TASK_TIMEOUT_SECONDS	300	Timeout before marking tasks as LOST

Development Setup

Prerequisites

• Python 3.12+
• uv package manager

Installation

git clone <repository-url>
cd django-ray
uv sync

Development Commands

make install     # Install dependencies
make format      # Format code with Ruff
make lint        # Lint code with Ruff
make typecheck   # Type check with ty
make test        # Run tests
make check       # Run lint + typecheck
make ci          # Run all CI checks
make docs-build  # Build docs (Zensical)
make docs-build-strict # Build docs in strict mode
make docs-serve  # Serve docs locally

Django Commands

make migrate          # Run migrations
make runserver        # Start dev server
make shell            # Django shell
make createsuperuser  # Create admin user

Worker Commands

make worker           # Ray Job API mode
make worker-local     # Local Ray (recommended)
make worker-sync      # Sync mode (no Ray)
make worker-all       # All queues, local Ray
make worker-cluster   # Connect to cluster

Quick Start (End-to-End Testing)

Terminal 1 - Start Django server:

make runserver

Terminal 2 - Start worker:

make worker-all

Browser - Test via API:

1. Open http://127.0.0.1:8000/api/docs (Swagger UI)
2. Try POST /api/enqueue/add/100/200
3. Check GET /api/executions - see task completed with result 300
4. View in Admin: http://127.0.0.1:8000/admin/django_ray/raytaskexecution/

Queue Configuration

# Single queue
python manage.py django_ray_worker --queue=default

# Multiple queues
python manage.py django_ray_worker --queue=default,high-priority,low-priority

# All configured queues
python manage.py django_ray_worker --all-queues

Docker

make docker-build

# Run modes:
docker run -p 8000:8000 django-ray:latest web          # Production
docker run -p 8000:8000 django-ray:latest web-dev      # Development
docker run django-ray:latest worker                     # Worker (local Ray)
docker run django-ray:latest worker-cluster             # Worker (cluster)

Kubernetes Deployment

Deploy using Kustomize manifests in k8s/:

# Build images
make k8s-build

# Deploy
make k8s-deploy

# Check status
make k8s-status

# With TLS enabled
make k8s-gen-tls-certs
make k8s-deploy-tls

See k8s/README.md for detailed deployment documentation.

Project Structure

django-ray/
├── src/django_ray/          # Library source code
│   ├── models.py            # RayTaskExecution, TaskWorkerLease
│   ├── admin.py             # Admin interface
│   ├── backends.py          # Django Task Backend
│   ├── conf/                # Settings
│   ├── runner/              # Task runners
│   │   ├── ray_job.py       # Ray Job Submission API
│   │   ├── ray_core.py      # Ray Core (@ray.remote)
│   │   ├── leasing.py       # Worker coordination
│   │   └── retry.py         # Retry logic
│   ├── runtime/             # Task execution
│   │   ├── entrypoint.py    # Execution entry point
│   │   ├── distributed.py   # parallel_map, scatter_gather
│   │   └── serialization.py
│   └── management/commands/
│       └── django_ray_worker.py
│
├── testproject/             # Example project (development only)
│   ├── api.py               # Example REST API
│   ├── tasks.py             # Example tasks
│   └── apps/                # Example apps
│
├── tests/                   # Test suite
├── docs/                    # Documentation
└── k8s/                     # Kubernetes manifests

Documentation

Published docs are served with Zensical at:

• https://django-ray.readthedocs.io/en/latest/

Read the Docs builds are configured in .readthedocs.yaml. The build installs uv, runs the strict Zensical build, and copies the generated site/ output into Read the Docs' HTML output directory.

Source docs remain in the docs/ directory:

• Getting Started - Installation and basic setup
• Configuration - All configuration options
• Worker Modes - Execution modes explained
• Tasks - Defining and enqueueing tasks
• Queues - Working with task queues
• Retry & Error Handling - Configuring retries

Deployment

• Kubernetes - Deploy to Kubernetes
• Docker - Running with Docker
• TLS - Securing Ray communication

Reference

• CLI Reference - Command-line options
• Settings Reference - All settings
• API Reference - REST API endpoints

License

This project is licensed under the BSD 3-Clause License - see the LICENSE file for details.