Make Your Django App Reliable with DBOS

This guide shows you how to add the open source DBOS Transact library to your existing Django application to durably execute it and make it resilient to any failure.

In summary you'll need to:

• Start DBOS with your AppConfig's ready method
• Annotate your service methods with DBOS decorators to make them durable
• Start Django with the --noreload flag.

Installation and Requirements

info

The guide is based on the Django quickstart, will show you how to make your application reliable with DBOS Transact.

Setting up the Django quickstart

This application was created with:

python3 -m venv .venv
source .venv/bin/activate
pip install django
django-admin startproject djangodbos .
python manage.py startapp polls

Then, configure djangodbos/settings.py to use Postgres and run python manage.py migrate.

Install DBOS Python with:

pip install dbos

Starting DBOS

In your Django application AppConfig, start DBOS inside the ready method. You can configure the DBOS instance before launching DBOS.

import os
from django.apps import AppConfig
from dbos import DBOS, DBOSConfig

class PollsConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'polls'

    def ready(self):
        dbos_config: DBOSConfig = {
            "name": "django-app",
            "system_database_url": os.environ.get("DBOS_SYSTEM_DATABASE_URL"),
        }
        DBOS(config=dbos_config)
        DBOS.launch()
        return super().ready()

We recommend you call python manage.py runserver with the --noreload flag to avoid repeatedly relaunching DBOS during development.

Making Your Views Reliable

You can make a Django view durable using DBOS workflows

In this example, we'll write a callWorkflow endpoint that invokes a workflow of two steps.

def callWorkflow(request, a, b):
    return JsonResponse(workflow(a, b))


@DBOS.step()
def step_one(a):
    print("Step one completed!", a)

@DBOS.step()
def step_two(b):
    print("Step two completed!", b)

@DBOS.workflow()
def workflow(a, b):
    step_one(a)
    step_two(b)
    return {"result": "success"}

Update polls/urls.py and run your app with python manage.py runserver --noreload to access the view at http://localhost:8000/polls/callWorkflow/a/b.