Step-by-Step Guide to Creating a Multi-tenant SaaS Application Using Django REST Framework

Building a multi-tenant software as a service (SaaS) application allows you to serve multiple customers (tenants) from a single application instance. Each tenant’s data is isolated and remains invisible to other tenants. In this blog post, we’ll explore how to create a multi-tenant SaaS application using Django and the Django REST Framework.

Prerequisites

• Basic knowledge of Python and Django
• Django and Django REST Framework installed
• PostgreSQL database (recommended for handling multiple tenants)

Setting Up the Project

Create a New Django Project

First, start by creating a new Django project if you haven’t already:

django-admin startproject my_sass_project
cd my_sass_project

Install Required Packages

Next, install the Django Tenants package, which helps in managing multiple tenants:

pip install django-tenants

Configure Django for Multi-Tenancy

Configure Database

Modify your settings.py to use PostgreSQL, which supports schema-based tenancy:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'your_db_name',
        'USER': 'your_db_user',
        'PASSWORD': 'your_db_password',
        'HOST': 'localhost',
        'PORT': '',
    }
}

Configure Django-Tenants

Add django_tenants.routers.TenantSyncRouter to your DATABASE_ROUTERS in settings.py:

DATABASE_ROUTERS = ('django_tenants.routers.TenantSyncRouter',)

Also, update INSTALLED_APPS and MIDDLEWARE as required by Django Tenants.

Development of Tenant-aware Components

Creating Models

When creating models, inherit from TenantMixin to make them tenant-aware. For example:

from django_tenants.models import TenantMixin

class MyModel(TenantMixin, models.Model):
    name = models.CharField(max_length=255)
    created_on = models.DateField(auto_now_add=True)

Handling Tenant Identification

Use a middleware to set the current tenant based on the request, usually done by subdomain or URL parameter.

API Setup using Django REST Framework

Create Serializers and Views

Use Django REST Framework to create serializers and views for your models:

# serializers.py
from rest_framework import serializers
from .models import MyModel

class MyModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = MyModel
        fields = '__all__'

# views.py
from rest_framework import viewsets
from .models import MyModel
from .serializers import MyModelSerializer

class MyModelViewSet(viewsets.ModelViewSet):
    queryset = MyModel.objects.all()
    serializer_class = MyModelSerializer

Configuring URLs

Register the API routes with Django’s URL dispatcher:

# urls.py
from django.urls import include, path
from rest_framework.routers import DefaultRouter
from .views import MyModelViewSet

router = DefaultRouter()
router.register(r'mymodel', MyModelViewSet)

urlpatterns = [
    path('api/', include(router.urls)),
]

Conclusion

Creating a multi-tenant SaaS app with Django REST Framework involves setting up a tenant-aware infrastructure, building tenant-aware models, and exposing these via APIs. By following this guide, you can build a robust multi-tenant application that can efficiently serve multiple tenants from a single instance.