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https://github.com/citusdata/django-multitenant
Python/Django support for distributed multi-tenant databases like Postgres+Citus
https://github.com/citusdata/django-multitenant
Last synced: about 15 hours ago
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Python/Django support for distributed multi-tenant databases like Postgres+Citus
- Host: GitHub
- URL: https://github.com/citusdata/django-multitenant
- Owner: citusdata
- License: mit
- Created: 2017-05-19T05:23:40.000Z (over 7 years ago)
- Default Branch: main
- Last Pushed: 2024-07-17T11:22:36.000Z (5 months ago)
- Last Synced: 2024-12-04T18:17:35.691Z (8 days ago)
- Language: Python
- Size: 609 KB
- Stars: 747
- Watchers: 41
- Forks: 123
- Open Issues: 64
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
- starred-awesome - django-multitenant - Python/Django support for distributed multi-tenant databases like Postgres+Citus (Python)
- stars - citusdata/django-multitenant - Python/Django support for distributed multi-tenant databases like Postgres+Citus (Python)
- stars - citusdata/django-multitenant - Python/Django support for distributed multi-tenant databases like Postgres+Citus (Python)
README
# django-multitenant
[](https://github.com/citusdata/django-multitenant/actions/workflows/django-multitenant-tests.yml) [](https://django-multitenant.readthedocs.io/en/latest/?badge=latest) [](https://codecov.io/gh/citusdata/django-multitenant) [](https://badge.fury.io/py/django-multitenant)
Python/Django support for distributed multi-tenant databases like Postgres+Citus
Enables easy scale-out by adding the tenant context to your queries, enabling the database (e.g. Citus) to efficiently route queries to the right database node.
There are architecures for building multi-tenant databases viz. **Create one database per tenant**, **Create one schema per tenant** and **Have all tenants share the same table(s)**. This library is based on the 3rd design i.e **Have all tenants share the same table(s)**, it assumes that all the tenant relates models/tables have a tenant_id column for representing a tenant.
The following link talks more about the trade-offs on when and how to choose the right architecture for your multi-tenant database:
https://www.citusdata.com/blog/2016/10/03/designing-your-saas-database-for-high-scalability/
The following blogpost is a good starting point to start to use django-multitenant
https://www.citusdata.com/blog/2023/05/09/evolving-django-multitenant-to-build-scalable-saas-apps-on-postgres-and-citus/
**Other useful links on multi-tenancy**:
1. https://www.citusdata.com/blog/2017/03/09/multi-tenant-sharding-tutorial/
1. https://www.citusdata.com/blog/2017/06/02/scaling-complex-sql-transactions/
1. https://www.youtube.com/watch?v=RKSwjaZKXL0
## Installation:
1. `pip install --no-cache-dir django_multitenant`
## Supported Django versions/Pre-requisites.
| Python | Django |Citus |
| ----------------------| --------------|---------------|
| 3.8 3.9 3.10 3.11 | 4.2 | 11 12 |
| 3.8 3.9 3.10 3.11 | 4.1 | 11 12 |
| 3.8 3.9 3.10 3.11 | 4.0 | 10 11 12 |
| 3.7 | 3.2 | 10 11 12 |
## Usage:
In order to use this library you can either use Mixins or have your models inherit from our custom model class.
### Changes in Models:
1. In whichever files you want to use the library import it:
```python
from django_multitenant.fields import *
from django_multitenant.models import *
```
2. All models should inherit the TenantModel class.
`Ex: class Product(TenantModel):`
3. Define a static variable named tenant_id and specify the tenant column using this variable.You can define tenant_id in three ways. Any of them is acceptable
* Using TenantMeta.tenant_field_name variable
* Using TenantMeta.tenant_id variable
* Using tenant_id field
> **Warning**
> Using tenant_id field directly in the class is not suggested since it may cause collision if class has a field named with 'tenant'
4. All foreign keys to TenantModel subclasses should use TenantForeignKey in place of
models.ForeignKey
5. A sample model implementing the above 2 steps:
```python
class Store(TenantModel):
name = models.CharField(max_length=50)
address = models.CharField(max_length=255)
email = models.CharField(max_length=50)
class TenantMeta:
tenant_field_name = "id"
class Product(TenantModel):
store = models.ForeignKey(Store)
name = models.CharField(max_length=255)
description = models.TextField()
class Meta:
unique_together = ["id", "store"]
class TenantMeta:
tenant_field_name = "store_id"
class Purchase(TenantModel):
store = models.ForeignKey(Store)
product_purchased = TenantForeignKey(Product)
class TenantMeta:
tenant_field_name = "store_id"
```
### Changes in Models using mixins:
1. In whichever files you want to use the library import it by just saying
```python
from django_multitenant.mixins import *
```
1. All models should use the `TenantModelMixin` and the django `models.Model` or your customer Model class
`Ex: class Product(TenantModelMixin, models.Model):`
1. Define a static variable named tenant_id and specify the tenant column using this variable.
`Ex: tenant_id='store_id'`
1. All foreign keys to TenantModel subclasses should use TenantForeignKey in place of
models.ForeignKey
1. Referenced table in TenantForeignKey should include a unique key including tenant_id and primary key
```
Ex:
class Meta:
unique_together = ["id", "store"]
```
1. A sample model implementing the above 3 steps:
```python
class ProductManager(TenantManagerMixin, models.Manager):
pass
class Product(TenantModelMixin, models.Model):
store = models.ForeignKey(Store)
tenant_id='store_id'
name = models.CharField(max_length=255)
description = models.TextField()
objects = ProductManager()
class Meta:
unique_together = ["id", "store"]
class PurchaseManager(TenantManagerMixin, models.Manager):
pass
class Purchase(TenantModelMixin, models.Model):
store = models.ForeignKey(Store)
tenant_id='store_id'
product_purchased = TenantForeignKey(Product)
objects = PurchaseManager()
```
### Automating composite foreign keys at db layer:
1. Creating foreign keys between tenant related models using TenantForeignKey would automate adding tenant_id to reference queries (ex. product.purchases) and join queries (ex. product__name). If you want to ensure to create composite foreign keys (with tenant_id) at the db layer, you should change the database ENGINE in the settings.py to `django_multitenant.backends.postgresql`.
```python
'default': {
'ENGINE': 'django_multitenant.backends.postgresql',
......
......
......
}
```
### Where to Set the Tenant?
1. Write authentication logic using a middleware which also sets/unsets a tenant for each session/request. This way developers need not worry about setting a tenant on a per view basis. Just set it while authentication and the library would ensure the rest (adding tenant_id filters to the queries). A sample implementation of the above is as follows:
```python
from django_multitenant.utils import set_current_tenant
class MultitenantMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
if request.user and not request.user.is_anonymous:
set_current_tenant(request.user.employee.company)
return self.get_response(request)
```
In your settings, you will need to update the `MIDDLEWARE` setting to include the one you created.
```python
MIDDLEWARE = [
# ...
# existing items
# ...
'appname.middleware.MultitenantMiddleware'
]
```
2. Set the tenant using set_current_tenant(t) api in all the views which you want to be scoped based on tenant. This would scope all the django API calls automatically(without specifying explicit filters) to a single tenant. If the current_tenant is not set, then the default/native API without tenant scoping is used.
```python
def application_function:
# current_tenant can be stored as a SESSION variable when a user logs in.
# This should be done by the app
t = current_tenant
#set the tenant
set_current_tenant(t);
#Django ORM API calls;
#Command 1;
#Command 2;
#Command 3;
#Command 4;
#Command 5;
```
## Supported APIs:
1. Most of the APIs under Model.objects.*.
1. Model.save() injects tenant_id for tenant inherited models.
```python
s=Store.objects.all()[0]
set_current_tenant(s)
#All the below API calls would add suitable tenant filters.
#Simple get_queryset()
Product.objects.get_queryset()
#Simple join
Purchase.objects.filter(id=1).filter(store__name='The Awesome Store').filter(product__description='All products are awesome')
#Update
Purchase.objects.filter(id=1).update(id=1)
#Save
p=Product(8,1,'Awesome Shoe','These shoes are awesome')
p.save()
#Simple aggregates
Product.objects.count()
Product.objects.filter(store__name='The Awesome Store').count()
#Subqueries
Product.objects.filter(name='Awesome Shoe');
Purchase.objects.filter(product__in=p);
```
## Credits
This library uses similar logic of setting/getting tenant object as in [django-simple-multitenant](https://github.com/pombredanne/django-simple-multitenant). We thank the authors for their efforts.
## License
Copyright (C) 2023, Citus Data
Licensed under the MIT license, see LICENSE file for details.