django-pghistory¶
django-pghistory
tracks changes to your Django models using Postgres triggers, providing:
- Reliable history tracking everywhere with no changes to your application code.
- Structured history models that mirror the fields of your models.
- Grouping of history with additional context attached, such as the logged-in user.
django-pghistory
has a number of ways in which you can configure history tracking for your application's needs and for performance and scale. An admin integration and middleware is included out of the box too.
Quick Start¶
Decorate your model with pghistory.track. For example:
import pghistory
@pghistory.track()
class TrackedModel(models.Model):
int_field = models.IntegerField()
text_field = models.TextField()
Above we've tracked TrackedModel
. Copies of the model will be stored in a dynamically-created event model on every insert and update.
Run python manage.py makemigrations
followed by migrate
and voila, every change to TrackedModel
is now stored. This includes bulk methods and even changes that happen in raw SQL. For example:
from myapp.models import TrackedModel
m = TrackedModel.objects.create(int_field=1, text_field="hello")
m.int_field = 2
m.save()
print(m.events.values("pgh_obj", "int_field"))
> [{'pgh_obj': 1, 'int_field': 1}, {'pgh_obj': 1, 'int_field': 2}]
Above we printed the history of int_field
. We also printed pgh_obj
, which references the tracked object. We'll cover how these fields and additional metadata fields are tracked later.
django-pghistory
can track a subset of fields and conditionally store events based on specific field transitions. Users can also store free-form context from the application in event metadata, all with no additional database queries. See the next steps below on how to dive deeper and configure it for your use case.
Compatibility¶
django-pghistory
is compatible with Python 3.9 - 3.13, Django 4.2 - 5.1, Psycopg 2 - 3, and Postgres 13 - 17.
Next Steps¶
We recommend everyone first read:
- Installation for how to install the library.
- Basics for an overview and terminology guide.
After this, there are several usage guides:
- Event Tracking for tracking historical events on models.
- Collecting Context for attaching dynamic application context to events.
- Configuring Event Models for configuring event models.
- Aggregating Events and Diffs for aggregating events across event models.
- Admin Integration for an overview of the Django admin integration.
- Reverting Objects for reverting models to previous versions.
There's additional help in these sections:
- Frequently Asked Questions for common questions.
- Troubleshooting for advice on known issues.
- Performance and Scaling for tips on performance and scaling.
- Upgrading for upgrading to new versions.
Finally, core API information exists in these sections:
- Settings for all available Django settings.
- Module for documentation of the
pghistory
module. - Release Notes for information about every release.
- Contributing Guide for details on contributing to the codebase.