eventsourcing-django 0.2.0

Python package for eventsourcing with Django.

Event Sourcing with Django

This package supports using the Python eventsourcing library with Django ORM.

To use Django with your Python eventsourcing applications:

• install the Python package eventsourcing_django
• add 'eventsourcing_django' to your Django project's INSTALLED_APPS setting
• migrate your database for this Django app
• set the environment variable PERSISTENCE_MODULE to 'eventsourcing_django'

See below for more information.

Installation

Use pip to install the stable distribution from the Python Package Index. Please note, it is recommended to install Python packages into a Python virtual environment.

$ pip install eventsourcing_django

Django

If you are using Django 3.2 or later, add 'eventsourcing_django' to your Django project's INSTALLED_APPS setting.

INSTALLED_APPS = [
    ...
    'eventsourcing_django',
]

If you are using Django 2.2, 3.0 or 3.1, please add 'eventsourcing_django.apps.EventsourcingConfig' to your Django project's INSTALLED_APPS setting.

INSTALLED_APPS = [
    ...
    'eventsourcing_django.apps.EventsourcingConfig',
]

To migrate your database, please run Django's manage.py migrate command.

$ python manage.py migrate eventsourcing_django

Event sourcing

Define aggregates and applications in the usual way.

from eventsourcing.application import Application
from eventsourcing.domain import Aggregate, event
from uuid import uuid5, NAMESPACE_URL


class TrainingSchool(Application):
    def register(self, name):
        dog = Dog(name)
        self.save(dog)

    def add_trick(self, name, trick):
        dog = self.repository.get(Dog.create_id(name))
        dog.add_trick(trick)
        self.save(dog)

    def get_tricks(self, name):
        dog = self.repository.get(Dog.create_id(name))
        return dog.tricks


class Dog(Aggregate):
    @event('Registered')
    def __init__(self, name):
        self.name = name
        self.tricks = []

    @staticmethod
    def create_id(name):
        return uuid5(NAMESPACE_URL, f'/dogs/{name}')

    @event('TrickAdded')
    def add_trick(self, trick):
        self.tricks.append(trick)

Construct and use the application in the usual way. Set PERSISTENCE_MODULE to 'eventsourcing_django' in the application's environment. You may wish to construct the application object on a signal when the Django project is "ready". You can use the ready() method of the AppConfig class in the apps.py module of a Django app.

school = TrainingSchool(env={
    "PERSISTENCE_MODULE": "eventsourcing_django",
})

The application's methods may be called from Django views and forms.

school.register('Fido')
school.add_trick('Fido', 'roll over')
school.add_trick('Fido', 'play dead')
tricks = school.get_tricks('Fido')
assert tricks == ['roll over', 'play dead']

For more information, please refer to the Python eventsourcing library and the Django project.