README.md

A simple message queue for commands and events (CQRS) for Django.

• PyPI
• GitHub
• Full documentation
• Creator & Maintainer: Ambient Digital

Features

• Split up your business logic in commands and events
• Commands are imperatives telling your system what to do, events reflect that something has happened
• Register light-weight functions via a decorator to listen to your commands and events
• Message handlers receive the context of the message (command or event), providing an explicit API
• No magic, no side effects since the queue works synchronously

import dataclasses

from queuebie.runner import handle_message
from queuebie.messages import Command, Event
from queuebie import message_registry


# Example command
@dataclasses.dataclass(kw_only=True)
class BuyProduct(Command):
    product_id: int
    customer_id: int
    price: float
    currency: str


# Example event
@dataclasses.dataclass(kw_only=True)
class ProductBought(Event):
    product_id: int
    customer_id: int


# Example handler
@message_registry.register_command(BuyProduct)
def handle_buy_product(context: BuyProduct) -> Event:
    # Here lives your business logic

    return ProductBought(
        product_id=context.product_id,
        customer_id=context.customer_id,
    )


# Start queue and process messages
handle_message(
    BuyProduct(
        product_id=product.id,
        customer_id=customer.id,
        price=12.99,
        currency="EUR",
    )
)

Installation

• Install the package via pip:

  pip install django_queuebie

  or via pipenv:

  pipenv install django_queuebie

• Add module to INSTALLED_APPS within the main django settings.py:

  INSTALLED_APPS = (
      # ...
      "queuebie",
  )

Contribute

Setup package for development

• Create a Python virtualenv and activate it
• Install "pip-tools" with pip install -U pip-tools
• Compile the requirements with pip-compile --extra dev, -o requirements.txt pyproject.toml --resolver=backtracking
• Sync the dependencies with your virtualenv with pip-sync

Add functionality

• Create a new branch for your feature
• Change the dependency in your requirements.txt to a local (editable) one that points to your local file system: -e /Users/workspace/django-queuebie or via pip pip install -e /Users/workspace/django-queuebie
• Ensure the code passes the tests
• Create a pull request

Run tests

• Run tests

  pytest --ds settings tests
  

• Check coverage

  coverage run -m pytest --ds settings tests
  coverage report -m
  

Git hooks (via pre-commit)

We use pre-push hooks to ensure that only linted code reaches our remote repository and pipelines aren't triggered in vain.

To enable the configured pre-push hooks, you need to install pre-commit and run once:

pre-commit install -t pre-push -t pre-commit --install-hooks

This will permanently install the git hooks for both, frontend and backend, in your local .git/hooks folder. The hooks are configured in the .pre-commit-config.yaml.

You can check whether hooks work as intended using the run command:

pre-commit run [hook-id] [options]

Example: run single hook

pre-commit run ruff --all-files

Example: run all hooks of pre-push stage

pre-commit run --all-files --hook-stage push

Update documentation

• To build the documentation, run: sphinx-build docs/ docs/_build/html/.
• Open docs/_build/html/index.html to see the documentation.

Translation files

If you have added custom text, make sure to wrap it in _() where _ is gettext_lazy (from django.utils.translation import gettext_lazy as _).

How to create translation file:

• Navigate to django-queuebie
• python manage.py makemessages -l de
• Have a look at the new/changed files within queuebie/locale

How to compile translation files:

• Navigate to django-queuebie
• python manage.py compilemessages
• Have a look at the new/changed files within queuebie/locale

Publish to ReadTheDocs.io

• Fetch the latest changes in GitHub mirror and push them
• Trigger new build at ReadTheDocs.io (follow instructions in admin panel at RTD) if the GitHub webhook is not yet set up.

Publish to PyPi

• Update documentation about new/changed functionality

• Update the Changelog

• Increment version in main __init__.py

• Create pull request / merge to main

• This project uses the flit package to publish to PyPI. Thus, publishing should be as easy as running:

  flit publish
  

  To publish to TestPyPI use the following to ensure that you have set up your .pypirc as shown here and use the following command:

  flit publish --repository testpypi
  

Maintenance

Please note that this package supports the ambient-package-update. So you don't have to worry about the maintenance of this package. This updater is rendering all important configuration and setup files. It works similar to well-known updaters like pyupgrade or django-upgrade.

To run an update, refer to the documentation page of the "ambient-package-update".