Confucius
---------
.. rubric:: A simpler, clearer approach to configuration.
Quick Start
===========
.. code-block:: python
:name: config.py
from confucius import BaseConfig
class Config(BaseConfig)
HOST = '127.0.0.1'
PORT : int = 8000
DEBUG : bool = False
.. code-block:: python
:name: app.py
from myapp import Server
from config import Config
server = Server(Config.HOST, Config.PORT)
.. code-block:: sh
$ python app.py
- Starting server: 127.0.0.1:8000
$ PORT=80 python app.py
- Starting server: 127.0.0.1:80
$ DEBUG=y python app.py
- Starting debug server: 127.0.0.1:80
Types
=====
Any ``ANGRY_SNAKE_CASE`` attributes of a ``BaseConfig`` sub-class will be
intercepted by the meta-class, and checked for in the environment using
``os.getenv``.
Their type will be determined by their annotation in the class, or fall back to
``str``.
Methods will automatically behave like a ``property``, with access to ``self``.
Handling of type casting can be overridden [as it is for bool] by adding it to
the ``__types__`` dict:
.. code-block:: python
class Config(BaseConfig):
__types__ = {
json: lambda v: json.loads(v) if isinstance(v, str) else v,
}
LOGGING : json = {'version': 1 ...}
All types defined on parent ``Config`` classes will be merged with this dict.
Inheritance
===========
Classes, as usual, inherit from their parents. If the type of an attribute is
changed, it will raise an ``AssertionError``.
Methods
=======
Method in all-caps will be invoked, and can access ``self`` as usual:
.. code-block:: python
class Config(BaseConfig):
DB_ENGINE = 'postgresql'
DB_HOST = 'localhost'
DB_PORT : int = 5432
DB_USER = 'test_user'
DB_PASS = 'secret'
DB_NAME = 'test-db'
def CONNECTION_STRING(self):
return f'{self.DB_ENGINE}://{self.DB_USER}:{self.DB_PASS}@{self.DB_HOST}/{self.DB_NAME}'
Using in Django
---------------
In your ``settings.py``, put your settings class (or classes), then use the following code to select one to use:
.. code-block:: python
import os
MODE = os.getenv('DJANGO_MODE', 'Local')
globals().update(globals()[f'{ MODE.title() }Settings'].as_dict())
With Python 3.7
===============
In Python 3.7, a new feature was added which allowed you to define
`__getattr__` for a module (See `PEP 562`
<https://www.python.org/dev/peps/pep-0562/>).
The `BaseConfig` metaclass provides a `module_getattr_factory` factory method
to provide a `__getattr__` that will look up the `Config` object.
.. code-block:: python
from confucius import BaseConfig
class Config(BaseConfig):
DB_HOST = 'localhost'
DB_PORT = 5432
__getattr__ = Config.module_getattr_factory()
After importing this module, attempts to access attributes will resolve
normally and, if they're not found, call `__getattr__`, just like on an object.
