https://github.com/scampersand/bienvenue

Python module for reading config from environment for 12 factor apps
https://github.com/scampersand/bienvenue

Last synced: 25 days ago
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Python module for reading config from environment for 12 factor apps

• Host: GitHub
• URL: https://github.com/scampersand/bienvenue
• Owner: scampersand
• License: mit
• Created: 2017-01-28T23:04:13.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2018-09-24T16:40:27.000Z (over 6 years ago)
• Last Synced: 2024-11-07T05:42:25.492Z (3 months ago)
• Language: Python
• Size: 29.3 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst
  • License: LICENSE

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README

        
=========

bienvenue

=========

|PyPI| |Build Status| |Coverage Report| |Python Versions|

Python module for reading config from environment for `12-factor apps `_.

Supports Python 3.4+

Rationale

---------

In a 12-factor app, `config comes from the environment `_.

For example, on Heroku, config variables are set using ``heroku config:set`` on the command line,

then `passed to the application in the environment `_.

Reading and parsing config from the environment is tedious and error-prone. For

example, a Django app has ``settings.DEBUG`` which should be

either ``True`` or ``False``. The operator runs ``heroku config:set DJANGO_DEBUG

off`` intending to disable it, but the application only sees a non-empty string

and treats the value as ``True``.

This sort of problem can be handled case-by-case but doesn't need to be. Clearly

a configuration setting with a fallback boolean value should be interpreted as

boolean from the environment. Likewise a fallback integer setting indicates the

associated environment variable should be converted from string to int.

Sounds like a job for a small and well-tested Python module, right?

Installation

------------

Install from PyPI_:

.. code:: sh

    pip install bienvenue

Usage

-----

Bienvenue provides the function ``make_env_reader`` which returns a new

function for accessing the environment. For example:

.. code:: python

    from bienvenue import make_env_reader

    env = make_env_reader(prefix='MY_')

    DEBUG = env('DEBUG', False)

    SECRET_KEY = env('SECRET_KEY', 'fallback-secret-for-dev')

    ALLOWED_HOSTS = env('ALLOWED_HOSTS', [])

The env reader looks for ``MY_DEBUG`` in ``os.environ``. If it's not there,

the default value ``False`` will be returned. However if it's found, then the

value there will be interpreted according to the type of the default, in this

case boolean. Common strings such as on/off, true/false and yes/no are

interpreted into ``True`` or ``False``.

Likewise ``SECRET_KEY`` will be extracted from ``MY_SECRET_KEY`` and then

interpreted as a string value.

``ALLOWED_HOSTS`` will be extracted from ``MY_ALLOWED_HOSTS`` and JSON

decoded as a list, since the default value is a list.

If bienvenue encounters unknown types or values during parsing, it will log an

error and fall back to the provided default.

Legal

-----

Copyright 2017-2018 `Scampersand LLC `_

Released under the `MIT license `_

.. _PyPI: https://pypi.python.org/pypi/bienvenue

.. |Build Status| image:: https://img.shields.io/travis/scampersand/bienvenue/master.svg?style=plastic

   :target: https://travis-ci.org/scampersand/bienvenue?branch=master

.. |Coverage Report| image:: https://img.shields.io/codecov/c/github/scampersand/bienvenue/master.svg?style=plastic

   :target: https://codecov.io/gh/scampersand/bienvenue/branch/master

.. |PyPI| image:: https://img.shields.io/pypi/v/bienvenue.svg?style=plastic

   :target: PyPI_

.. |Python Versions| image:: https://img.shields.io/pypi/pyversions/bienvenue.svg?style=plastic

   :target: PyPI_