Read config from environment for 12 factor apps
Python module for reading config from environment for 12-factor apps. Supports Python 2.7 and 3.3+
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?
Install from PyPI:
pip install bienvenue
Bienvenue provides two major functions: unprefix and env. The former is a simple filter to remove a common prefix from the keys in a dictionary. The latter provides a similar interface as os.environ.get, that is a getter with fallback to a default, except that the default is required and provides type hinting for decoding the string value.
Here’s a snippet for your Django settings.py:
from functools import partial import os import bienvenue env = partial(bienvenue.env, bienvenue.unprefix('DJANGO_', os.environ))
Now environment settings can be extracted as follows:
DEBUG = env('DEBUG', True) SECRET_KEY = env('SECRET_KEY', 'fallback-secret-for-dev') ALLOWED_HOSTS = env('ALLOWED_HOSTS', )
In this example, DEBUG will be extracted from the environment variable DJANGO_DEBUG (because of calling bienvenue.unprefix above) and then interpreted as a boolean value, honoring common strings such as on/off, true/false, and yes/no.
Likewise SECRET_KEY will be extracted from DJANGO_SECRET_KEY and then interpreted as a string value.
ALLOWED_HOSTS will be extracted from DJANGO_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.
Copyright 2017 Scampersand LLC
Released under the MIT license
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
|Filename, size||File type||Python version||Upload date||Hashes|
|Filename, size bienvenue-1.0.0.tar.gz (4.8 kB)||File type Source||Python version None||Upload date||Hashes View hashes|