Everett is a configuration library.
:License: MPL v2
This library tries to do configuration with minimal "fanciness":
Configuration with Everett:
* is composeable and flexible
* can pull configuration from a variety of specified sources (environment, ini
files, dict, write-your-own)
* supports parsing values (bool, int, lists, ..., write-your-own)
* supports key namespaces
* facilitates writing tests that change configuration values
* supports component architectures with auto-documentation of configuration with
a Sphinx ``autoconfig`` directive
Everett is inspired by `python-decouple
<https: github.com="" henriquebastos="" python-decouple="">`_ and `configman
<https: configman.readthedocs.io="" en="" latest=""/>`_.
Why not other libs?
Most other libraries I looked at had one or more of the following issues:
* were tied to a specific web app framework
* didn't allow you to specify configuration sources
* had a global configuration object
* made it really hard to override specific configuration when writing tests
* had no facilities for auto-documenting configuration for components
You're writing a web app using some framework that doesn't provide
infrastructure for configuration.
You want to pull configuration from an INI file stored in a place specified by
``FOO_INI`` in the environment. You want to pull infrastructure values from the
environment. Values from the environment should override values from the INI
First, you set up your ``ConfigManager`` in your webapp::
from everett.manager import ConfigManager, ConfigOSEnv, ConfigIniEnv
self.config = ConfigManager([
# Set ``is_debug`` based on configuration
self.is_debug = self.config('debug', parser=bool)
Let's write some tests that verify behavior based on the ``debug`` configuration
from everett.manager import config_override
app = get_app()
app = get_app()
(``config_override`` works as a class decorator and a context manager, too.)
That probably covers most configuration requirements.
However, say your app needs to connect to RabbitMQ. One way to implement that
functionality is to wrap it up in a self-contained component::
from everett.component import RequiredConfigMixin, ConfigOptions
required_config = ConfigOptions()
doc='RabbitMQ host to connect to'
doc='Port to use',
doc='Queue to insert things into'
def __init__(self, config):
# Bind the configuration to just the configuration this
# component requires such that this component is
self.config = config.with_options(self)
self.host = self.config('host')
self.port = self.config('port')
self.queue_name = self.config('queue_name')
Then in your app, you instantiate a ``RabbitMQComponent``, but with configuration
in the ``rmq`` namespace::
queue = RabbitMQComponent(config.with_namespace('rmq'))
In your environment, you would provide ``RMQ_HOST``, etc for this component.
Say your app actually needs to connect to two separate queues--one for regular
processing and one for priority processing::
regular_queue = RabbitMQComponent(
priority_queue = RabbitMQComponent(
In your environment, you provide the regular queue configuration with
``RMQ_REGULAR_HOST``, etc and the priority queue configuration with
Same component code--two different instances.
$ pip install everett
# Clone the repository
$ git clone https://github.com/willkg/everett
# Create a virtualenvironment
# Install Everett and dev requirements
$ pip install -r requirements-dev.txt
0.6 (November 28th, 2016)
Feature: Change ``:show-docstring:`` to take an optional value which is the
attribute to pull docstring content from. This means you don't have to mix
programming documentation with user documentation--they can be in different
Feature: Add ``RequiredConfigMixin.get_runtime_config()`` which returns the
runtime configuration for a component or tree of components. This lets you print
runtime configuration at startup, generate INI files, etc.
Feature: Add ``ConfigObjEnv`` which lets you use an object for configuration.
This works with argparse's Namespace amongst other things.
Feature: Improve configuration-related exceptions. With Python 3, configuration
errors all derive from ``ConfigurationError`` and have helpful error messages
that should make it clear what's wrong with the configuration value. With Python
2, you can get other kinds of Exceptions thrown depending on the parser used,
but configuration error messages should still be helpful.
Documentation fixes and updates.
0.5 (November 8th, 2016)
Feature: Add ``:show-docstring:`` flag to ``autoconfig`` directive.
Feature: Add ``:hide-classname:`` flag to ``autoconfig`` directive.
Feature: Rewrite ``ConfigIniEnv`` to use configobj which allows for nested
sections in INI files. This also allows you to specify multiple INI files
and have later ones override earlier ones.
Bug: Fix ``autoconfig`` Sphinx directive and add tests--it was all kinds of
0.4 (October 27th, 2016)
Feature: Add ``raw_value`` argument to config calls. This makes it easier to
write code that prints configuration.
Bug: Fix ``listify(None)`` to return ````.
Documentation fixes and updates.
0.3.1 (October 12th, 2016)
Bug: Fix ``alternate_keys`` with components. Previously it worked for everything
but components. Now it works with components, too.
0.3 (October 6th, 2016)
Feature: Add ``ConfigManager.from_dict()`` shorthand for building configuration
Feature: Add ``.get_namespace()`` to ``ConfigManager`` and friends for getting
the complete namespace for a given config instance as a list of strings.
Feature: Make ``ConfigDictEnv`` case-insensitive to keys and namespaces.
Feature: Add ``alternate_keys`` to config call. This lets you specify a list
of keys in order to try if the primary key doesn't find a value. This is
helpful for deprecating keys that you used to use in a backwards-compatible
Feature: Add ``root:`` prefix to keys allowing you to look outside of the
current namespace and at the configuration root for configuration values.
0.2 (August 16th, 2016)
Feature: Add ``ConfigEnvFileEnv`` for supporting ``.env`` files. Thank you,
Feature: Change ``ConfigIniEnv`` to take a single path or list of paths. Thank
Feature: Add "on" and "off" as valid boolean values. This makes it easier to use
config for feature flippers. Thank you, Paul!
Feature: Make ``NO_VALUE`` falsy.
Bug: Fix ``__call__`` returning None--it should return ``NO_VALUE``.
Lots of docs updates: finished the section about making your own parsers, added
a section on using dj-database-url, added a section on django-cache-url and
expanded on existing examples.
0.1 (August 1st, 2016)
TODO: Brief introduction on what you do with files - including link to relevant help section.