Flask-Environment

Configure a Flask applications with various configuration formats.

Version

0.1.0

Description

Flask 0.10 support loading configuration from an environment variable and a Python module. This plugin extends that to include TOML and a backport of the JSON implementation expected in 1.0 (or 0.11, whatever the release after 0.10).

Supports Python 2.7, 3.4, 3.5.

Installation

$ pip install flask-environment

# With TOML support
$ pip install flask-environment[TOML]

Usage Flask<=0.10

Flask 0.10 doesn't allow overriding the configuration class whereas 1.0 will. Flask-Environment is build with 1.0 in mind and expects <=0.10 to override make_config on the application object.

import flask
from flask_environment import Config

class MyApp(flask.Flask):

    # Backport the logic of Flask.make_config replacing the default config
    # class with Flask-Environments
    def make_config(self, instance_relative=False):
        root_path = self.root_path

        if instance_relative:
            root_path = self.instance_path
        return Config(root_path, self.default_config)

app = MyApp(__name__)
app.config.from_toml('config.toml')

Usage Flask>0.10 (unreleased as of writing 12/5/2015)

import flask
from flask_environment import Config

class MyApp(flask.Flask):
    config_class = Config

app = MyApp(__name__)
app.config.from_toml('config.toml')

Environments

Flask-Environment adds the idea of environments to a configuration file. For different situations you might change the configuration even when the application is deployed to the same machine, this is most helpful with testing. You probably want to use a different database for testing than what you do for regular development.

Flask-Environment solves this problem with the concept of environments. Within a configuration file, create a new dict called environments with the keys being the name of the different environments you intend to declare.

Activate an environment like this:

app.config.from_toml('config.toml', environment='testing')

This will load all the default settings (everything not in an environment) and then the specified environment. Here is a sample TOML file demonstrating the idea.

SUPER_COOL_FEATURE = true
DEBUG = false

[environments.dev]
DEBUG = true

[environments.testing]
TESTING = true

If we loaded the dev environment, the application debug flag would be set to True and SUPER_COOL_FEATURE would be available.

While you could use this to provision different logical environments in the same file (beta, production) there really isn't a point. Environments are for changing configurations within the same logical environments. Maybe you have a production environment that spawns two apps that need two diverging configurations, environments fill that need.

Licence

MIT