YAEP - Yet Another Environment Package

As the name says, this package enters the crowded field of environment related packages. The main goal of this package is to provide you with the ability to populate your environment with a a source (by default reading a .env file) and then use a simple function in your configuration files to read these values or use defaults.

It's worth noting that this software is under active development and interfaces will change without warning.

Usage

Usage is simple. Early in the execution of your project, or in a dedicated module for configuration, import populate_env from the yaep package. Running this will populate your environment with values from your .env file. You can alternatively set the env_file argument or the ENV_FILE environment variable to read from another env file.

from yaep import populate_env
populate_env()

Now you can setup your configuration. For example, in a settings.py or config.py:

from yaep import env
DATABASE_URL = env('DATABASE_URL', 'sqlite://:memory:')

The env function has a few other useful tricks. For example, allowing for a default that is "sticky" - meaning if it is employed it is set in the environment.

os.getenv('foo')  # Returns None
FOO = env('FOO', 'bar', sticky=True)
os.getenv('FOO')  # Returns 'bar'

Additionally, you can by default allow for boolean-like values to be changed to booleans on the fly.

os.getenv('SOMETHING')  # Returns 'True'
env('SOMETHING')  # Returns True

By default a case-insensitive comparison to 'True' and 'False' is done, along with 1 and 0. You can change the available values by passing in a new boolean map:

env('pony', boolean_map={True: ['True', '1', 'Pony']})
# Returns True

On the subject of 1s and 0s - you might consider that if you are intending to get an integer that you will instead end up with 'True' or 'False' - you can overcome this by setting convert_booleans to False. Additionally, you can cast your return value explicitly by setting the type_class, though note that if convert_booleans is True that will override your type_class. Some examples:

# SOMETHING is set to '1' in the environment
env('SOMETHING') # Returns True
env('SOMETHING', convert_booleans=False) # Returns '1'
env('SOMETHING', convert_booleans=False, type_class=int) # Returns 1

Finally, you can also raise an exception if a value is not set in your environment:

env('IMPORTANT', default=yaep.exceptions.UnsetException)
# Raises yaep.exceptions.UnsetException

Using Other Environment Sources

A goal of the project is to be able to override or add to the default of pulling values in from an env file. Supporting alternate sources such as credential servers is the goal.

Work in this area is slated for a future release.