mdj2 / varlet

Varlet

Varlet lets you prompt for variables at runtime, and saves them to a variables module.

Install

pip install varlet

Usage

In your settings.py file add:

from varlet import variable

whenever you declare a variable that could change depending on the environment, use:

# It is OK to make this True if you are in dev
DEBUG = variable("DEBUG", default=False)

If this "DEBUG" variable is not defined in the variables module (somewhere in your python path), the user is prompted to enter a Python expression to set it.

When the prompt is displayed, the comments directly above the call to variable() are displayed, and the prompt has a default value as specified by the default argument.

Implementation Details

varlet assumes there is a variables module located somewhere in your Python path. If it is not found, it will attempt to create one based on the location of __main__.

When a variable is set to a value, varlet will eval the value (to make sure it is valid python), and then perform ast.literal_eval(repr(value)) to ensure that the value has a valid representation that can be written to a file. The repr(value) is then appended to the end of the variables module (along with any comments associated with the value).

If STDIN is not a tty-like interface, then a KeyError is raise if the variable is not set in the variables module.