envsettings

• Update django settings from environment variables by updating sys.modules
• Mostly using ast.literal_eval to convert string to python object.
• Tested by converting all default django settings to string and back to python object and then running django command.

todo

• simplify code
• verify settings after they are casted to python object

1. Usage:
   • in myproject.settings:

     import os
     import sys
     import ast
     
     from djangobuk_envsettings import update_from_env
     
     update_from_env(
         sys.modules[__name__],
         # default prefix for all variables
         pre='DJANGO_',
         # settings that can be updated from env
         # by default all settings are allowed (this option overrides)
         allowed=[
             'SECRET_KEY',
             'SITE_ID',
         ],
         # optional
         # extra settings and their types (to be used with extra_allowed)
         extra_mapping={
             'DATABASE_PATH': ast.literal_eval,
         },
         # optional
         # extra settings that can be updated from env
         extra_allowed=[
             'DATABASE_PATH',
         ]
     )
     
     # nothing more required
     DATABASES = {
         'default': {
             'ENGINE': 'django.db.backends.sqlite3',
             'NAME': DATABASE_PATH,
         }
     }