Flask configuration which allows different settings depending on the environment

default_settings.py

import os

# Get environment, or set to development by default
app_env = os.environ.get('APPLICATION_ENVIRONMENT') or 'development'

# Settings applied to all environments
SECRET_KEY = 'development key'

# Settings applied to specific environments
if app_env == 'production':
    DATABASE_URI = ''  # TODO: Enter your production database
    DEBUG = False
elif app_env == 'development':
    DATABASE_URI = ''  # TODO: Enter your dev database
    DEBUG = True
elif app_env == 'testing':
    DATABASE_URI = ''  # TODO: Enter your test database