I plan to store some application settings in environment variables, such as MYSQL_URL=mysql://... I use supervisord to manage the application process. How to load environment variables before the subprocess is started? Especially when these settings are changed, I hope a restart of the subprocess will load the new settings.
Also I'm wondering where to store these environment variables. A file that I can "export $(cat filename)"? Or some better ways. I'm curious how Heroku manage its environment variables.