[i_s]

I also try to use the {:system, "MY_VAR"} convention to get around the weird "lets-compile-in-config-values" problem, but unfortunately, it is not supported by many libraries. Even some of the essential libraries, like Ecto, support it for some config variables (db_url), but not for others, which seems crazy to me.

For some dependencies (like exq), I've needed to take them out of the "start" list, and start them manually, hand feeding them the configuration values.

This issue has been the biggest annoyance by far in what is otherwise a really nice platform/ecosystem.