Compability with Rails engine about config HOT 3 OPEN

@cjlarose wdyt?

from config.

We also use engines in ManageIQ, but our use case is a little different. Basically we use Rails engines as a plugin system, and one of the pluggable things is the config settings. These engines can bring their own settings.yml and we will add those to the set of YAML Sources.

To do this we built an initializer that essentially loads config from all of our engines and the main app, all in the expected override order, then replaces the Settings constant. You can see the code here and follow along: https://github.com/ManageIQ/manageiq/blob/0a1c16529c96eb5367ed311e08fcd881f94cc818/lib/vmdb/settings.rb#L30, but tl;dr we loop through all of the engines in our application and add YAML Sources for each of them.

Ideally, config should more or less just work with engines and ManageIQ shouldn't have to have a custom initializer. I'm not sure if they should automatically work with engines by detecting settings.yml files, or if it makes sense to have a Config parameter where you opt in to which engines you want to honor settings from.

The other question is which way does priority work? If a key appears in the main application's settings and an engine's settings, which one wins? In ManageIQ our priority is that engines override the main application, but I'm not sure that same decision applies outside of our specific application or not.

from config.

Ideally, config should more or less just work with engines and ManageIQ shouldn't have to have a custom initializer

Agree with this part. At the moment I can customize the code on my engine to make it work. Not a big issue. But would be nice if it could just work with Rails engine, since from the engine's perspective, it's just another gem.

At the moment I'm not sure either on the solution, or the gem's direction with Rails engine. Just opened an issue here in case others might face the same issues that I have.

from config.