Thanks for the article Qqwy.

My question is more like: “If i’m forced to split my apps across nodes, what is the best to do in my case ?”

And my case is as follows:

I have 3 apps in an umbrella project.

- backend
- backend_web
- scrapper_ikea

I know that I should be able to split scrapper_ikea on separate nodes, mostly to have multiple instances in parallel with different IPs.

So now I’m wondering if I should have {:backend, in_umbrella: true} in the scrapper_ikea app ?
If understand correctly this would start the backend app too, which (as of now) is only my Ecto repo, doesn’t seem like too much of a problem to have multiple repos instances running on multiple nodes, right ?

Another option would be to have {:backend, in_umbrella: true, app: false} in the scrapper_ikea app ?
Then the backend app is not launched, but if I got it right means I’m not going to be able to interact with the database, and I’d only be able to call functions as long as they don’t rely on a particular process being present.
Which leads me to thinking, maybe I should have a GenServer launched with the backend application, that is only there to proxy calls to the repo, for use by the scrapper instances.
This way, I’d still be able to interact with the repo from the scrapper apps, but only through the GenServer API, which is kind of strange, as I’d have to depend on an app where most code is not usable… so maybe make a fourth app, only there to have this glue/proxy code ?
As you can see I’m quite deeply confused as to how to do all this.