Question about the Bank OTP app about acme_bank HOT 2 CLOSED

My current rule of thumb is to extract an app if:

a) it doesn't seem app specific and it's reasonable to have it as Hex package (even if it never gets OSSed)
b) I want to deploy it separately and/or it has separate storage

So for AcmeBank good candidates for separate apps would be some 3rd party service wrappers (that could be Hex packages eventually) or maybe FraudDetector that does some ML stuff off DB (probably bypassing Ecto). That being said, I have apps/auth which does not fit either of these criteria and looking back, I think this extraction was a bit premature. Especially that in theory it has separate Repo from Bank and the schemas are not associated in any way, but in practice in both dev and "prod" it ends up running on the same PG db.

Another angle is to look what logic I consider unique to my app, what's really the value added (that I'd keep in core OTP app) and what's still needed but not quite my core competency (apps/messenger is a good example of that). To answer your question, I probably would not split up business logic into separate apps unless you can draw a really clear line and in the meantime use good code organisation within one OTP app to keep it well organised maintainable.

from acme_bank.

Thanks @wojtekmach - that makes sense. Thanks for the lightning fast reply :)

from acme_bank.