[programminggeek]

I've worked on two large applications that would both benefit from Clean Architecture and they don't feel like outliers, they feel like the natural progression from any MVC framework to an app of significant complexity.

The first was a very large PHP app that ran a fundraising website that processed millions of dollars in donations. It grew organically over time and there was need to change database structure or swap out whole modules of the infrastructure like the site search. It was mostly untestable and really could benefit some automated testing.

Over time the app was moved to a Ruby web API with Sinatra with a decent Service layer with great test coverage. It's been a massive improvement over what was there originally and moved towards more Clean Architecture principles over time. It never went full Clean Architecture because getting team buy-in was difficult and until you feel the pain of a complex, monolithic codebase with minimal tests and a few botched late night deploys, it is hard to feel the pain that Clean Architecture solves.

The second app I've seen that would benefit from Clean Architecture is a Rails app that is pretty vanilla Rails. Normal MVC and all that. Lots of ORM and so on. The tests ran slow and over time the required reporting complexity made the database queries slow and terrible. We've pulled things into a service layer and presenters which helps a bit, but doesn't solve everything. Now we are moving the app reporting into a very functional, immutable approach where we calculate and cache everything all at once in the background. We are only using the models for basic CRUD and for easily pulling out our data structure from the DB, which is then handed to a bunch of functions which calculate everything. It's very much a functional core, mutable shell approach. Even still, this isn't a fully Clean Architecture approach, but it's a lot closer, and it solves a lot of the problems that default Rails MVC doesn't.

Clean Architecture is probably best thought of as something people move towards over time as they feel the pain of not having it. Once you feel that pain, it is completely reasonable to want to start your projects clean and keep them that way, but good luck convincing other developers to join you if they haven't felt the pain.