Your Rails application has become a monolith. Your test suite takes 30 minutes to run, your models grow to several hundred (or thousand!) lines, and feature development slows to a crawl. New members of your team must read through massive amounts of code before they can feel confident making changes. You’ve watched Uncle Bob’s Architecture the Lost Years, Matt Wynne’s Hexagonal Rails and read Martin Fowler’s Microservices and are convinced that the time has come to start breaking things up into smaller, simpler, faster components – but you’re unsure of where to begin.
In this article, I will demonstrate an approach to breaking a monolithic-style Rails application apart into microservices using plain Ruby classes and a simple RPC framework – all deployed to Heroku. I’ll show you how to work through this migration incrementally; you’ll be able to decompose things down as far as makes sense for your codebase. As a special bonus, I’ll show you how you can use Barrister RPC to alleviate much of the pain associated with documenting and creating API clients for the components of your now-distributed system. I’m skipping the advocacy; if you’re here it’s because you already love yourself some microservices but don’t know how to implement them yourself.