Tom MacWright

A year of Rails


I spent most of 2020 working with Ruby on Rails. I moved a project from Next.js + Rust to… Rails, baby! Back to the future. My earlier post on Second-guessing the modern web was inspired by this experience, that for the product we were building, a ‘modern’ stack was not working as well as a traditional one.

We didn’t do competitive analysis against Laravel, Django, or Phoenix. They’re similar, not radically better or worse. There are multiple acceptable solutions to a problem, and this was more a matter of choosing the right kind of solution than pursuing some kind of perfect choice and burning hours and motivation doing the window-shopping.

What helped Rails win was that the team had a little more experience in Ruby (with the exception of myself), and we found plenty of resources for developing and deploying the stack. Rails fit perfectly into the ideology of Choosing boring technology. Another part of the product would be the hard, innovative part, so it made no sense to grapple with bleeding-edge web frameworks.

This was a really fun experience. There’s a lot to love about Rails. Other communities could learn a bit from the Ruby & Rails culture and wisdom. I won’t implement everything in Rails, but it’ll be part of the toolbox.

Before this, I hadn’t touched the stuff. And I bet a lot of people are like that - they came of age in the world of React and Go, and haven’t tried anything even remotely similar to Rails. For their benefit, and to debrief from 2020, here are some notes on the experience. Plus, Rails-like projects in JavaScript are ramping up quickly, and it’s fun to know the origins.

The good

Debugging Rails apps is amazing

A while ago, I wrote on Twitter

the real reason why javascript developers don’t use breakpoints and use console.log is that breakpoints don’t work

After years of working in JavaScript, I’m used to bad debugging experiences. The Chrome debugger’s automatic pause on caught exceptions is amazing, sometimes. But throwing a debugger statement in some React code is dodgy as hell. Sometimes it works, mostly it doesn’t. You have to deal with code that might not have the right sourcemap to translate from bundled & minified code to original source. Subtle abstractions like React hooks and advanced transpiler stuff like Regenerator mean that your code’s stacktrace probably looks nothing like what you expect, with lots of internal garbage. Sure, you can learn better techniques for diagnosing and debugging errors, but it’s not just you - the debugging story in JavaScript is pretty bad. This applies even to Node.js, where one of the debugging stories is to connect Chrome’s debugger to a Node.js instance: a finicky solution that doesn’t consistently work.

In Rails, there is byebug. You write byebug in your source code, and you get an interactive REPL right there. It works in views, controllers, database migrations, everywhere. It almost always works. Variables are named what you expect. The whole system is paused at that moment, and you can actually interact with it, using all of the Rails utilities and your installed gems.

If a page crashes unexpectedly, you get a similar REPL experience, in your browser, automatically. With an automatically cleaned-up stacktrace that excludes Rails’s own frames. Like the byebug interface, this REPL actually works and is consistently helpful in finding root causes. Rarely will you need to use puts to print something to the console because this debugging system is so good.

The magic mostly works

Our Rails app didn’t have any require statements. You mention a module’s name, and it’s automatically included, using Zeitwerk, a tool that comes standard with Rails.

This kind of system was terrifying to me before. What if you accidentally import something just by mentioning it? What if two things have the same name and you import the wrong one? How do you really know what’s happening? Sure, you’re happy now, with all of that annoying importing and exporting taken care of, but the sky might fall.

Or maybe it just… doesn’t. Maybe impure, vaguely risky techniques are just a net positive over time, and making everything fully explicit isn’t really necessary? Now when I’m using other systems, I wonder - what if I could just mention one of my React components and it would just… be there? Sure, the system would have to complain if there were two components with the same name, and it would have to make assumptions about directory structure, but overall, wouldn’t this be nice?

This applies to a lot of other parts of the system too. Rails is famous for doing pluralization - you name a model Post and you automatically get an interface called posts. But what, you ask, of words with uneven pluralization rules? Rails actually does the right thing, almost always. And when it fails, you can override it. It actually just saves time, reliably.

Testing works

I’ve tried to test front-end applications. I’ve set up nightwatch, jest, enzyme, cypress, and probably 5-10 other frameworks. Front-end testing is universally terrible. Projects like Cypress are throwing untold hours into making it less terrible, taking on massive amounts of complexity to abstract away from fickle browser behavior and complex interactions.

But it still sucks. Frontend testing has no good attributes: it’s unreliable, hard to automate, hard to debug when it fails, and often doesn’t even assert for important behaviors, so it doesn’t actually identify regressions. Running frontend tests in CI is resource-heavy, requiring you to set up headless X windows environments on servers or use specialized CI services that produce screencasts of test runs.

Testing fully-server-rendered applications, on the other hand, is amazing. A vanilla testing setup with Rails & RSpec can give you fast, stable, concise, and actually-useful test coverage. You can actually assert for behavior and navigate through an application like a user would. These tests are solving a simpler problem - making requests and parsing responses, without the need for a full browser or headless browser, without multiple kinds of state to track.

Not only do the tests work better, the testing culture is a completely different universe. There are entire books written about how to write RSpec tests that catch bugs, allow software evolution, and aren’t filled with boilerplate.

Gems are so powerful

Powerful and dangerous.

I’m used to modules as they work in other systems - Python, Node, Elm, and so on. They provide objects, functions, and variables that you can import and combine into your code explicitly. Usually they sit on some specific level of abstraction - it’s a utility for connecting to servers or a React component you can use.

Gems can do so much more. You install something like Devise into your system and it adds views, routes, methods, utilities, you name it. It’s not like “loading some functions”, it’s more like composing a whole different app into your app, implicitly.

This is obviously terrifying. It means that you can’t look at your directories of views and your file of routes.rb and know what exists at a glance. There are other layers, lurking in the ephemeral space of third-party code. They interact in serious but uncertain ways.

But it’s also pretty incredible - the idea that something like passport, Node’s middleware, could instead be a full-fledged authentication system. It means that you have to write a lot less code, and it also means that the people who use that code have a lot more code in common. That gems can work on a higher level of abstraction, making it possible to cobble together software faster, to write less ‘glue code.’

There’s so much good writing about Rails

Even if you don’t write Ruby, you should pay attention to Sandi Metz. She’s incredibly wise and has so many incredible ideas to share.

And then there’s arkency, ThoughtBot, and so many other thoughtful writers with years of experience in Rails. Sometimes it’s a little shocking to google for some obscure problem and see a decade of discussion about it.

The best practices are also formalized into tools like Code Climate and reek. I’ve never seen so many actually-useful suggestions come out of automated systems as I did in the world of Ruby and Rails.


Ruby is a pretty pleasant language to work in. Sure, it has a lot of syntax and a sprawling standard library, but you don’t have to use all of that if you don’t want to. It took me a while to adjust to the object-oriented way of doing things - in particular, the idea that you can’t just have a free-range function floating out there, unassociated with a class or module, like you can in JavaScript. And you can’t just create an arbitrary one-off object - you either need to define a class to create an object, or use a Hash to store data.

But Ruby’s standard library isn’t that huge. I’ve seen JavaScript’s ‘standard library’ grow a lot too, and frankly it’s nice to have methods like String.prototype.padStart instead of having every little thing in userspace. The only part that felt actively weird was activesupport - a gem that extends Ruby’s core objects, but is part of Rails. It felt weird to have string methods that would only work if your environment was Rails.

The Dash app for documentation rocketed from my pile of unused tools to an absolute must-have. In the world of Ruby and Rails, with most gems having pretty good, semi-standard documentation, you can search for, and get answers, super fast. The Ruby language documentation and the Rails documentation is absolutely great. The JavaScript equivalent - MDN - pales in comparison.

The bad

The asset pipeline

Remember SASS and the YUI Compressor? These are, unfortunately, defaults in the asset pipeline. There’s Webpacker too, which has a parallel approach to CSS and images as the asset pipeline. It has opinionated integrations with stuff like React. Ah, and I should mention that Rails’s JavaScript utilities are written in… CoffeeScript.

I get it - it’s hard to keep up with the latest trends in frontend. But this is one area where Rails’s strong backwards compatibility feels iffy. I wish that Rails was more opinionated about the frontend, and that it had better opinions.

Best practice churn

In Smalltalk, everything happens somewhere else. - Adele Goldberg

Ruby, as today’s Smalltalk, has the same issue. The community venerates small - that methods should be short, files should be small, complexity should be controlled. This begs the question of where it all goes - certainly not in controllers, which should be skinny, and not in views, which should have very little logic at all, and maybe not in models either. Maybe in Service Objects, or policies, or decorators?

I found myself falling victim to this. I’d try to win CodeClimate’s approval by moving code around, perfecting the art of making everything small or at most medium-sized, extracting concerns until most files looked okay. This was time well-spent on learning, but I have to admit that it doesn’t actually matter for an early-stage startup’s product.

In stark contrast to the folks who say that Rails is for prototypes, there’s a lot of attention paid to long-lived engineering efforts - adopting patterns that let many team work on the same ‘monolith’, identifying shotgun surgery - a term I first heard from Sandi Metz.

ActiveRecord is great, except when it isn’t

One of the hardest bugs we encountered happened with ActiveRecord. We were creating a set of changes to apply to a model, using their in-memory instances to do some stuff, and then finally applying them. This broke because one of the ActiveRecord methods automatically ‘committed’ those changes, quietly.

ActiveRecord is kind of like this - a lot of the times it’s pleasantly implicit, letting you just assign a value and automatically saving that to the database. But then it’ll do something implicitly that you don’t want to happen, and figuring out why this happened and how to stop it from happening is a real challenge.

Most of the time, to be clear - it’s a really great system. It provides lots of ways to generate efficient-enough queries, knowing full well that SQL performance is often the bottleneck of web applications. Most of the time it’s really nice that it automatically casts and deserializes query results. But when it goes bad, the diagnosis and the cure can be pretty ugly.

The other issue with ActiveRecord is that it has efficient methods and inefficient methods right next to each other, because it automatically turns your ‘query builder’ into an array when you call array-like methods. So, for example:


Is wildly inefficient. It might fetch and deserialized a million records just to sort them and give you the first. On the other hand,

Dogs.order(height: :desc).first

Is fast - it sorts in the database and fetches a single record. Rails is both offering smart and easy ways to write optimized code, but also making it really easy to write inefficient code.

A Rails-like framework is a really good thing to have in your toolbox, and there’s a lot to learn from the Ruby community. My hope is that we see these sorts of abstractions in new languages and frameworks, and see more of the Ruby community’s culture filter into the programming world.