Rails 5.1: Loving JavaScript, System Tests, Encrypted Secrets, and more

Posted by dhh, April 27, 2017 @ 2:05 pm in Releases

In celebration of the 12th RailsConf in Phoenix, Arizona this week, we’re proud to announce that Rails 5.1 is ready in its final form! We’ve spent over 4,100 commits since Rails 5.0 making everything EASIER, SIMPLER, and, uhhh, FUNNER? (That’s a RailsConf joke).

The highlight reel hasn’t really changed since the first beta, but here’s a repeat:

Loving JavaScript

We’ve had a stormy, perhaps even contentious, relationship with JavaScript over the years. But that time is past. JavaScript has improved immensely over the past few years, particularly with the advent of ES6, and with package and compilation tools like Yarn and webpack. Rails is embracing both of these solutions with open arms and letting whatever past water flow under the bridge.

JavaScript and Ruby share a deep philosophical bond over language design, if not ecosystem management. Let’s focus on the aspects we have in common and help Rails programmers extract the best from JavaScript with the help of some key guiding conventions.

The improvements in Rails 5.1 focus on three major parts:

  1. Manage JavaScript dependencies from NPM via Yarn. Think of Yarn like Bundler for JavaScript (it even has Yehuda Katz involved!). This makes it easy to depend on libraries like React or anything else from NPM. Everything you depend on via Yarn is then made available to be required in the asset pipeline, just like vendored dependencies would have been. Just use the binstub bin/yarn to add dependencies.

  2. Optionally compile JavaScript with webpack. While there are a million different module bundlers/compilers for JavaScript, webpack is quickly emerging as the preeminent choice. We’ve made it easy to use webpack with Rails through the new Webpacker gem that you can configure automatically on new projects with --webpack (or even --webpack=react, --webpack=angular, or --webpack=vue for a tailored configuration). This is fully compatible with the asset pipeline, which you can continue to use for images, fonts, sounds, whatever. You can even have some JavaScript on the asset pipeline and some done via webpack. It’s all managed via Yarn that’s on by default.

  3. Drop jQuery as a default dependency. We used to require jQuery in order to provide features like data-remote, data-confirm, and the other parts of Rails UJS. This dependency is no longer necessary as we’ve rewritten rails-ujs to use vanilla JavaScript. You’re of course still free to use jQuery, but you no longer have to.

Thanks to Liceth Ovalles for her work on Yarn integration, Dangyi Liu for his work on rails-ujs, and Guillermo Iguaran for chaperoning the whole thing!

System tests

In my 2014 keynote at RailsConf, I spoke at length about how an over focus on unit tests (and TDD) has lead us astray. While unit tests are part of a complete testing solution, they’re not the most important one. Integration tests that verify behavior all the way from controllers through models and views should play a much bigger part. Rails already has a great answer for these baked in.

But integration tests do not help you test the entire system, if that system relies on JavaScript. And most major web systems today rely at least to some extent on JavaScript. That’s where system tests driven by a real browser come in.

There’s long been an answer for system tests like this in Ruby called Capybara. It’s just been kind of a journey to configure properly for Rails. So now we’ve baked them straight into the framework! You get a lovely wrapping of Capybara that’s preconfigured for Chrome and enhanced to provide failure screenshots as part of Action Dispatch. You also don’t have to worry about extra database cleanup strategies anymore because the baked in transactional tests now rollback system test changes.

These tests are not without trade-offs. It’s of course still slower to run through a whole browser setup than just test a model with a stubbed out database. But it also tests so much more. You’d do well to familiarize yourself with system tests and have them as part of your testing answer.

Thanks to Eileen M. Uchitelle for her work extracting this from Basecamp!

Encrypted secrets

If you’re checking production passwords, API keys, and other secrets undisguised into your revision control system, you’re doing it wrong. That’s not safe and you should stop it! Now that’s an easy prescription, but without a coherent answer to what you should do instead, it’s also not that helpful.

People have long been loading up the ENV to store these secrets or used a variety of other solutions. There are all sorts of trade-offs and drawbacks to the ENV-model, not least of which that you still need to store those secrets for real somewhere else.

Inspired by Ara T. Howard’s sekrets gem, we’ve built encrypted secrets management into Rails 5.1. You can setup a new encrypted secrets file with bin/rails secrets:setup. That’ll generate a master key you’ll store outside of the repository, but allow you to commit the actual production secrets to your revision control. They’re then decrypted in production either through an injected key file or through RAILS_MASTER_KEY in the ENV.

Thank you to Kasper Timm Hansen for the work on this and Ara for the inspiration!

Parameterized mailers

Action Mailer is modeled on Action Controller. It shares underpinnings through Abstract Controller, but it’s long been disadvantaged from its controller cousin in the way it can share logic between actions.

In Action Controller, it’s common to use before_action and similar callbacks to extract logic that applies to multiple actions. This is doable because the params hash is available before the action is invoked. But in Action Mailer, we’ve been using regular method signatures with explicit arguments, so those arguments haven’t been available to filters that run before the actions.

With Parameterized Mailers, we now give you the option of calling mailers with parameters that, like in controllers, are available before the action is invoked. This combines with the default to/from/reply_to headers to dramatically DRY-up some mailer actions.

It’s completely backwards compatible and you can convert just the mailers that stand to gain the most from extraction first.

Direct & resolved routes

We have a lovely, simple API for declaring new resource routes. But if you’d like to add new programmatic routes that has logic determining the final destination based on the parameters, well, you’d have to row your own boat with helpers and other messy approaches.

With directed routes, you can now declare programmatic routes that have the full power of Ruby to do different things depending on the parameters passed.

With resolved routes, you can reprogram the polymorphic look-up for models based straight to compatible methods. So this allow you to turn link_to @comment into a final route like message_path(@comment.parent, anchor: "comment_#{@comment.id}").

Thank you to Andrew White for making all this work!

Unify form_tag/form_for with form_with

We’ve long had two parallel structures for creating forms. Those that were based off records through form_for, where we used convention over configuration to extract the details, and manually configured ones using form_tag. Now we’ve unified these two hierarchies with form_with. A single root tree that you can configure through an inferred record or manually. It’s much nicer and simpler.

Thanks to Kasper Timm Hansen for this one too!

Everything else

In addition to the highlight reel, we have hundreds of other fixes and improvements across all the frameworks. Please peruse the CHANGELOGs to acquaint yourself with all the goodies:

We have a great summary of the high-level changes in the release notes.

Your release manager for Rails 5.1 was Rafael França.

As per our maintenance policy, the release of Rails 5.1 means that bug fixes will only apply to 5.1.x, regular security issues to 5.1.x and 5.0.x, and severe security issues to 5.1.x, 5.0.x, and 4.2.x. This means 4.x and below will essentially be unsupported!

Thank you to everyone in the community for their diligent job testing the beta and release candidates of Rails 5.1! We made more than 600 commits following bug reports and concerns raised through this process. Thank you! Gracias! Merci! TAK!