Every so often a new version of Ruby on Rails is released that requires more than a few tiny changes to upgrade. Today we’ll upgrade Ruby on Rails for our meal planning application from 5.0 to 5.1.
- Upgrade Ruby on Rails to version 5.1
- Explore the changes to Rails 5.1
The jump from Rails 5.0 to 5.1 isn’t a breaking change so the upgrade process shouldn’t be too difficult for us. Especially since this Rails application is rather small. That doesn’t mean that there aren’t things that we’ll want to change in our setup though.
Upgrading to Newest Patch Version
meal_plan app hasn’t been updated in awhile so it’s currently running
126.96.36.199 (which is admittedly a weird version number). The best practice for upgrading a Rails application is to do this in steps fixing things along the way. This application sadly doesn’t have a lot of tests so we can’t really utilize the full upgrade process, but we’ll go through the steps.
The first thing that we need to do is change our version pinning for the
rails gem to match the highest patch version using “~> 5.0.0”:
gem 'rails', '~> 5.0.0'
To update this we need to run
bundle update and let the
Gemfile.lock be updated. Since we’re doing this mostly with Docker images we will use our existing image to run the
$ docker-compose run --rm app bundle update
Once that’s finished we will need to build our image again to actually run our application using this version:
$ docker-compose up -d --build app
With the application updated to the nearest patch version and running we can run our tests and see if we get any errors or deprecation warnings:
$ docker-compose exec app rake test Run options: --seed 239 # Running: ............. Finished in 1.036273s, 12.5450 runs/s, 21.2299 assertions/s. 13 runs, 22 assertions, 0 failures, 0 errors, 0 skips
Our very limited test suite is working alright, but we should poke around in the application a little to see if there are any deprecation warnings that show in the logs.
Upgrading the Minor Version
Since our upgrade to Rails 5.0.2 worked just fine we’re ready to repeat the process going to Rails 5.1.
gem 'rails', '~> 5.1.0'
(I’ll let you repeat the steps from the previous section for yourself)
Our tests still pass, but if you try to navigate to the application on port 3000 you won’t actually see anything. Looking at
docker-compose ps we can see that we’re mapping the ports correctly:
$ docker-compose ps Name Command State Ports ------------------------------------------------------------------------------- mealplan_app_1 /bin/sh -c script/start Up 0.0.0.0:3000->3000/tcp mealplan_db_1 docker-entrypoint.sh postgres Up 5432/tcp
docker-compose exec to take a look at what is going on inside of our container. The main thing we want to know is what processes are running, and we’ll use
ps -aux for that.
$ docker-compose exec app bash root@8dbdfdd6f725:/usr/src/app ps -aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0.0 0.0 4336 800 ? Ss 11:05 0:00 /bin/sh -c script/start root 6 0.0 0.0 20056 2732 ? S 11:05 0:00 /bin/bash -e script/start root 7 0.5 0.8 1168040 71320 ? Sl 11:05 0:01 puma 3.8.2 (tcp://0.0.0.0:9292) [app] root 48 1.0 0.0 20248 3060 ? Ss 11:10 0:00 bash root 54 0.0 0.0 17500 2068 ? R+ 11:11 0:00 ps -aux
It looks like puma is bound to the wrong port for some reason. We were relying on the port defaulting properly to port 3000, but it looks like there is an issue somewhere. Let’s add the
PORT variable to the
.env file and restart our containers.
PORT=3000 POSTGRES_USER=coderjourney POSTGRES_PASSWORD=abcd1234
$ docker-compose stop && docker-compose up -d
Now when we browse to our application we can see that it’s loaded just fine.
Update the Rails Files
The final step that we need to take to upgrade to this particular version of Rails is to run
rails app:update. This rails subcommand will essentially take us through the files that would be generated if we created a new rails application. Our application has some tweaks that make it not quite a stock application, but it’s pretty close.
$ docker-compose exec app bash root@8dbdfdd6f725:/usr/src/app# rails app:update
You’ll need to step through all of the changes to look at the file diff when there are conflicts and determine how you would like to handle them.
Keeping Rails up to date is a good idea to ensure that you’re not running potentially vulnerable code and there could always be performance improvements. Additionally, minor releases such as Rails 5.1.0 can come with additional features. For instance, Rails 5.1.0 comes with support for Webpack and Yarn to be worked into the frontend toolchain. I encourage you to check out all of the changes in the Release notes for Rails 5.1.0.