Hi everybody, this post is the first of a serie I'd like to write, revolving around rails and CI/CD.
In this one I'll show you how to setup a proper CI for your new rails project.
I tried to give you the simplest example in order to focus on what's interesting, the configuration, I hope you'll find it useful.
Here is the repo alongside this article: https://gitlab.com/mpressen/rails_with_gitlab_ci
Init project
$ rails new rails_with_gitlab_ci --database=postgresql
$ cd rail_with_gitlab_ci
$ rails db:create db:migrate
$ rails server
Perfect time to commit and push our code :
$ git add -A
$ git commit -m 'init rails project with postgresql'
$ git remote add origin git@gitlab.com:$(username)/rails_with_gitlab_ci.git
$ git push --set-upstream origin master
Add failing tests
Let's create a failing controller test :
# test/controllers/dummy_controller_test.rb
require 'test_helper'
class DummyControllerTest < ActionDispatch::IntegrationTest
test "the truth" do
assert false
end
end
And a failing system test :
# test/system/dummy_system_test.rb
require 'application_system_test_case'
class DummySystemTest < ApplicationSystemTestCase
test 'the truth' do
assert false
end
end
Setup gitlab CI
# .gitlab-ci.yml
image: ruby
stages:
- test
tests:
stage: test
services:
- postgres
- name: selenium/standalone-chrome
alias: chrome
cache:
paths:
- apt-cache
- node_modules
- vendor/bundle
variables:
DB_HOST: postgres
POSTGRES_USER: postgres
POSTGRES_PASSWORD: root
SELENIUM_REMOTE_URL: http://chrome:4444/wd/hub
RAILS_ENV: test
BUNDLE_PATH: vendor/bundle
before_script:
- export APT_CACHE_DIR=`pwd`/apt-cache && mkdir -pv $APT_CACHE_DIR
- curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
- echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
- apt-get update -qq && apt-get -o dir::cache::archives="$APT_CACHE_DIR" install -yqq yarn
- yarn install
- bundle install
- bundle exec rails db:setup
script:
- bundle exec rails test test/*
# config/database.yml
...
#
default: &default
...
host: <%= ENV["DB_HOST"] %>
username: <%= ENV["POSTGRES_USER"] %>
password: <%= ENV["POSTGRES_PASSWORD"] %>
...
This config caches back and front dependencies for speed and computation cost (a must).
My favorite part is the use of a third docker image, selenium/standalone-chrome that avoids a pain point (chrome versions ...) some might have encountered before. With this config, it's another container that runs an headless chrome navigator on system tests.
# test/application_system_test_case.rb
require "test_helper"
class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
if ENV['SELENIUM_REMOTE_URL']
Capybara.server_host = '0.0.0.0'
driven_by :selenium, using: :headless_chrome, screen_size: [800, 800], options: { url: ENV['SELENIUM_REMOTE_URL'] }
else
driven_by :selenium, using: :chrome, screen_size: [1400, 1400]
end
def setup
if ENV['SELENIUM_REMOTE_URL']
net = Socket.ip_address_list.detect(&:ipv4_private?)
ip = net.nil? ? 'localhost' : net.ip_address
Capybara.app_host = "http://#{ip}"
end
super
end
end
group :test do
...
gem 'webdrivers', require: !ENV['SELENIUM_REMOTE_URL']
end
Let's try it !
$ git add -A
$ git commit -m 'setup gitlab CI'
$ git push
Now, let's replace assert false by assert true in our dummy tests, commit and push.
Yeah !
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