Gitlab CI Setup with Rails

I had a few problems getting up and running with docker-based gitlab-ci builds, so here’s a description of my setup. I’m using gitlab.com (not self-hosted) and their hosted CI at ci.gitlab.com BUT I am using private build runners on my own Ubuntu 14.04 server.

Installation

This is a bit vague because I did this a few weeks ago but here’s what I remember

1. Install gitlab-ci-multi-runner from the apt repo (Instructions)
2. Install docker using the same instructions

Runner Config

1. Enter your gitlab-ci URL and the key from the /runners page in gitlab-ci
2. If you have execjs in your Gemfile.lock, you should specify your docker image as mwallasch/docker-ruby-node. Otherwise you can use ruby:2.2
3. You can add tags on a runner via the web settings in CI. I couldn’t find how to do it from the config file.
4. Speaking of config files, the multi-runner is installed as root so look at /etc/gitlab-runner/config.toml. My final one looks kind of like this:

   concurrent = 1
   
   [[runners]]
     name = "docker-runner-1"
     url = "https://ci.gitlab.com/"
     token = "XXXXXXXXXXXXXXXXXXXXXX"
     limit = 1
     executor = "docker"
     [runners.docker]
       image = "mwallasch/docker-ruby-node"
       privileged = false
       volumes = ["/cache"]
       services = ["postgres:latest", "redis:latest"]
   

   See that volume? The default config wizard added that, we’ll use it later.

Project Config

1. Add .gitliab-ci.yml in your rails project.

   # Run before each script
   before_script:
     - gem install bundler
     - touch log/application.log
     - touch log/test.log
     - bundle install --jobs $(nproc) --path=/cache/bundler
     - cp config/database.gitlab-ci.yml config/database.yml
     - "bundle exec rake db:create RAILS_ENV=test"
     - "RAILS_ENV=test bundle exec rake db:reset"
   
   job1:
       script: "bundle exec rspec"
       tags:
           - ruby
           - postgres
           - docker
   

   • I added some tags here and setup my runner with matching tags in the CI web config. Note that I have a specific database.yml just for the CI environment, since we’re using docker services for postgres and redis (more below)
   • Note --jobs $(nproc) to speed up bundle installation.
   • Note --path=/cache/bundler which puts the gems on the persistent cache volume configured in config.toml
2. Set up the database config. In config/database.gitlab-ci.yml:

   
   test: &test
     adapter: postgresql
     pool: 5
     timeout: 5000
     host: postgres
     database: mydbname
     user: postgres
   
   

Took some pain to get here but I do like that I can own the hardware the builds run on.