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Building and Testing Rails With GitLab CI

If you haven’t already, check out Basic Docker Image for Rails since we will building our project with Docker.

Setup GitLab CI

GitLab has very good documentation which you can reference when going through this section.

Within your application directory:

touch .gitlab-ci.yml

Then open up the file and copy/pasta the following

image: ruby:2.6.3-stretch
stages:
  - build
  - test
variables:
  BUILD_IMAGE: ${CI_REGISTRY_IMAGE}/${CI_COMMIT_REF_SLUG}:${CI_COMMIT_SHA}
build-container:
  stage: build
  image: docker:latest
  services:
    - docker:dind
  script:
    - echo "Building Docker Image $BUILD_IMAGE"
    - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN registry.gitlab.com
    - docker build -t $BUILD_IMAGE .
    - docker push $BUILD_IMAGE
rspec:
  stage: test
  image: ${BUILD_IMAGE}
  services:
    - postgres:latest
  variables:
    POSTGRES_HOST: postgres
    POSTGRES_USERNAME: postgres
    POSTGRES_PASSWORD: postgres
    RAILS_ENV: test
  before_script:
    - gem install bundler
    - bundle install
  script:
    - bundle exec rspec --color --tty

rubocop:
  stage: test
  image: ${BUILD_IMAGE}
  before_script:
    - gem install bundler
    - bundle install
  script:
    - bundle exec rubocop

This setup is based on a basic rails application with rspec and rubocop setup.

There are 3 jobs we’ve specified. Thebuild-container job will build our docker image and push it to the gitlab registry. The rspec job runs our tests and rubocop lints our code.

Altogether the CI will look like this:

The pipeline created for GitLab CI

NEXT UP: Deploying to Elastic Beanstalk