A short Ruby script to run tests from `.gitlab-ci.yml` using Docker

gitlab-ci-tests.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'yaml'

GITLAB_CI_YML = File.expand_path('.gitlab-ci.yml')

puts "Using #{GITLAB_CI_YML}"

def sys(cmd)
  puts cmd
  system(cmd)
end

def safe_run_job(h, services, variables)
  links = services.map { |_image_name, _tag, name| "--link #{name}" }
  script = (['cd /src'] + h['script']).join(' && ')
  cmd = %w[docker run --rm -it -v $(pwd):/src] + links + variables + [h['image']] + %w[bash -c] + [%('#{script}')]
  ok = sys(cmd.join(' '))
rescue
  services.each do |_image_name, _tag, name|
    sys %(docker stop #{name} && docker rm #{name})
  end
end

# rubocop:disable Metrics/BlockLength
YAML.load_file(GITLAB_CI_YML).values.each do |h|
  # rubocop:enable Metrics/BlockLength
  next unless h.is_a?(Hash) && h.key?('stage') && h['stage'] == 'test'

  services = h.fetch('services', []).map do |s|
    case s
    when String
      name, tag = s.split(':')
      [name, tag, name]
    when Hash
      name, tag = s['name'].split(':')
      [name, tag, s['alias']]
    else
      raise "Don't know how to handle a (#{s.class}): #{s.inspect}"
    end
  end

  variables = h.fetch('variables', []).map do |var, val|
    "-e #{var}='#{val}'"
  end

  services.each do |image_name, tag, name|
    puts "image_name, tag, name => #{image_name}, #{tag}, #{name}"
    image = "#{image_name}:#{tag}"
    sys %(docker images --format '{{.Repository}}:{{.Tag}}'|grep ^#{image}$ || docker pull #{image})
    sys %(docker run -d --name #{name} #{variables.join(' ')} #{image})
  end

  exit 1 unless safe_run_job(h, services, variables)
end