ruby_app.rb

class CoachCli::CI::ConfigGenerators::RubyApp < CoachCli::CI::ConfigGenerator
  def generate_jobs
    [
      lint_job,
    ]
  end

  private

  def lint_job
    CoachCli::CI::CircleCiJob.new(
      name: "#{project.name}--lint",
      config: lint_job_config,
      project: project,
      allow_failures: allow_failures
    ).tap do |job|
      job.add_steps(checkout_step)
      job.add_steps(bundle_steps)
      job.add_steps(yarn_steps) if project.file_exists?('package.json')
      job.add_steps(gradle_steps) if project.file_exists?('build.gradle')
      job.add_steps(rubocop_step)
      job.add_steps(scss_lint_step) if project.file_exists?('.scss-lint.yml')
      job.add_steps(erb_lint_step) if project.file_exists?('.erb-lint.yml')
      job.add_steps(brakeman_step) if project.file_exists?('config/brakeman.yml')
      job.add_steps(store_artifacts_step)
    end
  end

  def lint_job_config
    from_yaml(<<~YAML)
      resource_class: #{project.resource_class}
      docker:
        - image: #{container_image}
          environment:
            GEM_SOURCE: https://rubygems.org
            RAILS_ENV: test
            RACK_ENV: test
    YAML
  end

  def container_image
    "#{CoachCli::CI::EC2ContainerRepository.hostname}/betterment/#{project.runtime}:#{project.runtime_version}"
  end

  def store_artifacts_step
    CoachCli::CI::Steps::StoreArtifacts.new
  end

  def bundle_steps
    CoachCli::CI::Steps::Bundle.new(project: project, gemfile: Gemfile)
  end

  def gradle_steps
    [CoachCli::CI::Steps::GradleInstall.new(project: project), CoachCli::CI::Steps::GradleBuild.new(project: project)]
  end

  def rubocop_step
    CoachCli::CI::Steps::Rubocop.new(project: project)
  end

  def scss_lint_step
    CoachCli::CI::Steps::ScssLint.new(project: project)
  end

  def erb_lint_step
    CoachCli::CI::Steps::ErbLint.new(project: project)
  end

  def brakeman_step
    CoachCli::CI::Steps::Brakeman.new(project: project)
  end

  def checkout_step
    CoachCli::CI::Steps::Checkout.new
  end

  def from_yaml(input)
    YAML.safe_load(input)
  end
end

maybe just carve off a part of it for illustrative purposes?

class CoachCli::CI::ConfigGenerators::RubyApp < CoachCli::CI::ConfigGenerator
def generate_jobs
    [lint_job, ...]
  end

# more jobs...

def lint_job
    CoachCli::CI::CircleCiJob.new(
      name: "#{project.name}--lint",
      config: lint_job_config,
      project: project,
      allow_failures: allow_failures
    ).tap do |job|
      job.add_steps(checkout_step)
      job.add_steps(bundle_steps)
      job.add_steps(yarn_steps) if project.file_exists?('package.json')
      job.add_steps(rubocop_step)
      job.add_steps(scss_lint_step) if project.file_exists?('.scss-lint.yml')
      job.add_steps(erb_lint_step) if project.file_exists?('.erb-lint.yml')
      job.add_steps(brakeman_step) if project.file_exists?('config/brakeman.yml')
      job.add_steps(store_artifacts_step)
    end
  end

  def lint_job_config
    from_yaml(<<~YAML)
      resource_class: #{project.resource_class}
      docker:
        - image: #{container_image}
          environment:
            GEM_SOURCE: https://rubygems.org
            RAILS_ENV: test
            RACK_ENV: test
    YAML
  end

  def checkout_step
    CoachCli::CI::Steps::Checkout.new
  end

  # more steps...