Selenium Chrome Headless with Ruby

Docker image with Selenium with Headless Chrome built on base Ruby image

Usage

Create your dockerfile for tests, with version corresponding to desired Ruby version and Chrome version:

# ruby 2.6.2 with selenium and headless chrome version 73
FROM selenium_chrome_headless_ruby:2.6.2-chrome_73

# bundle install
WORKDIR /app
COPY Gemfile Gemfile.lock .
RUN gem install bundler && bundle install

# copy e2e tests
COPY . .

# run e2e tests on chrome headless
RUN bundle exec rake features

Note that chrome requires the image's /dev/shm to be large enough, which can be modified with the docker run option --shm-size or the docker-compose option shm_size:, e.g.:

docker run --tty=true --shm-size=1g my-image-from-selenium_chrome_headless_ruby

Further, your Selenium driver must be configured to run chrome with the --no-sandbox option. For example, in Capybara:

Capybara.register_driver :chrome_headless do |app|
  capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(
    chromeOptions: {
      args: %w[ no-sandbox headless disable-gpu window-size=1280,1024]
    }
  )

  Capybara::Selenium::Driver.new(app, browser: :chrome, desired_capabilities: capabilities)
end

Updating chrome

Update the variables in .env: update CHROME_VERSION to latest version of google-chrome-stable package. Determine this by running apt-get update -y && apt-get upgrade -y google-chrome-stable on a prebuilt image. Then update CHROMIUM_DRIVER_VERSION to the matching major version from this page. Then update CHROME_VERSION_SHORT to the major version number.

Updating ruby

Update variables in .env and RUBY_DOCKER_TAG values in .circleci/config.yml.