Dokcer環境等で発生するSelenium::WebDriver::Error::UnknownErrorの対処法

Dokcer環境などのCUI環境でcapybara/selenium/chromedriverを利用する際は no-sandbox/disable-dev-shm-usageオプションが必要

Selenium::WebDriver::Error::UnknownError:
                unknown error: Chrome failed to start: exited abnormally.
                  (unknown error: DevToolsActivePort file doesn't exist)
                  (The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

capybara.rb

...
Capybara.register_driver :selenium_chrome_headless do |app|
  options = ::Selenium::WebDriver::Chrome::Options.new
  options.add_argument('--headless') 
  options.add_argument('--no-sandbox') # chrootで隔離された環境(Sandbox)での動作を無効
  options.add_argument('--disable-dev-shm-usage') # 共有メモリファイルの場所を/dev/shmから/tmpに移動
  options.add_argument('--disable-gpu')
  options.add_argument('--window-size=2500,2500')
  Capybara::Selenium::Driver.new(app, browser: :chrome, options: options)
end

Capybara.javascript_driver = :selenium_chrome_headless