How to use --remote-debugging-port with chromedriver

[Julie Silvestri]

I am using Selenium to run headless Chrome with Capybara, which works great, except I cannot figure out how to use remote debugging.  When I add `--remote-debugging-port=4444` or `--remote-debugging-port=9222` or `--remote-debugging-port=9521`, Selenium no longer connects to the browser to run the test -- I get a Net::ReadTimeout.

How do I get remote debugging to work?  Here is my code for reference:

Capybara.register_driver :selenium do |app|

     # from https://github.com/SeleniumHQ/selenium/issues/3738

     capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(loggingPrefs: {browser: 'ALL'})

     options = Selenium::WebDriver::Chrome::Options.new

     options.add_argument '--disable-infobars' # hide info bar about chrome automating test

     # if we don't use this flag, every selenium test will die with the error:

     # "unknown error: Chrome failed to start: exited abnormally"

     options.add_argument '--no-sandbox'

     port = 9521

   options.add_preference 'debuggerAddress', "127.0.0.1:#{port}"

   # BREAKS THINGS if uncommented
   # options.add_argument "--remote-debugging-port=#{port}"

     options.add_argument '--headless'

     options.add_argument '--window-size=1600,2400'

     options.add_preference('profile.default_content_settings.popups', 0)

     options.add_preference('download.default_directory', DownloadHelpers::PATH.to_s)

     Capybara::Selenium::Driver.new(

       app,

       clear_local_storage: true,

       clear_session_storage: true,

       browser: :chrome,

       options: options,

       desired_capabilities: capabilities,

     )

   end

    

[Roger Sillito]

I found this issue on the Chromium bug tracker which sheds some light - I'm currently pursuing the crmux idea: https://bugs.chromium.org/p/chromedriver/issues/detail?id=878

[Julie Silvestri]

Thanks!  I have tried crmux, but Selenium seems to connect to a different port (e.g. 9531 or 9532), so it is still not working.  I tried hard-coding in my gem for it to connect to 9522, but then I get the error:

Selenium::WebDriver::Error::WebDriverError:

            unable to bind to locking port 9522 within 45 seconds

I will also post on the link you sent.