Issues when deploying on self-hosted Coolify

[CodeGradox]

Today I tested deploying my rails app running ferrum_pdf with Coolify. Deploying Rails went fine with nixpacks, but then I realized that I also had to add a browserless/chrome service for ferrum to work. It took a few hours for me to figure it out, because ferrum was unable to connect to the browserless service.

With the help of AI, I was able to make it work.
The AI had to monkey patch the Ferrum::Client::Websocket initializer. Without it, I was getting an SSL error. I have very little knowledge about the inner workings of SSL, so I don't know it it's due to Coolify running with a Caddy proxy behind a Cloudflare Proxied DNS. 😬

  def initialize(url, max_receive_size, logger)
    @url    = url
    @logger = logger
    uri     = URI.parse(@url)
    port    = uri.port || DEFAULT_PORTS[uri.scheme]

    if port == 443
      tcp = TCPSocket.new(uri.host, port)
      ssl_context = OpenSSL::SSL::SSLContext.new

      @sock = OpenSSL::SSL::SSLSocket.new(tcp, ssl_context)
      @sock.sync_close = true
      # THIS IS THE FIX
      @sock.hostname = uri.host # Set SNI hostname for proper SSL handshake
      @sock.connect
    else
      @sock = TCPSocket.new(uri.host, port)
    end

    max_receive_size ||= ::WebSocket::Driver::MAX_LENGTH
    @driver = ::WebSocket::Driver.client(self, max_length: max_receive_size)
    @messages = Queue.new

    @screenshot_commands = Concurrent::Hash.new if SKIP_LOGGING_SCREENSHOTS

    @driver.on(:open, &method(:on_open))
    @driver.on(:message, &method(:on_message))
    @driver.on(:close, &method(:on_close))

    start

    @driver.start
  end
end

Secondly, I realized that setting ws_url in the FerrumPdf config did not have any effect. I find this weird, since the source code looked like it simply passed all config options to a Ferrum::Browser initializer. In the end, I had to create my own Ferrum::Browser instance in the controller which I then passed to FerrumPdf.render_pdf.

# application_controller.rb
def browser
  return if ENV["BROWSERLESS_WS_ENDPOINT"].blank?

  Ferrum::Browser.new("no-sandbox" => true, ws_url: ENV["BROWSERLESS_WS_ENDPOINT"])
end

# tasks_controller.rb
def show
   pdf_data = FerrumPdf.render_pdf(html: html_string, browser: browser)
end

Using url instead of ws_url gave me this error:

(ms-pdf):10:in 'Class#new': undefined method 'host' for nil (NoMethodError)

        @host = @ws_url.host
                       ^^^^^
	from (ms-pdf):10:in '<main>'

And my ws_url looks something like this: wss://<domain>?token=<token>. For the url variable I used https.

My current ferrum_pdf.rb initializer looks like this:

FerrumPdf.configure do |config|
  config.browser_options = {
    "no-sandbox" => true,
    # ws_url: ENV["BROWSERLESS_WS_ENDPOINT"]
  }

  config.page_options.base_url = ENV.fetch("HOSTNAME", "http://localhost:3000")
  config.page_options.wait_for_idle_options = { connections: 0, duration: 0.05, timeout: 15 }

  config.pdf_options.paper_width = 8.27
  config.pdf_options.paper_height = 11.7
  config.pdf_options.print_background = true
end

It's not ideal, but it works! It seems a bit... hacky?

Specs

• ruby 3.4.0
• rails 8.0.3
• ferrum_pdf 2.1.0
• coolify 4.0.0-beta.433