Trying to reach localhost from inside Selenium docker - selenium-webdriver

Question

I'm trying to run my tests using Selenium docker,
I have a local grunt server running on port 9000, I' launched the following selenium docker:
docker run -d -p 4444:4444 -p 5900:5900 selenium/standalone-chrome-debug
Then I've launched my tests (using Capybara) and opened VNC to watch the tests, but all I get is chrome messgae "This site can’t be reached".
cabybara.rb:
isWindows = (/cygwin|mswin|mingw|bccwin|wince|emx/ =~ RUBY_PLATFORM) != nil
require 'capybara/rspec'
require 'capybara'
require 'capybara/dsl'
require_relative 'sinatra_proxy'
require 'selenium/webdriver'
require 'selenium/webdriver/remote/http/curb' if !isWindows
Capybara.register_driver :selenium_chrome do |app|
http_client = isWindows ? nil : Selenium::WebDriver::Remote::Http::Curb.new
options = {
http_client: http_client,
browser: :chrome,
# service_log_path: 'chromedriver.out', # Enable Selenium logs
switches: ["--disable-web-security", '--user-agent="Chrome under Selenium for Capybara"']
}
options[:url] = "http://172.17.0.2:4444/wd/hub"
Capybara::Selenium::Driver.new app, options
end
Capybara.default_driver = :selenium_chrome
Capybara.app = SinatraProxy.new
Capybara.app_host = "http://127.0.0.1:9000"
Capybara.server_host = '0.0.0.0'
ip addr show docker0
ip addr show docker0
6: docker0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
link/ether 02:22:ec:65:9e:f1 brd ff:ff:ff:ff:ff:ff
inet 172.17.0.1/16 scope global docker0
valid_lft forever preferred_lft forever
inet6 fe40::42:ecdd:fe73:9ef4/64 scope link
valid_lft forever preferred_lft forever
Needed to be the IP of docker host, used:
ip route show | grep docker0 | awk '{print $9}'
for Capybara.app_host (DOCKER_HOST_IP:PORT) and Capybara.server_host (DOCKER_HOST_IP)

Answer 1

Use:
Capybara.app_host = "http://yourhostip:9000"
not localhost. For docker container localhost is itself.
Also I recommend not calling docker by its internal ip just use:
options[:url] = "http://localhost:4444/wd/hub"
But first solve the former problem
Regards