How to disable “Cannot Render Console from…” on Rails

Question

I\'m using Ubuntu/vagrant as my development environment. I\'m getting these messages on rails console:

Started GET \"/assets/home-fcec5b5a277ac7c20cc9f45a209         


        

Answer 1

You can whitelist single IP's or whole networks.

Say you want to share your console with 192.168.0.100. You can do this:

class Application < Rails::Application
  config.web_console.whitelisted_ips = '192.168.0.100'
end

If you want to whitelist the whole private network, you can do:

class Application < Rails::Application
  config.web_console.whitelisted_ips = '192.168.0.0/16'
end

If you don't wanna see this message anymore, set this option to false:

class Application < Rails::Application
  config.web_console.whiny_requests = false
end

Be careful what you wish for, 'cause you might just get it all

This is probably only for development purposes so you might prefer to place it under config/environments/development.rb instead of config/application.rb.

Answer 2

Auto discovery within your config/development.rb

config.web_console.whitelisted_ips = Socket.ip_address_list.reduce([]) do |res, addrinfo|
    addrinfo.ipv4? ? res << IPAddr.new(addrinfo.ip_address).mask(24) : res
end

Of course might need to add

require 'socket'
require 'ipaddr'

Within your file.

Answer 3

You need to whitelist the 10.0.2.2 network space in the Web Console config.

So you'll want something like this:

class Application < Rails::Application
  config.web_console.whitelisted_ips = '10.0.2.2'
end

Read here for more information.

As pointed out by pguardiario, this wants to go into config/environments/development.rb rather than config/application.rb so it is only applied in your development environment.

Answer 4

If you are using Docker most likely you don't want neither to introduce new ENV variables nor to hardcode your specific IP address.

Instead you may want to check that you are in Docker using /proc/1/cgroup, and to allow your host IP (both for web_console and better_errors). Add to your config/environments/development.rb

  # https://stackoverflow.com/a/20012536/4862360
  if File.read('/proc/1/cgroup').include?('docker')
    # https://stackoverflow.com/a/24716645/4862360
    host_ip = `/sbin/ip route|awk '/default/ { print $3 }'`.strip

    BetterErrors::Middleware.allow_ip!(host_ip) if defined?(BetterErrors::Middleware)
    config.web_console.whitelisted_ips << host_ip
  end

Answer 5

For me, whitelisted_ips didn't seem to work in a new project. The Readme states the corresponding configuration entry is supposed to be permissions now:

Rails.application.configure do
  config.web_console.permissions = '192.168.0.0/16'
end

https://github.com/rails/web-console/blob/master/README.markdown

Answer 6

Hardcoding an IP into a configuration file isn't good. What about other devs? What if the ip changes?

Docker-related config should not leak into the rails app whenever possible. That's why you should use env vars in the config/environments/development.rb file:

class Application < Rails::Application
  # Check if we use Docker to allow docker ip through web-console
  if ENV['DOCKERIZED'] == 'true'
    config.web_console.whitelisted_ips = ENV['DOCKER_HOST_IP']
  end
end

You should set correct env vars in a .env file, not tracked into version control.

In docker-compose.yml you can inject env vars from this file with env_file:

app:
  build: .
  ports:
   - "3000:3000"
  volumes:
    - .:/app
  links:
    - db
  environment:
    - DOCKERIZED=true
  env_file:
    - ".env"

Based on the feebdack received in comments, we can also build a solution without environment variables:

class Application < Rails::Application
  # Check if we use Docker to allow docker ip through web-console
  if File.file?('/.dockerenv') == true
    host_ip = `/sbin/ip route|awk '/default/ { print $3 }'`.strip
    config.web_console.whitelisted_ips << host_ip
  end
end

I'll leave the solutions with env var for learning purposes.