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.