kosmotaur / docker-env

Utility for Ruby on Rails developers using Docker

Docker::Env

This is a small utility for Ruby on Rails developers using Docker in their development environment. It creates environment variables similar to those created by docker inside a container linked to other containers. It's purpose is to allow you to run your dockerized Rails application outside of docker container, while still allowing to connect to other services that are running inside docker containers.

Usage example

Consider following fig/docker-compose yaml:

mongodb:
    image: dockerfile/mongodb
    command: mongod --smallfiles
    ports:
        - "27017"
        - "28017"

app:
    build: .
    command: rails s
    volumes:
        - .:/app
    ports:
        - "3000:3000"
    links:
        - mongodb

Environment variables created by docker inside the 'app' container will be similar to this:

MONGODB_1_NAME=/cnpback_app_run_41/mongodb_1
MONGODB_1_PORT=tcp://172.17.0.85:27017
MONGODB_1_PORT_27017_TCP=tcp://172.17.0.85:27017
MONGODB_1_PORT_27017_TCP_ADDR=172.17.0.85
MONGODB_1_PORT_27017_TCP_PORT=27017
MONGODB_1_PORT_27017_TCP_PROTO=tcp
MONGODB_1_PORT_28017_TCP=tcp://172.17.0.85:28017
MONGODB_1_PORT_28017_TCP_ADDR=172.17.0.85
MONGODB_1_PORT_28017_TCP_PORT=28017
MONGODB_1_PORT_28017_TCP_PROTO=tcp
MONGODB_NAME=/cnpback_app_run_41/mongodb
MONGODB_PORT=tcp://172.17.0.85:27017
MONGODB_PORT_27017_TCP=tcp://172.17.0.85:27017
MONGODB_PORT_27017_TCP_ADDR=172.17.0.85
MONGODB_PORT_27017_TCP_PORT=27017
MONGODB_PORT_27017_TCP_PROTO=tcp
MONGODB_PORT_28017_TCP=tcp://172.17.0.85:28017
MONGODB_PORT_28017_TCP_ADDR=172.17.0.85
MONGODB_PORT_28017_TCP_PORT=28017
MONGODB_PORT_28017_TCP_PROTO=tcp

Now, let's suppose your mongoid.yml file has this entry:

development:
    sessions:
        default:
        database: your_app_development
        hosts:
            - <%= "#{ENV['MONGODB_1_PORT_27017_TCP_ADDR']}:#{ENV['MONGODB_1_PORT_27017_TCP_PORT']}" %>

And you want to run your application outside of the docker container (for example to connect with a debugger from your IDE) without changing your configuration files and without setting any environment variables manually.

When installed in your Gemfile, docker-env will create a subset of these variables for you:

MONGODB_1_PORT_27017_TCP_ADDR=172.17.0.85
MONGODB_1_PORT_27017_TCP_PORT=27017
MONGODB_1_PORT_28017_TCP_ADDR=172.17.0.85
MONGODB_1_PORT_28017_TCP_PORT=28017
MONGODB_PORT_27017_TCP_ADDR=172.17.0.85
MONGODB_PORT_27017_TCP_PORT=27017
MONGODB_PORT_28017_TCP_ADDR=172.17.0.85
MONGODB_PORT_28017_TCP_PORT=28017

Installation

Add this line to your application's Gemfile:

gem 'docker-env', group: :development, github: 'cthulhu666/docker-env'

And then execute:

$ bundle

Contributing

1. Fork it ( https://github.com/[my-github-username]/docker-env/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request