Docker Development Environment

A development environment for Rails applications using docker.

Tested on Linux and Mac OS X.

Requirements

• Docker
• VirtualBox (only on OSX)
• boot2docker (only on OSX)

Install on OSX (using Homebrew)

Musophobia? Read on:

brew tap phinze/homebrew-cask
brew install brew-cask
brew cask install virtualbox
brew cask install boot2docker
brew install docker

Install on Linux (Tested on Ubuntu and Fedora

# Install docker
curl -sL https://get.docker.io/ | sudo sh
sudo adduser $USER docker

Install living-in-a-box

git clone https://github.com/gewo/living-in-a-box.git $HOME/.living-in-a-box
export PATH="~/.living-in-a-box/bin:$PATH" # you want to make this permanent

Docker images

Get started

First you want to start the background services, that is:

• redis
• mongodb
• mysql

On OSX a the boot2docker VM will be started for the docker daemon, which is not available on OSX.

# Start it up. On the first run it will pull all the necessary images
# from the docker registry.
dev start

Start developing

From your project folder just run:

dev shell

This will open a bash shell inside the docker container with the background services linked to it. The /mnt-folder inside the container is synced to your current path.

An example:

$ cd /path/to/project
$ dev shell
docker$ cd /mnt # equals /path/to/project on the host
docker$ bundle install
docker$ bundle exec rake db:create db:schema:load db:migrate db:seed
docker$ bundle exec rails server
docker$ exit
$

Data in the background-services will be persisted in Data Volumes.

Environment Variables

PORT

Normally the containers port is mapped to a random port on your host machine. You can specify the PORT environment variable to use a fixed one:

$ dev shell             # port 3000 forwarded to 0.0.0.0:49157
$ PORT=3456 dev shell   # port 3000 forwarded to 0.0.0.0:3456

SYNC_DOTFILES

When setting SYNC_DOTFILES=1 a few of your favorite dotfiles are bind-mounted inside the container and your shell is set to zsh if that's also your current $SHELL.

When you want to specify custom files that should be synced into your containers home directory you can set the DOTFILES environment variable.

$ SYNC_DOTFILES=1 dev shell                    # sync default dotfiles
$ SYNC_DOTFILES=1 DOTFILES=".ctags" dev shell  # sync your `~/.ctags`

SHELL

Set the shell to use in your container.

$ SHELL=fish dev shell
docker <><

EXTRA_ARGS

Sometimes you may want to pass additional arguments to the docker run command.

Lets say you want to forward the Redis port to your local system:

$ EXTRA_ARGS="--publish 127.0.0.1:9736:6379" dev shell
docker$

# another shell on your host
$ redis-cli -p 9736 INFO | grep redis_version
redis_version:2.6.15
$

RUBY_VER

Per default dev shell uses the gewo/ruby image. Some guessing is done to automatically find out the correct version of ruby from your Gemfile. Sometimes you want to specify the version manually:

$ RUBY_VER=1.9.3 dev shell
docker$ ruby -v
ruby 1.9.3p392 (2013-02-22 revision 39386) [x86_64-linux]
docker$

IMAGE

The docker image. IMAGE by default is the latest ruby image.

$ IMAGE=gewo/ruby:1.9.3 dev shell
docker$ ruby -v
ruby 1.9.3p392 (2013-02-22 revision 39386) [x86_64-linux]
docker$

{MONGODB,REDIS,MYSQL}_VER

Set version of background services on dev start

$ # Run the mongodb server with image gewo/mongodb:2.4.10. Other images
$ # use :latest per default.
$ MONGODB_VER=2.4.10 dev start

Commands

shell

dev shell [IMAGE]

IMAGE by default is the latest ruby image.

Example

$ dev shell gewo/node
docker$ nodejs -v
v0.10.29
docker$

TODO

A lot.