Simple Setup of Rails Development Environment using Docker @ OS X

Setup.md

Setting-up

This does not covers installation of docker and compose

Also, presuming myapp is already created

For this example RoR app Will have

• Web server
• Postgres DB

Inside rails app create Dockerfile

We'll start with the Dockerfile, which describes how to build our virtual environment to host a Rails app.

FROM ruby:2.2.0
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev
RUN mkdir /myapp
WORKDIR /myapp
ADD Gemfile /myapp/Gemfile
RUN bundle install
ADD . /myapp

Inside rails app docker-compose.yml

Docker Compose lets us define our containers and how they should be linked together with a simple yaml file.

db:
  image: postgres
  ports:
    - "5432"
web:
  build: .
  command: bundle exec rails s -p 3000 -b '0.0.0.0'
  volumes:
    - .:/myapp
  ports:
    - "3000:3000"
  links:
    - db

Inside rails app change database.yml

default: &default  
  adapter: postgresql
  encoding: unicode
  username: postgres
  host: <%= ENV['MYAPP_DB_1_PORT_5432_TCP_ADDR'] %>
  port: <%= ENV['MYAPP_DB_1_PORT_5432_TCP_PORT'] %>
  pool: 5

development:  
  <<: *default
  database: myapp_development

test:  
  <<: *default
  database: myapp_test

We can run the following command to see all ENV Variables from our service

docker-compose run web env

Inside rails app add the following line to GEMFILE

gem 'therubyracer',  platforms: :ruby

Building Containers

docker-compose build

Setting up database and migrations

docker-compose run web rake db:create
docker-compose run web rake db:migrate

Running the app

docker-compose up

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