OpenShift is a Rails friendly PaaS - Part 2

In this second part of my mini-series focused on Ruby on Rails applications running on OpenShift. In this post I will discuss setting up Ruby on Rails project leveraging MongoDB.

Ruby on Rails application

With the data backend being MongoDB, there is no need to have ActiveRecord available in you application. So, let's create new Rails application without ActiveRecord.

rails new mongorails --skip-active-record

Without ActiveRecord the application has no ORM to help with the Model layer. As MongoDB is a document oriented database it provides ODMs - Object-Document-Mappers. In this article I will be using Mongoid ODM.

Setting up Mongoid

To provide connection configuration Mongoid loads config/mongoid.yml file automatically.In this second part of my mini-series focused on Ruby on Rails applications running on OpenShift. In this post I will discuss setting up Ruby on Rails project leveraging MongoDB.

Ruby on Rails application

With the data backend being MongoDB, there is no need to have ActiveRecord available in you application. So, let's create new Rails application without ActiveRecord.

rails new mongorails --skip-active-record

Without ActiveRecord the application has no ORM to help with the Model layer. As MongoDB is a document oriented database it provides ODMs - Object-Document-Mappers. In this article I will be using Mongoid ODM.

Setting up Mongoid

To provide connection configuration Mongoid loads config/mongoid.yml file automatically. Let's create the file and add an OpenShift specific configuration for production environment.

production:

  sessions:

    default:

      database: <%= ENV['OPENSHIFT_APP_NAME'] %>

      hosts:

        - <%= ENV['OPENSHIFT_MONGODB_DB_HOST'] || 'localhost' %>:<%= ENV['OPENSHIFT_MONGODB_DB_PORT'] || 27017 %>

      username: <%= ENV['OPENSHIFT_MONGODB_DB_USERNAME'] %>

      password: <%= ENV['OPENSHIFT_MONGODB_DB_PASSWORD'] %>

Configuring gems

The configuration is in place, let's modify Gemfile in the root of you application. To add the mongoid gem, use line as

gem 'mongoid'

Once edited, you need to bundle the gems to create updated Gemfile.lock

bundle install

Configuring an OpenShift gear with Ruby and MongoDB support

We now have our configuration complete. Now, let's create new OpenShift application:

rhc app create mongorails ruby-1.9

and embed the MongoDB cartridge into the application

rhc cartridge add mongodb-2.0 -a mongorails

and move the source code of the application into the repository OpenShift created for you locally. Commit the files to Git and push to OpenShift.

git add .

git commit -m "Initial commit"

git push origin master

Conclusion

That's it. You now have a Ruby on Rails application with MongoDB backend in the cloud, ready for your next big idea!