Cassandra Object Rails

Cassandra Object uses ActiveModel to mimic much of the behavior in ActiveRecord.

Installation

Add the following to your Gemfile:

gem 'cassandra_object_rails'

Defining Models

class Widget < CassandraObject::Base
  string :name
  string :description
  integer :price
  array :colors, unique: true

  validates :name, presence: :true

  before_create do
    self.description = "#{name} is the best product ever"
  end
end

Connecting to the Server

CassandraObject::Base.config = {
  keyspace: 'my_app_development',
  servers: '127.0.0.1:9160',
  thrift: {
    timeout: 20,
    retries: 2
  }
}

Connecting your rails application with Cassandra

in your config/cassandra.yml

development:
  keyspace: 'my_app_development'
  servers: '127.0.0.1:9160'

test:
  keyspace: 'my_app_development'
  servers: '127.0.0.1:9160'

production:
  keyspace: 'my_app_development'
  servers: '127.0.0.1:9160'

Creating and updating records

Cassandra Object has equivalent methods as ActiveRecord:

widget = Widget.new
widget.valid?
widget = Widget.create(name: 'Acme', price: 100)
widget.update_attribute(:price, 1200)
widget.update_attributes(price: 1200, name: 'Acme Corporation')
widget.attributes = {price: 300}
widget.price_was
widget.save
widget.save!

Finding records

widget = Widget.find(uuid)
widget = Widget.first
widgets = Widget.all
Widget.find_each do |widget|
  ...
end

Query

Some lightweight scoping features are available:

Widget.where('color' => 'red')
Widget.select(['name', 'color'])
Widget.limit(10)

Keyspace

Creating cassandra keyspace defined on cassandra.yml

rake cassandra:create

Droping cassandra keyspace

rake cassandra:drop

Adding column family

CassandraObject::Schema.create_column_family 'Widgets'