Armada makes it simple and easy to combine ActiveModel and FleetDB together.
To install the gem:
gem install armada
Make sure to download FleetDB and run it:
wget http://fleetdb.s3.amazonaws.com/fleetdb-standalone.jar
java -cp fleetdb-standalone.jar fleetdb.server -f swan.fdb
Documentation for the FleetDB server can be found at the FleetDB website.
Begin by requiring Armada in your script or application.
require "armada"
Be sure to set the timezone, as Armada currently makes use of it.
Time.zone = "UTC"
To start Armada with the default settings, enter the following line:
# This is the same as Armada.setup!(:address => "127.0.0.1", :port => 3400, :password => nil)
Armada.setup!
To change the address, port, or password, Armada.setup! accepts these as keys in an option hash.
Armada.setup!(:address => "4.8.15.16", :port => 2342, :password => "dharma")
This sets up the basic fundamentals of Armada. The following sections will detail how to fully utilize Armada's power.
Creating models in Armada is very easy. The following code creates an Airplane model with a tail number attribute.
class Airplane < Armada::Model
add_columns :tail_number
end
Armada models are fully compliant with ActiveModel.
plane = Airplane.new(:tail_number => 815)
plane.persisted? #=> false
plane.destroy #=> false
plane.valid? #=> true
plane.errors #=> []
plane.save #=> true
plane.persisted? #=> true
plane.destroy #=> true
plane.persisted? #=> false
Armada models can also enjoy the added benefits of validation and automatic timestamps.
class Airplane < Armada::Model
add_columns :tail_number, :created_at, :updated_at
validates :tail_number, :inclusion => {:in => [815, 316]}, :uniqueness => true
end
plane = Airplane.new(:tail_number => 816)
plane.valid? #=> false
plane.tail_number = 316
plane.save #=> true
plane.attributes #=> {"id"=>"b20e1cmt8mmjd7dzxu7wcjyg2", "tail_number"=>316,
"created_at"=>1272324264, "updated_at"=>1272324264}
All Armada models are given an id if none is specified during creation. This is a requirement of FleetDB. The default generation method is generate_unique_id in Armada::Model. Note that Armada models can be treated very similarly to ActiveRecord models.
All querying is handled through instances of Armada::Relation, which handle everything. Read the FleetDB query docs for more detailed information.
plane1 = Airplane.new(:tail_number => 815)
plane2 = Airplane.new(:tail_number => 316)
plane1.save
plane2.save
# Until specified, FleetDB has no order.
Airplane.all #=> [plane1, plane2] | [plane2, plane1]
Airplane.where(:tail_number => 815).all #=> [plane1]
Airplane.where(:tail_number => 815).first #=> plane1
# Using the FleetDB count command
Airplane.where(:tail_number => 815).count #=> 1
# Armada::Relation sets :order to :asc by default
Airplane.order(:tail_number).all #=> [plane2, plane1]
Airplane.order(:tail_number => :desc).all #=> [plane1, plane1]
# Armada::Relation supports offset and limit just like SQL
Airplane.order(:tail_number).limit(1).all #=> [plane2]
Airplane.order(:tail_number).offset(1).all #=> [plane1]
# The :only option allows choosing specific attributes
Airplane.order(:tail_number).only(:tail_number).all #=> [316, 815]
- Mark McGranaghan - For developing FleetDB and providing a sample Ruby client.
Copyright © 2010 Sam Aarons, released under the MIT license