Goa

This Gem aids in creating a Rails Engine that has access to models in a separate database than the hosting application.

Installation

Add this line to your application's Gemfile:

gem 'goa'

And then execute:

$ bundle

Or install it yourself as:

$ gem install goa

Usage

• Create a Rails engine:

rails plugin new my_goa_gem --mountable

• Configure your database as you would a Rails application:

Add a config/database.yml to your application and configure the development, test, production and staging environments as appropriate for your database connection.

• Add Models to your gem as you would a Rails application, except make sure they share a common base class and a common database connection:

  app/models/my_goa_gem/base.rb

require 'goa'

class MyGoaGem::Base < ActiveRecord::Base
  self.abstract_class = true

  # Establish connection in a base class so all models will share the connection
  establish_connection GOA::Config.database_config(MyGoaGem::Engine.root)
end

• Create a Rakefile in your Rails Engine's lib/tasks folder:

  lib/tasks/my_goa_gem.rake

require 'goa'

GOA::RakeTasks.new.add_rake_tasks

You can now execute this in either your Rails engine or Rails application to migrate both the Rails application database and the database specified by your GOA gem:

bundle exec rake app:db:drop app:db:create app:db:schema:load app:db:migrate app:db:test:prepare

• Add to your test_helper.rb/spec_helper.rb to clean your database in both your Engine and Application:

Add this into both your client Engine Gem and the application that uses your Engine Gem where MyGoaGem::Base is the ActiveRecord base class for your models.

require 'goa'
require 'goa/database_cleaner'

RSpec.configure do |config|
  config.before(:suite) do
    GOA::DatabaseCleaner.truncate_database(MyGoaGem::Base)
  end

  config.before(:each) do
    GOA::DatabaseCleaner.begin_transaction(MyGoaGem::Base)
  end

  config.after(:each) do
    GOA::DatabaseCleaner.end_transaction(MyGoaGem::Base)
  end

  # ...
end