Deltacloud is now modular and offers the drivers API

The Deltacloud API revamp is now done and pushed to our master GIT repo. The revamp itself does not affect the backward compatibility nor introduces any API schema changes. The main goal of this work is to make Deltacloud API a modular Sinatra application, thus pluggable to any other Rack-based web application (Rails, Padrino, Sinatra, etc..). As a side effect, since we do not use the Sinatra methods in a global namespace, this revamp also introduces the possibility to use Deltacloud API as a Ruby library. It means that in case you don’t want to use the REST server or for some reason (networking, security, etc…) you can’t, you can now just require ‘deltacloud/api’ and profit from the drivers API. Please note that the library code is now very experimental and we don’t promise that it will work as you expect or it will not change in the near future.

So how does the Sinatra::Base code work? After you install the ‘deltacloud-core’ gem, you should be able to just require ‘deltacloud_rack’ and then mount the DC API container in this way:

require 'deltacloud_rack'

Deltacloud::configure do |server|
  server.root_url '/api'
  server.version '0.5.0'
  server.klass 'Deltacloud::API'
end

run Rack::Builder.new {
  use Rack::MatrixParams
  use Rack::DriverSelect

  run Rack::URLMap.new(
    "/" => MyApplication.new,
    "/api" => Deltacloud[:klass],
  )
}

There are several use-cases when the Sinatra::Base approach could be useful. In case you need for some reason to add your own collections or just introduce some ‘stateful’ operations, it should be much more easy now than with the Sinatra::Application we were using before.

The other, very nifty feature is that you can now use Deltacloud drivers API in your Ruby applications without even starting a REST server. This could be handy if you’re stuck with gems like ‘fog’, or your application requires a very consistent API with the same abstraction for all cloud providers.

There is a small code example how you can use the library code:

require 'deltacloud/api'

Deltacloud.new(:ec2, :user => API_KEY, :password => API_SECRET) do |c|
  c.create_instance('ami-12345')
end
#
# or
#
Deltacloud.new(:mock) do |driver|
  puts driver.hardware_profiles
end

The drivers API is described here, but the new, more detailed documentation should appear soon. Meanwhile, you can use the YARD documentation I generated.