add a provider module, working toward conistency and discoverability from top down

lib/fog.rb

@@ -24,6 +24,7 @@ require 'fog/errors'
 require 'fog/hmac'
 require 'fog/model'
 require 'fog/parser'
+require 'fog/provider'
 require 'fog/service'
 require 'fog/ssh'
 

lib/fog/aws.rb

@@ -1,11 +1,14 @@
-require 'fog/aws/ec2.rb'
-require 'fog/aws/elb.rb'
-require 'fog/aws/s3'
-require 'fog/aws/simpledb'
-
 module Fog
   module AWS
 
+    extend Fog::Provider
+
+    service_path 'fog/aws'
+    service 'ec2'
+    service 'elb'
+    service 's3'
+    service 'simpledb'
+
     def self.indexed_param(key, values, offset = 0)
       params = {}
       unless key.include?('%d')

lib/fog/provider.rb

@@ -0,0 +1,18 @@
+module Fog
+  module Provider
+
+    def service_path(new_path)
+      @service_path = new_path
+    end
+
+    def service(new_service)
+      services << new_service
+      require File.join(@service_path, new_service.to_s)
+    end
+
+    def services
+      @services ||= []
+    end
+
+  end
+end

lib/fog/rackspace.rb

@@ -1,9 +1,12 @@
-require 'fog/rackspace/files'
-require 'fog/rackspace/servers'
-
 module Fog
   module Rackspace
 
+    extend Fog::Provider
+
+    service_path 'fog/rackspace'
+    service 'files'
+    service 'servers'
+
     def self.authenticate(options)
       rackspace_auth_url = options[:rackspace_auth_url] || "auth.api.rackspacecloud.com"
       connection = Fog::Connection.new("https://" + rackspace_auth_url)