(QENG-1906) Refactor initialize to allow config passing

Prior to this commit, several pieces of vmpooler performed configuration
and initialization steps within 'initialize'. This made it difficult to
pass in mock objects for testing purposes.

This commit performs a single configuration and passes the results to
the various pieces of vmpooler.

lib/vmpooler.rb

@@ -18,4 +18,47 @@ module Vmpooler
       require File.expand_path(File.join(File.dirname(__FILE__), 'vmpooler', lib))
     end
   end
+
+  def self.config(filepath='vmpooler.yaml')
+    # Load the configuration file
+    config_file = File.expand_path(filepath)
+    parsed_config = YAML.load_file(config_file)
+
+    # Set some defaults
+    parsed_config[:redis]             ||= {}
+    parsed_config[:redis]['server']   ||= 'localhost'
+    parsed_config[:redis]['data_ttl'] ||= 168
+
+    parsed_config[:config]['task_limit']   ||= 10
+    parsed_config[:config]['vm_checktime'] ||= 15
+    parsed_config[:config]['vm_lifetime']  ||= 24
+
+    if parsed_config[:graphite]['server']
+      parsed_config[:graphite]['prefix'] ||= 'vmpooler'
+    end
+
+    parsed_config[:uptime] = Time.now
+
+    parsed_config
+  end
+
+  def self.new_redis(host='localhost')
+    Redis.new(host: host)
+  end
+
+  def self.new_logger(logfile)
+    Vmpooler::Logger.new logfile
+  end
+
+  def self.new_graphite(server)
+    if server.nil? or server.empty? or server.length == 0
+      nil
+    else
+      Vmpooler::Graphite.new server
+    end
+  end
+
+  def self.pools(conf)
+    conf[:pools]
+  end
 end