build randomization script

this script genereates envrionment property file necessary to do
jenkins randomization testing

dev-tools/build_randomization.rb

@@ -0,0 +1,71 @@
+#!/usr/bin/env ruby
+# Licensed to  ElasticSearch and Shay Banon under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the 'License'); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an 'AS IS' BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License
+#
+# generate property file for the jdk randomization test
+# 
+#
+require 'yaml'
+
+class JDKSelector
+  attr_reader :directory, :jdk_list
+
+  def initialize(directory)
+    @directory = directory
+  end
+
+  # get selection of available jdks from jenkins automatic install directory
+  def get_jdk
+    @jdk_list = Dir.entries(directory).select do |x| 
+      x.chars.first == 'J' 
+    end.map do |y|
+      File.join(directory, y)
+    end
+    self
+  end
+
+  # do ranomize selection from a given array
+  def select_one(selection_array = nil)
+    selection_array ||= @jdk_list
+    selection_array[rand(selection_array.size)]
+  end
+end
+
+# given a jdk directory selection, generate revelant environment variables
+def get_env_matrix(data_array)
+  [*data_array].map do |x|
+    {
+      'PATH' => File.join(x,'bin') + ':' + ENV['PATH'],
+      'JAVA_HOME' => x
+    }
+  end
+end
+
+# pick first element out of array of hashes, generate write java property file
+def generate_property_file(directory, data)
+  #array transformation
+  content = data.first.map do |key, value|
+    "%s=%s"%[key, value]
+  end
+  File.open(File.join(directory,'prop.txt'), 'w') do |file| 
+              file.write(content.join("\n")) 
+  end
+end
+
+jdk_selector = JDKSelector.new('/var/lib/jenkins/tools/hudson.model.JDK')
+path_matrix = get_env_matrix(jdk_selector.get_jdk.select_one)
+
+working_directory = ENV['WORKSPACE'] || '/var/tmp'
+generate_property_file(working_directory, path_matrix)