Object wrapper for the EC2 Metadata URL on Openstack & EC2 vm's

foo.rb

class EC2Metadata                                                               
  def initialize()                                                              
    meta_url   = "169.254.169.254"                                              
    @meta_base = "/2008-02-01/meta-data/"                                       
    @conn      = Net::HTTP.new(meta_url)                                        
  end                                                                           
                                                                                
  def method_missing(name, *args)                                               
    name =  name.to_s.gsub("_", "-")                                            
    req  =  get_url(name)                                                       
    ret  =  get_data(req)                                                       
    if ret.include?("\n")                                                             
      ret = ret.split                                                           
    end                                                                         
    return ret                                                                  
  end                                                                           
                                                                                
  def ec2_methods                                                               
    methods = get_data(get_url("")).split                                       
    return methods.collect {|m| m.gsub("-", "_").gsub("/","")}                  
  end                                                                           
                                                                                
  private                                                                       
  def get_url(arg)                                                              
    return "#{@meta_base}/#{arg}"                                               
  end                                                                           
                                                                                
  def get_data(request_uri)                                                     
    request   = Net::HTTP::Get.new(request_uri)                                 
    response  = @conn.request(request)                                          
    raise Net::HTTPNotFound if response.code != "200"                                                                                                                                     
    return response.body                                                        
  end                                                                           
end