class AWS::EC2::Tag

def delete(value = nil)
  tag_opts = { :key => key }
  tag_opts[:value] = value if value
  client.delete_tags(:resources => [resource.id], :tags => [tag_opts])
  nil
end

def get_resource attr
  client.describe_tags(:filters => [
    { :name => "key", :values => [key] },
    { :name => "resource-type", :values => [resource.tagging_resource_type] },
    { :name => "resource-id", :values => [resource.send(:__resource_id__)] }
  ])
end

def initialize resource, key, options = {}
  @resource = resource
  @key = key.to_s
  super
end

def inspect
  "<#{self.class}:#{local_cache_key}>"
end

def local_cache_key
  response_index_key
end

def response_index_key
  type = resource.tagging_resource_type
  id = resource.send(:__resource_id__)
  "#{type}:#{id}:#{key}"
end