resource.rb

class GeoEngineer::Resource
  validate -> { validate_has_tag(:Name) if support_tags? }
  validate -> { validate_has_tag(:ProjectName) if self.project? && support_tags? }

  validate :validate_project_name_correct

  def validate_project_name_correct
    bad_name = support_tags? && self.project && tags['ProjectName'] != self.project.full_name
    "ProjectName tag should equal \"#{project.full_name}\" for resource \"#{type}.#{id}\"" if bad_name
  end
end