exception_cascading.rb

class InvalidDataException < StandardError

  attr_accessor :filename

end

def do_something_with_file(filename)
  begin
    self.do_something_with_data(File.read(filename))
  rescue InvalidDataException => e
    e.filename = filename
    raise e
  end
end

def do_something_with_data(data)
  if !data.start_with?('ABCD')
    raise InvalidDataException
  end

  # ...
end