Synnefo » snf-ganeti

def _my_uuidgen():

  """Poor-man's uuidgen using the uuidgen binary.

  """

  result = utils.RunCmd(["uuidgen", "-r"])

  if result.failed:

    return None

  return result.stdout.rstrip('\n')

try:

  import uuid

  _uuidgen = uuid.uuid4

except ImportError:

  _uuidgen = _my_uuidgen

    self._temporary_ids = set()

  def _ComputeAllLVs(self):

    """Compute the list of all LVs.

    """

    self._OpenConfig()

    self._ReleaseLock()

    lvnames = set()

    for instance in self._config_data.instances.values():

      node_data = instance.MapLVsByNode()

      for lv_list in node_data.values():

        lvnames.update(lv_list)

    return lvnames

  def GenerateUniqueID(self, exceptions=None):

    """Generate an unique disk name.

    This checks the current node, instances and disk names for

    duplicates.

    Args:

      - exceptions: a list with some other names which should be checked

                    for uniqueness (used for example when you want to get

                    more than one id at one time without adding each one in

                    turn to the config file

    Returns: the unique id as a string

    """

    existing = set()

    existing.update(self._temporary_ids)

    existing.update(self._ComputeAllLVs())

    existing.update(self._config_data.instances.keys())

    existing.update(self._config_data.nodes.keys())

    if exceptions is not None:

      existing.update(exceptions)

    retries = 64

    while retries > 0:

      unique_id = _uuidgen()

      if unique_id not in existing and unique_id is not None:

        break

    else:

      raise errors.ConfigurationError, ("Not able generate an unique ID"

                                        " (last tried ID: %s" % unique_id)

    self._temporary_ids.add(unique_id)

    return unique_id

    all_lvs = instance.MapLVsByNode()

    logger.Info("Instance '%s' DISK_LAYOUT: %s" % (instance.name, all_lvs))