'Return size of an existing volume'

def manage_existing_get_size(self, volume, external_ref):

    LOG.debug('Volume    name    :    %(name)s        External    ref    :    %(ref)s', {'name': volume['name'], 'ref': external_ref})
    target_vol_name = self._get_existing_volume_ref_name(external_ref)
    vol_info = self.APIExecutor.get_vol_info(target_vol_name)
    LOG.debug('Volume    size    :    %(size)s        Volume-name    :    %(name)s', {'size': vol_info['size'], 'name': vol_info['name']})
    return int((vol_info['size'] / units.Ki))
