Synnefo » snf-ganeti

#!/usr/bin/python

#

# Copyright (C) 2007 Google Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Tool to upgrade the configuration file.

The upgrade is done by unpickling the configuration file into custom classes

derivating from dict. We then update the configuration by modifying these

dicts. To save the configuration, it's pickled into a buffer and unpickled

again using the Ganeti objects before being finally pickled into a file.

Not using the custom classes wouldn't allow us to rename or remove attributes

between versions without loosing their values.

"""

import os

import os.path

import sys

import optparse

import cPickle

import tempfile

from cStringIO import StringIO

from ganeti import objects

class Error(Exception):

  """Generic exception"""

  pass

def _BaseFindGlobal(module, name):

  """Helper function for the other FindGlobal functions.

  """

  return getattr(sys.modules[module], name)

# Internal config representation

class UpgradeDict(dict):

  """Base class for internal config classes.

  """

  def __setstate__(self, state):

    self.update(state)

  def __getstate__(self):

    return self.copy()

class UpgradeConfigData(UpgradeDict): pass

class UpgradeCluster(UpgradeDict): pass

class UpgradeNode(UpgradeDict): pass

class UpgradeInstance(UpgradeDict): pass

class UpgradeDisk(UpgradeDict): pass

class UpgradeNIC(UpgradeDict): pass

class UpgradeOS(UpgradeDict): pass

_ClassMap = {

  objects.ConfigData: UpgradeConfigData,

  objects.Cluster: UpgradeCluster,

  objects.Node: UpgradeNode,

  objects.Instance: UpgradeInstance,

  objects.Disk: UpgradeDisk,

  objects.NIC: UpgradeNIC,

  objects.OS: UpgradeOS,

}

# Build mapping dicts

WriteMapping = dict()

ReadMapping = dict()

for key, value in _ClassMap.iteritems():

  WriteMapping[value.__name__] = key

  ReadMapping[key.__name__] = value

# Read config

def _ReadFindGlobal(module, name):

  """Wraps Ganeti config classes to internal ones.

  """

  if module == "ganeti.objects" and name in ReadMapping:

    return ReadMapping[name]

  return _BaseFindGlobal(module, name)

def ReadConfig(path):

  """Reads configuration file.

  """

  f = open(path, 'r')

  try:

    loader = cPickle.Unpickler(f)

    loader.find_global = _ReadFindGlobal

    data = loader.load()

  finally:

    f.close()

  return data

# Write config

def _WriteFindGlobal(module, name):

  """Maps our internal config classes to Ganeti's.

  """

  if module == "__main__" and name in WriteMapping:

    return WriteMapping[name]

  return _BaseFindGlobal(module, name)

def WriteConfig(path, data, dry_run):

  """Writes the configuration file.

  """

  buf = StringIO()

  # Write intermediate representation

  dumper = cPickle.Pickler(buf, cPickle.HIGHEST_PROTOCOL)

  dumper.dump(data)

  del dumper

  # Convert back to Ganeti objects

  buf.seek(0)

  loader = cPickle.Unpickler(buf)

  loader.find_global = _WriteFindGlobal

  data = loader.load()

  # Write target file

  (fd, name) = tempfile.mkstemp(dir=os.path.dirname(path))

  f = os.fdopen(fd, 'w')

  try:

    try:

      dumper = cPickle.Pickler(f, cPickle.HIGHEST_PROTOCOL)

      dumper.dump(data)

      f.flush()

      if dry_run:

        os.unlink(name)

      else:

        os.rename(name, path)

    except:

      os.unlink(name)

      raise

  finally:

    f.close()

def UpdateFromVersion2To3(cfg):

  """Updates the configuration from version 2 to 3.

  """

  if cfg['cluster']['config_version'] != 2:

    return

  # Add port pool

  if 'tcpudp_port_pool' not in cfg['cluster']:

    cfg['cluster']['tcpudp_port_pool'] = set()

  # Add bridge settings

  if 'default_bridge' not in cfg['cluster']:

    cfg['cluster']['default_bridge'] = 'xen-br0'

  for inst in cfg['instances'].values():

    for nic in inst['nics']:

      if 'bridge' not in nic:

        nic['bridge'] = None

  cfg['cluster']['config_version'] = 3

# Main program

if __name__ == "__main__":

  # Option parsing

  parser = optparse.OptionParser()

  parser.add_option('--dry-run', dest='dry_run',

                    action="store_true",

                    help="Try to do the conversion, but don't write "

                      "output file")

  parser.add_option('--verbose', dest='verbose',

                    action="store_true",

                    help="Verbose output")

  (options, args) = parser.parse_args()

  # Option checking

  if args:

    cfg_file = args[0]

  else:

    raise Error("Configuration file not specified")

  config = ReadConfig(cfg_file)

  UpdateFromVersion2To3(config)

  if options.verbose:

    import pprint

    pprint.pprint(config)

  WriteConfig(cfg_file, config, options.dry_run)