lib/cmdlib/query.py

#
#

# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 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.
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# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.


"""Logical units for queries."""

from ganeti import constants
from ganeti import errors
from ganeti import query
from ganeti.cmdlib.backup import ExportQuery
from ganeti.cmdlib.base import NoHooksLU
from ganeti.cmdlib.cluster import ClusterQuery
from ganeti.cmdlib.group import GroupQuery
from ganeti.cmdlib.instance_query import InstanceQuery
from ganeti.cmdlib.misc import ExtStorageQuery
from ganeti.cmdlib.network import NetworkQuery
from ganeti.cmdlib.node import NodeQuery
from ganeti.cmdlib.operating_system import OsQuery


#: Query type implementations
_QUERY_IMPL = {
  constants.QR_CLUSTER: ClusterQuery,
  constants.QR_INSTANCE: InstanceQuery,
  constants.QR_NODE: NodeQuery,
  constants.QR_GROUP: GroupQuery,
  constants.QR_NETWORK: NetworkQuery,
  constants.QR_OS: OsQuery,
  constants.QR_EXTSTORAGE: ExtStorageQuery,
  constants.QR_EXPORT: ExportQuery,
  }

assert set(_QUERY_IMPL.keys()) == constants.QR_VIA_OP


def _GetQueryImplementation(name):
  """Returns the implemtnation for a query type.

  @param name: Query type, must be one of L{constants.QR_VIA_OP}

  """
  try:
    return _QUERY_IMPL[name]
  except KeyError:
    raise errors.OpPrereqError("Unknown query resource '%s'" % name,
                               errors.ECODE_INVAL)


class LUQuery(NoHooksLU):
  """Query for resources/items of a certain kind.

  """
  # pylint: disable=W0142
  REQ_BGL = False

  def CheckArguments(self):
    qcls = _GetQueryImplementation(self.op.what)

    self.impl = qcls(self.op.qfilter, self.op.fields, self.op.use_locking)

  def ExpandNames(self):
    self.impl.ExpandNames(self)

  def DeclareLocks(self, level):
    self.impl.DeclareLocks(self, level)

  def Exec(self, feedback_fn):
    return self.impl.NewStyleQuery(self)


class LUQueryFields(NoHooksLU):
  """Query for resources/items of a certain kind.

  """
  # pylint: disable=W0142
  REQ_BGL = False

  def CheckArguments(self):
    self.qcls = _GetQueryImplementation(self.op.what)

  def ExpandNames(self):
    self.needed_locks = {}

  def Exec(self, feedback_fn):
    return query.QueryFields(self.qcls.FIELDS, self.op.fields)