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# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Google Inc.

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

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

# (at your option) any later version.

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# 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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# 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.

"""OpCodes base module

This module implements part of the data structures which define the

cluster operations - the so-called opcodes.

Every operation which modifies the cluster state is expressed via

opcodes.

"""

# this are practically structures, so disable the message about too

# few public methods:

# pylint: disable=R0903

import copy

import logging

import re

from ganeti import constants

from ganeti import errors

from ganeti import ht

from ganeti import outils

#: OP_ID conversion regular expression

_OPID_RE = re.compile("([a-z])([A-Z])")

SUMMARY_PREFIX = {

  "CLUSTER_": "C_",

  "GROUP_": "G_",

  "NODE_": "N_",

  "INSTANCE_": "I_",

  }

#: Attribute name for dependencies

DEPEND_ATTR = "depends"

#: Attribute name for comment

COMMENT_ATTR = "comment"

def _NameComponents(name):

  """Split an opcode class name into its components

  @type name: string

  @param name: the class name, as OpXxxYyy

  @rtype: array of strings

  @return: the components of the name

  """

  assert name.startswith("Op")

  # Note: (?<=[a-z])(?=[A-Z]) would be ideal, since it wouldn't

  # consume any input, and hence we would just have all the elements

  # in the list, one by one; but it seems that split doesn't work on

  # non-consuming input, hence we have to process the input string a

  # bit

  name = _OPID_RE.sub(r"\1,\2", name)

  elems = name.split(",")

  return elems

def _NameToId(name):

  """Convert an opcode class name to an OP_ID.

  @type name: string

  @param name: the class name, as OpXxxYyy

  @rtype: string

  @return: the name in the OP_XXXX_YYYY format

  """

  if not name.startswith("Op"):

    return None

  return "_".join(n.upper() for n in _NameComponents(name))

def NameToReasonSrc(name):

  """Convert an opcode class name to a source string for the reason trail

  @type name: string

  @param name: the class name, as OpXxxYyy

  @rtype: string

  @return: the name in the OP_XXXX_YYYY format

  """

  if not name.startswith("Op"):

    return None

  return "%s:%s" % (constants.OPCODE_REASON_SRC_OPCODE,

                    "_".join(n.lower() for n in _NameComponents(name)))

class _AutoOpParamSlots(outils.AutoSlots):

  """Meta class for opcode definitions.

  """

  def __new__(mcs, name, bases, attrs):

    """Called when a class should be created.

    @param mcs: The meta class

    @param name: Name of created class

    @param bases: Base classes

    @type attrs: dict

    @param attrs: Class attributes

    """

    assert "OP_ID" not in attrs, "Class '%s' defining OP_ID" % name

    slots = mcs._GetSlots(attrs)

    assert "OP_DSC_FIELD" not in attrs or attrs["OP_DSC_FIELD"] in slots, \

      "Class '%s' uses unknown field in OP_DSC_FIELD" % name

    assert ("OP_DSC_FORMATTER" not in attrs or

            callable(attrs["OP_DSC_FORMATTER"])), \

      ("Class '%s' uses non-callable in OP_DSC_FORMATTER (%s)" %

       (name, type(attrs["OP_DSC_FORMATTER"])))

    attrs["OP_ID"] = _NameToId(name)

    return outils.AutoSlots.__new__(mcs, name, bases, attrs)

  @classmethod

  def _GetSlots(mcs, attrs):

    """Build the slots out of OP_PARAMS.

    """

    # Always set OP_PARAMS to avoid duplicates in BaseOpCode.GetAllParams

    params = attrs.setdefault("OP_PARAMS", [])

    # Use parameter names as slots

    return [pname for (pname, _, _, _) in params]

class BaseOpCode(outils.ValidatedSlots):

  """A simple serializable object.

  This object serves as a parent class for OpCode without any custom

  field handling.

  """

  # pylint: disable=E1101

  # as OP_ID is dynamically defined

  __metaclass__ = _AutoOpParamSlots

  def __getstate__(self):

    """Generic serializer.

    This method just returns the contents of the instance as a

    dictionary.

    @rtype:  C{dict}

    @return: the instance attributes and their values

    """

    state = {}

    for name in self.GetAllSlots():

      if hasattr(self, name):

        state[name] = getattr(self, name)

    return state

  def __setstate__(self, state):

    """Generic unserializer.

    This method just restores from the serialized state the attributes

    of the current instance.

    @param state: the serialized opcode data

    @type state:  C{dict}

    """

    if not isinstance(state, dict):

      raise ValueError("Invalid data to __setstate__: expected dict, got %s" %

                       type(state))

    for name in self.GetAllSlots():

      if name not in state and hasattr(self, name):

        delattr(self, name)

    for name in state:

      setattr(self, name, state[name])

  @classmethod

  def GetAllParams(cls):

    """Compute list of all parameters for an opcode.

    """

    slots = []

    for parent in cls.__mro__:

      slots.extend(getattr(parent, "OP_PARAMS", []))

    return slots

  def Validate(self, set_defaults): # pylint: disable=W0221

    """Validate opcode parameters, optionally setting default values.

    @type set_defaults: bool

    @param set_defaults: Whether to set default values

    @raise errors.OpPrereqError: When a parameter value doesn't match

                                 requirements

    """

    for (attr_name, default, test, _) in self.GetAllParams():

      assert callable(test)

      if hasattr(self, attr_name):

        attr_val = getattr(self, attr_name)

      else:

        attr_val = copy.deepcopy(default)

      if test(attr_val):

        if set_defaults:

          setattr(self, attr_name, attr_val)

      elif ht.TInt(attr_val) and test(float(attr_val)):

        if set_defaults:

          setattr(self, attr_name, float(attr_val))

      else:

        logging.error("OpCode %s, parameter %s, has invalid type %s/value"

                      " '%s' expecting type %s",

                      self.OP_ID, attr_name, type(attr_val), attr_val, test)

        if attr_val is None:

          logging.error("OpCode %s, parameter %s, has default value None which"

                        " is does not check against the parameter's type: this"

                        " means this parameter is required but no value was"

                        " given",

                        self.OP_ID, attr_name)

        raise errors.OpPrereqError("Parameter '%s.%s' fails validation" %

                                   (self.OP_ID, attr_name),

                                   errors.ECODE_INVAL)

def BuildJobDepCheck(relative):

  """Builds check for job dependencies (L{DEPEND_ATTR}).

  @type relative: bool

  @param relative: Whether to accept relative job IDs (negative)

  @rtype: callable

  """

  if relative:

    job_id = ht.TOr(ht.TJobId, ht.TRelativeJobId)

  else:

    job_id = ht.TJobId

  job_dep = \

    ht.TAnd(ht.TOr(ht.TListOf(ht.TAny), ht.TTuple),

            ht.TIsLength(2),

            ht.TItems([job_id,

                       ht.TListOf(ht.TElemOf(constants.JOBS_FINALIZED))]))

  return ht.TMaybe(ht.TListOf(job_dep))

TNoRelativeJobDependencies = BuildJobDepCheck(False)

def RequireSharedFileStorage():

  """Checks that shared file storage is enabled.

  While it doesn't really fit into this module, L{utils} was deemed too large

  of a dependency to be imported for just one or two functions.

  @raise errors.OpPrereqError: when shared file storage is disabled

  """

  if not constants.ENABLE_SHARED_FILE_STORAGE:

    raise errors.OpPrereqError("Shared file storage disabled at"

                               " configure time", errors.ECODE_INVAL)