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#

# Copyright (C) 2007, 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

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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.

"""QA configuration.

"""

import os

from ganeti import constants

from ganeti import utils

from ganeti import serializer

from ganeti import compat

import qa_error

_INSTANCE_CHECK_KEY = "instance-check"

_ENABLED_HV_KEY = "enabled-hypervisors"

#: Cluster-wide run-time value of the exclusive storage flag

_exclusive_storage = None

cfg = {}

def Load(path):

  """Loads the passed configuration file.

  """

  global cfg # pylint: disable=W0603

  cfg = serializer.LoadJson(utils.ReadFile(path))

  Validate()

def Validate():

  if len(cfg["nodes"]) < 1:

    raise qa_error.Error("Need at least one node")

  if len(cfg["instances"]) < 1:

    raise qa_error.Error("Need at least one instance")

  if len(cfg["disk"]) != len(cfg["disk-growth"]):

    raise qa_error.Error("Config options 'disk' and 'disk-growth' must have"

                         " the same number of items")

  check = GetInstanceCheckScript()

  if check:

    try:

      os.stat(check)

    except EnvironmentError, err:

      raise qa_error.Error("Can't find instance check script '%s': %s" %

                           (check, err))

  enabled_hv = frozenset(GetEnabledHypervisors())

  if not enabled_hv:

    raise qa_error.Error("No hypervisor is enabled")

  difference = enabled_hv - constants.HYPER_TYPES

  if difference:

    raise qa_error.Error("Unknown hypervisor(s) enabled: %s" %

                         utils.CommaJoin(difference))

def get(name, default=None):

  return cfg.get(name, default)

class Either:

  def __init__(self, tests):

    """Initializes this class.

    @type tests: list or string

    @param tests: List of test names

    @see: L{TestEnabled} for details

    """

    self.tests = tests

def _MakeSequence(value):

  """Make sequence of single argument.

  If the single argument is not already a list or tuple, a list with the

  argument as a single item is returned.

  """

  if isinstance(value, (list, tuple)):

    return value

  else:

    return [value]

def _TestEnabledInner(check_fn, names, fn):

  """Evaluate test conditions.

  @type check_fn: callable

  @param check_fn: Callback to check whether a test is enabled

  @type names: sequence or string

  @param names: Test name(s)

  @type fn: callable

  @param fn: Aggregation function

  @rtype: bool

  @return: Whether test is enabled

  """

  names = _MakeSequence(names)

  result = []

  for name in names:

    if isinstance(name, Either):

      value = _TestEnabledInner(check_fn, name.tests, compat.any)

    elif isinstance(name, (list, tuple)):

      value = _TestEnabledInner(check_fn, name, compat.all)

    else:

      value = check_fn(name)

    result.append(value)

  return fn(result)

def TestEnabled(tests, _cfg=None):

  """Returns True if the given tests are enabled.

  @param tests: A single test as a string, or a list of tests to check; can

    contain L{Either} for OR conditions, AND is default

  """

  if _cfg is None:

    _cfg = cfg

  # Get settings for all tests

  cfg_tests = _cfg.get("tests", {})

  # Get default setting

  default = cfg_tests.get("default", True)

  return _TestEnabledInner(lambda name: cfg_tests.get(name, default),

                           tests, compat.all)

def GetInstanceCheckScript():

  """Returns path to instance check script or C{None}.

  """

  return cfg.get(_INSTANCE_CHECK_KEY, None)

def GetEnabledHypervisors():

  """Returns list of enabled hypervisors.

  @rtype: list

  """

  try:

    value = cfg[_ENABLED_HV_KEY]

  except KeyError:

    return [constants.DEFAULT_ENABLED_HYPERVISOR]

  else:

    if isinstance(value, basestring):

      # The configuration key ("enabled-hypervisors") implies there can be

      # multiple values. Multiple hypervisors are comma-separated on the

      # command line option to "gnt-cluster init", so we need to handle them

      # equally here.

      return value.split(",")

    else:

      return value

def GetDefaultHypervisor():

  """Returns the default hypervisor to be used.

  """

  return GetEnabledHypervisors()[0]

def GetInstanceNicMac(inst, default=None):

  """Returns MAC address for instance's network interface.

  """

  return inst.get("nic.mac/0", default)

def GetMasterNode():

  return cfg["nodes"][0]

def AcquireInstance():

  """Returns an instance which isn't in use.

  """

  # Filter out unwanted instances

  tmp_flt = lambda inst: not inst.get("_used", False)

  instances = filter(tmp_flt, cfg["instances"])

  del tmp_flt

  if len(instances) == 0:

    raise qa_error.OutOfInstancesError("No instances left")

  inst = instances[0]

  inst["_used"] = True

  inst["_template"] = None

  return inst

def ReleaseInstance(inst):

  inst["_used"] = False

def GetInstanceTemplate(inst):

  """Return the disk template of an instance.

  """

  templ = inst["_template"]

  assert templ is not None

  return templ

def SetInstanceTemplate(inst, template):

  """Set the disk template for an instance.

  """

  inst["_template"] = template

def SetExclusiveStorage(value):

  """Set the expected value of the exclusive_storage flag for the cluster.

  """

  global _exclusive_storage # pylint: disable=W0603

  _exclusive_storage = bool(value)

def GetExclusiveStorage():

  """Get the expected value of the exclusive_storage flag for the cluster.

  """

  val = _exclusive_storage

  assert val is not None

  return val

def IsTemplateSupported(templ):

  """Is the given templated supported by the current configuration?

  """

  if GetExclusiveStorage():

    return templ in constants.DTS_EXCL_STORAGE

  else:

    return True

def AcquireNode(exclude=None):

  """Returns the least used node.

  """

  master = GetMasterNode()

  # Filter out unwanted nodes

  # TODO: Maybe combine filters

  if exclude is None:

    nodes = cfg["nodes"][:]

  elif isinstance(exclude, (list, tuple)):

    nodes = filter(lambda node: node not in exclude, cfg["nodes"])

  else:

    nodes = filter(lambda node: node != exclude, cfg["nodes"])

  tmp_flt = lambda node: node.get("_added", False) or node == master

  nodes = filter(tmp_flt, nodes)

  del tmp_flt

  if len(nodes) == 0:

    raise qa_error.OutOfNodesError("No nodes left")

  # Get node with least number of uses

  def compare(a, b):

    result = cmp(a.get("_count", 0), b.get("_count", 0))

    if result == 0:

      result = cmp(a["primary"], b["primary"])

    return result

  nodes.sort(cmp=compare)

  node = nodes[0]

  node["_count"] = node.get("_count", 0) + 1

  return node

def AcquireManyNodes(num, exclude=None):

  """Return the least used nodes.

  @type num: int

  @param num: Number of nodes; can be 0.

  @type exclude: list of nodes or C{None}

  @param exclude: nodes to be excluded from the choice

  @rtype: list of nodes

  @return: C{num} different nodes

  """

  nodes = []

  if exclude is None:

    exclude = []

  elif isinstance(exclude, (list, tuple)):

    # Don't modify the incoming argument

    exclude = list(exclude)

  else:

    exclude = [exclude]

  try:

    for _ in range(0, num):

      n = AcquireNode(exclude=exclude)

      nodes.append(n)

      exclude.append(n)

  except qa_error.OutOfNodesError:

    ReleaseManyNodes(nodes)

    raise

  return nodes

def ReleaseNode(node):

  node["_count"] = node.get("_count", 0) - 1

def ReleaseManyNodes(nodes):

  for n in nodes:

    ReleaseNode(n)