Synnefo » snf-ganeti

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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

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# 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"

#: QA configuration (L{_QaConfig})

_config = None

class _QaInstance(object):

  __slots__ = [

    "name",

    "nicmac",

    "_used",

    "_disk_template",

    ]

  def __init__(self, name, nicmac):

    """Initializes instances of this class.

    """

    self.name = name

    self.nicmac = nicmac

    self._used = None

    self._disk_template = None

  @classmethod

  def FromDict(cls, data):

    """Creates instance object from JSON dictionary.

    """

    nicmac = []

    macaddr = data.get("nic.mac/0")

    if macaddr:

      nicmac.append(macaddr)

    return cls(name=data["name"], nicmac=nicmac)

  def Use(self):

    """Marks instance as being in use.

    """

    assert not self._used

    assert self._disk_template is None

    self._used = True

  def Release(self):

    """Releases instance and makes it available again.

    """

    assert self._used, \

      ("Instance '%s' was never acquired or released more than once" %

       self.name)

    self._used = False

    self._disk_template = None

  def GetNicMacAddr(self, idx, default):

    """Returns MAC address for NIC.

    @type idx: int

    @param idx: NIC index

    @param default: Default value

    """

    if len(self.nicmac) > idx:

      return self.nicmac[idx]

    else:

      return default

  def SetDiskTemplate(self, template):

    """Set the disk template.

    """

    assert template in constants.DISK_TEMPLATES

    self._disk_template = template

  @property

  def used(self):

    """Returns boolean denoting whether instance is in use.

    """

    return self._used

  @property

  def disk_template(self):

    """Returns the current disk template.

    """

    return self._disk_template

class _QaNode(object):

  __slots__ = [

    "primary",

    "secondary",

    "_added",

    "_use_count",

    ]

  def __init__(self, primary, secondary):

    """Initializes instances of this class.

    """

    self.primary = primary

    self.secondary = secondary

    self._added = False

    self._use_count = 0

  @classmethod

  def FromDict(cls, data):

    """Creates node object from JSON dictionary.

    """

    return cls(primary=data["primary"], secondary=data.get("secondary"))

  def Use(self):

    """Marks a node as being in use.

    """

    assert self._use_count >= 0

    self._use_count += 1

    return self

  def Release(self):

    """Release a node (opposite of L{Use}).

    """

    assert self.use_count > 0

    self._use_count -= 1

  def MarkAdded(self):

    """Marks node as having been added to a cluster.

    """

    assert not self._added

    self._added = True

  def MarkRemoved(self):

    """Marks node as having been removed from a cluster.

    """

    assert self._added

    self._added = False

  @property

  def added(self):

    """Returns whether a node is part of a cluster.

    """

    return self._added

  @property

  def use_count(self):

    """Returns number of current uses (controlled by L{Use} and L{Release}).

    """

    return self._use_count

_RESOURCE_CONVERTER = {

  "instances": _QaInstance.FromDict,

  "nodes": _QaNode.FromDict,

  }

def _ConvertResources((key, value)):

  """Converts cluster resources in configuration to Python objects.

  """

  fn = _RESOURCE_CONVERTER.get(key, None)

  if fn:

    return (key, map(fn, value))

  else:

    return (key, value)

class _QaConfig(object):

  def __init__(self, data):

    """Initializes instances of this class.

    """

    self._data = data

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

    self._exclusive_storage = None

  @classmethod

  def Load(cls, filename):

    """Loads a configuration file and produces a configuration object.

    @type filename: string

    @param filename: Path to configuration file

    @rtype: L{_QaConfig}

    """

    data = serializer.LoadJson(utils.ReadFile(filename))

    result = cls(dict(map(_ConvertResources,

                          data.items()))) # pylint: disable=E1103

    result.Validate()

    return result

  def Validate(self):

    """Validates loaded configuration data.

    """

    if not self.get("name"):

      raise qa_error.Error("Cluster name is required")

    if not self.get("nodes"):

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

    if not self.get("instances"):

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

    if (self.get("disk") is None or

        self.get("disk-growth") is None or

        len(self.get("disk")) != len(self.get("disk-growth"))):

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

                           " and have the same number of items")

    check = self.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(self.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 __getitem__(self, name):

    """Returns configuration value.

    @type name: string

    @param name: Name of configuration entry

    """

    return self._data[name]

  def get(self, name, default=None):

    """Returns configuration value.

    @type name: string

    @param name: Name of configuration entry

    @param default: Default value

    """

    return self._data.get(name, default)

  def GetMasterNode(self):

    """Returns the default master node for the cluster.

    """

    return self["nodes"][0]

  def GetInstanceCheckScript(self):

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

    """

    return self._data.get(_INSTANCE_CHECK_KEY, None)

  def GetEnabledHypervisors(self):

    """Returns list of enabled hypervisors.

    @rtype: list

    """

    try:

      value = self._data[_ENABLED_HV_KEY]

    except KeyError:

      return [constants.DEFAULT_ENABLED_HYPERVISOR]

    else:

      if value is None:

        return []

      elif 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(self):

    """Returns the default hypervisor to be used.

    """

    return self.GetEnabledHypervisors()[0]

  def SetExclusiveStorage(self, value):

    """Set the expected value of the C{exclusive_storage} flag for the cluster.

    """

    self._exclusive_storage = bool(value)

  def GetExclusiveStorage(self):

    """Get the expected value of the C{exclusive_storage} flag for the cluster.

    """

    value = self._exclusive_storage

    assert value is not None

    return value

  def IsTemplateSupported(self, templ):

    """Is the given disk template supported by the current configuration?

    """

    return (not self.GetExclusiveStorage() or

            templ in constants.DTS_EXCL_STORAGE)

def Load(path):

  """Loads the passed configuration file.

  """

  global _config # pylint: disable=W0603

  _config = _QaConfig.Load(path)

def GetConfig():

  """Returns the configuration object.

  """

  if _config is None:

    raise RuntimeError("Configuration not yet loaded")

  return _config

def get(name, default=None):

  """Wrapper for L{_QaConfig.get}.

  """

  return GetConfig().get(name, default=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 = GetConfig()

  else:

    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(*args):

  """Wrapper for L{_QaConfig.GetInstanceCheckScript}.

  """

  return GetConfig().GetInstanceCheckScript(*args)

def GetEnabledHypervisors(*args):

  """Wrapper for L{_QaConfig.GetEnabledHypervisors}.

  """

  return GetConfig().GetEnabledHypervisors(*args)

def GetDefaultHypervisor(*args):

  """Wrapper for L{_QaConfig.GetDefaultHypervisor}.

  """

  return GetConfig().GetDefaultHypervisor(*args)

def GetMasterNode():

  """Wrapper for L{_QaConfig.GetMasterNode}.

  """

  return GetConfig().GetMasterNode()

def AcquireInstance(_cfg=None):

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

  """

  if _cfg is None:

    cfg = GetConfig()

  else:

    cfg = _cfg

  # Filter out unwanted instances

  instances = filter(lambda inst: not inst.used, cfg["instances"])

  if not instances:

    raise qa_error.OutOfInstancesError("No instances left")

  instance = instances[0]

  instance.Use()

  return instance

def SetExclusiveStorage(value):

  """Wrapper for L{_QaConfig.SetExclusiveStorage}.

  """

  return GetConfig().SetExclusiveStorage(value)

def GetExclusiveStorage():

  """Wrapper for L{_QaConfig.GetExclusiveStorage}.

  """

  return GetConfig().GetExclusiveStorage()

def IsTemplateSupported(templ):

  """Wrapper for L{_QaConfig.GetExclusiveStorage}.

  """

  return GetConfig().IsTemplateSupported(templ)

def AcquireNode(exclude=None, _cfg=None):

  """Returns the least used node.

  """

  if _cfg is None:

    cfg = GetConfig()

  else:

    cfg = _cfg

  master = cfg.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"])

  nodes = filter(lambda node: node.added or node == master, nodes)

  if not nodes:

    raise qa_error.OutOfNodesError("No nodes left")

  # Get node with least number of uses

  # TODO: Switch to computing sort key instead of comparing directly

  def compare(a, b):

    result = cmp(a.use_count, b.use_count)

    if result == 0:

      result = cmp(a.primary, b.primary)

    return result

  nodes.sort(cmp=compare)

  return nodes[0].Use()

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 ReleaseManyNodes(nodes):

  for node in nodes:

    node.Release()