query.py 12.6 KB
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#
#

# Copyright (C) 2010 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.


"""Module for query operations"""

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import logging
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import operator
import re

from ganeti import constants
from ganeti import errors
from ganeti import utils
from ganeti import compat
from ganeti import objects
from ganeti import ht


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(NQ_CONFIG,
 NQ_INST,
 NQ_LIVE,
 NQ_GROUP) = range(1, 5)


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FIELD_NAME_RE = re.compile(r"^[a-z0-9/._]+$")
TITLE_RE = re.compile(r"^[^\s]+$")

#: Verification function for each field type
_VERIFY_FN = {
  constants.QFT_UNKNOWN: ht.TNone,
  constants.QFT_TEXT: ht.TString,
  constants.QFT_BOOL: ht.TBool,
  constants.QFT_NUMBER: ht.TInt,
  constants.QFT_UNIT: ht.TInt,
  constants.QFT_TIMESTAMP: ht.TOr(ht.TInt, ht.TFloat),
  constants.QFT_OTHER: lambda _: True,
  }


def _GetUnknownField(ctx, item): # pylint: disable-msg=W0613
  """Gets the contents of an unknown field.

  """
  return (constants.QRFS_UNKNOWN, None)


def _GetQueryFields(fielddefs, selected):
  """Calculates the internal list of selected fields.

  Unknown fields are returned as L{constants.QFT_UNKNOWN}.

  @type fielddefs: dict
  @param fielddefs: Field definitions
  @type selected: list of strings
  @param selected: List of selected fields

  """
  result = []

  for name in selected:
    try:
      fdef = fielddefs[name]
    except KeyError:
      fdef = (_MakeField(name, name, constants.QFT_UNKNOWN),
              None, _GetUnknownField)

    assert len(fdef) == 3

    result.append(fdef)

  return result


def GetAllFields(fielddefs):
  """Extract L{objects.QueryFieldDefinition} from field definitions.

  @rtype: list of L{objects.QueryFieldDefinition}

  """
  return [fdef for (fdef, _, _) in fielddefs]


class Query:
  def __init__(self, fieldlist, selected):
    """Initializes this class.

    The field definition is a dictionary with the field's name as a key and a
    tuple containing, in order, the field definition object
    (L{objects.QueryFieldDefinition}, the data kind to help calling code
    collect data and a retrieval function. The retrieval function is called
    with two parameters, in order, the data container and the item in container
    (see L{Query.Query}).

    Users of this class can call L{RequestedData} before preparing the data
    container to determine what data is needed.

    @type fieldlist: dictionary
    @param fieldlist: Field definitions
    @type selected: list of strings
    @param selected: List of selected fields

    """
    self._fields = _GetQueryFields(fieldlist, selected)

  def RequestedData(self):
    """Gets requested kinds of data.

    @rtype: frozenset

    """
    return frozenset(datakind
                     for (_, datakind, _) in self._fields
                     if datakind is not None)

  def GetFields(self):
    """Returns the list of fields for this query.

    Includes unknown fields.

    @rtype: List of L{objects.QueryFieldDefinition}

    """
    return GetAllFields(self._fields)

  def Query(self, ctx):
    """Execute a query.

    @param ctx: Data container passed to field retrieval functions, must
      support iteration using C{__iter__}

    """
    result = [[fn(ctx, item) for (_, _, fn) in self._fields]
              for item in ctx]

    # Verify result
    if __debug__:
      for (idx, row) in enumerate(result):
        assert _VerifyResultRow(self._fields, row), \
               ("Inconsistent result for fields %s in row %s: %r" %
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                (GetAllFields(self._fields), idx, row))
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    return result

  def OldStyleQuery(self, ctx):
    """Query with "old" query result format.

    See L{Query.Query} for arguments.

    """
    unknown = set(fdef.name
                  for (fdef, _, _) in self._fields
                  if fdef.kind == constants.QFT_UNKNOWN)
    if unknown:
      raise errors.OpPrereqError("Unknown output fields selected: %s" %
                                 (utils.CommaJoin(unknown), ),
                                 errors.ECODE_INVAL)

    return [[value for (_, value) in row]
            for row in self.Query(ctx)]


def _VerifyResultRow(fields, row):
  """Verifies the contents of a query result row.

  @type fields: list
  @param fields: Field definitions for result
  @type row: list of tuples
  @param row: Row data

  """
  return (len(row) == len(fields) and
          compat.all((status == constants.QRFS_NORMAL and
                      _VERIFY_FN[fdef.kind](value)) or
                     # Value for an abnormal status must be None
                     (status != constants.QRFS_NORMAL and value is None)
                     for ((status, value), (fdef, _, _)) in zip(row, fields)))


def _PrepareFieldList(fields):
  """Prepares field list for use by L{Query}.

  Converts the list to a dictionary and does some verification.

  @type fields: list of tuples; (L{objects.QueryFieldDefinition}, data kind,
    retrieval function)
  @param fields: List of fields
  @rtype: dict
  @return: Field dictionary for L{Query}

  """
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  if __debug__:
    duplicates = utils.FindDuplicates(fdef.title.lower()
                                      for (fdef, _, _) in fields)
    assert not duplicates, "Duplicate title(s) found: %r" % duplicates
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  result = {}

  for field in fields:
    (fdef, _, fn) = field

    assert fdef.name and fdef.title, "Name and title are required"
    assert FIELD_NAME_RE.match(fdef.name)
    assert TITLE_RE.match(fdef.title)
    assert callable(fn)
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    assert fdef.name not in result, \
           "Duplicate field name '%s' found" % fdef.name
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    result[fdef.name] = field

  assert len(result) == len(fields)
  assert compat.all(name == fdef.name
                    for (name, (fdef, _, _)) in result.items())

  return result


def _MakeField(name, title, kind):
  """Wrapper for creating L{objects.QueryFieldDefinition} instances.

  @param name: Field name as a regular expression
  @param title: Human-readable title
  @param kind: Field type

  """
  return objects.QueryFieldDefinition(name=name, title=title, kind=kind)
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def _GetNodeRole(node, master_name):
  """Determine node role.

  @type node: L{objects.Node}
  @param node: Node object
  @type master_name: string
  @param master_name: Master node name

  """
  if node.name == master_name:
    return "M"
  elif node.master_candidate:
    return "C"
  elif node.drained:
    return "D"
  elif node.offline:
    return "O"
  else:
    return "R"


def _GetItemAttr(attr):
  """Returns a field function to return an attribute of the item.

  @param attr: Attribute name

  """
  getter = operator.attrgetter(attr)
  return lambda _, item: (constants.QRFS_NORMAL, getter(item))


class NodeQueryData:
  """Data container for node data queries.

  """
  def __init__(self, nodes, live_data, master_name, node_to_primary,
               node_to_secondary, groups):
    """Initializes this class.

    """
    self.nodes = nodes
    self.live_data = live_data
    self.master_name = master_name
    self.node_to_primary = node_to_primary
    self.node_to_secondary = node_to_secondary
    self.groups = groups

    # Used for individual rows
    self.curlive_data = None

  def __iter__(self):
    """Iterate over all nodes.

    This function has side-effects and only one instance of the resulting
    generator should be used at a time.

    """
    for node in self.nodes:
      if self.live_data:
        self.curlive_data = self.live_data.get(node.name, None)
      else:
        self.curlive_data = None
      yield node


#: Fields that are direct attributes of an L{objects.Node} object
_NODE_SIMPLE_FIELDS = {
  "ctime": ("CTime", constants.QFT_TIMESTAMP),
  "drained": ("Drained", constants.QFT_BOOL),
  "master_candidate": ("MasterC", constants.QFT_BOOL),
  "master_capable": ("MasterCapable", constants.QFT_BOOL),
  "mtime": ("MTime", constants.QFT_TIMESTAMP),
  "name": ("Node", constants.QFT_TEXT),
  "offline": ("Offline", constants.QFT_BOOL),
  "serial_no": ("SerialNo", constants.QFT_NUMBER),
  "uuid": ("UUID", constants.QFT_TEXT),
  "vm_capable": ("VMCapable", constants.QFT_BOOL),
  }


#: Fields requiring talking to the node
_NODE_LIVE_FIELDS = {
  "bootid": ("BootID", constants.QFT_TEXT, "bootid"),
  "cnodes": ("CNodes", constants.QFT_NUMBER, "cpu_nodes"),
  "csockets": ("CSockets", constants.QFT_NUMBER, "cpu_sockets"),
  "ctotal": ("CTotal", constants.QFT_NUMBER, "cpu_total"),
  "dfree": ("DFree", constants.QFT_UNIT, "vg_free"),
  "dtotal": ("DTotal", constants.QFT_UNIT, "vg_size"),
  "mfree": ("MFree", constants.QFT_UNIT, "memory_free"),
  "mnode": ("MNode", constants.QFT_UNIT, "memory_dom0"),
  "mtotal": ("MTotal", constants.QFT_UNIT, "memory_total"),
  }


def _GetNodeGroup(ctx, node):
  """Returns the name of a node's group.

  @type ctx: L{NodeQueryData}
  @type node: L{objects.Node}
  @param node: Node object

  """
  ng = ctx.groups.get(node.group, None)
  if ng is None:
    # Nodes always have a group, or the configuration is corrupt
    return (constants.QRFS_UNAVAIL, None)

  return (constants.QRFS_NORMAL, ng.name)


def _GetLiveNodeField(field, kind, ctx, _):
  """Gets the value of a "live" field from L{NodeQueryData}.

  @param field: Live field name
  @param kind: Data kind, one of L{constants.QFT_ALL}
  @type ctx: L{NodeQueryData}

  """
  if not ctx.curlive_data:
    return (constants.QRFS_NODATA, None)

  try:
    value = ctx.curlive_data[field]
  except KeyError:
    return (constants.QRFS_UNAVAIL, None)

  if kind == constants.QFT_TEXT:
    return (constants.QRFS_NORMAL, value)

  assert kind in (constants.QFT_NUMBER, constants.QFT_UNIT)

  # Try to convert into number
  try:
    return (constants.QRFS_NORMAL, int(value))
  except (ValueError, TypeError):
    logging.exception("Failed to convert node field '%s' (value %r) to int",
                      value, field)
    return (constants.QRFS_UNAVAIL, None)


def _BuildNodeFields():
  """Builds list of fields for node queries.

  """
  fields = [
    (_MakeField("pip", "PrimaryIP", constants.QFT_TEXT), NQ_CONFIG,
     lambda ctx, node: (constants.QRFS_NORMAL, node.primary_ip)),
    (_MakeField("sip", "SecondaryIP", constants.QFT_TEXT), NQ_CONFIG,
     lambda ctx, node: (constants.QRFS_NORMAL, node.secondary_ip)),
    (_MakeField("tags", "Tags", constants.QFT_OTHER), NQ_CONFIG,
     lambda ctx, node: (constants.QRFS_NORMAL, list(node.GetTags()))),
    (_MakeField("master", "IsMaster", constants.QFT_BOOL), NQ_CONFIG,
     lambda ctx, node: (constants.QRFS_NORMAL, node.name == ctx.master_name)),
    (_MakeField("role", "Role", constants.QFT_TEXT), NQ_CONFIG,
     lambda ctx, node: (constants.QRFS_NORMAL,
                        _GetNodeRole(node, ctx.master_name))),
    (_MakeField("group", "Group", constants.QFT_TEXT), NQ_GROUP, _GetNodeGroup),
    (_MakeField("group.uuid", "GroupUUID", constants.QFT_TEXT),
     NQ_CONFIG, lambda ctx, node: (constants.QRFS_NORMAL, node.group)),
    ]

  def _GetLength(getter):
    return lambda ctx, node: (constants.QRFS_NORMAL,
                              len(getter(ctx)[node.name]))

  def _GetList(getter):
    return lambda ctx, node: (constants.QRFS_NORMAL,
                              list(getter(ctx)[node.name]))

  # Add fields operating on instance lists
  for prefix, titleprefix, getter in \
      [("p", "Pri", operator.attrgetter("node_to_primary")),
       ("s", "Sec", operator.attrgetter("node_to_secondary"))]:
    fields.extend([
      (_MakeField("%sinst_cnt" % prefix, "%sinst" % prefix.upper(),
                  constants.QFT_NUMBER),
       NQ_INST, _GetLength(getter)),
      (_MakeField("%sinst_list" % prefix, "%sInstances" % titleprefix,
                  constants.QFT_OTHER),
       NQ_INST, _GetList(getter)),
      ])

  # Add simple fields
  fields.extend([(_MakeField(name, title, kind), NQ_CONFIG, _GetItemAttr(name))
                 for (name, (title, kind)) in _NODE_SIMPLE_FIELDS.items()])

  # Add fields requiring live data
  fields.extend([
    (_MakeField(name, title, kind), NQ_LIVE,
     compat.partial(_GetLiveNodeField, nfield, kind))
    for (name, (title, kind, nfield)) in _NODE_LIVE_FIELDS.items()
    ])

  return _PrepareFieldList(fields)


#: Fields available for node queries
NODE_FIELDS = _BuildNodeFields()