Synnefo » snf-ganeti » ganeti-local

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# Copyright (C) 2010 Google Inc.

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"""User-id pool related functions.

The user-id pool is cluster-wide configuration option.

It is stored as a list of user-id ranges.

This module contains functions used for manipulating the

user-id pool parameter and for requesting/returning user-ids

from the pool.

"""

from ganeti import errors

from ganeti import constants

from ganeti import utils

def ParseUidPool(value, separator=None):

  """Parse a user-id pool definition.

  @param value: string representation of the user-id pool.

                The accepted input format is a list of integer ranges.

                The boundaries are inclusive.

                Example: '1000-5000,8000,9000-9010'.

  @param separator: the separator character between the uids/uid-ranges.

                    Defaults to a comma.

  @return: a list of integer pairs (lower, higher range boundaries)

  """

  if separator is None:

    separator = ","

  ranges = []

  for range_def in value.split(separator):

    if not range_def:

      # Skip empty strings

      continue

    boundaries = range_def.split("-")

    n_elements = len(boundaries)

    if n_elements > 2:

      raise errors.OpPrereqError(

          "Invalid user-id range definition. Only one hyphen allowed: %s"

          % boundaries)

    try:

      lower = int(boundaries[0])

    except (ValueError, TypeError), err:

      raise errors.OpPrereqError("Invalid user-id value for lower boundary of"

                                 " user-id range: %s"

                                 % str(err), errors.ECODE_INVAL)

    try:

      higher = int(boundaries[n_elements - 1])

    except (ValueError, TypeError), err:

      raise errors.OpPrereqError("Invalid user-id value for higher boundary of"

                                 " user-id range: %s"

                                 % str(err), errors.ECODE_INVAL)

    ranges.append((lower, higher))

  ranges.sort()

  return ranges

def AddToUidPool(uid_pool, add_uids):

  """Add a list of user-ids/user-id ranges to a user-id pool.

  @param uid_pool: a user-id pool (list of integer tuples)

  @param add_uids: user-id ranges to be added to the pool

                   (list of integer tuples)

  """

  for uid_range in add_uids:

    if uid_range not in uid_pool:

      uid_pool.append(uid_range)

  uid_pool.sort()

def RemoveFromUidPool(uid_pool, remove_uids):

  """Remove a list of user-ids/user-id ranges from a user-id pool.

  @param uid_pool: a user-id pool (list of integer tuples)

  @param remove_uids: user-id ranges to be removed from the pool

                      (list of integer tuples)

  """

  for uid_range in remove_uids:

    if uid_range not in uid_pool:

      raise errors.OpPrereqError(

          "User-id range to be removed is not found in the current"

          " user-id pool: %s" % uid_range, errors.ECODE_INVAL)

    uid_pool.remove(uid_range)

def _FormatUidRange(lower, higher):

  """Convert a user-id range definition into a string.

  """

  if lower == higher:

    return str(lower)

  return "%s-%s" % (lower, higher)

def FormatUidPool(uid_pool, separator=None):

  """Convert the internal representation of the user-id pool into a string.

  The output format is also accepted by ParseUidPool()

  @param uid_pool: a list of integer pairs representing UID ranges

  @param separator: the separator character between the uids/uid-ranges.

                    Defaults to ", ".

  @return: a string with the formatted results

  """

  if separator is None:

    separator = ", "

  return separator.join([_FormatUidRange(lower, higher)

                         for lower, higher in uid_pool])

def CheckUidPool(uid_pool):

  """Sanity check user-id pool range definition values.

  @param uid_pool: a list of integer pairs (lower, higher range boundaries)

  """

  for lower, higher in uid_pool:

    if lower > higher:

      raise errors.OpPrereqError(

          "Lower user-id range boundary value (%s)"

          " is larger than higher boundary value (%s)" %

          (lower, higher), errors.ECODE_INVAL)

    if lower < constants.UIDPOOL_UID_MIN:

      raise errors.OpPrereqError(

          "Lower user-id range boundary value (%s)"

          " is smaller than UIDPOOL_UID_MIN (%s)." %

          (lower, constants.UIDPOOL_UID_MIN),

          errors.ECODE_INVAL)

    if higher > constants.UIDPOOL_UID_MAX:

      raise errors.OpPrereqError(

          "Higher user-id boundary value (%s)"

          " is larger than UIDPOOL_UID_MAX (%s)." %

          (higher, constants.UIDPOOL_UID_MAX),

          errors.ECODE_INVAL)

def ExpandUidPool(uid_pool):

  """Expands a uid-pool definition to a list of uids.

  @param uid_pool: a list of integer pairs (lower, higher range boundaries)

  @return: a list of integers

  """

  uids = set()

  for lower, higher in uid_pool:

    uids.update(range(lower, higher + 1))

  return list(uids)