Add lib/uidpool.py module

Signed-off-by: Balazs Lecz <leczb@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

lib/constants.py

@@ -839,3 +839,7 @@ CONFD_CLIENT_EXPIRE_TIMEOUT = 10
 #   (assuming we can't use jumbo frames)
 # We just set this to 60K, which should be enough
 MAX_UDP_DATA_SIZE = 61440
+
+# User-id pool minimum/maximum acceptable user-ids.
+UIDPOOL_UID_MIN = 0
+UIDPOOL_UID_MAX = 2**32-1 # Assuming 32 bit user-ids

lib/uidpool.py

+#
+#
+
+# 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.
+
+
+"""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
+
+
+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 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)