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authorJonathan Holloway <jholloway@redhat.com>2018-01-23 02:02:38 +0100
committerNigel Babu <nigelb@redhat.com>2018-02-26 10:42:31 +0000
commitab7a71cc4b2862d267c3e6fae67c711e51abca77 (patch)
tree42060d76949e5c8bb4736c2ecdf1ecf68eed6df5 /glustolibs-gluster/glustolibs/gluster/layout.py
parent1374783418db58f6f4fe153d83082549bf2d000f (diff)
initial dht libs
* glusterfile.py - helper for gluster client and backend files. * glusterdir.py - helper for gluster client and backend dirs. * brickdir.py - helper for collection and hashing of brickdirs (from pathinfo data). * layout.py - base class for simple DHT layout validation. * dht_test_util.py - utility module to walk a directory tree and run tests against files. * constants.py - definitions for constants used in DHT libraries. * exceptions.py - definitions for exceptions raised in DHT libraries. Change-Id: I44770a822e0ec79561b3aa048e555320f622116a Signed-off-by: Jonathan Holloway <jholloway@redhat.com>
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diff --git a/glustolibs-gluster/glustolibs/gluster/layout.py b/glustolibs-gluster/glustolibs/gluster/layout.py
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+#!/usr/bin/env python
+# Copyright (C) 2018 Red Hat, Inc. <http://www.redhat.com>
+#
+# 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
+# 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 library DHT layout class and related functions"""
+
+from glusto.core import Glusto as g
+from glustolibs.gluster.brickdir import BrickDir
+
+
+class Layout(object):
+ """Default layout class for equal-sized bricks.
+ Other layouts should inherit from this class
+ and override/add where needed.
+ """
+ def _get_layout(self):
+ """Discover brickdir data and cache in instance for further use"""
+ self._brickdirs = []
+ for brickdir_path in self._pathinfo['brickdir_paths']:
+ brickdir = BrickDir(brickdir_path)
+ g.log.debug("%s: %s" % (brickdir.path, brickdir.hashrange))
+ self._brickdirs.append(brickdir)
+
+ def __init__(self, pathinfo):
+ """Init the layout class
+
+ Args:
+ pathinfo (dict): pathinfo collected from client directory
+ """
+ self._pathinfo = pathinfo
+ self._get_layout()
+ self._zero_hashrange_brickdirs = None
+ self._brickdirs = None
+
+ @property
+ def brickdirs(self):
+ """list: a list of brickdirs associated with this layout"""
+ if self._brickdirs is None:
+ self._get_layout()
+
+ return self._brickdirs
+
+ @property
+ def is_complete(self):
+ """Layout starts at zero,
+ ends at 32-bits high,
+ and has no holes or overlaps
+ """
+ joined_hashranges = []
+ for brickdir in self.brickdirs:
+ # join all of the hashranges into a single list
+ joined_hashranges += brickdir.hashrange
+ g.log.debug("joined range list: %s" % joined_hashranges)
+ # remove duplicate hashes
+ collapsed_ranges = list(set(joined_hashranges))
+ # sort the range list for good measure
+ collapsed_ranges.sort()
+
+ # first hash in the list is 0?
+ if collapsed_ranges[0] != 0:
+ g.log.error('First hash in range (%d) is not zero' %
+ collapsed_ranges[0])
+ return False
+
+ # last hash in the list is 32-bits high?
+ if collapsed_ranges[-1] != int(0xffffffff):
+ g.log.error('Last hash in ranges (%s) is not 0xffffffff' %
+ hex(collapsed_ranges[-1]))
+ return False
+
+ # remove the first and last hashes
+ clipped_ranges = collapsed_ranges[1:-1]
+ g.log.debug('clipped: %s' % clipped_ranges)
+
+ # walk through the list in pairs and look for diff == 1
+ iter_ranges = iter(clipped_ranges)
+ for first in iter_ranges:
+ second = next(iter_ranges)
+ hash_difference = second - first
+ g.log.debug('%d - %d = %d' % (second, first, hash_difference))
+ if hash_difference > 1:
+ g.log.error("Layout has holes")
+
+ return False
+ elif hash_difference < 1:
+ g.log.error("Layout has overlaps")
+
+ return False
+
+ return True
+
+ @property
+ def has_zero_hashranges(self):
+ """Check brickdirs for zero hashrange"""
+ # TODO: change this to use self.zero_hashrange_brickdirs and set bool
+ low_and_high_zero = False
+ for brickdir in self._brickdirs:
+ if brickdir.has_zero_hashrange:
+ low_and_high_zero = True
+
+ return low_and_high_zero
+
+ @property
+ def zero_hashrange_brickdirs(self):
+ """list: the list of zero_hashrange_brickdirs"""
+ if self._zero_hashrange_brickdirs is None:
+ zero_hashrange_brickdirs = []
+ for brickdir in self._brickdirs:
+ if brickdir.has_zero_hashrange():
+ zero_hashrange_brickdirs.append(brickdir)
+ self._zero_hashrange_brickdirs = zero_hashrange_brickdirs
+
+ return self._zero_hashrange_brickdirs
+
+ @property
+ def is_balanced(self):
+ """Checks for balanced distribution in equal-sized bricks"""
+ baseline_size = None
+ for brickdir in self._brickdirs:
+ hashrange_low = brickdir.hashrange_low
+ hashrange_high = brickdir.hashrange_high
+
+ if baseline_size is None:
+ baseline_size = int(hashrange_high) - int(hashrange_low)
+ g.log.debug('Baseline size: %d' % baseline_size)
+ continue
+ else:
+ size = int(hashrange_high) - int(hashrange_low)
+ g.log.debug('Hashrange size: %d' % size)
+
+ # if any of the range diffs differ, exit immediately False
+ if int(size) != int(baseline_size):
+ g.log.error('Brick distribution is not balanced.')
+ return False
+
+ return True