1 files changed, 149 insertions, 0 deletions
diff --git a/glustolibs-gluster/glustolibs/gluster/layout.py b/glustolibs-gluster/glustolibs/gluster/layout.py
new file mode 100644
index 000000000..c1ddb40f8
--- /dev/null
+++ b/glustolibs-gluster/glustolibs/gluster/layout.py
@@ -0,0 +1,149 @@
+#!/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