Merge pull request datastax#944 from damien-instaclustr/token-fix

Token range ownership

Author: mambocab

CHANGELOG.rst

@@ -1,5 +1,12 @@
+3.15.0
+======
+Bug Fixes
+---------
+* Tokenmap.get_replicas returns the wrong value if token coincides with the end of the range (PYTHON-978)
+
 3.14.0
 ======
+April 17, 2018
 
 Features
 --------

cassandra/metadata.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 from binascii import unhexlify
-from bisect import bisect_right
+from bisect import bisect_left
 from collections import defaultdict, Mapping
 from functools import total_ordering
 from hashlib import md5
@@ -1486,10 +1486,9 @@ def get_replicas(self, keyspace, token):
             tokens_to_hosts = self.tokens_to_hosts_by_ks.get(keyspace, None)
 
         if tokens_to_hosts:
-            # token range ownership is exclusive on the LHS (the start token), so
-            # we use bisect_right, which, in the case of a tie/exact match,
-            # picks an insertion point to the right of the existing match
-            point = bisect_right(self.ring, token)
+            # The values in self.ring correspond to the end of the
+            # token range up to and including the value listed.
+            point = bisect_left(self.ring, token)
             if point == len(self.ring):
                 return tokens_to_hosts[self.ring[0]]
             else:

tests/integration/standard/test_metadata.py

@@ -1172,8 +1172,8 @@ def test_token_map(self):
 
         for i, token in enumerate(ring):
             self.assertEqual(set(get_replicas('test3rf', token)), set(owners))
-            self.assertEqual(set(get_replicas('test2rf', token)), set([owners[(i + 1) % 3], owners[(i + 2) % 3]]))
-            self.assertEqual(set(get_replicas('test1rf', token)), set([owners[(i + 1) % 3]]))
+            self.assertEqual(set(get_replicas('test2rf', token)), set([owners[i], owners[(i + 1) % 3]]))
+            self.assertEqual(set(get_replicas('test1rf', token)), set([owners[i]]))
         cluster.shutdown()
 
 

tests/unit/test_metadata.py

@@ -312,8 +312,7 @@ def _get_replicas(self, token_klass):
         token_map = TokenMap(token_klass, token_to_primary_replica, tokens, metadata)
 
         # tokens match node tokens exactly
-        for i, token in enumerate(tokens):
-            expected_host = hosts[(i + 1) % len(hosts)]
+        for token, expected_host in zip(tokens, hosts):
             replicas = token_map.get_replicas("ks", token)
             self.assertEqual(set(replicas), {expected_host})