bugfix in zookeeper module:

when master node was being attached to patroni/zookeeper (no cluster in
zookeeper yet) patroni has never tried to "refetch" cluster from DCS.
It was leeding to demote...

patroni/zookeeper.py

@@ -165,8 +165,8 @@ class ZooKeeper(AbstractDCS):
             failover = Failover.from_node(failover[1].version, failover[0])
 
         # get last leader operation
-        self.last_leader_operation = self.get_node(self.leader_optime_path) if self.fetch_cluster else None
-        self.last_leader_operation = 0 if self.last_leader_operation is None else int(self.last_leader_operation[0])
+        optime = self.get_node(self.leader_optime_path) if self._OPTIME in nodes and self.fetch_cluster else None
+        self.last_leader_operation = 0 if optime is None else int(optime[0])
         self._cluster = Cluster(initialize, leader, self.last_leader_operation, members, failover)
 
     def _load_cluster(self):
@@ -280,5 +280,6 @@ class ZooKeeper(AbstractDCS):
             logger.exception("Unable to delete initialize key")
 
     def watch(self, timeout):
-        self.fetch_cluster = super(ZooKeeper, self).watch(timeout)
+        if super(ZooKeeper, self).watch(timeout):
+            self.fetch_cluster = True
         return self.fetch_cluster

tests/test_zookeeper.py

@@ -172,5 +172,5 @@ class TestZooKeeper(unittest.TestCase):
 
     def test_watch(self):
         self.zk.watch(0)
-        self.zk.event.isSet = lambda: False
+        self.zk.event.isSet = lambda: True
         self.zk.watch(0)