From 1ed91a93c6b38b3151489cafbc18b008f6f7adce Mon Sep 17 00:00:00 2001
From: Alexander Kukushkin <cyberdemn@gmail.com>
Date: Thu, 16 Feb 2017 17:07:09 +0100
Subject: [PATCH] Handle EtcdEventIndexCleared and EtcdWatcherCleared
 exceptions (#387)

If this case it doesn't make sense to retry, because it brings nothing
but produces a log of exceptions in the log...
---
 patroni/dcs/etcd.py | 2 ++
 tests/test_etcd.py  | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/patroni/dcs/etcd.py b/patroni/dcs/etcd.py
index 4cb1f391..3aececdd 100644
--- a/patroni/dcs/etcd.py
+++ b/patroni/dcs/etcd.py
@@ -530,6 +530,8 @@ class Etcd(AbstractDCS):
                 except etcd.EtcdWatchTimedOut:
                     self._client.http.clear()
                     return False
+                except (etcd.EtcdEventIndexCleared, etcd.EtcdWatcherCleared):  # Watch failed
+                    return True  # leave the loop, because watch with the same parameters will fail anyway
                 except etcd.EtcdException:
                     logger.exception('watch')
 
diff --git a/tests/test_etcd.py b/tests/test_etcd.py
index 3dd93da6..38513982 100644
--- a/tests/test_etcd.py
+++ b/tests/test_etcd.py
@@ -61,6 +61,8 @@ def etcd_watch(self, key, index=None, timeout=None, recursive=None):
         return etcd.EtcdResult('delete', {})
     elif timeout == 10.0:
         raise etcd.EtcdException
+    elif timeout == 20.0:
+        raise etcd.EtcdEventIndexCleared
 
 
 def etcd_write(self, key, value, **kwargs):
@@ -307,6 +309,7 @@ class TestEtcd(unittest.TestCase):
         self.etcd.watch(20729, 1.5)
         self.etcd.watch(20729, 4.5)
         with patch.object(AbstractDCS, 'watch', Mock()):
+            self.assertTrue(self.etcd.watch(20729, 19.5))
             self.etcd.watch(20729, 9.5)
 
     def test_other_exceptions(self):