Small optimization

Don't compare values of configuration if modify_index didn't changed

patroni/__init__.py

@@ -41,7 +41,7 @@ class Patroni(object):
             try:
                 cluster = self.dcs.get_cluster()
                 if cluster and cluster.config:
-                    self.config.set_dynamic_configuration(cluster.config.data)
+                    self.config.set_dynamic_configuration(cluster.config)
                 elif not self.config.dynamic_configuration and 'bootstrap' in self.config:
                     self.config.set_dynamic_configuration(self.config['bootstrap']['dcs'])
                 break
@@ -101,7 +101,7 @@ class Patroni(object):
             logger.info(self.ha.run_cycle())
 
             cluster = self.dcs.cluster
-            if cluster and cluster.config and self.config.set_dynamic_configuration(cluster.config.data):
+            if cluster and cluster.config and self.config.set_dynamic_configuration(cluster.config):
                 self.reload_config()
 
             if not self.postgresql.data_directory_empty():

patroni/config.py

@@ -5,6 +5,7 @@ import tempfile
 import yaml
 
 from copy import deepcopy
+from patroni.dcs import ClusterConfig
 from patroni.postgresql import Postgresql
 from patroni.utils import deep_compare
 
@@ -42,6 +43,7 @@ class Config(object):
 
     def __init__(self, config_file=None, config_env=None):
         self._config_file = None if config_env else config_file
+        self._modify_index = -1
         self._dynamic_configuration = {}
         self._local_configuration = yaml.safe_load(config_env) if config_env else self._load_config_file()
         self.__effective_configuration = self._build_effective_configuration(self._dynamic_configuration,
@@ -94,7 +96,14 @@ class Config(object):
                     except Exception:
                         logger.error('Can not remove temporary file %s', tmpfile)
 
+    # configuration could be either ClusterConfig or dict
     def set_dynamic_configuration(self, configuration):
+        if isinstance(configuration, ClusterConfig):
+            if self._modify_index == configuration.modify_index:
+                return False  # If the index didn't changed there is nothing to do
+            self._modify_index = configuration.modify_index
+            configuration = configuration.data
+
         if not deep_compare(self._dynamic_configuration, configuration):
             try:
                 self.__effective_configuration = self._build_effective_configuration(configuration,

patroni/dcs/__init__.py

@@ -164,10 +164,10 @@ class Failover(namedtuple('Failover', 'index,leader,candidate,scheduled_at')):
         return Failover(index, data.get('leader'), data.get('member'), data.get('scheduled_at'))
 
 
-class ClusterConfig(namedtuple('ClusterConfig', 'index,data')):
+class ClusterConfig(namedtuple('ClusterConfig', 'index,data,modify_index')):
 
     @staticmethod
-    def from_node(index, data):
+    def from_node(index, data, modify_index=None):
         """
         >>> ClusterConfig.from_node(1, '{') is None
         True
@@ -177,7 +177,7 @@ class ClusterConfig(namedtuple('ClusterConfig', 'index,data')):
             data = json.loads(data)
         except (TypeError, ValueError):
             return None
-        return ClusterConfig(index, data)
+        return ClusterConfig(index, data, modify_index or index)
 
 
 class Cluster(namedtuple('Cluster', 'initialize,config,leader,last_leader_operation,members,failover')):

patroni/dcs/consul.py

@@ -34,7 +34,7 @@ class HTTPClient(std.HTTPClient):
         defaults_attr_name = '__defaults__' if six.PY3 else 'func_defaults'
         defaults = list(getattr(request_func, defaults_attr_name))
         code = request_func.__code__ if six.PY3 else request_func.func_code
-        defaults[code.co_varnames[code.co_argcount - len(defaults):code.co_argcount].index('timeout')] = 5
+        defaults[code.co_varnames[code.co_argcount - len(defaults):code.co_argcount].index('timeout')] = timeout
         setattr(request_func, defaults_attr_name, tuple(defaults))  # monkeypatching
 
     def get(self, callback, path, params=None):

patroni/dcs/zookeeper.py

@@ -150,7 +150,7 @@ class ZooKeeper(AbstractDCS):
 
         # get global dynamic configuration
         config = self.get_node(self.config_path, watch=self.cluster_watcher) if self._CONFIG in nodes else None
-        config = config and ClusterConfig.from_node(config[1].version, config[0])
+        config = config and ClusterConfig.from_node(config[1].version, config[0], config[1].mzxid)
 
         # get list of members
         members = self.load_members() if self._MEMBERS[:-1] in nodes else []
@@ -209,7 +209,7 @@ class ZooKeeper(AbstractDCS):
             self._client.retry(self._client.set, self.failover_path, value.encode('utf-8'), version=index or -1)
             return True
         except NoNodeError:
-            return value == '' or (not index and self._create(self.failover_path, value))
+            return value == '' or (index is None and self._create(self.failover_path, value))
         except:
             logging.exception('set_failover_value')
             return False
@@ -219,7 +219,7 @@ class ZooKeeper(AbstractDCS):
             self._client.retry(self._client.set, self.config_path, value.encode('utf-8'), version=index or -1)
             return True
         except NoNodeError:
-            return value == '' or (not index and self._create(self.config_path, value))
+            return index is None and self._create(self.config_path, value)
         except Exception:
             logging.exception('set_config_value')
             return False

tests/test_patroni.py

@@ -71,6 +71,8 @@ class TestPatroni(unittest.TestCase):
         self.p.api.start = Mock()
         self.p.config._dynamic_configuration = {}
         self.assertRaises(SleepException, self.p.run)
+        with patch('patroni.config.Config.set_dynamic_configuration', Mock(return_value=True)):
+            self.assertRaises(SleepException, self.p.run)
         with patch('patroni.postgresql.Postgresql.data_directory_empty', Mock(return_value=False)):
             self.assertRaises(SleepException, self.p.run)