Update hacking for Python3

The repo is Python 3 now, so update hacking to version 3.0 which
supports Python 3.

Fix problems found.

Update local hacking checks for new flake8.

Remove hacking and friends from lower-constraints, they are not needed
to be installed at run-time.

Change-Id: Ia6af344ec8441dc98a0820176373dcff3a8c80d5

watcher/decision_engine/datasources/ceilometer.py

@@ -188,7 +188,7 @@ class CeilometerHelper(base.DataSourceBase):
         item_value = None
         if statistic:
             item_value = statistic[-1]._info.get('aggregate').get(aggregate)
-            if meter_name is 'host_airflow':
+            if meter_name == 'host_airflow':
                 # Airflow from hardware.ipmi.node.airflow is reported as
                 # 1/10 th of actual CFM
                 item_value *= 10

watcher/decision_engine/datasources/gnocchi.py

@@ -116,7 +116,7 @@ class GnocchiHelper(base.DataSourceBase):
             # measure has structure [time, granularity, value]
             return_value = statistics[-1][2]
 
-            if meter_name is 'host_airflow':
+            if meter_name == 'host_airflow':
                 # Airflow from hardware.ipmi.node.airflow is reported as
                 # 1/10 th of actual CFM
                 return_value *= 10

watcher/decision_engine/datasources/grafana.py

@@ -72,7 +72,7 @@ class GrafanaHelper(base.DataSourceBase):
 
         # Very basic url parsing
         parse = urlparse.urlparse(self._base_url)
-        if parse.scheme is '' or parse.netloc is '' or parse.path is '':
+        if parse.scheme == '' or parse.netloc == '' or parse.path == '':
             LOG.critical("GrafanaHelper url not properly configured, "
                          "check base_url and project_id")
             return

watcher/decision_engine/datasources/manager.py

@@ -112,10 +112,10 @@ class DataSourceManager(object):
         datasource is attempted.
         """
 
-        if not self.datasources or len(self.datasources) is 0:
+        if not self.datasources or len(self.datasources) == 0:
             raise exception.NoDatasourceAvailable
 
-        if not metrics or len(metrics) is 0:
+        if not metrics or len(metrics) == 0:
             LOG.critical("Can not retrieve datasource without specifying "
                          "list of required metrics.")
             raise exception.InvalidParameter(parameter='metrics',
@@ -125,11 +125,11 @@ class DataSourceManager(object):
             no_metric = False
             for metric in metrics:
                 if (metric not in self.metric_map[datasource] or
-                   self.metric_map[datasource].get(metric) is None):
-                        no_metric = True
-                        LOG.warning("Datasource: {0} could not be used due to "
-                                    "metric: {1}".format(datasource, metric))
-                        break
+                        self.metric_map[datasource].get(metric) is None):
+                    no_metric = True
+                    LOG.warning("Datasource: {0} could not be used due to "
+                                "metric: {1}".format(datasource, metric))
+                    break
             if not no_metric:
                 # Try to use a specific datasource but attempt additional
                 # datasources upon exceptions (if config has more datasources)

watcher/decision_engine/strategy/strategies/basic_consolidation.py

@@ -401,7 +401,7 @@ class BasicConsolidation(base.ServerConsolidationBaseStrategy):
         self._pre_execute()
 
         # backwards compatibility for node parameter.
-        if self.aggregation_method['node'] is not '':
+        if self.aggregation_method['node'] != '':
             LOG.warning('Parameter node has been renamed to compute_node and '
                         'will be removed in next release.')
             self.aggregation_method['compute_node'] = \

watcher/decision_engine/strategy/strategies/workload_stabilization.py

@@ -514,7 +514,7 @@ class WorkloadStabilization(base.WorkloadStabilizationBaseStrategy):
                 self.aggregation_method['node']
 
         # backwards compatibility for node parameter with period.
-        if self.periods['node'] is not 0:
+        if self.periods['node'] != 0:
             LOG.warning('Parameter node has been renamed to compute_node and '
                         'will be removed in next release.')
             self.periods['compute_node'] = self.periods['node']