Integration of Ceilometer in Watcher

In current implementation is not easy to use ceilometer.
Watcher must query metrics from the Telemetry v2 API to allow an easiest integration with OpenStack components (especially devstack).

blueprint telemetry-integration
Change-Id: Ide515472f1d160925d9f4aabf48c96dea4f6bc05

watcher/metrics_engine/cluster_history/ceilometer.py

@@ -0,0 +1,49 @@
+# -*- encoding: utf-8 -*-
+# Copyright (c) 2015 b<>com
+#
+# Authors: Jean-Emile DARTOIS <jean-emile.dartois@b-com.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+from oslo_config import cfg
+from oslo_log import log
+from watcher.common.ceilometer import Client
+
+from watcher.metrics_engine.cluster_history.api import BaseClusterHistory
+
+CONF = cfg.CONF
+LOG = log.getLogger(__name__)
+
+
+class CeilometerClusterHistory(BaseClusterHistory):
+    def __init__(self):
+        self.ceilometer = Client()
+
+    def statistic_list(self, meter_name, query=None, period=None):
+        return self.ceilometer.statistic_list(meter_name, query, period)
+
+    def query_sample(self, meter_name, query, limit=1):
+        return self.ceilometer.query_sample(meter_name, query, limit)
+
+    def get_last_sample_values(self, resource_id, meter_name, limit=1):
+        return self.ceilometer.get_last_sample_values(resource_id, meter_name,
+                                                      limit)
+
+    def statistic_aggregation(self, resource_id, meter_name, period,
+                              aggregate='avg'):
+        return self.ceilometer.statistic_aggregation(resource_id, meter_name,
+                                                     period,
+                                                     aggregate)