Add a "force_granularity" option to gnocchi collector's extra_args

This adds an option allowing to force the granularity to use when doing metric
aggregations. If not specified or set to 0, the lowest available aggregation
method will be used.

Change-Id: I1ad36c3ac4125b4af285fddc3a4a649d5dc3b395

cloudkitty/collector/gnocchi.py

@@ -25,6 +25,7 @@ from oslo_log import log as logging
 from voluptuous import All
 from voluptuous import In
 from voluptuous import Length
+from voluptuous import Range
 from voluptuous import Required
 from voluptuous import Schema
 
@@ -99,6 +100,7 @@ GNOCCHI_EXTRA_SCHEMA = {
         Required('resource_key', default='id'): All(str, Length(min=1)),
         Required('aggregation_method', default='max'):
             In(['max', 'mean', 'min', 'rate:max', 'rate:mean', 'rate:min']),
+        Required('force_granularity', default=0): All(int, Range(min=0)),
     },
 }
 
@@ -291,11 +293,11 @@ class GnocchiCollector(collector.BaseCollector):
         # Get gnocchi specific conf
         extra_args = self.conf[metric_name]['extra_args']
 
-        # get ressource type
+        # get resource type
         resource_type = extra_args['resource_type']
         scope_key = CONF.collect.scope_key
 
-        # build search query using ressource type and project_id if provided
+        # build search query using resource type and project_id if provided
         query_parameters = list()
         query_parameters.append(
             self.gen_filter(cop="=", type=resource_type))
@@ -313,14 +315,17 @@ class GnocchiCollector(collector.BaseCollector):
         # get groupby
         groupby = self.conf[metric_name]['groupby']
 
+        agg_kwargs = {
+            'resource_type': resource_type,
+            'start': start,
+            'stop': end,
+            'groupby': groupby,
+            'search': self.extend_filter(*query_parameters),
+        }
+        if extra_args['force_granularity'] > 0:
+            agg_kwargs['granularity'] = extra_args['force_granularity']
         try:
-            return self._conn.aggregates.fetch(
-                op,
-                resource_type=resource_type,
-                start=start,
-                stop=end,
-                groupby=groupby,
-                search=self.extend_filter(*query_parameters))
+            return self._conn.aggregates.fetch(op, **agg_kwargs)
         except (gexceptions.MetricNotFound, gexceptions.BadRequest) as e:
             # FIXME(peschk_l): gnocchiclient seems to be raising a BadRequest
             # when it should be raising MetricNotFound

cloudkitty/tests/collectors/test_validation.py

@@ -70,6 +70,7 @@ class MetricConfigValidationTest(tests.TestCase):
         expected_output['metric_one']['groupby'] += ['project_id', 'id']
         expected_output['metric_one']['extra_args'] = {
             'aggregation_method': 'max',
+            'force_granularity': 0,
             'resource_type': 'res',
             'resource_key': 'id',
         }
@@ -79,6 +80,19 @@ class MetricConfigValidationTest(tests.TestCase):
             expected_output,
         )
 
+    def test_gnocchi_minimal_config_negative_forced_aggregation(self):
+        data = copy.deepcopy(self.base_data)
+        data['metrics']['metric_one']['extra_args'] = {
+            'resource_type': 'res',
+            'force_aggregation': -42,
+        }
+
+        self.assertRaises(
+            verror.MultipleInvalid,
+            collector.gnocchi.GnocchiCollector.check_configuration,
+            data,
+        )
+
     def test_monasca_minimal_config_no_extra_args(self):
         data = copy.deepcopy(self.base_data)
         expected_output = copy.deepcopy(self.base_output)

doc/source/admin/configuration/collector.rst

@@ -255,6 +255,10 @@ Gnocchi
   when retrieving measures from gnocchi. Must be one of ``min``, ``max``,
   ``mean``.
 
+* ``force_granularity``: Defaults to ``0``. If > 0, this granularity will be
+  used for metric aggregations. Else, the lowest available granularity will be
+  used (meaning the granularity covering the longest period).
+
 Monasca
 ~~~~~~~
 

releasenotes/notes/added-forced-granularity-gnocchi-d52e988194197248.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    A ``force_granularity`` option has been added to the gnocchi collector's
+    ``extra_args``. It allows to force a granularity to use when doing metric
+    aggregations. If not specified or set to 0, the lowest available
+    granularity will be used.