simplify gnocchi batch push setup

we run through samples and format samples and resources to what
gnocchi expects. this simplifies that process a little:
- don't needlessly sort and group by metric name
- build a full resource model iff resource needs to be created

Change-Id: I2ac25b3b0978eed664c500e645bae2d1b4ae6781

ceilometer/publisher/gnocchi.py

@@ -292,8 +292,7 @@ def _get_resource_definition_from_event(self, event_type):
     def publish_samples(self, data):
         # NOTE(sileht): skip sample generated by gnocchi itself
         data = [s for s in data if not self._is_gnocchi_activity(s)]
-
-        data.sort(key=lambda s: (s.resource_id, s.name))
+        data.sort(key=operator.attrgetter('resource_id'))
         resource_grouped_samples = itertools.groupby(
             data, key=operator.attrgetter('resource_id'))
 
@@ -303,13 +302,8 @@ def publish_samples(self, data):
             # NOTE(sileht): / is forbidden by Gnocchi
             resource_id = resource_id.replace('/', '_')
 
-            metric_grouped_samples = itertools.groupby(
-                list(samples_of_resource),
-                key=operator.attrgetter('name'))
-
-            res_info = {}
-            for metric_name, samples in metric_grouped_samples:
-                samples = list(samples)
+            for sample in samples_of_resource:
+                metric_name = sample.name
                 rd = self.metric_map.get(metric_name)
                 if rd is None:
                     if metric_name not in self._already_logged_metric_names:
@@ -320,28 +314,22 @@ def publish_samples(self, data):
                 if rd.cfg.get("ignore"):
                     continue
 
-                res_info['resource_type'] = rd.cfg['resource_type']
-                res_info.setdefault("resource", {}).update({
-                    "id": resource_id,
-                    "user_id": samples[0].user_id,
-                    "project_id": samples[0].project_id,
-                    "metrics": rd.metrics,
-                })
-
-                for sample in samples:
-                    res_info.setdefault("resource_extra", {}).update(
-                        rd.sample_attributes(sample))
-                    m = measures.setdefault(resource_id, {}).setdefault(
-                        metric_name, [])
-                    m.append({'timestamp': sample.timestamp,
-                              'value': sample.volume})
-                    unit = sample.unit
-                    metric = sample.name
-                    res_info['resource']['metrics'][metric]['unit'] = unit
-
-                res_info["resource"].update(res_info["resource_extra"])
-                if res_info:
-                    gnocchi_data[resource_id] = res_info
+                if resource_id not in gnocchi_data:
+                    gnocchi_data[resource_id] = {
+                        'resource_type': rd.cfg['resource_type'],
+                        'resource': {"id": resource_id,
+                                     "user_id": sample.user_id,
+                                     "project_id": sample.project_id,
+                                     "metrics": rd.metrics}}
+
+                gnocchi_data[resource_id].setdefault(
+                    "resource_extra", {}).update(rd.sample_attributes(sample))
+                measures.setdefault(resource_id, {}).setdefault(
+                    metric_name, []).append({'timestamp': sample.timestamp,
+                                             'value': sample.volume})
+                # TODO(gordc): unit should really be part of metric definition
+                gnocchi_data[resource_id]['resource']['metrics'][
+                    metric_name]['unit'] = sample.unit
 
         try:
             self.batch_measures(measures, gnocchi_data)
@@ -369,7 +357,8 @@ def _extract_resources_from_error(e, resource_infos):
         resource_ids = set([r['original_resource_id']
                             for r in e.message['detail']])
         return [(resource_infos[rid]['resource_type'],
-                 resource_infos[rid]['resource'])
+                 resource_infos[rid]['resource'],
+                 resource_infos[rid]['resource_extra'])
                 for rid in resource_ids]
 
     def batch_measures(self, measures, resource_infos):
@@ -385,8 +374,9 @@ def batch_measures(self, measures, resource_infos):
                 raise
 
             resources = self._extract_resources_from_error(e, resource_infos)
-            for resource_type, resource in resources:
+            for resource_type, resource, resource_extra in resources:
                 try:
+                    resource.update(resource_extra)
                     self._if_not_cached("create", resource_type, resource,
                                         self._create_resource)
                 except gnocchi_exc.ResourceAlreadyExists: