Optimize getting unit in "metering" dashboard

Currently we using a meter-list for getting a "unit" for metric.
Meter list get all available metric on environment,
it's may be a thousands of records.
It's better to use sample-list for this metric with "limit" 1.
This request gets a 1 sample for queried metric.

Change-Id: I4bf0ab7ebcbcae1ddc90d8ee01d5f5a84ed4fbba
Related-bug: #1444456

openstack_dashboard/api/ceilometer.py

@@ -289,10 +289,10 @@ def resource_list(request, query=None, ceilometer_usage_object=None):
     return [Resource(r, ceilometer_usage_object) for r in resources]
 
 
-def sample_list(request, meter_name, query=None):
+def sample_list(request, meter_name, query=None, limit=None):
     """List the samples for this meters."""
     samples = ceilometerclient(request).samples.list(meter_name=meter_name,
-                                                     q=query)
+                                                     q=query, limit=limit)
     return [Sample(s) for s in samples]
 
 

openstack_dashboard/dashboards/admin/metering/tests.py

@@ -77,12 +77,13 @@ class MeteringLineChartTabTests(test.BaseAdminViewTests):
         self.assertEqual(data.get('settings'), {})
 
     @test.create_stubs({api.keystone: ('tenant_list',),
-                        api.ceilometer: ('meter_list',
+                        api.ceilometer: ('sample_list',
                                          'statistic_list',
                                          ), })
     def test_stats_for_line_chart(self):
-        api.ceilometer.meter_list(IsA(http.HttpRequest))\
+        api.ceilometer.sample_list(IsA(http.HttpRequest),
-            .AndReturn(self.testdata.meters.list())
+                                   IsA(unicode),
+                                   limit=IsA(int)).AndReturn([])
         api.ceilometer.statistic_list(IsA(http.HttpRequest),
                                       'memory',
                                       period=IsA(int),
@@ -109,12 +110,13 @@ class MeteringLineChartTabTests(test.BaseAdminViewTests):
                             expected_names)
 
     @test.create_stubs({api.keystone: ('tenant_list',),
-                        api.ceilometer: ('meter_list',
+                        api.ceilometer: ('sample_list',
                                          'statistic_list',
                                          ), })
     def test_stats_for_line_chart_attr_max(self):
-        api.ceilometer.meter_list(IsA(http.HttpRequest))\
+        api.ceilometer.sample_list(IsA(http.HttpRequest),
-            .AndReturn(self.testdata.meters.list())
+                                   IsA(unicode),
+                                   limit=IsA(int)).AndReturn([])
         api.ceilometer.statistic_list(IsA(http.HttpRequest),
                                       'memory', period=IsA(int),
                                       query=IsA(list))\
@@ -141,13 +143,14 @@ class MeteringLineChartTabTests(test.BaseAdminViewTests):
                             expected_names)
 
     @test.create_stubs({api.keystone: ('tenant_list',),
-                        api.ceilometer: ('meter_list',
+                        api.ceilometer: ('sample_list',
                                          'resource_list',
                                          'statistic_list'
                                          ), })
     def test_stats_for_line_chart_no_group(self):
-        api.ceilometer.meter_list(IsA(http.HttpRequest))\
+        api.ceilometer.sample_list(IsA(http.HttpRequest),
-            .AndReturn(self.testdata.meters.list())
+                                   IsA(unicode),
+                                   limit=IsA(int)).AndReturn([])
         api.ceilometer.resource_list(IsA(http.HttpRequest), query=None,
                                      ceilometer_usage_object=None)\
             .AndReturn(self.testdata.api_resources.list())

openstack_dashboard/test/api_tests/ceilometer_tests.py

@@ -26,8 +26,9 @@ class CeilometerApiTests(test.APITestCase):
         meter_name = "meter_name"
         ceilometerclient = self.stub_ceilometerclient()
         ceilometerclient.samples = self.mox.CreateMockAnything()
-        ceilometerclient.samples.list(meter_name=meter_name, q=[]).\
+        ceilometerclient.samples.list(meter_name=meter_name,
-            AndReturn(samples)
+                                      q=[],
+                                      limit=None).AndReturn(samples)
         self.mox.ReplayAll()
 
         ret_list = api.ceilometer.sample_list(self.request,

openstack_dashboard/utils/metering.py

@@ -165,6 +165,14 @@ def normalize_series_by_unit(series):
     return series
 
 
+def get_unit(meter, request):
+    sample_list = api.ceilometer.sample_list(request, meter, limit=1)
+    unit = ""
+    if sample_list:
+        unit = sample_list[0].counter_unit
+    return unit
+
+
 class ProjectAggregatesQuery(object):
     def __init__(self, request, date_from, date_to,
                  period=None, additional_query=[]):
@@ -196,11 +204,7 @@ class ProjectAggregatesQuery(object):
             self.queries[tenant.name] = tenant_query
 
     def query(self, meter):
-        meter_list = [m for m in api.ceilometer.meter_list(self.request)
+        unit = get_unit(meter, self.request)
-                      if m.name == meter]
-        unit = ""
-        if len(meter_list) > 0:
-            unit = meter_list[0].unit
         ceilometer_usage = api.ceilometer.CeilometerUsage(self.request)
         resources = ceilometer_usage.resource_aggregates_with_statistics(
             self.queries, [meter], period=self.period,
@@ -231,12 +235,7 @@ class MeterQuery(ProjectAggregatesQuery):
                     return True
             return False
 
-        meter_list = [m for m in api.ceilometer.meter_list(self.request)
+        unit = get_unit(meter, self.request)
-                      if m.name == meter]
-
-        unit = ""
-        if len(meter_list) > 0:
-            unit = meter_list[0].unit
 
         ceilometer_usage = api.ceilometer.CeilometerUsage(self.request)
         resources = ceilometer_usage.resources_with_statistics(