Add helper class for stats/metrics conversion (#355)

c24t · web-flow · commit d9384fdfafeb · 2018-10-22T15:07:12.000-07:00
diff --git a/opencensus/stats/metric_utils.py b/opencensus/stats/metric_utils.py
@@ -0,0 +1,83 @@
+# Copyright 2018, OpenCensus Authors
+#
+# 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.
+"""
+Utilities to convert stats data models to metrics data models.
+"""
+
+from opencensus.metrics import label_key
+from opencensus.metrics.export import metric_descriptor
+from opencensus.stats import aggregation as aggregation_module
+from opencensus.stats import measure as measure_module
+
+# To check that an aggregation's reported type matches its class
+AGGREGATION_TYPE_MAP = {
+    aggregation_module.Type.SUM:
+    aggregation_module.SumAggregation,
+    aggregation_module.Type.COUNT:
+    aggregation_module.CountAggregation,
+    aggregation_module.Type.DISTRIBUTION:
+    aggregation_module.DistributionAggregation,
+    aggregation_module.Type.LASTVALUE:
+    aggregation_module.LastValueAggregation,
+}
+
+
+def get_metric_type(measure, aggregation):
+    """Get the corresponding metric type for the given stats type.
+
+    :type measure: (:class: '~opencensus.stats.measure.BaseMeasure')
+    :param measure: the measure for which to find a metric type
+
+    :type aggregation: (:class:
+    '~opencensus.stats.aggregation.BaseAggregation')
+    :param aggregation: the aggregation for which to find a metric type
+    """
+    if aggregation.aggregation_type == aggregation_module.Type.NONE:
+        raise ValueError("aggregation type must not be NONE")
+    assert isinstance(aggregation,
+                      AGGREGATION_TYPE_MAP[aggregation.aggregation_type])
+
+    if aggregation.aggregation_type == aggregation_module.Type.SUM:
+        if isinstance(measure, measure_module.MeasureInt):
+            return metric_descriptor.MetricDescriptorType.CUMULATIVE_INT64
+        elif isinstance(measure, measure_module.MeasureFloat):
+            return metric_descriptor.MetricDescriptorType.CUMULATIVE_DOUBLE
+        else:
+            raise ValueError
+    elif aggregation.aggregation_type == aggregation_module.Type.COUNT:
+        return metric_descriptor.MetricDescriptorType.CUMULATIVE_INT64
+    elif aggregation.aggregation_type == aggregation_module.Type.DISTRIBUTION:
+        return metric_descriptor.MetricDescriptorType.CUMULATIVE_DISTRIBUTION
+    elif aggregation.aggregation_type == aggregation_module.Type.LASTVALUE:
+        if isinstance(measure, measure_module.MeasureInt):
+            return metric_descriptor.MetricDescriptorType.GAUGE_INT64
+        elif isinstance(measure, measure_module.MeasureFloat):
+            return metric_descriptor.MetricDescriptorType.GAUGE_DOUBLE
+        else:
+            raise ValueError
+    else:
+        raise AssertionError  # pragma: NO COVER
+
+
+def view_to_metric_descriptor(view):
+    """Get a MetricDescriptor for given view data.
+
+    :type view: (:class: '~opencensus.stats.view.View')
+    :param view: the view data to for which to build a metric descriptor
+    """
+    return metric_descriptor.MetricDescriptor(
+        view.name, view.description, view.measure.unit,
+        get_metric_type(view.measure, view.aggregation),
+        # TODO: add label key description
+        [label_key.LabelKey(tk, "") for tk in view.columns])
diff --git a/tests/unit/stats/test_metric_utils.py b/tests/unit/stats/test_metric_utils.py
@@ -0,0 +1,102 @@
+# Copyright 2018, OpenCensus Authors
+#
+# 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.
+
+try:
+    import mock
+except ImportError:
+    from unittest import mock
+
+import unittest
+
+from opencensus.metrics.export import metric_descriptor
+from opencensus.stats import aggregation
+from opencensus.stats import measure
+from opencensus.stats import metric_utils
+from opencensus.stats import view
+
+
+class TestMetricUtils(unittest.TestCase):
+    def test_get_metric_type(self):
+        measure_int = mock.Mock(spec=measure.MeasureInt)
+        measure_float = mock.Mock(spec=measure.MeasureFloat)
+        agg_sum = mock.Mock(spec=aggregation.SumAggregation)
+        agg_sum.aggregation_type = aggregation.Type.SUM
+        agg_count = mock.Mock(spec=aggregation.CountAggregation)
+        agg_count.aggregation_type = aggregation.Type.COUNT
+        agg_dist = mock.Mock(spec=aggregation.DistributionAggregation)
+        agg_dist.aggregation_type = aggregation.Type.DISTRIBUTION
+        agg_lv = mock.Mock(spec=aggregation.LastValueAggregation)
+        agg_lv.aggregation_type = aggregation.Type.LASTVALUE
+
+        view_to_metric_type = {
+            (measure_int, agg_sum):
+            metric_descriptor.MetricDescriptorType.CUMULATIVE_INT64,
+            (measure_int, agg_count):
+            metric_descriptor.MetricDescriptorType.CUMULATIVE_INT64,
+            (measure_int, agg_dist):
+            metric_descriptor.MetricDescriptorType.CUMULATIVE_DISTRIBUTION,
+            (measure_int, agg_lv):
+            metric_descriptor.MetricDescriptorType.GAUGE_INT64,
+            (measure_float, agg_sum):
+            metric_descriptor.MetricDescriptorType.CUMULATIVE_DOUBLE,
+            (measure_float, agg_count):
+            metric_descriptor.MetricDescriptorType.CUMULATIVE_INT64,
+            (measure_float, agg_dist):
+            metric_descriptor.MetricDescriptorType.CUMULATIVE_DISTRIBUTION,
+            (measure_float, agg_lv):
+            metric_descriptor.MetricDescriptorType.GAUGE_DOUBLE,
+        }
+
+        for (mm, ma), metric_type in view_to_metric_type.items():
+            self.assertEqual(metric_utils.get_metric_type(mm, ma), metric_type)
+
+    def test_get_metric_type_bad_aggregation(self):
+        base_agg = mock.Mock(spec=aggregation.BaseAggregation)
+        base_agg.aggregation_type = aggregation.Type.NONE
+        with self.assertRaises(ValueError):
+            metric_utils.get_metric_type(mock.Mock(), base_agg)
+
+        bad_agg = mock.Mock(spec=aggregation.SumAggregation)
+        bad_agg.aggregation_type = aggregation.Type.COUNT
+        with self.assertRaises(AssertionError):
+            metric_utils.get_metric_type(mock.Mock(), bad_agg)
+
+    def test_get_metric_type_bad_measure(self):
+        base_measure = mock.Mock(spec=measure.BaseMeasure)
+        agg_sum = mock.Mock(spec=aggregation.SumAggregation)
+        agg_sum.aggregation_type = aggregation.Type.SUM
+        agg_lv = mock.Mock(spec=aggregation.LastValueAggregation)
+        agg_lv.aggregation_type = aggregation.Type.LASTVALUE
+        with self.assertRaises(ValueError):
+            metric_utils.get_metric_type(base_measure, agg_sum)
+        with self.assertRaises(ValueError):
+            metric_utils.get_metric_type(base_measure, agg_lv)
+
+    def test_view_to_metric_descriptor(self):
+        mock_measure = mock.Mock(spec=measure.MeasureFloat)
+        mock_agg = mock.Mock(spec=aggregation.SumAggregation)
+        mock_agg.aggregation_type = aggregation.Type.SUM
+        test_view = view.View("name", "description", ["tk1", "tk2"],
+                              mock_measure, mock_agg)
+
+        md = metric_utils.view_to_metric_descriptor(test_view)
+        self.assertTrue(isinstance(md, metric_descriptor.MetricDescriptor))
+        self.assertEqual(md.name, test_view.name)
+        self.assertEqual(md.description, test_view.description)
+        self.assertEqual(md.unit, test_view.measure.unit)
+        self.assertEqual(
+            md.type, metric_descriptor.MetricDescriptorType.CUMULATIVE_DOUBLE)
+        self.assertTrue(
+            all(lk.key == col
+                for lk, col in zip(md.label_keys, test_view.columns)))
