Adds metric utils to convert Stats data models to Metric data models (#191)

Author: isaikevych

packages/opencensus-core/src/index.ts

@@ -47,6 +47,7 @@ export * from './stats/stats';
 export * from './stats/view';
 export * from './stats/recorder';
 export * from './stats/bucket-boundaries';
+export * from './stats/metric-utils';
 
 // interfaces
 export * from './stats/types';

packages/opencensus-core/src/metrics/export/types.ts

@@ -135,16 +135,8 @@ export interface TimeSeries {
   readonly points: Point[];
 }
 
-/** Properties of a LabelValue. */
-export interface LabelValue {
-  /** The value for the label */
-  readonly value: string;
-  /**
-   * If false the value field is ignored and considered not set.
-   * This is used to differentiate a missing label from an empty string.
-   */
-  readonly hasValue: boolean;
-}
+/** The LabelValue type. null value indicates an unset. */
+export type LabelValue = string|null;
 
 /** A timestamped measurement. */
 export interface Point {
@@ -260,7 +252,7 @@ export interface Exemplar {
   /** The observation (sampling) time of the above value. */
   readonly timestamp: Timestamp;
   /** Contextual information about the example value. */
-  readonly attachments: ({[k: string]: string}|null);
+  readonly attachments: {[key: string]: string};
 }
 
 /**

packages/opencensus-core/src/stats/metric-utils.ts

@@ -0,0 +1,78 @@
+/**
+ * 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.
+ */
+
+
+import {LabelKey, LabelValue, MetricDescriptor, MetricDescriptorType} from '../metrics/export/types';
+
+import {AggregationType, Measure, MeasureType, Tags, View} from './types';
+
+/** Utils to convert Stats data models to Metric data models */
+export class MetricUtils {
+  /**
+   * Gets the corresponding metric type for the given stats type.
+   * @param measure The measure for which to find a metric type
+   * @param aggregation The aggregation for which to find a metric type
+   */
+  private static getType(measure: Measure, aggregation: AggregationType):
+      MetricDescriptorType {
+    if (aggregation === AggregationType.SUM) {
+      switch (measure.type) {
+        case MeasureType.INT64:
+          return MetricDescriptorType.CUMULATIVE_INT64;
+        case MeasureType.DOUBLE:
+          return MetricDescriptorType.CUMULATIVE_DOUBLE;
+        default:
+          throw new Error(`Unknown measure type ${measure.type}`);
+      }
+    } else if (aggregation === AggregationType.COUNT) {
+      return MetricDescriptorType.CUMULATIVE_INT64;
+    } else if (aggregation === AggregationType.DISTRIBUTION) {
+      return MetricDescriptorType.CUMULATIVE_DISTRIBUTION;
+    } else if (aggregation === AggregationType.LAST_VALUE) {
+      switch (measure.type) {
+        case MeasureType.INT64:
+          return MetricDescriptorType.GAUGE_INT64;
+        case MeasureType.DOUBLE:
+          return MetricDescriptorType.GAUGE_DOUBLE;
+        default:
+          throw new Error(`Unknown measure type ${measure.type}`);
+      }
+    }
+    throw new Error(`Unknown aggregation type ${aggregation}`);
+  }
+
+  /**
+   * Gets a MetricDescriptor for given view.
+   * @param view The view for which to build a metric descriptor
+   */
+  static viewToMetricDescriptor(view: View): MetricDescriptor {
+    return {
+      name: view.name,
+      description: view.description,
+      unit: view.measure.unit,
+      type: MetricUtils.getType(view.measure, view.aggregation),
+      labelKeys: view.getColumns().map(tag => ({key: tag} as LabelKey))
+    };
+  }
+
+  /**
+   * Converts tag values to label values.
+   * @param tags
+   */
+  static tagValuesToLabelValues(tags: Tags): LabelValue[] {
+    return Object.keys(tags).map(key => tags[key] as LabelValue);
+  }
+}

packages/opencensus-core/test/test-metric-utils.ts

@@ -0,0 +1,53 @@
+/**
+ * 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.
+ */
+
+import * as assert from 'assert';
+
+import {BaseView, MetricUtils} from '../src';
+import {MetricDescriptorType} from '../src/metrics/export/types';
+import {AggregationType, Measure, MeasureType, MeasureUnit, Tags} from '../src/stats/types';
+
+
+describe('MetricUtil', () => {
+  it('should convert view to MetricDescriptor', () => {
+    const VIEW_DESCRIPTION = 'view description';
+    const measure: Measure = {
+      name: 'Test Measure',
+      type: MeasureType.DOUBLE,
+      unit: MeasureUnit.UNIT
+    };
+    const tagKeys = ['testKey1', 'testKey2'];
+    const view = new BaseView(
+        'test/view/name', measure, AggregationType.LAST_VALUE, tagKeys,
+        VIEW_DESCRIPTION);
+    const metricDescriptor = MetricUtils.viewToMetricDescriptor(view);
+
+    assert.ok(metricDescriptor);
+    assert.strictEqual(metricDescriptor.name, view.name);
+    assert.strictEqual(metricDescriptor.unit, MeasureUnit.UNIT);
+    assert.strictEqual(
+        metricDescriptor.type, MetricDescriptorType.GAUGE_DOUBLE);
+    assert.strictEqual(metricDescriptor.description, VIEW_DESCRIPTION);
+    assert.deepStrictEqual(
+        metricDescriptor.labelKeys, [{key: 'testKey1'}, {key: 'testKey2'}]);
+  });
+
+  it('should convert tag values to label values', () => {
+    const tags: Tags = {test: 'test1', tag: 'test2', empty: '', fake: null};
+    assert.deepStrictEqual(
+        MetricUtils.tagValuesToLabelValues(tags), ['test1', 'test2', '', null]);
+  });
+});