Update stats, zpages, prometheus packages with new Tags API (#307)

* Use Tags API

* replace not found key values by null and fix nit

CHANGELOG.md

@@ -5,6 +5,7 @@ All notable changes to this project will be documented in this file.
 ## Unreleased
 - Add Metrics API.
 - Add Resource API.
+- Add Tags API.
 - Add Gauges (`DoubleGauge`, `LongGauge`, `DerivedDoubleGauge`, `DerivedLongGauge`) APIs.
 - Add support for supplying instrumentation configuration via tracing option. Option argument added to instrumentation interface.
 - Add ignoreIncomingPaths and ignoreOutgoingUrls support to the http and https tracing instrumentations.
@@ -14,26 +15,82 @@ All notable changes to this project will be documented in this file.
 
 - Modify `Logger` interface: `level` made optional, `silly` removed.
 - The ```new Stats()``` has been deprecated on Stats class. The global singleton ```globalStats``` object should be used instead. Also, ```registerView()``` is separated out from ```createView()```.
+- Use ```TagKey```, ```TagValue``` and ```TagMap``` to create the tag keys, tag values.
 
 ##### Old code
 ```js
 const { Stats } = require("@opencensus/core");
 const stats = new Stats();
 
+// Counts/groups the lengths of lines read in.
+const mLineLengths = stats.createMeasureInt64(
+  "demo/line_lengths",
+  MeasureUnit.BYTE,
+  "The distribution of line lengths"
+);
+
+// Create tag keys
+const tagKeys = ["method", "status"];
+
 // Create and register the view
-stats.createView(...);
+stats.createView(
+  "demo/lines_in",
+  mLineLengths,
+  AggregationType.COUNT,
+  tagKeys,
+  "The number of lines from standard input"
+);
+
+// Records measurements
+stats.record({
+  measure: mLineLengths,
+  tags,
+  value: 2
+});
+
 ```
 
 ##### New code
 ```js
-// Get the global singleton stats object
+// Gets the global stats instance
 const { globalStats } = require("@opencensus/core");
 
-// Create the view
-const view = globalStats.createView(...);
-
-// register the view
+// Counts/groups the lengths of lines read in.
+const mLineLengths = globalStats.createMeasureInt64(
+  "demo/line_lengths",
+  MeasureUnit.BYTE,
+  "The distribution of line lengths"
+);
+
+// Creates the method and status key
+const methodKey = {name: "method"};
+const statusKey = {name: "status"};
+
+// Creates the view
+const view = globalStats.createView(
+  "demo/lines_in",
+  mLineLengths,
+  AggregationType.COUNT,
+  [methodKey, statusKey],
+  "The number of lines from standard input"
+);
+
+// Registers the view
 globalStats.registerView(view);
+
+// Creates tags map -> key/value pair
+const tagMap = new TagMap();
+tagMap.set(methodKey, {value: 'REPL'});
+tagMap.set(statusKey, {value: 'OK'});
+
+// Creates measurements (measure + value)
+const measurements = [{
+  measure: mLineLengths,
+  value: 2
+}];
+
+// Records measurement with tagMap
+globalStats.record(measurements, tagMap);
 ```
 
 ## 0.0.8 - 2018-12-14

packages/opencensus-core/src/exporters/console-exporter.ts

@@ -16,6 +16,7 @@
 
 import * as loggerTypes from '../common/types';
 import {Measurement, View} from '../stats/types';
+import {TagKey, TagValue} from '../tags/types';
 import * as modelTypes from '../trace/model/types';
 
 import {ExporterBuffer} from './exporter-buffer';
@@ -93,7 +94,8 @@ export class ConsoleStatsExporter implements types.StatsEventListener {
    * @param view recorded view from measurement
    * @param measurement recorded measurement
    */
-  onRecord(views: View[], measurement: Measurement) {
+  onRecord(
+      views: View[], measurement: Measurement, tags: Map<TagKey, TagValue>) {
     console.log(`Measurement recorded: ${measurement.measure.name}`);
   }
 

packages/opencensus-core/src/exporters/types.ts

@@ -15,6 +15,7 @@
  */
 
 import {Measurement, View} from '../stats/types';
+import {TagKey, TagValue} from '../tags/types';
 import * as configTypes from '../trace/config/types';
 import * as modelTypes from '../trace/model/types';
 
@@ -44,7 +45,9 @@ export interface StatsEventListener {
    * @param views The views related to the measurement
    * @param measurement The recorded measurement
    */
-  onRecord(views: View[], measurement: Measurement): void;
+  onRecord(
+      views: View[], measurement: Measurement,
+      tags: Map<TagKey, TagValue>): void;
 
   /**
    * Starts the exporter that polls Metric from Metrics library and send

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

@@ -15,9 +15,10 @@
  */
 
 
-import {LabelKey, LabelValue, MetricDescriptor, MetricDescriptorType} from '../metrics/export/types';
+import {LabelValue, MetricDescriptor, MetricDescriptorType} from '../metrics/export/types';
+import {TagValue} from '../tags/types';
 
-import {AggregationType, Measure, MeasureType, Tags, View} from './types';
+import {AggregationType, Measure, MeasureType, View} from './types';
 
 /** Utils to convert Stats data models to Metric data models */
 export class MetricUtils {
@@ -61,25 +62,24 @@ export class MetricUtils {
    * @returns {MetricDescriptor}
    */
   static viewToMetricDescriptor(view: View): MetricDescriptor {
-    // TODO(mayurkale): add description
     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, description: ''} as LabelKey))
+          // TODO(mayurkale): add description
+          tagKey => ({key: tagKey.name, description: ''}))
     };
   }
 
   /**
-   * Converts tags to label values.
-   * @param tags
+   * Converts tag values to label values.
+   * @param tagValues
    * @returns {LabelValue[]} List of label values
    */
-  static tagsToLabelValues(tags: Tags): LabelValue[] {
-    return Object.keys(tags).map(key => {
-      return {value: tags[key]} as LabelValue;
-    });
+  static tagValuesToLabelValues(tagValues: TagValue[]): LabelValue[] {
+    return tagValues.map(
+        (tagValue) => ({value: tagValue ? tagValue.value : null}));
   }
 }

packages/opencensus-core/src/stats/recorder.ts

@@ -14,8 +14,11 @@
  * limitations under the License.
  */
 
+import {TagKey, TagValue} from '../tags/types';
 import {AggregationData, AggregationType, CountData, DistributionData, LastValueData, Measurement, MeasureType, SumData} from './types';
 
+const UNKNOWN_TAG_VALUE: TagValue = null;
+
 export class Recorder {
   static addMeasurement(
       aggregationData: AggregationData,
@@ -40,6 +43,15 @@ export class Recorder {
     }
   }
 
+  /** Gets the tag values from tags and columns */
+  static getTagValues(tags: Map<TagKey, TagValue>, columns: TagKey[]):
+      TagValue[] {
+    return columns.map(
+        (tagKey) =>
+            (tags.get(tagKey) ||
+             /** replace not found key values by null. */ UNKNOWN_TAG_VALUE));
+  }
+
   private static addToDistribution(
       distributionData: DistributionData, value: number): DistributionData {
     distributionData.count += 1;

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

@@ -19,6 +19,8 @@ import * as loggerTypes from '../common/types';
 import {StatsEventListener} from '../exporters/types';
 import {Metric} from '../metrics/export/types';
 import {Metrics} from '../metrics/metrics';
+import {TagMap} from '../tags/tag-map';
+import {TagKey} from '../tags/types';
 
 import {MetricProducerForStats} from './metric-producer';
 import {AggregationType, Measure, Measurement, MeasureType, MeasureUnit, Stats, View} from './types';
@@ -83,7 +85,7 @@ export class BaseStats implements Stats {
    */
   createView(
       name: string, measure: Measure, aggregation: AggregationType,
-      tagKeys: string[], description: string,
+      tagKeys: TagKey[], description: string,
       bucketBoundaries?: number[]): View {
     const view = new BaseView(
         name, measure, aggregation, tagKeys, description, bucketBoundaries);
@@ -156,27 +158,35 @@ export class BaseStats implements Stats {
   /**
    * Updates all views with the new measurements.
    * @param measurements A list of measurements to record
+   * @param tags optional The tags to which the value is applied.
+   *  tags could either be explicitly passed to the method, or implicitly
+   *  read from current execution context.
    */
-  record(...measurements: Measurement[]): void {
+  record(measurements: Measurement[], tags?: TagMap): void {
     if (this.hasNegativeValue(measurements)) {
       this.logger.warn(`Dropping measurments ${measurements}, value to record
           must be non-negative.`);
       return;
     }
 
+    if (!tags) {
+      // TODO(mayurkale): read tags current execution context
+      tags = new TagMap();
+    }
+
     for (const measurement of measurements) {
       const views = this.registeredViews[measurement.measure.name];
       if (!views) {
         break;
       }
       // Updates all views
       for (const view of views) {
-        view.recordMeasurement(measurement);
+        view.recordMeasurement(measurement, tags);
       }
 
       // Notifies all exporters
       for (const exporter of this.statsEventListeners) {
-        exporter.onRecord(views, measurement);
+        exporter.onRecord(views, measurement, tags.tags);
       }
     }
   }

packages/opencensus-core/src/stats/types.ts

@@ -16,6 +16,8 @@
 
 import {StatsEventListener} from '../exporters/types';
 import {Metric} from '../metrics/export/types';
+import {TagMap} from '../tags/tag-map';
+import {TagKey, TagValue} from '../tags/types';
 
 /** Main interface for stats. */
 export interface Stats {
@@ -31,7 +33,7 @@ export interface Stats {
    */
   createView(
       name: string, measure: Measure, aggregation: AggregationType,
-      tagKeys: string[], description: string,
+      tagKeys: TagKey[], description: string,
       bucketBoundaries?: number[]): View;
 
   /**
@@ -62,8 +64,11 @@ export interface Stats {
   /**
    * Updates all views with the new measurements.
    * @param measurements A list of measurements to record
+   * @param tags optional The tags to which the value is applied.
+   *  tags could either be explicitly passed to the method, or implicitly
+   *  read from current execution context.
    */
-  record(...measurements: Measurement[]): void;
+  record(measurements: Measurement[], tags?: TagMap): void;
 
   /**
    * Remove all registered Views and exporters from the stats.
@@ -83,12 +88,6 @@ export interface Stats {
   registerExporter(exporter: StatsEventListener): void;
 }
 
-
-/** Tags are maps of names -> values */
-export interface Tags {
-  [key: string]: string;
-}
-
 /**
  * Describes the type of the individual values/measurements recorded by an
  * application. It includes information such as the type of measurement, the
@@ -140,8 +139,6 @@ export interface Measurement {
    * up to Number.MAX_SAFE_INTERGER.
    */
   readonly value: number;
-  /** The tags to which the value is applied */
-  readonly tags: Tags;
 }
 
 /**
@@ -176,15 +173,16 @@ export interface View {
    *
    * Measurements with measurement type INT64 will have its value truncated.
    * @param measurement The measurement to record
+   * @param tags The tags to which the value is applied
    */
-  recordMeasurement(measurement: Measurement): void;
+  recordMeasurement(measurement: Measurement, tags: TagMap): void;
   /**
    * Returns a snapshot of an AggregationData for that tags/labels values.
-   * @param tags The desired data's tags
+   * @param tagValues The desired data's tag values.
    */
-  getSnapshot(tags: Tags): AggregationData;
+  getSnapshot(tagValues: TagValue[]): AggregationData;
   /** Gets the view's tag keys */
-  getColumns(): string[];
+  getColumns(): TagKey[];
   /** Gets view`s metric */
   getMetric(start: number): Metric;
 }
@@ -204,8 +202,8 @@ export enum AggregationType {
 export interface AggregationMetadata {
   /** The aggregation type of the aggregation data */
   readonly type: AggregationType;
-  /** The tags/labels that this AggregationData collects and aggregates */
-  readonly tags: Tags;
+  /** The tagValues that this AggregationData collects and aggregates */
+  readonly tagValues: TagValue[];
   /** The latest timestamp a new data point was recorded */
   timestamp: number;
 }