Aggregators refactoring

packages/opentelemetry-exporter-prometheus/test/prometheus.test.ts

@@ -21,6 +21,7 @@ import {
   Meter,
   MeterProvider,
   Point,
+  Sum,
 } from '@opentelemetry/metrics';
 import * as assert from 'assert';
 import * as http from 'http';
@@ -30,10 +31,10 @@ const mockedHrTime: HrTime = [1586347902211, 0];
 const mockedTimeMS = 1586347902211000;
 
 describe('PrometheusExporter', () => {
-  let toPoint: () => Point;
+  let toPoint: () => Point<Sum>;
   before(() => {
     toPoint = SumAggregator.prototype.toPoint;
-    SumAggregator.prototype.toPoint = function (): Point {
+    SumAggregator.prototype.toPoint = function (): Point<Sum> {
       const point = toPoint.apply(this);
       point.timestamp = mockedHrTime;
       return point;

packages/opentelemetry-metrics/src/export/aggregators/MinMaxLastSumCount.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { Aggregator, Point } from '../types';
+import { Aggregator, AggregatorKind, Point } from '../types';
 import { HrTime } from '@opentelemetry/api';
 import { hrTime } from '@opentelemetry/core';
 import { Distribution } from '../types';
@@ -23,6 +23,7 @@ import { Distribution } from '../types';
  * Basic aggregator keeping all raw values (events, sum, max, last and min).
  */
 export class MinMaxLastSumCountAggregator implements Aggregator {
+  public kind = AggregatorKind.MIN_MAX_LAST_SUM_COUNT;
   private _distribution: Distribution;
   private _lastUpdateTime: HrTime = [0, 0];
 
@@ -45,7 +46,7 @@ export class MinMaxLastSumCountAggregator implements Aggregator {
     this._lastUpdateTime = hrTime();
   }
 
-  toPoint(): Point {
+  toPoint(): Point<Distribution> {
     return {
       value: this._distribution,
       timestamp: this._lastUpdateTime,

packages/opentelemetry-metrics/src/export/aggregators/Sum.ts

@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import { Aggregator, Point } from '../types';
+import { Aggregator, AggregatorKind, Point, Sum } from '../types';
 import { HrTime } from '@opentelemetry/api';
 import { hrTime } from '@opentelemetry/core';
 
 /** Basic aggregator which calculates a Sum from individual measurements. */
 export class SumAggregator implements Aggregator {
+  public kind = AggregatorKind.SUM;
   private _current: number = 0;
   private _lastUpdateTime: HrTime = [0, 0];
 
@@ -28,7 +29,7 @@ export class SumAggregator implements Aggregator {
     this._lastUpdateTime = hrTime();
   }
 
-  toPoint(): Point {
+  toPoint(): Point<Sum> {
     return {
       value: this._current,
       timestamp: this._lastUpdateTime,

packages/opentelemetry-metrics/src/export/aggregators/histogram.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { Aggregator, Point, Histogram } from '../types';
+import { Aggregator, Point, Histogram, AggregatorKind } from '../types';
 import { HrTime } from '@opentelemetry/api';
 import { hrTime } from '@opentelemetry/core';
 
@@ -23,6 +23,7 @@ import { hrTime } from '@opentelemetry/core';
  * and provides the total sum and count of all observations.
  */
 export class HistogramAggregator implements Aggregator {
+  public kind = AggregatorKind.HISTOGRAM;
   private _lastCheckpoint: Histogram;
   private _currentCheckpoint: Histogram;
   private _lastCheckpointTime: HrTime;
@@ -61,7 +62,7 @@ export class HistogramAggregator implements Aggregator {
     this._currentCheckpoint = this._newEmptyCheckpoint();
   }
 
-  toPoint(): Point {
+  toPoint(): Point<Histogram> {
     return {
       value: this._lastCheckpoint,
       timestamp: this._lastCheckpointTime,

packages/opentelemetry-metrics/src/export/types.ts

@@ -42,6 +42,15 @@ export interface Distribution {
   sum: number;
 }
 
+export enum AggregatorKind {
+  SUM = ' SUM',
+  MIN_MAX_LAST_SUM_COUNT = 'MIN_MAX_LAST_SUM_COUNT',
+  DISTRIBUTION = 'DISTRIBUTION',
+  HISTOGRAM = 'HISTOGRAM',
+}
+
+export type AggregatorTypes = Sum | LastValue | Distribution | Histogram;
+
 export interface Histogram {
   /**
    * Buckets are implemented using two different array:
@@ -104,14 +113,17 @@ export interface MetricExporter {
  * aggregated values and taking a snapshot of these values upon export.
  */
 export interface Aggregator {
+  /** Kind of aggregator. */
+  kind: AggregatorKind;
+
   /** Updates the current with the new value. */
   update(value: number): void;
 
   /** Returns snapshot of the current point (value with timestamp). */
-  toPoint(): Point;
+  toPoint(): Point<AggregatorTypes>;
 }
 
-export interface Point {
-  value: Sum | LastValue | Distribution | Histogram;
+export interface Point<T> {
+  value: T;
   timestamp: HrTime;
 }

packages/opentelemetry-metrics/test/Meter.test.ts

@@ -21,7 +21,6 @@ import {
   Metric,
   CounterMetric,
   MetricKind,
-  Sum,
   MeterProvider,
   ValueRecorderMetric,
   ValueObserverMetric,
@@ -566,16 +565,13 @@ describe('Meter', () => {
 
         await meter.collect();
         const [record1] = meter.getBatcher().checkPointSet();
-        assert.deepStrictEqual(
-          record1.aggregator.toPoint().value as Distribution,
-          {
-            count: 0,
-            last: 0,
-            max: -Infinity,
-            min: Infinity,
-            sum: 0,
-          }
-        );
+        assert.deepStrictEqual(record1.aggregator.toPoint().value, {
+          count: 0,
+          last: 0,
+          max: -Infinity,
+          min: Infinity,
+          sum: 0,
+        });
       });
 
       it('should not set the instrument data when disabled', async () => {
@@ -587,16 +583,13 @@ describe('Meter', () => {
 
         await meter.collect();
         const [record1] = meter.getBatcher().checkPointSet();
-        assert.deepStrictEqual(
-          record1.aggregator.toPoint().value as Distribution,
-          {
-            count: 0,
-            last: 0,
-            max: -Infinity,
-            min: Infinity,
-            sum: 0,
-          }
-        );
+        assert.deepStrictEqual(record1.aggregator.toPoint().value, {
+          count: 0,
+          last: 0,
+          max: -Infinity,
+          min: Infinity,
+          sum: 0,
+        });
       });
 
       it(
@@ -612,16 +605,13 @@ describe('Meter', () => {
 
           await meter.collect();
           const [record1] = meter.getBatcher().checkPointSet();
-          assert.deepStrictEqual(
-            record1.aggregator.toPoint().value as Distribution,
-            {
-              count: 2,
-              last: 50,
-              max: 50,
-              min: -10,
-              sum: 40,
-            }
-          );
+          assert.deepStrictEqual(record1.aggregator.toPoint().value, {
+            count: 2,
+            last: 50,
+            max: 50,
+            min: -10,
+            sum: 40,
+          });
           assert.ok(
             hrTimeToNanoseconds(record1.aggregator.toPoint().timestamp) >
               hrTimeToNanoseconds(performanceTimeOrigin)
@@ -639,16 +629,13 @@ describe('Meter', () => {
         boundValueRecorder2.record(100);
         await meter.collect();
         const [record1] = meter.getBatcher().checkPointSet();
-        assert.deepStrictEqual(
-          record1.aggregator.toPoint().value as Distribution,
-          {
-            count: 2,
-            last: 100,
-            max: 100,
-            min: 10,
-            sum: 110,
-          }
-        );
+        assert.deepStrictEqual(record1.aggregator.toPoint().value, {
+          count: 2,
+          last: 100,
+          max: 100,
+          min: 10,
+          sum: 110,
+        });
         assert.strictEqual(boundValueRecorder1, boundValueRecorder2);
       });
     });
@@ -1234,7 +1221,7 @@ describe('Meter', () => {
             const value = cpuUsageMetric
               .bind({ foo: 'bar' })
               .getAggregator()
-              .toPoint().value as Distribution;
+              .toPoint().value;
 
             assert.deepStrictEqual(value, {
               count: 0,
@@ -1294,7 +1281,7 @@ describe('Meter', () => {
         valueType: api.ValueType.DOUBLE,
       });
       assert.strictEqual(record[0].labels, labels);
-      const value = record[0].aggregator.toPoint().value as Sum;
+      const value = record[0].aggregator.toPoint().value;
       assert.strictEqual(value, 10.45);
     });
 
@@ -1320,7 +1307,7 @@ describe('Meter', () => {
         valueType: api.ValueType.INT,
       });
       assert.strictEqual(record[0].labels, labels);
-      const value = record[0].aggregator.toPoint().value as Sum;
+      const value = record[0].aggregator.toPoint().value;
       assert.strictEqual(value, 10);
     });
   });
@@ -1351,7 +1338,7 @@ function ensureMetric(
   value?: Distribution
 ) {
   assert.ok(metric.aggregator instanceof MinMaxLastSumCountAggregator);
-  const distribution = metric.aggregator.toPoint().value as Distribution;
+  const distribution = metric.aggregator.toPoint().value;
   if (value) {
     assert.deepStrictEqual(distribution, value);
   } else {

packages/opentelemetry-metrics/test/export/aggregators/histogram.test.ts

@@ -16,7 +16,6 @@
 
 import * as assert from 'assert';
 import { HistogramAggregator } from '../../../src/export/aggregators';
-import { Histogram } from '../../../src';
 
 describe('HistogramAggregator', () => {
   describe('constructor()', () => {
@@ -28,7 +27,7 @@ describe('HistogramAggregator', () => {
 
     it('should sort boundaries', () => {
       const aggregator = new HistogramAggregator([500, 300, 700]);
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.deepEqual(point.buckets.boundaries, [300, 500, 700]);
     });
 
@@ -43,7 +42,7 @@ describe('HistogramAggregator', () => {
     it('should not update checkpoint', () => {
       const aggregator = new HistogramAggregator([100, 200]);
       aggregator.update(150);
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.equal(point.count, 0);
       assert.equal(point.sum, 0);
     });
@@ -52,7 +51,7 @@ describe('HistogramAggregator', () => {
       const aggregator = new HistogramAggregator([100, 200]);
       aggregator.update(150);
       aggregator.reset();
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.equal(point.count, 1);
       assert.equal(point.sum, 150);
       assert.equal(point.buckets.counts[0], 0);
@@ -64,7 +63,7 @@ describe('HistogramAggregator', () => {
       const aggregator = new HistogramAggregator([100, 200]);
       aggregator.update(50);
       aggregator.reset();
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.equal(point.count, 1);
       assert.equal(point.sum, 50);
       assert.equal(point.buckets.counts[0], 1);
@@ -76,7 +75,7 @@ describe('HistogramAggregator', () => {
       const aggregator = new HistogramAggregator([100, 200]);
       aggregator.update(250);
       aggregator.reset();
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.equal(point.count, 1);
       assert.equal(point.sum, 250);
       assert.equal(point.buckets.counts[0], 0);
@@ -88,11 +87,11 @@ describe('HistogramAggregator', () => {
   describe('.count', () => {
     it('should return last checkpoint count', () => {
       const aggregator = new HistogramAggregator([100]);
-      let point = aggregator.toPoint().value as Histogram;
+      let point = aggregator.toPoint().value;
       assert.equal(point.count, point.count);
       aggregator.update(10);
       aggregator.reset();
-      point = aggregator.toPoint().value as Histogram;
+      point = aggregator.toPoint().value;
       assert.equal(point.count, 1);
       assert.equal(point.count, point.count);
     });
@@ -101,19 +100,19 @@ describe('HistogramAggregator', () => {
   describe('.sum', () => {
     it('should return last checkpoint sum', () => {
       const aggregator = new HistogramAggregator([100]);
-      let point = aggregator.toPoint().value as Histogram;
+      let point = aggregator.toPoint().value;
       assert.equal(point.sum, point.sum);
       aggregator.update(10);
       aggregator.reset();
-      point = aggregator.toPoint().value as Histogram;
+      point = aggregator.toPoint().value;
       assert.equal(point.sum, 10);
     });
   });
 
   describe('.reset()', () => {
     it('should create a empty checkoint by default', () => {
       const aggregator = new HistogramAggregator([100]);
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.deepEqual(point.buckets.boundaries, [100]);
       assert(point.buckets.counts.every(count => count === 0));
       // should contains one bucket for each boundary + one for values outside of the largest boundary
@@ -127,7 +126,7 @@ describe('HistogramAggregator', () => {
       const aggregator = new HistogramAggregator([100]);
       aggregator.update(10);
       aggregator.reset();
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.equal(point.count, 1);
       assert.equal(point.sum, 10);
       assert.deepEqual(point.buckets.boundaries, [100]);
@@ -139,7 +138,7 @@ describe('HistogramAggregator', () => {
   describe('.toPoint()', () => {
     it('should return default checkpoint', () => {
       const aggregator = new HistogramAggregator([100]);
-      const point = aggregator.toPoint().value as Histogram;
+      const point = aggregator.toPoint().value;
       assert.deepEqual(aggregator.toPoint().value, point);
       assert(aggregator.toPoint().timestamp.every(nbr => nbr > 0));
     });