feat: exponential histogram - part 3 - export (open-telemetry#3506)

CHANGELOG.md

@@ -11,7 +11,7 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 
 ### :rocket: (Enhancement)
 
-* feat(sdk-metrics): add exponential histogram accumulation / aggregator [#3505](https://github.com/open-telemetry/opentelemetry-js/pull/3505) @mwear
+* feat(sdk-metrics): add exponential histogram support [#3505](https://github.com/open-telemetry/opentelemetry-js/pull/3505), [#3506](https://github.com/open-telemetry/opentelemetry-js/pull/3506) @mwear
 * feat(resources): collect additional process attributes [#3605](https://github.com/open-telemetry/opentelemetry-js/pull/3605) @mwear
 
 ### :bug: (Bug Fix)

experimental/packages/otlp-transformer/src/metrics/internal.ts

@@ -28,6 +28,7 @@ import {
 import { toAttributes } from '../common/internal';
 import {
   EAggregationTemporality,
+  IExponentialHistogramDataPoint,
   IHistogramDataPoint,
   IMetric,
   INumberDataPoint,
@@ -91,6 +92,11 @@ export function toMetric(metricData: MetricData): IMetric {
       aggregationTemporality,
       dataPoints: toHistogramDataPoints(metricData),
     };
+  } else if (metricData.dataPointType === DataPointType.EXPONENTIAL_HISTOGRAM) {
+    out.exponentialHistogram = {
+      aggregationTemporality,
+      dataPoints: toExponentialHistogramDataPoints(metricData),
+    };
   }
 
   return out;
@@ -141,6 +147,33 @@ function toHistogramDataPoints(metricData: MetricData): IHistogramDataPoint[] {
   });
 }
 
+function toExponentialHistogramDataPoints(
+  metricData: MetricData
+): IExponentialHistogramDataPoint[] {
+  return metricData.dataPoints.map(dataPoint => {
+    const histogram = dataPoint.value as ExponentialHistogram;
+    return {
+      attributes: toAttributes(dataPoint.attributes),
+      count: histogram.count,
+      min: histogram.min,
+      max: histogram.max,
+      sum: histogram.sum,
+      positive: {
+        offset: histogram.positive.offset,
+        bucketCounts: histogram.positive.bucketCounts,
+      },
+      negative: {
+        offset: histogram.negative.offset,
+        bucketCounts: histogram.negative.bucketCounts,
+      },
+      scale: histogram.scale,
+      zeroCount: histogram.zeroCount,
+      startTimeUnixNano: hrTimeToNanoseconds(dataPoint.startTime),
+      timeUnixNano: hrTimeToNanoseconds(dataPoint.endTime),
+    };
+  });
+}
+
 function toAggregationTemporality(
   temporality: AggregationTemporality
 ): EAggregationTemporality {

experimental/packages/otlp-transformer/src/metrics/types.ts

@@ -184,7 +184,7 @@ export interface IExponentialHistogramDataPoint {
   startTimeUnixNano?: number;
 
   /** ExponentialHistogramDataPoint timeUnixNano */
-  timeUnixNano?: string;
+  timeUnixNano?: number;
 
   /** ExponentialHistogramDataPoint count */
   count?: number;
@@ -209,6 +209,12 @@ export interface IExponentialHistogramDataPoint {
 
   /** ExponentialHistogramDataPoint exemplars */
   exemplars?: IExemplar[];
+
+  /** ExponentialHistogramDataPoint min */
+  min?: number;
+
+  /** ExponentialHistogramDataPoint max */
+  max?: number;
 }
 
 /** Properties of a SummaryDataPoint. */

experimental/packages/otlp-transformer/test/metrics.test.ts

@@ -265,6 +265,47 @@ describe('Metrics', () => {
       };
     }
 
+    function createExponentialHistogramMetrics(
+      count: number,
+      sum: number,
+      scale: number,
+      zeroCount: number,
+      positive: { offset: number; bucketCounts: number[] },
+      negative: { offset: number; bucketCounts: number[] },
+      aggregationTemporality: AggregationTemporality,
+      min?: number,
+      max?: number
+    ): MetricData {
+      return {
+        descriptor: {
+          description: 'this is a description',
+          type: InstrumentType.HISTOGRAM,
+          name: 'xhist',
+          unit: '1',
+          valueType: ValueType.INT,
+        },
+        aggregationTemporality,
+        dataPointType: DataPointType.EXPONENTIAL_HISTOGRAM,
+        dataPoints: [
+          {
+            value: {
+              sum: sum,
+              count: count,
+              min: min,
+              max: max,
+              zeroCount: zeroCount,
+              scale: scale,
+              positive: positive,
+              negative: negative,
+            },
+            startTime: START_TIME,
+            endTime: END_TIME,
+            attributes: ATTRIBUTES,
+          },
+        ],
+      };
+    }
+
     function createResourceMetrics(metricData: MetricData[]): ResourceMetrics {
       const resource = new Resource({
         'resource-attribute': 'resource attribute value',
@@ -608,5 +649,133 @@ describe('Metrics', () => {
         });
       });
     });
+
+    describe('serializes an exponential histogram metric record', () => {
+      it('with min/max', () => {
+        const exportRequest = createExportMetricsServiceRequest([
+          createResourceMetrics([
+            createExponentialHistogramMetrics(
+              3,
+              10,
+              1,
+              0,
+              { offset: 0, bucketCounts: [1, 0, 0, 0, 1, 0, 1, 0] },
+              { offset: 0, bucketCounts: [0] },
+              AggregationTemporality.CUMULATIVE,
+              1,
+              8
+            ),
+          ]),
+        ]);
+
+        assert.ok(exportRequest);
+
+        assert.deepStrictEqual(exportRequest, {
+          resourceMetrics: [
+            {
+              resource: expectedResource,
+              schemaUrl: undefined,
+              scopeMetrics: [
+                {
+                  scope: expectedScope,
+                  schemaUrl: expectedSchemaUrl,
+                  metrics: [
+                    {
+                      name: 'xhist',
+                      description: 'this is a description',
+                      unit: '1',
+                      exponentialHistogram: {
+                        aggregationTemporality:
+                          EAggregationTemporality.AGGREGATION_TEMPORALITY_CUMULATIVE,
+                        dataPoints: [
+                          {
+                            attributes: expectedAttributes,
+                            count: 3,
+                            sum: 10,
+                            min: 1,
+                            max: 8,
+                            zeroCount: 0,
+                            scale: 1,
+                            positive: {
+                              offset: 0,
+                              bucketCounts: [1, 0, 0, 0, 1, 0, 1, 0],
+                            },
+                            negative: { offset: 0, bucketCounts: [0] },
+                            startTimeUnixNano: hrTimeToNanoseconds(START_TIME),
+                            timeUnixNano: hrTimeToNanoseconds(END_TIME),
+                          },
+                        ],
+                      },
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        });
+      });
+
+      it('without min/max', () => {
+        const exportRequest = createExportMetricsServiceRequest([
+          createResourceMetrics([
+            createExponentialHistogramMetrics(
+              3,
+              10,
+              1,
+              0,
+              { offset: 0, bucketCounts: [1, 0, 0, 0, 1, 0, 1, 0] },
+              { offset: 0, bucketCounts: [0] },
+              AggregationTemporality.CUMULATIVE
+            ),
+          ]),
+        ]);
+
+        assert.ok(exportRequest);
+
+        assert.deepStrictEqual(exportRequest, {
+          resourceMetrics: [
+            {
+              resource: expectedResource,
+              schemaUrl: undefined,
+              scopeMetrics: [
+                {
+                  scope: expectedScope,
+                  schemaUrl: expectedSchemaUrl,
+                  metrics: [
+                    {
+                      name: 'xhist',
+                      description: 'this is a description',
+                      unit: '1',
+                      exponentialHistogram: {
+                        aggregationTemporality:
+                          EAggregationTemporality.AGGREGATION_TEMPORALITY_CUMULATIVE,
+                        dataPoints: [
+                          {
+                            attributes: expectedAttributes,
+                            count: 3,
+                            sum: 10,
+                            min: undefined,
+                            max: undefined,
+                            zeroCount: 0,
+                            scale: 1,
+                            positive: {
+                              offset: 0,
+                              bucketCounts: [1, 0, 0, 0, 1, 0, 1, 0],
+                            },
+                            negative: { offset: 0, bucketCounts: [0] },
+                            startTimeUnixNano: hrTimeToNanoseconds(START_TIME),
+                            timeUnixNano: hrTimeToNanoseconds(END_TIME),
+                          },
+                        ],
+                      },
+                    },
+                  ],
+                },
+              ],
+            },
+          ],
+        });
+      });
+    });
   });
 });

packages/sdk-metrics/src/aggregator/index.ts

@@ -16,6 +16,7 @@
 
 export * from './Drop';
 export * from './Histogram';
+export * from './ExponentialHistogram';
 export * from './LastValue';
 export * from './Sum';
 export { Aggregator } from './types';

packages/sdk-metrics/src/index.ts

@@ -34,6 +34,7 @@ export {
   SumMetricData,
   GaugeMetricData,
   HistogramMetricData,
+  ExponentialHistogramMetricData,
   ResourceMetrics,
   ScopeMetrics,
   MetricData,
@@ -60,6 +61,7 @@ export { MeterProvider, MeterProviderOptions } from './MeterProvider';
 export {
   DefaultAggregation,
   ExplicitBucketHistogramAggregation,
+  ExponentialHistogramAggregation,
   DropAggregation,
   HistogramAggregation,
   LastValueAggregation,

packages/sdk-metrics/src/view/Aggregation.ts

@@ -21,6 +21,7 @@ import {
   DropAggregator,
   LastValueAggregator,
   HistogramAggregator,
+  ExponentialHistogramAggregator,
 } from '../aggregator';
 import { Accumulation } from '../aggregator/types';
 import { InstrumentDescriptor, InstrumentType } from '../InstrumentDescriptor';
@@ -52,6 +53,10 @@ export abstract class Aggregation {
     return HISTOGRAM_AGGREGATION;
   }
 
+  static ExponentialHistogram(): Aggregation {
+    return EXPONENTIAL_HISTOGRAM_AGGREGATION;
+  }
+
   static Default(): Aggregation {
     return DEFAULT_AGGREGATION;
   }
@@ -144,6 +149,21 @@ export class ExplicitBucketHistogramAggregation extends Aggregation {
   }
 }
 
+export class ExponentialHistogramAggregation extends Aggregation {
+  constructor(
+    private readonly _maxSize: number = 160,
+    private readonly _recordMinMax = true
+  ) {
+    super();
+  }
+  createAggregator(_instrument: InstrumentDescriptor) {
+    return new ExponentialHistogramAggregator(
+      this._maxSize,
+      this._recordMinMax
+    );
+  }
+}
+
 /**
  * The default aggregation.
  */
@@ -179,4 +199,5 @@ const DROP_AGGREGATION = new DropAggregation();
 const SUM_AGGREGATION = new SumAggregation();
 const LAST_VALUE_AGGREGATION = new LastValueAggregation();
 const HISTOGRAM_AGGREGATION = new HistogramAggregation();
+const EXPONENTIAL_HISTOGRAM_AGGREGATION = new ExponentialHistogramAggregation();
 const DEFAULT_AGGREGATION = new DefaultAggregation();