feat(sdk-metrics-base): meter registration (open-telemetry#2666)

experimental/packages/opentelemetry-sdk-metrics-base/src/Meter.ts

@@ -34,7 +34,9 @@ export class Meter implements metrics.Meter {
 
   // instrumentation library required by spec to be on meter
   // spec requires provider config changes to apply to previously created meters, achieved by holding a reference to the provider
-  constructor(private _meterProviderSharedState: MeterProviderSharedState, private _instrumentationLibrary: InstrumentationLibrary) { }
+  constructor(private _meterProviderSharedState: MeterProviderSharedState, private _instrumentationLibrary: InstrumentationLibrary) {
+    this._meterProviderSharedState.meters.push(this);
+  }
 
   /** this exists just to prevent ts errors from unused variables and may be removed */
   getInstrumentationLibrary(): InstrumentationLibrary {

experimental/packages/opentelemetry-sdk-metrics-base/src/MeterProvider.ts

@@ -35,8 +35,8 @@ export class MeterProvider {
   private _sharedState: MeterProviderSharedState;
   private _shutdown = false;
 
-  constructor(options: MeterProviderOptions) {
-    this._sharedState = new MeterProviderSharedState(options.resource ?? Resource.empty());
+  constructor(options?: MeterProviderOptions) {
+    this._sharedState = new MeterProviderSharedState(options?.resource ?? Resource.empty());
   }
 
   getMeter(name: string, version = '', options: metrics.MeterOptions = {}): metrics.Meter {
@@ -46,10 +46,6 @@ export class MeterProvider {
         return metrics.NOOP_METER;
     }
 
-    // Spec leaves it unspecified if creating a meter with duplicate
-    // name/version returns the same meter. We create a new one here
-    // for simplicity. This may change in the future.
-    // TODO: consider returning the same meter if the same name/version is used
     return new Meter(this._sharedState, { name, version, schemaUrl: options.schemaUrl });
   }
 

experimental/packages/opentelemetry-sdk-metrics-base/src/state/MeterProviderSharedState.ts

@@ -30,7 +30,7 @@ export class MeterProviderSharedState {
 
   metricCollectors: MetricCollector[] = [];
 
-  meters: Map<string, Meter> = new Map();
+  meters: Meter[] = [];
 
   constructor(public resource: Resource) {}
 }

experimental/packages/opentelemetry-sdk-metrics-base/src/state/MetricCollector.ts

@@ -34,7 +34,7 @@ export class MetricCollector implements MetricProducer {
 
   async collect(): Promise<MetricData[]> {
     const collectionTime = hrTime();
-    const results = await Promise.all(Array.from(this._sharedState.meters.values())
+    const results = await Promise.all(this._sharedState.meters
       .map(meter => meter.collect(this, collectionTime)));
 
     return results.reduce((cumulation, current) => cumulation.concat(current), []);

experimental/packages/opentelemetry-sdk-metrics-base/test/MeterProvider.test.ts

@@ -0,0 +1,50 @@
+/*
+ * Copyright The OpenTelemetry 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
+ *
+ *      https://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 { NOOP_METER } from '@opentelemetry/api-metrics-wip';
+import { Meter } from '../src/Meter';
+import { MeterProvider } from '../src/MeterProvider';
+import { defaultResource } from './util';
+
+describe('MeterProvider', () => {
+  describe('constructor', () => {
+    it('should construct without exceptions', () => {
+      const meterProvider = new MeterProvider();
+      assert(meterProvider instanceof MeterProvider);
+    });
+
+    it('construct with resource', () => {
+      const meterProvider = new MeterProvider({ resource: defaultResource });
+      assert(meterProvider instanceof MeterProvider);
+    });
+  });
+
+  describe('getMeter', () => {
+    it('should get a meter', () => {
+      const meterProvider = new MeterProvider();
+      const meter = meterProvider.getMeter('meter1', '1.0.0');
+      assert(meter instanceof Meter);
+    });
+
+    it('get a noop meter on shutdown', () => {
+      const meterProvider = new MeterProvider();
+      meterProvider.shutdown();
+      const meter = meterProvider.getMeter('meter1', '1.0.0');
+      assert.strictEqual(meter, NOOP_METER);
+    });
+  });
+});

experimental/packages/opentelemetry-sdk-metrics-base/test/export/TestMetricReader.ts

@@ -15,6 +15,7 @@
  */
 
 import { MetricReader } from '../../src';
+import { MetricCollector } from '../../src/state/MetricCollector';
 
 /**
  * A test metric reader that implements no-op onForceFlush() and onShutdown() handlers.
@@ -27,4 +28,8 @@ export class TestMetricReader extends MetricReader {
   protected onShutdown(): Promise<void> {
     return Promise.resolve(undefined);
   }
+
+  getMetricCollector(): MetricCollector {
+    return this['_metricProducer'] as MetricCollector;
+  }
 }

experimental/packages/opentelemetry-sdk-metrics-base/test/state/MetricCollector.test.ts

@@ -16,10 +16,10 @@
 
 import * as assert from 'assert';
 import * as sinon from 'sinon';
+import { MeterProvider } from '../../src';
 import { AggregationTemporality } from '../../src/export/AggregationTemporality';
 import { MetricData, PointDataType } from '../../src/export/MetricData';
 import { MetricExporter } from '../../src/export/MetricExporter';
-import { Meter } from '../../src/Meter';
 import { MeterProviderSharedState } from '../../src/state/MeterProviderSharedState';
 import { MetricCollector } from '../../src/state/MetricCollector';
 import { defaultInstrumentationLibrary, defaultResource, assertMetricData, assertPointData } from '../util';
@@ -64,15 +64,15 @@ describe('MetricCollector', () => {
 
   describe('collect', () => {
     function setupInstruments(exporter: MetricExporter) {
-      // TODO(legendecas): setup with MeterProvider when meter identity was settled.
-      const meterProviderSharedState = new MeterProviderSharedState(defaultResource);
+      const meterProvider = new MeterProvider({ resource: defaultResource });
 
       const reader = new TestMetricReader(exporter.getPreferredAggregationTemporality());
-      const metricCollector = new MetricCollector(meterProviderSharedState, reader);
-      meterProviderSharedState.metricCollectors.push(metricCollector);
+      meterProvider.addMetricReader(reader);
+      const metricCollector = reader.getMetricCollector();
 
-      const meter = new Meter(meterProviderSharedState, defaultInstrumentationLibrary);
-      meterProviderSharedState.meters.set('test-meter', meter);
+      const meter = meterProvider.getMeter(defaultInstrumentationLibrary.name, defaultInstrumentationLibrary.version, {
+        schemaUrl: defaultInstrumentationLibrary.schemaUrl,
+      });
 
       return { metricCollector, meter };
     }