Add MetricProducerManager to keep track of all MetricProducers (#253)

* Add MetricProducerManager to keep set of MetricProducer

* fix review comments

* fix review comments

* Fix JSDoc and change copyright 2018 -> 2019

* Fix JSDoc comments

packages/opencensus-core/src/metrics/export/metric-producer.ts → packages/opencensus-core/src/metrics/export/base-metric-producer.ts

@@ -14,13 +14,13 @@
  * limitations under the License.
  */
 
-import {Metric} from './types';
+import {Metric, MetricProducer} from './types';
 
 /**
  * A MetricProducer producer that can be registered for exporting using
  * MetricProducerManager.
  */
-export abstract class MetricProducer {
+export abstract class BaseMetricProducer implements MetricProducer {
   /**
    * Gets a collection of produced Metric`s to be exported.
    * @returns {Metric[]} List of metrics

packages/opencensus-core/src/metrics/export/metric-producer-manager.ts

@@ -0,0 +1,69 @@
+/**
+ * Copyright 2019, 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 {validateNotNull} from '../../common/validations';
+import {MetricProducer, MetricProducerManager} from './types';
+
+/**
+ * Keeps a set of MetricProducer that is used by exporters to determine the
+ * metrics that need to be exported.
+ */
+class BaseMetricProducerManager implements MetricProducerManager {
+  private metricProducers: Set<MetricProducer> = new Set<MetricProducer>();
+
+  /**
+   * Adds the MetricProducer to the manager if it is not already present.
+   *
+   * @param {MetricProducer} The MetricProducer to be added to the manager.
+   */
+  add(metricProducer: MetricProducer): void {
+    validateNotNull(metricProducer, 'metricProducer');
+    if (!this.metricProducers.has(metricProducer)) {
+      this.metricProducers.add(metricProducer);
+    }
+  }
+
+  /**
+   * Removes the MetricProducer to the manager if it is present.
+   *
+   * @param {MetricProducer} The MetricProducer to be removed from the manager.
+   */
+  remove(metricProducer: MetricProducer): void {
+    validateNotNull(metricProducer, 'metricProducer');
+    this.metricProducers.delete(metricProducer);
+  }
+
+  /**
+   * Clears all MetricProducers.
+   */
+  removeAll(): void {
+    this.metricProducers.clear();
+  }
+
+  /**
+   * Returns all registered MetricProducers that should be exported.
+   *
+   * This method should be used by any metrics exporter that automatically
+   * exports data for MetricProducer registered with the MetricProducerManager.
+   *
+   * @return {Set<MetricProducer>} The Set of MetricProducers.
+   */
+  getAllMetricProducer(): Set<MetricProducer> {
+    return this.metricProducers;
+  }
+}
+
+export const metricProducerManagerInstance = new BaseMetricProducerManager();

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

@@ -326,3 +326,27 @@ export interface Timestamp {
    */
   nanos: number|null;
 }
+
+/**
+ * Keeps a set of MetricProducer that is used by exporters to determine the
+ * metrics that need to be exported.
+ */
+export interface MetricProducerManager {
+  /** Adds the MetricProducer to the manager */
+  add(metricProducer: MetricProducer): void;
+  /** Removes the MetricProducer to the manager */
+  remove(metricProducer: MetricProducer): void;
+  /** Clears all MetricProducers */
+  removeAll(): void;
+  /** Gets all registered MetricProducers that should be exported */
+  getAllMetricProducer(): Set<MetricProducer>;
+}
+
+/**
+ * A MetricProducer producer that can be registered for exporting using
+ * MetricProducerManager.
+ */
+export interface MetricProducer {
+  /** Gets a collection of produced Metric`s to be exported */
+  getMetrics(): Metric[];
+}

packages/opencensus-core/src/metrics/metric-component.ts

@@ -0,0 +1,42 @@
+/**
+ * Copyright 2019, 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 {metricProducerManagerInstance} from './export/metric-producer-manager';
+import {MetricRegistry} from './metric-registry';
+
+/**
+ * Class that holds the implementation instance for MetricRegistry.
+ */
+export class MetricsComponent {
+  private metricRegistry: MetricRegistry;
+
+  constructor() {
+    this.metricRegistry = new MetricRegistry();
+
+    // Register the MetricRegistry's MetricProducer to the global
+    // MetricProducerManager.
+    metricProducerManagerInstance.add(this.metricRegistry.getMetricProducer());
+  }
+
+  /**
+   * Returns the MetricRegistry.
+   *
+   * @return {MetricRegistry}.
+   */
+  getMetricRegistry(): MetricRegistry {
+    return this.metricRegistry;
+  }
+}

packages/opencensus-core/src/metrics/metric-registry.ts

@@ -15,10 +15,10 @@
  */
 
 import {validateArrayElementsNotNull, validateNotNull} from '../common/validations';
-import {MeasureUnit} from '../stats/types';
+import {MeasureUnit,} from '../stats/types';
 
-import {MetricProducer} from './export/metric-producer';
-import {LabelKey, Metric, MetricDescriptorType} from './export/types';
+import {BaseMetricProducer} from './export/base-metric-producer';
+import {LabelKey, Metric, MetricDescriptorType, MetricProducer} from './export/types';
 import {DerivedGauge} from './gauges/derived-gauge';
 import {Gauge} from './gauges/gauge';
 import {Meter} from './gauges/types';
@@ -184,7 +184,7 @@ export class MetricRegistry {
  *  MetricProducer that is used by exporters to determine the metrics that
  *  need to be exported.
  */
-class MetricProducerForRegistry extends MetricProducer {
+class MetricProducerForRegistry extends BaseMetricProducer {
   private registeredMetrics: Map<string, Meter>;
 
   constructor(registeredMetrics: Map<string, Meter>) {

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

@@ -14,21 +14,24 @@
  * limitations under the License.
  */
 
+import {metricProducerManagerInstance} from './export/metric-producer-manager';
+import {MetricProducerManager} from './export/types';
+import {MetricsComponent} from './metric-component';
 import {MetricRegistry} from './metric-registry';
 
+/**
+ * Class for accessing the default MetricsComponent.
+ */
 export class Metrics {
-  private static readonly METRIC_REGISTRY = Metrics.newMetricRegistry();
+  private static readonly METRIC_COMPONENT = new MetricsComponent();
 
-  /**
-   * Returns the global MetricRegistry.
-   *
-   * @return {MetricRegistry}.
-   */
-  static getMetricRegistry(): MetricRegistry {
-    return Metrics.METRIC_REGISTRY;
+  /** @return {MetricProducerManager} The global MetricProducerManager. */
+  static getMetricProducerManager(): MetricProducerManager {
+    return metricProducerManagerInstance;
   }
 
-  private static newMetricRegistry(): MetricRegistry {
-    return new MetricRegistry();
+  /** @return {MetricRegistry} The global MetricRegistry. */
+  static getMetricRegistry(): MetricRegistry {
+    return Metrics.METRIC_COMPONENT.getMetricRegistry();
   }
 }

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

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {MetricProducer} from '../metrics/export/metric-producer';
+import {BaseMetricProducer} from '../metrics/export/base-metric-producer';
 import {Metric} from '../metrics/export/types';
 
 import {Stats} from './stats';
@@ -23,7 +23,7 @@ import {Stats} from './stats';
  * A MetricProducer producer that can be registered for exporting using
  * MetricProducerManager.
  */
-export class MetricProducerForStats extends MetricProducer {
+export class MetricProducerForStats extends BaseMetricProducer {
   private statsManager: Stats;
 
   /**

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

@@ -36,6 +36,14 @@ export class Stats {
    */
   constructor(logger = defaultLogger) {
     this.logger = logger.logger();
+
+    // TODO (mayurkale): Decide how to inject MetricProducerForStats.
+    // It should be something like below, but looks like not the right place.
+
+    // Create a new MetricProducerForStats and register it to
+    // MetricProducerManager when Stats is initialized.
+    // const metricProducer: MetricProducer = new MetricProducerForStats(this);
+    // Metrics.getMetricProducerManager().add(metricProducer);
   }
 
   /**

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

@@ -0,0 +1,34 @@
+/**
+ * Copyright 2019, 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 {metricProducerManagerInstance} from '../src/metrics/export/metric-producer-manager';
+import {MetricsComponent} from '../src/metrics/metric-component';
+import {MetricRegistry} from '../src/metrics/metric-registry';
+
+describe('MetricsComponent()', () => {
+  const metricsComponent: MetricsComponent = new MetricsComponent();
+
+  it('should return a MetricRegistry instance', () => {
+    assert.ok(metricsComponent.getMetricRegistry() instanceof MetricRegistry);
+  });
+
+  it('should register metricRegistry to MetricProducerManger', () => {
+    assert.equal(metricProducerManagerInstance.getAllMetricProducer().size, 1);
+    assert.ok(metricProducerManagerInstance.getAllMetricProducer().has(
+        metricsComponent.getMetricRegistry().getMetricProducer()));
+  });
+});

packages/opencensus-core/test/test-metric-producer-manager.ts

@@ -0,0 +1,91 @@
+/**
+ * Copyright 2019, 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 {metricProducerManagerInstance} from '../src/metrics/export/metric-producer-manager';
+import {MetricRegistry} from '../src/metrics/metric-registry';
+
+describe('MetricProducerManager()', () => {
+  const registry: MetricRegistry = new MetricRegistry();
+  const metricProducer = registry.getMetricProducer();
+  const registryOther: MetricRegistry = new MetricRegistry();
+  const metricProducerOther = registryOther.getMetricProducer();
+
+  beforeEach(() => {
+    metricProducerManagerInstance.removeAll();
+  });
+
+  describe('add()', () => {
+    it('should throw an error when the metricproducer is null', () => {
+      assert.throws(() => {
+        metricProducerManagerInstance.add(null);
+      }, /^Error: Missing mandatory metricProducer parameter$/);
+    });
+
+    it('add metricproducer', () => {
+      metricProducerManagerInstance.add(metricProducer);
+      const metricProducerList =
+          metricProducerManagerInstance.getAllMetricProducer();
+
+      assert.notDeepEqual(metricProducerList, null);
+      assert.equal(metricProducerList.size, 1);
+    });
+
+    it('should not add same metricproducer metricProducerManagerInstance',
+       () => {
+         metricProducerManagerInstance.add(metricProducer);
+         metricProducerManagerInstance.add(metricProducer);
+         metricProducerManagerInstance.add(metricProducer);
+         const metricProducerList =
+             metricProducerManagerInstance.getAllMetricProducer();
+
+         assert.equal(metricProducerList.size, 1);
+         assert.ok(metricProducerList.has(metricProducer));
+       });
+
+    it('should add different metricproducer metricProducerManagerInstance',
+       () => {
+         metricProducerManagerInstance.add(metricProducer);
+         metricProducerManagerInstance.add(metricProducerOther);
+         const metricProducerList =
+             metricProducerManagerInstance.getAllMetricProducer();
+
+         assert.equal(metricProducerList.size, 2);
+         assert.ok(metricProducerList.has(metricProducer));
+         assert.ok(metricProducerList.has(metricProducerOther));
+       });
+  });
+
+  describe('remove()', () => {
+    it('should throw an error when the metricproducer is null', () => {
+      assert.throws(() => {
+        metricProducerManagerInstance.add(null);
+      }, /^Error: Missing mandatory metricProducer parameter$/);
+    });
+
+    it('remove metricproducer', () => {
+      metricProducerManagerInstance.add(metricProducer);
+
+      const metricProducerList =
+          metricProducerManagerInstance.getAllMetricProducer();
+      assert.equal(metricProducerList.size, 1);
+      assert.ok(metricProducerList.has(metricProducer));
+
+      metricProducerManagerInstance.remove(metricProducer);
+      assert.equal(metricProducerList.size, 0);
+    });
+  });
+});