feat: implement named meter

examples/prometheus/index.js

@@ -1,9 +1,9 @@
 "use strict";
 
-const { Meter } = require("@opentelemetry/metrics");
+const { MeterRegistry } = require("@opentelemetry/metrics");
 const { PrometheusExporter } = require("@opentelemetry/exporter-prometheus");
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('example-prometheus');
 
 const exporter = new PrometheusExporter(
   {

getting-started/README.md

@@ -238,19 +238,19 @@ Create a file named `monitoring.js` and add the following code:
 ```javascript
 'use strict';
 
-const { Meter } = require("@opentelemetry/metrics");
+const { MeterRegistry } = require("@opentelemetry/metrics");
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 ```
 
 Now, you can require this file from your application code and use the `Meter` to create and manage metrics. The simplest of these metrics is a counter. Let's create and export from our `monitoring.js` file a middleware function that express can use to count all requests by route. Modify the `monitoring.js` file so that it looks like this:
 
 ```javascript
 'use strict';
 
-const { Meter } = require("@opentelemetry/metrics");
+const { MeterRegistry } = require("@opentelemetry/metrics");
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 
 const requestCount = meter.createCounter("requests", {
   monotonic: true,
@@ -301,10 +301,10 @@ Next, modify your `monitoring.js` file to look like this:
 ```javascript
 "use strict";
 
-const { Meter } = require("@opentelemetry/metrics");
+const { MeterRegistry } = require("@opentelemetry/metrics");
 const { PrometheusExporter } = require("@opentelemetry/exporter-prometheus");
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 
 meter.addExporter(
   new PrometheusExporter(

getting-started/monitored-example/monitoring.js

@@ -1,9 +1,9 @@
 "use strict";
 
-const { Meter } = require("@opentelemetry/metrics");
+const { MeterRegistry } = require("@opentelemetry/metrics");
 const { PrometheusExporter } = require("@opentelemetry/exporter-prometheus");
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('example-monitored');
 
 meter.addExporter(
   new PrometheusExporter(

getting-started/ts-example/README.md

@@ -236,18 +236,18 @@ In order to create and monitor metrics, we will need a `Meter`. In OpenTelemetry
 Create a file named `monitoring.ts` and add the following code:
 
 ```typescript
-import { Meter } from "@opentelemetry/metrics";
+import { MeterRegistry } from "@opentelemetry/metrics";
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 ```
 
 Now, you can require this file from your application code and use the `Meter` to create and manage metrics. The simplest of these metrics is a counter. Let's create and export from our `monitoring.ts` file a middleware function that express can use to count all requests by route. Modify the `monitoring.ts` file so that it looks like this:
 
 ```typescript
-import { Meter } from "@opentelemetry/metrics";
+import { MeterRegistry } from "@opentelemetry/metrics";
 import { Metric, BoundCounter } from "@opentelemetry/types";
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 
 const requestCount: Metric<BoundCounter> = meter.createCounter("requests", {
   monotonic: true,
@@ -296,11 +296,11 @@ $ npm install @opentelemetry/exporter-prometheus
 Next, modify your `monitoring.ts` file to look like this:
 
 ```typescript
-import { Meter } from "@opentelemetry/metrics";
+import { MeterRegistry } from "@opentelemetry/metrics";
 import { Metric, BoundCounter } from "@opentelemetry/types";
 import { PrometheusExporter } from "@opentelemetry/exporter-prometheus";
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 
 meter.addExporter(
   new PrometheusExporter({ startServer: true }, () => {

getting-started/ts-example/monitoring.ts

@@ -1,8 +1,8 @@
-import { Meter } from "@opentelemetry/metrics";
+import { MeterRegistry } from "@opentelemetry/metrics";
 import { Metric, BoundCounter } from "@opentelemetry/types";
 import { PrometheusExporter } from "@opentelemetry/exporter-prometheus";
 
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('example-ts');
 
 meter.addExporter(
   new PrometheusExporter({ startServer: true }, () => {

packages/opentelemetry-core/src/metrics/NoopMeter.ts

@@ -165,6 +165,8 @@ export class NoopBoundMeasure implements BoundMeasure {
   }
 }
 
+export const noopMeter = new NoopMeter();
+
 export const NOOP_BOUND_GAUGE = new NoopBoundGauge();
 export const NOOP_GAUGE_METRIC = new NoopGaugeMetric(NOOP_BOUND_GAUGE);
 

packages/opentelemetry-core/src/metrics/NoopMeterRegistry.ts

@@ -0,0 +1,28 @@
+/*!
+ * Copyright 2019, 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 types from '@opentelemetry/types';
+import { noopMeter } from './NoopMeter';
+
+/**
+ * An implementation of the {@link MeterRegistry} which returns an impotent Meter
+ * for all calls to `getMeter`
+ */
+export class NoopMeterRegistry implements types.MeterRegistry {
+  getMeter(_name?: string, _version?: string): types.Meter {
+    return noopMeter;
+  }
+}

packages/opentelemetry-core/test/metrics/NoopMeter.test.ts

@@ -16,7 +16,6 @@
 
 import * as assert from 'assert';
 import {
-  NoopMeter,
   NOOP_BOUND_GAUGE,
   NOOP_GAUGE_METRIC,
   NOOP_BOUND_COUNTER,
@@ -25,10 +24,11 @@ import {
   NOOP_MEASURE_METRIC,
 } from '../../src/metrics/NoopMeter';
 import { Labels } from '@opentelemetry/types';
+import { NoopMeterRegistry } from '../../src/metrics/NoopMeterRegistry';
 
 describe('NoopMeter', () => {
   it('should not crash', () => {
-    const meter = new NoopMeter();
+    const meter = new NoopMeterRegistry().getMeter('test-noop');
     const counter = meter.createCounter('some-name');
     const labels = {} as Labels;
     const labelSet = meter.labels(labels);

packages/opentelemetry-exporter-prometheus/README.md

@@ -22,14 +22,14 @@ Create & register the exporter on your application.
 
 ```js
 const { PrometheusExporter } = require('@opentelemetry/exporter-prometheus');
-const { Meter }  = require('@opentelemetry/metrics');
+const { MeterRegistry }  = require('@opentelemetry/metrics');
 
 // Add your port and startServer to the Prometheus options
 const options = {port: 9464, startServer: true};
 const exporter = new PrometheusExporter(options);
 
 // Register the exporter
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('exporter-prometheus');
 meter.addExporter(exporter);
 
 // Now, start recording data

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

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-import { CounterMetric, GaugeMetric, Meter } from '@opentelemetry/metrics';
+import {
+  CounterMetric,
+  GaugeMetric,
+  Meter,
+  MeterRegistry,
+} from '@opentelemetry/metrics';
 import * as assert from 'assert';
 import * as http from 'http';
 import { PrometheusExporter } from '../src';
@@ -166,7 +171,7 @@ describe('PrometheusExporter', () => {
 
     beforeEach(done => {
       exporter = new PrometheusExporter();
-      meter = new Meter();
+      meter = new MeterRegistry().getMeter('test-prometheus');
       exporter.startServer(done);
     });
 
@@ -382,7 +387,7 @@ describe('PrometheusExporter', () => {
     let exporter: PrometheusExporter | undefined;
 
     beforeEach(() => {
-      meter = new Meter();
+      meter = new MeterRegistry().getMeter('test-prometheus');
       gauge = meter.createGauge('gauge') as GaugeMetric;
       gauge.bind(meter.labels({ key1: 'labelValue1' })).set(10);
     });

packages/opentelemetry-metrics/README.md

@@ -19,10 +19,10 @@ npm install --save @opentelemetry/metrics
 Choose this kind of metric when the value is a quantity, the sum is of primary interest, and the event count and value distribution are not of primary interest. Counters are defined as `Monotonic = true` by default, meaning that positive values are expected.
 
 ```js
-const { Meter } = require('@opentelemetry/metrics');
+const { MeterRegistry } = require('@opentelemetry/metrics');
 
 // Initialize the Meter to capture measurements in various ways.
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 
 const counter = meter.createCounter('metric_name', {
   labelKeys: ["pid"],
@@ -40,10 +40,10 @@ boundCounter.add(10);
 Gauge metrics express a pre-calculated value. Generally, this kind of metric should be used when the metric cannot be expressed as a sum or because the measurement interval is arbitrary. Use this kind of metric when the measurement is not a quantity, and the sum and event count are not of interest. Gauges are defined as `Monotonic = false` by default, meaning that new values are permitted to make positive or negative changes to the gauge. There is no restriction on the sign of the input for gauges.
 
 ```js
-const { Meter } = require('@opentelemetry/metrics');
+const { MeterRegistry } = require('@opentelemetry/metrics');
 
 // Initialize the Meter to capture measurements in various ways.
-const meter = new Meter();
+const meter = new MeterRegistry().getMeter('your-meter-name');
 
 const gauge = meter.createGauge('metric_name', {
   labelKeys: ["pid"],

packages/opentelemetry-metrics/src/MeterRegistry.ts

@@ -0,0 +1,42 @@
+/*!
+ * Copyright 2019, 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 { ConsoleLogger } from '@opentelemetry/core';
+import * as types from '@opentelemetry/types';
+import { Logger } from '@opentelemetry/types';
+import { Meter } from '.';
+import { DEFAULT_CONFIG, MeterConfig } from './types';
+
+/**
+ * This class represents a meter registry which platform libraries can extend
+ */
+export class MeterRegistry implements types.MeterRegistry {
+  private readonly _meters: Map<string, Meter> = new Map();
+  readonly logger: Logger;
+
+  constructor(private _config: MeterConfig = DEFAULT_CONFIG) {
+    this.logger = _config.logger || new ConsoleLogger(_config.logLevel);
+  }
+
+  getMeter(name: string, version = '*', config?: MeterConfig): Meter {
+    const key = `${name}@${version}`;
+    if (!this._meters.has(key)) {
+      this._meters.set(key, new Meter(config || this._config));
+    }
+
+    return this._meters.get(key)!;
+  }
+}

packages/opentelemetry-metrics/src/index.ts

@@ -17,5 +17,6 @@
 export * from './BoundInstrument';
 export * from './Meter';
 export * from './Metric';
+export * from './MeterRegistry';
 export * from './export/ConsoleMetricExporter';
 export * from './export/types';

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

@@ -31,6 +31,7 @@ import {
   hrTimeToMilliseconds,
 } from '@opentelemetry/core';
 import { NoopExporter } from './mocks/Exporter';
+import { MeterRegistry } from '../src/MeterRegistry';
 
 const performanceTimeOrigin = hrTime();
 
@@ -43,9 +44,9 @@ describe('Meter', () => {
   const hrTime: types.HrTime = [22, 400000000];
 
   beforeEach(() => {
-    meter = new Meter({
+    meter = new MeterRegistry({
       logger: new NoopLogger(),
-    });
+    }).getMeter('test-meter');
     labelSet = meter.labels(labels);
   });
 

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

@@ -0,0 +1,68 @@
+/*!
+ * Copyright 2019, 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 { NoopLogger } from '@opentelemetry/core';
+import * as assert from 'assert';
+import { MeterRegistry, Meter } from '../src';
+
+describe('MeterRegistry', () => {
+  describe('constructor', () => {
+    it('should construct an instance without any options', () => {
+      const registry = new MeterRegistry();
+      assert.ok(registry instanceof MeterRegistry);
+    });
+
+    it('should construct an instance with logger', () => {
+      const registry = new MeterRegistry({
+        logger: new NoopLogger(),
+      });
+      assert.ok(registry instanceof MeterRegistry);
+    });
+  });
+
+  describe('getMeter', () => {
+    it('should return an instance of Meter', () => {
+      const meter = new MeterRegistry().getMeter('test-meter-registry');
+      assert.ok(meter instanceof Meter);
+    });
+
+    it('should return the meter with default version without a version option', () => {
+      const registry = new MeterRegistry();
+      const meter1 = registry.getMeter('default');
+      const meter2 = registry.getMeter('default', '*');
+      assert.deepEqual(meter1, meter2);
+    });
+
+    it('should return the same Meter instance with same name & version', () => {
+      const registry = new MeterRegistry();
+      const meter1 = registry.getMeter('meter1', 'ver1');
+      const meter2 = registry.getMeter('meter1', 'ver1');
+      assert.deepEqual(meter1, meter2);
+    });
+
+    it('should return different Meter instance with different name or version', () => {
+      const registry = new MeterRegistry();
+
+      const meter1 = registry.getMeter('meter1', 'ver1');
+      const meter2 = registry.getMeter('meter1');
+      assert.notEqual(meter1, meter2);
+
+      const meter3 = registry.getMeter('meter2', 'ver2');
+      const meter4 = registry.getMeter('meter3', 'ver2');
+      assert.notEqual(meter3, meter4);
+    });
+  });
+});