feat(metrics-sdk): bootstrap views api (#2625)

Co-authored-by: Valentin Marchaud <contact@vmarchaud.fr>

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

@@ -0,0 +1,36 @@
+/*
+ * 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 { MetricOptions, ValueType } from '@opentelemetry/api-metrics';
+import { InstrumentType } from './Instruments';
+
+export interface InstrumentDescriptor {
+  readonly name: string;
+  readonly description: string;
+  readonly unit: string;
+  readonly type: InstrumentType;
+  readonly valueType: ValueType;
+}
+
+export function createInstrumentDescriptor(name: string, type: InstrumentType, options?: MetricOptions): InstrumentDescriptor {
+  return {
+    name,
+    type,
+    description: options?.description ?? '',
+    unit: options?.unit ?? '1',
+    valueType: options?.valueType ?? ValueType.DOUBLE,
+  };
+}

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

@@ -16,55 +16,51 @@
 
 import * as api from '@opentelemetry/api';
 import * as metrics from '@opentelemetry/api-metrics';
-import { Meter } from './Meter';
+import { InstrumentDescriptor } from './InstrumentDescriptor';
+import { WritableMetricStorage } from './state/WritableMetricStorage';
 
 // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#instrument
 
 export enum InstrumentType {
-    COUNTER = 'COUNTER',
-    HISTOGRAM = 'HISTOGRAM',
-    UP_DOWN_COUNTER = 'UP_DOWN_COUNTER',
-    OBSERVABLE_COUNTER = 'OBSERVABLE_COUNTER',
-    OBSERVABLE_GAUGE = 'OBSERVABLE_GAUGE',
-    OBSERVABLE_UP_DOWN_COUNTER = 'OBSERVABLE_UP_DOWN_COUNTER',
+  COUNTER = 'COUNTER',
+  HISTOGRAM = 'HISTOGRAM',
+  UP_DOWN_COUNTER = 'UP_DOWN_COUNTER',
+  OBSERVABLE_COUNTER = 'OBSERVABLE_COUNTER',
+  OBSERVABLE_GAUGE = 'OBSERVABLE_GAUGE',
+  OBSERVABLE_UP_DOWN_COUNTER = 'OBSERVABLE_UP_DOWN_COUNTER',
 }
 
 export class SyncInstrument {
-    constructor(private _meter: Meter, private _name: string) { }
+  constructor(private _writableMetricStorage: WritableMetricStorage, private _descriptor: InstrumentDescriptor) { }
 
-    getName(): string {
-        return this._name;
-    }
+  getName(): string {
+    return this._descriptor.name;
+  }
 
-
-    aggregate(value: number, attributes: metrics.Attributes = {}, ctx: api.Context = api.context.active()) {
-        this._meter.aggregate(this, {
-            value,
-            attributes,
-            context: ctx,
-        });
-    }
+  aggregate(value: number, attributes: metrics.Attributes = {}, context: api.Context = api.context.active()) {
+    this._writableMetricStorage.record(value, attributes, context);
+  }
 }
 
 export class UpDownCounter extends SyncInstrument implements metrics.Counter {
-    add(value: number, attributes?: metrics.Attributes, ctx?: api.Context): void {
-        this.aggregate(value, attributes, ctx);
-    }
+  add(value: number, attributes?: metrics.Attributes, ctx?: api.Context): void {
+    this.aggregate(value, attributes, ctx);
+  }
 }
 
 export class Counter extends SyncInstrument implements metrics.Counter {
-    add(value: number, attributes?: metrics.Attributes, ctx?: api.Context): void {
-        if (value < 0) {
-            api.diag.warn(`negative value provided to counter ${this.getName()}: ${value}`);
-            return;
-        }
-
-        this.aggregate(value, attributes, ctx);
+  add(value: number, attributes?: metrics.Attributes, ctx?: api.Context): void {
+    if (value < 0) {
+      api.diag.warn(`negative value provided to counter ${this.getName()}: ${value}`);
+      return;
     }
+
+    this.aggregate(value, attributes, ctx);
+  }
 }
 
 export class Histogram extends SyncInstrument implements metrics.Histogram {
-    record(value: number, attributes?: metrics.Attributes, ctx?: api.Context): void {
-        this.aggregate(value, attributes, ctx);
-    }
+  record(value: number, attributes?: metrics.Attributes, ctx?: api.Context): void {
+    this.aggregate(value, attributes, ctx);
+  }
 }

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

@@ -16,50 +16,68 @@
 
 import * as metrics from '@opentelemetry/api-metrics';
 import { InstrumentationLibrary } from '@opentelemetry/core';
-import { Counter, Histogram, UpDownCounter } from './Instruments';
-import { Measurement } from './Measurement';
-import { MeterProvider } from './MeterProvider';
+import { createInstrumentDescriptor, InstrumentDescriptor } from './InstrumentDescriptor';
+import { Counter, Histogram, InstrumentType, UpDownCounter } from './Instruments';
+import { MeterProviderSharedState } from './state/MeterProviderSharedState';
+import { MultiMetricStorage } from './state/MultiWritableMetricStorage';
+import { NoopWritableMetricStorage, WritableMetricStorage } from './state/WritableMetricStorage';
 
 // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#meter
 
 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 _provider: MeterProvider, private _instrumentationLibrary: InstrumentationLibrary, private _schemaUrl?: string) { }
+  private _metricStorageRegistry = new Map<string, WritableMetricStorage>();
 
-    /** this exists just to prevent ts errors from unused variables and may be removed */
-    getSchemaUrl(): string | undefined {
-        return this._schemaUrl;
-    }
+  // 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) { }
 
-    /** this exists just to prevent ts errors from unused variables and may be removed */
-    getInstrumentationLibrary(): InstrumentationLibrary {
-        return this._instrumentationLibrary;
-    }
+  /** this exists just to prevent ts errors from unused variables and may be removed */
+  getInstrumentationLibrary(): InstrumentationLibrary {
+    return this._instrumentationLibrary;
+  }
 
-    createHistogram(_name: string, _options?: metrics.MetricOptions): Histogram {
-        return new Histogram(this, _name);
-    }
-
-    createCounter(_name: string, _options?: metrics.MetricOptions): metrics.Counter {
-        return new Counter(this, _name);
-    }
+  createHistogram(name: string, options?: metrics.MetricOptions): Histogram {
+    const descriptor = createInstrumentDescriptor(name, InstrumentType.HISTOGRAM, options);
+    const storage = this._registerMetricStorage(descriptor);
+    return new Histogram(storage, descriptor);
+  }
 
-    createUpDownCounter(_name: string, _options?: metrics.MetricOptions): metrics.UpDownCounter {
-        return new UpDownCounter(this, _name);
-    }
+  createCounter(name: string, options?: metrics.MetricOptions): metrics.Counter {
+    const descriptor = createInstrumentDescriptor(name, InstrumentType.COUNTER, options);
+    const storage = this._registerMetricStorage(descriptor);
+    return new Counter(storage, descriptor);
+  }
 
-    createObservableGauge(_name: string, _options?: metrics.MetricOptions, _callback?: (observableResult: metrics.ObservableResult) => void): metrics.ObservableBase {
-        throw new Error('Method not implemented.');
-    }
-    createObservableCounter(_name: string, _options?: metrics.MetricOptions, _callback?: (observableResult: metrics.ObservableResult) => void): metrics.ObservableBase {
-        throw new Error('Method not implemented.');
-    }
-    createObservableUpDownCounter(_name: string, _options?: metrics.MetricOptions, _callback?: (observableResult: metrics.ObservableResult) => void): metrics.ObservableBase {
-        throw new Error('Method not implemented.');
-    }
+  createUpDownCounter(name: string, options?: metrics.MetricOptions): metrics.UpDownCounter {
+    const descriptor = createInstrumentDescriptor(name, InstrumentType.UP_DOWN_COUNTER, options);
+    const storage = this._registerMetricStorage(descriptor);
+    return new UpDownCounter(storage, descriptor);
+  }
+
+  createObservableGauge(_name: string, _options?: metrics.MetricOptions, _callback?: (observableResult: metrics.ObservableResult) => void): metrics.ObservableBase {
+    throw new Error('Method not implemented.');
+  }
+
+  createObservableCounter(_name: string, _options?: metrics.MetricOptions, _callback?: (observableResult: metrics.ObservableResult) => void): metrics.ObservableBase {
+    throw new Error('Method not implemented.');
+  }
+
+  createObservableUpDownCounter(_name: string, _options?: metrics.MetricOptions, _callback?: (observableResult: metrics.ObservableResult) => void): metrics.ObservableBase {
+    throw new Error('Method not implemented.');
+  }
 
-    public aggregate(metric: unknown, measurement: Measurement) {
-        this._provider.aggregate(this, metric, measurement);
+  private _registerMetricStorage(descriptor: InstrumentDescriptor) {
+    const views = this._meterProviderSharedState.viewRegistry.findViews(descriptor, this._instrumentationLibrary);
+    const storages = views.map(_view => {
+      // TODO: create actual metric storages.
+      const storage = new NoopWritableMetricStorage();
+      // TODO: handle conflicts
+      this._metricStorageRegistry.set(descriptor.name, storage);
+      return storage;
+    });
+    if (storages.length === 1)  {
+      return storages[0];
     }
+    return new MultiMetricStorage(storages);
+  }
 }