feat: add TraceParams config (#227)

* feat: add TraceParams config

* fix: remove extend dependency

packages/opentelemetry-basic-tracer/src/BasicTracer.ts

@@ -16,9 +16,6 @@
 
 import * as types from '@opentelemetry/types';
 import {
-  ALWAYS_SAMPLER,
-  BinaryTraceContext,
-  HttpTraceContext,
   randomTraceId,
   isValid,
   randomSpanId,
@@ -31,9 +28,10 @@ import {
   TraceOptions,
   Logger,
 } from '@opentelemetry/types';
-import { BasicTracerConfig } from '../src/types';
+import { BasicTracerConfig, TraceParams } from '../src/types';
 import { ScopeManager } from '@opentelemetry/scope-base';
 import { Span } from './Span';
+import { mergeConfig } from './utility';
 
 /**
  * This class represents a basic tracer.
@@ -44,17 +42,20 @@ export class BasicTracer implements types.Tracer {
   private readonly _httpTextFormat: types.HttpTextFormat;
   private readonly _sampler: types.Sampler;
   private readonly _scopeManager: ScopeManager;
+  private readonly _traceParams: TraceParams;
   readonly logger: Logger;
 
   /**
    * Constructs a new Tracer instance.
    */
   constructor(config: BasicTracerConfig) {
-    this._binaryFormat = config.binaryFormat || new BinaryTraceContext();
-    this._defaultAttributes = config.defaultAttributes || {};
-    this._httpTextFormat = config.httpTextFormat || new HttpTraceContext();
-    this._sampler = config.sampler || ALWAYS_SAMPLER;
-    this._scopeManager = config.scopeManager;
+    const localConfig = mergeConfig(config);
+    this._binaryFormat = localConfig.binaryFormat;
+    this._defaultAttributes = localConfig.defaultAttributes;
+    this._httpTextFormat = localConfig.httpTextFormat;
+    this._sampler = localConfig.sampler;
+    this._scopeManager = localConfig.scopeManager;
+    this._traceParams = localConfig.traceParams;
     this.logger = config.logger || new ConsoleLogger(config.logLevel);
   }
 
@@ -157,6 +158,11 @@ export class BasicTracer implements types.Tracer {
     return this._httpTextFormat;
   }
 
+  /** Returns the active {@link TraceParams}. */
+  getActiveTraceParams(): TraceParams {
+    return this._traceParams;
+  }
+
   private _getParentSpanContext(
     parent: types.Span | types.SpanContext | undefined
   ): types.SpanContext | undefined {

packages/opentelemetry-basic-tracer/src/config.ts

@@ -0,0 +1,52 @@
+/**
+ * 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 {
+  ALWAYS_SAMPLER,
+  BinaryTraceContext,
+  HttpTraceContext,
+  LogLevel,
+} from '@opentelemetry/core';
+import { NoopScopeManager } from '@opentelemetry/scope-base';
+
+/** Default limit for Message events per span */
+export const DEFAULT_MAX_EVENTS_PER_SPAN = 128;
+/** Default limit for Attributes per span */
+export const DEFAULT_MAX_ATTRIBUTES_PER_SPAN = 32;
+/** Default limit for Links per span */
+export const DEFAULT_MAX_LINKS_PER_SPAN = 32;
+
+/**
+ * Default configuration. For fields with primitive values, any user-provided
+ * value will override the corresponding default value. For fields with
+ * non-primitive values (like `traceParams`), the user-provided value will be
+ * used to extend the default value.
+ */
+export const defaultConfig = {
+  defaultAttributes: {},
+  binaryFormat: new BinaryTraceContext(),
+  httpTextFormat: new HttpTraceContext(),
+  logLevel: LogLevel.DEBUG,
+  sampler: ALWAYS_SAMPLER,
+  scopeManager: new NoopScopeManager(),
+  traceParams: {
+    numberOfAttributesPerSpan: DEFAULT_MAX_ATTRIBUTES_PER_SPAN,
+    numberOfLinksPerSpan: DEFAULT_MAX_LINKS_PER_SPAN,
+    numberOfEventsPerSpan: DEFAULT_MAX_EVENTS_PER_SPAN,
+  },
+  // @todo add support for plugins
+  // plugins: {},
+};

packages/opentelemetry-basic-tracer/src/types.ts

@@ -61,4 +61,17 @@ export interface BasicTracerConfig {
    * Scope manager keeps context across in-process operations.
    */
   scopeManager: ScopeManager;
+
+  /** Trace Parameters */
+  traceParams?: TraceParams;
+}
+
+/** Global configuration of trace service */
+export interface TraceParams {
+  /** numberOfAttributesPerSpan is number of attributes per span */
+  numberOfAttributesPerSpan?: number;
+  /** numberOfLinksPerSpan is number of links per span */
+  numberOfLinksPerSpan?: number;
+  /** numberOfEventsPerSpan is number of message events per span */
+  numberOfEventsPerSpan?: number;
 }

packages/opentelemetry-basic-tracer/src/utility.ts

@@ -0,0 +1,43 @@
+/**
+ * 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 { BasicTracerConfig } from './types';
+import {
+  DEFAULT_MAX_ATTRIBUTES_PER_SPAN,
+  DEFAULT_MAX_EVENTS_PER_SPAN,
+  DEFAULT_MAX_LINKS_PER_SPAN,
+} from './config';
+import { defaultConfig } from './config';
+
+/**
+ * Function to merge Default configuration (as specified in './config') with
+ * user provided configurations.
+ */
+export function mergeConfig(userConfig: BasicTracerConfig) {
+  const traceParams = userConfig.traceParams;
+  const target = Object.assign({}, defaultConfig, userConfig);
+
+  // the user-provided value will be used to extend the default value.
+  if (traceParams) {
+    target.traceParams.numberOfAttributesPerSpan =
+      traceParams.numberOfAttributesPerSpan || DEFAULT_MAX_ATTRIBUTES_PER_SPAN;
+    target.traceParams.numberOfEventsPerSpan =
+      traceParams.numberOfEventsPerSpan || DEFAULT_MAX_EVENTS_PER_SPAN;
+    target.traceParams.numberOfLinksPerSpan =
+      traceParams.numberOfLinksPerSpan || DEFAULT_MAX_LINKS_PER_SPAN;
+  }
+  return target;
+}

packages/opentelemetry-basic-tracer/test/BasicTracer.test.ts

@@ -70,6 +70,59 @@ describe('BasicTracer', () => {
       assert.ok(tracer instanceof BasicTracer);
     });
 
+    it('should construct an instance with default trace params', () => {
+      const tracer = new BasicTracer({
+        scopeManager: new NoopScopeManager(),
+      });
+      assert.deepStrictEqual(tracer.getActiveTraceParams(), {
+        numberOfAttributesPerSpan: 32,
+        numberOfEventsPerSpan: 128,
+        numberOfLinksPerSpan: 32,
+      });
+    });
+
+    it('should construct an instance with customized numberOfAttributesPerSpan trace params', () => {
+      const tracer = new BasicTracer({
+        scopeManager: new NoopScopeManager(),
+        traceParams: {
+          numberOfAttributesPerSpan: 100,
+        },
+      });
+      assert.deepStrictEqual(tracer.getActiveTraceParams(), {
+        numberOfAttributesPerSpan: 100,
+        numberOfEventsPerSpan: 128,
+        numberOfLinksPerSpan: 32,
+      });
+    });
+
+    it('should construct an instance with customized numberOfEventsPerSpan trace params', () => {
+      const tracer = new BasicTracer({
+        scopeManager: new NoopScopeManager(),
+        traceParams: {
+          numberOfEventsPerSpan: 300,
+        },
+      });
+      assert.deepStrictEqual(tracer.getActiveTraceParams(), {
+        numberOfAttributesPerSpan: 32,
+        numberOfEventsPerSpan: 300,
+        numberOfLinksPerSpan: 32,
+      });
+    });
+
+    it('should construct an instance with customized numberOfLinksPerSpan trace params', () => {
+      const tracer = new BasicTracer({
+        scopeManager: new NoopScopeManager(),
+        traceParams: {
+          numberOfLinksPerSpan: 10,
+        },
+      });
+      assert.deepStrictEqual(tracer.getActiveTraceParams(), {
+        numberOfAttributesPerSpan: 32,
+        numberOfEventsPerSpan: 128,
+        numberOfLinksPerSpan: 10,
+      });
+    });
+
     it('should construct an instance with default attributes', () => {
       const tracer = new BasicTracer({
         defaultAttributes: {