Review comments

experimental/packages/opentelemetry-instrumentation-http/test/functionals/utils.test.ts

@@ -252,7 +252,7 @@ describe('Utility', () => {
         'test',
         { spanId: '', traceId: '', traceFlags: TraceFlags.SAMPLED },
         SpanKind.INTERNAL,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
       );
       /* tslint:disable-next-line:no-any */
       utils.setSpanWithError(span, new Error(errorMessage));
@@ -488,7 +488,7 @@ describe('Utility', () => {
         'test',
         { spanId: '', traceId: '', traceFlags: TraceFlags.SAMPLED },
         SpanKind.INTERNAL,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
       );
     });
 

packages/opentelemetry-core/src/common/anchored-clock.ts

@@ -16,7 +16,7 @@
 
 /**
  * A utility for returning wall times anchored to a given point in time. Wall time measurements will
- * not be taken from the system, but instead are computed by adding performance.now() monotonic time
+ * not be taken from the system, but instead are computed by adding a monotonic clock time
  * to the anchor point.
  *
  * This is needed because the system time can change and result in unexpected situations like
@@ -31,23 +31,30 @@
  * https://github.com/open-telemetry/opentelemetry-java/blob/main/sdk/trace/src/main/java/io/opentelemetry/sdk/trace/AnchoredClock.java
  */
 export class AnchoredClock {
-  private constructor(
-    private _performance: Clock,
-    private _epochMillis: number,
-    private _performanceMillis: number,
-  ) { }
+  private _monotonicClock: Clock;
+  private _epochMillis: number;
+  private _performanceMillis: number;
 
-  /** Create a new AnchoredClock anchored to the current time returned by clock */
-  public static create(clock: Clock, performance: Clock) {
-    return new AnchoredClock(performance, clock.now(), performance.now());
+  /**
+   * Create a new AnchoredClock anchored to the current time returned by systemClock.
+   * 
+   * @param systemClock should be a clock that returns the number of milliseconds since January 1 1970 such as Date
+   * @param monotonicClock should be a clock that counts milliseconds monotonically such as window.performance or perf_hooks.performance
+   */
+  public constructor(systemClock: Clock, monotonicClock: Clock) {
+    this._monotonicClock = monotonicClock;
+    this._epochMillis = systemClock.now();
+    this._performanceMillis = monotonicClock.now();
   }
 
+  /**  */
+
   /**
    * Returns the current time by adding the number of milliseconds since the
    * AnchoredClock was created to the creation epoch time
    */
   public now(): number {
-    const delta = this._performance.now() - this._performanceMillis;
+    const delta = this._monotonicClock.now() - this._performanceMillis;
     return this._epochMillis + delta;
   }
 }

packages/opentelemetry-exporter-zipkin/test/common/transform.test.ts

@@ -68,7 +68,7 @@ describe('transform', () => {
         'my-span',
         spanContext,
         api.SpanKind.SERVER,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
         parentId
       );
       span.setAttributes({
@@ -120,7 +120,7 @@ describe('transform', () => {
         'my-span',
         spanContext,
         api.SpanKind.SERVER,
-        AnchoredClock.create(Date, otperformance)
+        new AnchoredClock(Date, otperformance)
       );
       span.end();
 
@@ -169,7 +169,7 @@ describe('transform', () => {
           'my-span',
           spanContext,
           item.ot,
-          AnchoredClock.create(Date, otperformance)
+          new AnchoredClock(Date, otperformance)
         );
         span.end();
 
@@ -212,7 +212,7 @@ describe('transform', () => {
         'my-span',
         spanContext,
         api.SpanKind.SERVER,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
         parentId
       );
       span.setAttributes({
@@ -243,7 +243,7 @@ describe('transform', () => {
         'my-span',
         spanContext,
         api.SpanKind.SERVER,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
         parentId
       );
       const status: api.SpanStatus = {
@@ -280,7 +280,7 @@ describe('transform', () => {
         'my-span',
         spanContext,
         api.SpanKind.SERVER,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
         parentId
       );
       const status: api.SpanStatus = {
@@ -322,7 +322,7 @@ describe('transform', () => {
         'my-span',
         spanContext,
         api.SpanKind.SERVER,
-        AnchoredClock.create(Date, otperformance),
+        new AnchoredClock(Date, otperformance),
         parentId
       );
       span.addEvent('my-event1');

packages/opentelemetry-sdk-trace-base/src/Span.ts

@@ -59,7 +59,7 @@ export class Span implements api.Span, ReadableSpan {
   private readonly _spanProcessor: SpanProcessor;
   private readonly _spanLimits: SpanLimits;
   private readonly _attributeValueLengthLimit: number;
-  private readonly clock: AnchoredClock;
+  private readonly _clock: AnchoredClock;
 
   /** Constructs a new Span instance. */
   constructor(
@@ -73,7 +73,7 @@ export class Span implements api.Span, ReadableSpan {
     links: api.Link[] = [],
     startTime?: api.TimeInput,
   ) {
-    this.clock = clock;
+    this._clock = clock;
     this.name = spanName;
     this._spanContext = spanContext;
     this.parentSpanId = parentSpanId;
@@ -150,7 +150,7 @@ export class Span implements api.Span, ReadableSpan {
       attributesOrStartTime = undefined;
     }
     if (typeof startTime === 'undefined') {
-      startTime = this.clock.now();
+      startTime = this._clock.now();
     }
 
     const attributes = sanitizeAttributes(attributesOrStartTime);
@@ -181,7 +181,7 @@ export class Span implements api.Span, ReadableSpan {
     }
     this._ended = true;
 
-    this.endTime = timeInputToHrTime(endTime ?? this.clock.now());
+    this.endTime = timeInputToHrTime(endTime ?? this._clock.now());
     this._duration = hrTimeDuration(this.startTime, this.endTime);
 
     if (this._duration[0] < 0) {
@@ -199,7 +199,7 @@ export class Span implements api.Span, ReadableSpan {
     return this._ended === false;
   }
 
-  recordException(exception: api.Exception, time: api.TimeInput = this.clock.now()): void {
+  recordException(exception: api.Exception, time: api.TimeInput = this._clock.now()): void {
     const attributes: api.SpanAttributes = {};
     if (typeof exception === 'string') {
       attributes[SemanticAttributes.EXCEPTION_MESSAGE] = exception;

packages/opentelemetry-sdk-trace-base/src/Tracer.ts

@@ -42,7 +42,6 @@ export class Tracer implements api.Tracer {
   private readonly _idGenerator: IdGenerator;
   readonly resource: Resource;
   readonly instrumentationLibrary: InstrumentationLibrary;
-  private clocks: WeakMap<api.Span, AnchoredClock> = new WeakMap();
 
   /**
    * Constructs a new Tracer instance.
@@ -126,10 +125,15 @@ export class Tracer implements api.Tracer {
 
     let clock: AnchoredClock | undefined;
     if (parentSpan) {
-      clock = this.clocks.get(parentSpan);
+      clock = (parentSpan as any)["_clock"];
     }
 
-    clock = clock ?? AnchoredClock.create(Date, otperformance);
+    if (!clock) {
+      clock = new AnchoredClock(Date, otperformance);
+      if (parentSpan) {
+        (parentSpan as any)["_clock"] = clock;
+      }
+    }
 
     const span = new Span(
       this,