fix(node): UnifygetDynamicSamplingContextFromSpan

We used to have a different implementation, that worked slightly different.

This had two problems:

1. We did not look up the root span in the OTEL implementation, but relied on already passing in the root span (in core, we convert it to root span)
2. We did not use frozen DSC properly

Now, the core implementation just works for both OTEL and core spans.

Author: mydea

packages/core/src/tracing/dynamicSamplingContext.ts

@@ -1,6 +1,7 @@
 import type { Client, DynamicSamplingContext, Span } from '@sentry/types';
 import {
   addNonEnumerableProperty,
+  baggageHeaderToDynamicSamplingContext,
   dropUndefinedKeys,
   dynamicSamplingContextToSentryBaggageHeader,
 } from '@sentry/utils';
@@ -66,15 +67,25 @@ export function getDynamicSamplingContextFromSpan(span: Span): Readonly<Partial<
   const dsc = getDynamicSamplingContextFromClient(spanToJSON(span).trace_id || '', client);
 
   const rootSpan = getRootSpan(span);
-  if (!rootSpan) {
-    return dsc;
-  }
 
+  // For core implementation, we freeze the DSC onto the span as a non-enumerable property
   const frozenDsc = (rootSpan as SpanWithMaybeDsc)[FROZEN_DSC_FIELD];
   if (frozenDsc) {
     return frozenDsc;
   }
 
+  // For OpenTelemetry, we freeze the DSC on the trace state
+  const traceState = rootSpan.spanContext().traceState;
+  const traceStateDsc = traceState && traceState.get('sentry.dsc');
+
+  // If the span has a DSC, we want it to take precedence
+  const dscOnTraceState = traceStateDsc && baggageHeaderToDynamicSamplingContext(traceStateDsc);
+
+  if (dscOnTraceState) {
+    return dscOnTraceState;
+  }
+
+  // Else, we generate it from the span
   const jsonSpan = spanToJSON(rootSpan);
   const attributes = jsonSpan.data || {};
   const maybeSampleRate = attributes[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE];
@@ -87,8 +98,9 @@ export function getDynamicSamplingContextFromSpan(span: Span): Readonly<Partial<
   const source = attributes[SEMANTIC_ATTRIBUTE_SENTRY_SOURCE];
 
   // after JSON conversion, txn.name becomes jsonSpan.description
-  if (source && source !== 'url') {
-    dsc.transaction = jsonSpan.description;
+  const name = jsonSpan.description;
+  if (source !== 'url' && name) {
+    dsc.transaction = name;
   }
 
   dsc.sampled = String(spanIsSampled(rootSpan));

packages/core/test/lib/tracing/dynamicSamplingContext.test.ts

@@ -1,4 +1,4 @@
-import type { TransactionSource } from '@sentry/types';
+import type { Span, SpanContextData, TransactionSource } from '@sentry/types';
 import {
   SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
   SEMANTIC_ATTRIBUTE_SENTRY_SOURCE,
@@ -33,6 +33,27 @@ describe('getDynamicSamplingContextFromSpan', () => {
     expect(dynamicSamplingContext).toStrictEqual({ environment: 'myEnv' });
   });
 
+  test('uses frozen DSC from traceState', () => {
+    const rootSpan = {
+      spanContext() {
+        return {
+          traceId: '1234',
+          spanId: '12345',
+          traceFlags: 0,
+          traceState: {
+            get() {
+              return 'sentry-environment=myEnv2';
+            },
+          } as unknown as SpanContextData['traceState'],
+        };
+      },
+    } as Span;
+
+    const dynamicSamplingContext = getDynamicSamplingContextFromSpan(rootSpan);
+
+    expect(dynamicSamplingContext).toStrictEqual({ environment: 'myEnv2' });
+  });
+
   test('returns a new DSC, if no DSC was provided during rootSpan creation (via attributes)', () => {
     const rootSpan = startInactiveSpan({ name: 'tx' });
 

packages/opentelemetry/src/index.ts

@@ -16,7 +16,8 @@ export {
   spanHasStatus,
 } from './utils/spanTypes';
 
-export { getDynamicSamplingContextFromSpan } from './utils/dynamicSamplingContext';
+// Re-export this for backwards compatibility (this used to be a different implementation)
+export { getDynamicSamplingContextFromSpan } from '@sentry/core';
 
 export { isSentryRequestSpan } from './utils/isSentryRequest';
 

packages/opentelemetry/src/propagator.ts

@@ -8,7 +8,13 @@ import type { continueTrace } from '@sentry/core';
 import { hasTracingEnabled } from '@sentry/core';
 import { getRootSpan } from '@sentry/core';
 import { spanToJSON } from '@sentry/core';
-import { getClient, getCurrentScope, getDynamicSamplingContextFromClient, getIsolationScope } from '@sentry/core';
+import {
+  getClient,
+  getCurrentScope,
+  getDynamicSamplingContextFromClient,
+  getDynamicSamplingContextFromSpan,
+  getIsolationScope,
+} from '@sentry/core';
 import type { DynamicSamplingContext, Options, PropagationContext } from '@sentry/types';
 import {
   LRUMap,
@@ -32,7 +38,6 @@ import {
 } from './constants';
 import { DEBUG_BUILD } from './debug-build';
 import { getScopesFromContext, setScopesOnContext } from './utils/contextData';
-import { getDynamicSamplingContextFromSpan } from './utils/dynamicSamplingContext';
 import { getSamplingDecision } from './utils/getSamplingDecision';
 import { setIsSetup } from './utils/setupCheck';
 

packages/opentelemetry/src/setupEventContextTrace.ts

@@ -1,8 +1,6 @@
+import { getDynamicSamplingContextFromSpan, getRootSpan } from '@sentry/core';
 import type { Client } from '@sentry/types';
 import { dropUndefinedKeys } from '@sentry/utils';
-import { getDynamicSamplingContextFromSpan } from './utils/dynamicSamplingContext';
-
-import { getRootSpan } from '@sentry/core';
 import { SENTRY_TRACE_STATE_PARENT_SPAN_ID } from './constants';
 import { getActiveSpan } from './utils/getActiveSpan';
 import { spanHasParentId } from './utils/spanTypes';

packages/opentelemetry/src/spanExporter.ts

@@ -5,6 +5,7 @@ import { SEMATTRS_HTTP_STATUS_CODE } from '@opentelemetry/semantic-conventions';
 import {
   captureEvent,
   getCapturedScopesOnSpan,
+  getDynamicSamplingContextFromSpan,
   getMetricSummaryJsonForSpan,
   timedEventsToMeasurements,
 } from '@sentry/core';
@@ -22,7 +23,6 @@ import { SENTRY_TRACE_STATE_PARENT_SPAN_ID } from './constants';
 import { DEBUG_BUILD } from './debug-build';
 import { SEMANTIC_ATTRIBUTE_SENTRY_PARENT_IS_REMOTE } from './semanticAttributes';
 import { convertOtelTimeToSeconds } from './utils/convertOtelTimeToSeconds';
-import { getDynamicSamplingContextFromSpan } from './utils/dynamicSamplingContext';
 import { getRequestSpanData } from './utils/getRequestSpanData';
 import type { SpanNode } from './utils/groupSpansWithParents';
 import { getLocalParentId } from './utils/groupSpansWithParents';
@@ -245,7 +245,7 @@ function createTransactionForOtelSpan(span: ReadableSpan): TransactionEvent {
         capturedSpanScope: capturedSpanScopes.scope,
         capturedSpanIsolationScope: capturedSpanScopes.isolationScope,
         sampleRate,
-        dynamicSamplingContext: getDynamicSamplingContextFromSpan(span),
+        dynamicSamplingContext: getDynamicSamplingContextFromSpan(span as unknown as Span),
       }),
     },
     ...(source && {

packages/opentelemetry/src/trace.ts

@@ -7,6 +7,7 @@ import {
   continueTrace as baseContinueTrace,
   getClient,
   getCurrentScope,
+  getDynamicSamplingContextFromSpan,
   getRootSpan,
   handleCallbackErrors,
   spanToJSON,
@@ -16,7 +17,6 @@ import { continueTraceAsRemoteSpan, makeTraceState } from './propagator';
 
 import type { OpenTelemetryClient, OpenTelemetrySpanContext } from './types';
 import { getContextFromScope, getScopesFromContext } from './utils/contextData';
-import { getDynamicSamplingContextFromSpan } from './utils/dynamicSamplingContext';
 import { getSamplingDecision } from './utils/getSamplingDecision';
 
 /**

packages/opentelemetry/src/utils/dynamicSamplingContext.ts

@@ -12,6 +12,7 @@ import {
   getClient,
   getCurrentScope,
   getDynamicSamplingContextFromClient,
+  getDynamicSamplingContextFromSpan,
   getRootSpan,
   spanIsSampled,
   spanToJSON,
@@ -24,7 +25,6 @@ import { makeTraceState } from '../src/propagator';
 import { SEMATTRS_HTTP_METHOD } from '@opentelemetry/semantic-conventions';
 import { continueTrace, startInactiveSpan, startSpan, startSpanManual } from '../src/trace';
 import type { AbstractSpan } from '../src/types';
-import { getDynamicSamplingContextFromSpan } from '../src/utils/dynamicSamplingContext';
 import { getActiveSpan } from '../src/utils/getActiveSpan';
 import { getSamplingDecision } from '../src/utils/getSamplingDecision';
 import { getSpanKind } from '../src/utils/getSpanKind';
@@ -983,24 +983,16 @@ describe('trace', () => {
       withScope(scope => {
         const propagationContext = scope.getPropagationContext();
 
-        const ctx = trace.setSpanContext(ROOT_CONTEXT, {
-          traceId: '12312012123120121231201212312012',
-          spanId: '1121201211212012',
-          isRemote: false,
-          traceFlags: TraceFlags.SAMPLED,
-          traceState: undefined,
-        });
-
-        context.with(ctx, () => {
+        startSpan({ name: 'parent span' }, parentSpan => {
           const span = startInactiveSpan({ name: 'test span' });
 
           expect(span).toBeDefined();
-          expect(spanToJSON(span).trace_id).toEqual('12312012123120121231201212312012');
-          expect(spanToJSON(span).parent_span_id).toEqual('1121201211212012');
+          expect(spanToJSON(span).trace_id).toEqual(parentSpan.spanContext().traceId);
+          expect(spanToJSON(span).parent_span_id).toEqual(parentSpan.spanContext().spanId);
           expect(getDynamicSamplingContextFromSpan(span)).toEqual({
             ...getDynamicSamplingContextFromClient(propagationContext.traceId, getClient()!),
-            trace_id: '12312012123120121231201212312012',
-            transaction: 'test span',
+            trace_id: parentSpan.spanContext().traceId,
+            transaction: 'parent span',
             sampled: 'true',
             sample_rate: '1',
           });