RUM-6870 use deterministic sampling for distributed tracing

DataDog · Dec 16, 2024 · ea85f27 · ea85f27
1 parent d984be1
commit ea85f27
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Showing 4 changed files with 14 additions and 11 deletions.
diff --git a/.../instrumentation/resourceTracking/distributedTracing/__tests__/distributedTracing.test.ts b/.../instrumentation/resourceTracking/distributedTracing/__tests__/distributedTracing.test.ts
@@ -6,7 +6,7 @@
 
 import { TracingIdentifier, TracingIdFormat } from '../TracingIdentifier';
 
-import { TracingIdentifierUtils } from './__utils__/tracingIdentifierUtils';
+import { TracingIdentifierUtils } from './__utils__/TracingIdentifierUtils';
 
 describe('TracingIdentifier', () => {
     it('M return an unique identifier W toString', async () => {

diff --git a/...s/core/src/rum/instrumentation/resourceTracking/distributedTracing/distributedTracing.tsx b/...s/core/src/rum/instrumentation/resourceTracking/distributedTracing/distributedTracing.tsx
@@ -12,6 +12,9 @@ import type { SpanId, TraceId } from './TracingIdentifier';
 import type { Hostname } from './firstPartyHosts';
 import { getPropagatorsForHost } from './firstPartyHosts';
 
+const knuthFactor = BigInt('1111111111111111111')
+const twoPow64 = BigInt('0x10000000000000000') // 2n ** 64n
+
 export type DdRumResourceTracingAttributes =
     | {
           tracingStrategy: 'KEEP';
@@ -62,9 +65,13 @@ const generateTracingAttributesWithSampling = (
     tracingSamplingRate: number,
     propagatorTypes: PropagatorType[]
 ): DdRumResourceTracingAttributes => {
-    const isSampled = Math.random() * 100 <= tracingSamplingRate;
+    const traceId = TracingIdentifier.createTraceId();
+    const hash = (traceId.id * knuthFactor) % twoPow64
+
+    const isSampled  =Number(hash) <= (tracingSamplingRate / 100) * Number(twoPow64)
+
     const tracingAttributes: DdRumResourceTracingAttributes = {
-        traceId: TracingIdentifier.createTraceId(),
+        traceId: traceId,
         spanId: TracingIdentifier.createSpanId(),
         samplingPriorityHeader: isSampled ? '1' : '0',
         tracingStrategy: 'KEEP',

diff --git a/...src/rum/instrumentation/resourceTracking/requestProxy/XHRProxy/__tests__/XHRProxy.test.ts b/...src/rum/instrumentation/resourceTracking/requestProxy/XHRProxy/__tests__/XHRProxy.test.ts
@@ -12,7 +12,7 @@ import { BufferSingleton } from '../../../../../../sdk/DatadogProvider/Buffer/Bu
 import { DdRum } from '../../../../../DdRum';
 import { PropagatorType } from '../../../../../types';
 import { XMLHttpRequestMock } from '../../../__tests__/__utils__/XMLHttpRequestMock';
-import { TracingIdentifierUtils } from '../../../distributedTracing/__tests__/__utils__/tracingIdentifierUtils';
+import { TracingIdentifierUtils } from '../../../distributedTracing/__tests__/__utils__/TracingIdentifierUtils';
 import {
     PARENT_ID_HEADER_KEY,
     TRACE_ID_HEADER_KEY,
@@ -323,15 +323,14 @@ describe('XHRProxy', () => {
             const method = 'GET';
             const url = 'https://api.example.com/v2/user';
             xhrProxy.onTrackingStart({
-                tracingSamplingRate: 50,
+                tracingSamplingRate: 0,
                 firstPartyHostsRegexMap: firstPartyHostsRegexMapBuilder([
                     {
                         match: 'api.example.com',
                         propagatorTypes: [PropagatorType.DATADOG]
                     }
                 ])
             });
-            jest.spyOn(global.Math, 'random').mockReturnValue(0.7);
 
             // WHEN
             const xhr = new XMLHttpRequestMock();
@@ -402,15 +401,14 @@ describe('XHRProxy', () => {
             const method = 'GET';
             const url = 'https://api.example.com/v2/user';
             xhrProxy.onTrackingStart({
-                tracingSamplingRate: 50,
+                tracingSamplingRate: 0,
                 firstPartyHostsRegexMap: firstPartyHostsRegexMapBuilder([
                     {
                         match: 'api.example.com',
                         propagatorTypes: [PropagatorType.DATADOG]
                     }
                 ])
             });
-            jest.spyOn(global.Math, 'random').mockReturnValue(0.7);
 
             // WHEN
             const xhr = new XMLHttpRequestMock();
@@ -811,7 +809,6 @@ describe('XHRProxy', () => {
                 tracingSamplingRate: 50,
                 firstPartyHostsRegexMap: firstPartyHostsRegexMapBuilder([])
             });
-            jest.spyOn(global.Math, 'random').mockReturnValue(0.7);
 
             // WHEN
             const xhr = new XMLHttpRequestMock();
@@ -843,7 +840,7 @@ describe('XHRProxy', () => {
             const method = 'GET';
             const url = 'https://api.example.com/v2/user';
             xhrProxy.onTrackingStart({
-                tracingSamplingRate: 50,
+                tracingSamplingRate: 0,
                 firstPartyHostsRegexMap: firstPartyHostsRegexMapBuilder([
                     {
                         match: 'api.example.com',

diff --git a/packages/react-native-session-replay/package.json b/packages/react-native-session-replay/package.json
@@ -16,7 +16,6 @@
     },
     "license": "Apache-2.0",
     "main": "lib/commonjs/index",
-    "private": "true",
     "files": [
         "src/**",
         "lib/**",