Shadow: RUM-15702 Add trace sampling decision to DatadogEventBridge (v1)

packages/core/src/transport/eventBridge.ts

@@ -8,6 +8,7 @@ export interface BrowserWindowWithEventBridge extends Window {
 export interface DatadogEventBridge {
   getCapabilities?(): string
   getPrivacyLevel?(): DefaultPrivacyLevel
+  getIsTraceSampled?(): boolean | null
   getAllowedWebViewHosts(): string
   send(msg: string): void
 }
@@ -30,6 +31,12 @@ export function getEventBridge<T, E>() {
     getPrivacyLevel() {
       return eventBridgeGlobal.getPrivacyLevel?.()
     },
+    getIsTraceSampled() {
+      const value = eventBridgeGlobal.getIsTraceSampled?.()
+      if (value === true || value === false) {
+        return value
+      }
+    },
     getAllowedWebViewHosts() {
       return JSON.parse(eventBridgeGlobal.getAllowedWebViewHosts()) as string[]
     },

packages/core/test/emulate/mockEventBridge.ts

@@ -7,12 +7,19 @@ export function mockEventBridge({
   allowedWebViewHosts = [window.location.hostname],
   privacyLevel = DefaultPrivacyLevel.MASK,
   capabilities = [BridgeCapability.RECORDS],
-}: { allowedWebViewHosts?: string[]; privacyLevel?: DefaultPrivacyLevel; capabilities?: BridgeCapability[] } = {}) {
+  isTraceSampled,
+}: {
+  allowedWebViewHosts?: string[]
+  privacyLevel?: DefaultPrivacyLevel
+  capabilities?: BridgeCapability[]
+  isTraceSampled?: boolean
+} = {}) {
   const eventBridge: DatadogEventBridge = {
     send: (_msg: string) => undefined,
     getAllowedWebViewHosts: () => JSON.stringify(allowedWebViewHosts),
     getCapabilities: () => JSON.stringify(capabilities),
     getPrivacyLevel: () => privacyLevel,
+    getIsTraceSampled: isTraceSampled !== undefined ? () => isTraceSampled : undefined,
   }
 
   ;(window as BrowserWindowWithEventBridge).DatadogEventBridge = eventBridge

packages/rum-core/src/boot/preStartRum.spec.ts

@@ -141,6 +141,27 @@ describe('preStartRum', () => {
         )
       })
 
+      it('should set traceSampleRate to 100 when the bridge reports trace is sampled', () => {
+        mockEventBridge({ isTraceSampled: true })
+        const hybridInitConfiguration: HybridInitConfiguration = {}
+        strategy.init(hybridInitConfiguration as RumInitConfiguration, PUBLIC_API)
+        expect((strategy.initConfiguration as RumInitConfiguration)?.traceSampleRate).toEqual(100)
+      })
+
+      it('should set traceSampleRate to 0 when the bridge reports trace is not sampled', () => {
+        mockEventBridge({ isTraceSampled: false })
+        const hybridInitConfiguration: HybridInitConfiguration = {}
+        strategy.init(hybridInitConfiguration as RumInitConfiguration, PUBLIC_API)
+        expect((strategy.initConfiguration as RumInitConfiguration)?.traceSampleRate).toEqual(0)
+      })
+
+      it('should preserve the original traceSampleRate when the bridge does not provide isTraceSampled', () => {
+        mockEventBridge()
+        const hybridInitConfiguration: HybridInitConfiguration = { traceSampleRate: 50 }
+        strategy.init(hybridInitConfiguration as RumInitConfiguration, PUBLIC_API)
+        expect((strategy.initConfiguration as RumInitConfiguration)?.traceSampleRate).toEqual(50)
+      })
+
       it('should initialize even if session cannot be handled', () => {
         mockEventBridge()
         spyOnProperty(document, 'cookie', 'get').and.returnValue('')

packages/rum-core/src/boot/preStartRum.ts

@@ -326,12 +326,15 @@ export function createPreStartStrategy(
 }
 
 function overrideInitConfigurationForBridge(initConfiguration: RumInitConfiguration): RumInitConfiguration {
+  const bridge = getEventBridge()
+  const isTraceSampled = bridge?.getIsTraceSampled()
   return {
     ...initConfiguration,
     applicationId: '00000000-aaaa-0000-aaaa-000000000000',
     clientToken: 'empty',
     sessionSampleRate: 100,
-    defaultPrivacyLevel: initConfiguration.defaultPrivacyLevel ?? getEventBridge()?.getPrivacyLevel(),
+    defaultPrivacyLevel: initConfiguration.defaultPrivacyLevel ?? bridge?.getPrivacyLevel(),
+    traceSampleRate: isTraceSampled !== undefined ? (isTraceSampled ? 100 : 0) : initConfiguration.traceSampleRate,
   }
 }
 

test/e2e/lib/framework/createTest.ts

@@ -14,7 +14,7 @@ import { IntakeRegistry } from './intakeRegistry'
 import { flushEvents } from './flushEvents'
 import type { Servers } from './httpServers'
 import { getTestServers, waitForServersIdle } from './httpServers'
-import type { CallerLocation, SetupFactory, SetupOptions, UrlHook } from './pageSetups'
+import type { CallerLocation, EventBridgeOptions, SetupFactory, SetupOptions, UrlHook } from './pageSetups'
 import { html, DEFAULT_SETUPS, npmSetup, appSetup, formatConfiguration } from './pageSetups'
 import { createIntakeServerApp } from './serverApps/intake'
 import { createMockServerApp } from './serverApps/mock'
@@ -52,7 +52,7 @@ class TestBuilder {
   private head = ''
   private body = ''
   private baseUrlHooks: UrlHook[] = []
-  private eventBridge = false
+  private eventBridge: EventBridgeOptions | undefined
   private setups: Array<{ factory: SetupFactory; name?: string }> = DEFAULT_SETUPS
   private testFixture: typeof test = test
   private extension: {
@@ -101,8 +101,8 @@ class TestBuilder {
     return this
   }
 
-  withEventBridge() {
-    this.eventBridge = true
+  withEventBridge(options: EventBridgeOptions = {}) {
+    this.eventBridge = options
     return this
   }
 

test/e2e/lib/framework/pageSetups.ts

@@ -12,7 +12,7 @@ export interface SetupOptions {
   logsInit: (initConfiguration: LogsInitConfiguration) => void
   rumInit: (initConfiguration: RumInitConfiguration) => void
   remoteConfiguration?: RemoteConfiguration
-  eventBridge: boolean
+  eventBridge?: EventBridgeOptions
   head?: string
   body?: string
   baseUrlHooks: UrlHook[]
@@ -41,6 +41,10 @@ export interface WorkerOptions {
   logsConfiguration?: LogsInitConfiguration
 }
 
+export interface EventBridgeOptions {
+  isTraceSampled?: boolean
+}
+
 export type SetupFactory = (options: SetupOptions, servers: Servers) => string
 export type UrlHook = (baseUrl: URL, servers: Servers, options: SetupOptions) => void
 
@@ -60,7 +64,7 @@ export function asyncSetup(options: SetupOptions, servers: Servers) {
   let footer = ''
 
   if (options.eventBridge) {
-    header += setupEventBridge(servers)
+    header += setupEventBridge(servers, options.eventBridge)
   }
 
   if (options.extension) {
@@ -108,7 +112,7 @@ export function bundleSetup(options: SetupOptions, servers: Servers) {
   let header = options.head || ''
 
   if (options.eventBridge) {
-    header += setupEventBridge(servers)
+    header += setupEventBridge(servers, options.eventBridge)
   }
 
   if (options.extension) {
@@ -143,7 +147,7 @@ export function npmSetup(options: SetupOptions, servers: Servers) {
   let header = options.head || ''
 
   if (options.eventBridge) {
-    header += setupEventBridge(servers)
+    header += setupEventBridge(servers, options.eventBridge)
   }
 
   if (options.extension) {
@@ -180,7 +184,7 @@ export function appSetup(options: SetupOptions, servers: Servers, appName: strin
   let header = options.head || ''
 
   if (options.eventBridge) {
-    header += setupEventBridge(servers)
+    header += setupEventBridge(servers, options.eventBridge)
   }
 
   if (options.extension) {
@@ -238,7 +242,7 @@ export function microfrontendSetup(options: SetupOptions, servers: Servers) {
   let header = options.head || ''
 
   if (options.eventBridge) {
-    header += setupEventBridge(servers)
+    header += setupEventBridge(servers, options.eventBridge)
   }
 
   if (options.extension) {
@@ -278,7 +282,7 @@ function js(parts: readonly string[], ...vars: string[]) {
   return parts.reduce((full, part, index) => full + vars[index - 1] + part)
 }
 
-function setupEventBridge(servers: Servers) {
+function setupEventBridge(servers: Servers, options: EventBridgeOptions = {}) {
   const baseHostname = new URL(servers.base.origin).hostname
 
   // Send EventBridge events to the intake so we can inspect them in our E2E test cases. The URL
@@ -289,6 +293,13 @@ function setupEventBridge(servers: Servers) {
     bridge: 'true',
   }).toString()}`
 
+  const isTraceSampledMethod =
+    options.isTraceSampled !== undefined
+      ? `getIsTraceSampled() {
+        return ${options.isTraceSampled}
+      },`
+      : ''
+
   return html`<script type="text/javascript">
     window.DatadogEventBridge = {
       getCapabilities() {
@@ -297,6 +308,7 @@ function setupEventBridge(servers: Servers) {
       getPrivacyLevel() {
         return 'mask'
       },
+      ${isTraceSampledMethod}
       getAllowedWebViewHosts() {
         return '["${baseHostname}"]'
       },

test/e2e/scenario/eventBridge.scenario.ts

@@ -102,6 +102,32 @@ test.describe('bridge present', () => {
       expect(intakeRegistry.hasOnlyBridgeRequests).toBe(true)
     })
 
+  createTest('override trace sample rate when bridge provides isTraceSampled true')
+    .withRum({ service: 'service', traceSampleRate: 0, allowedTracingUrls: ['LOCATION_ORIGIN'] })
+    .withEventBridge({ isTraceSampled: true })
+    .run(async ({ flushEvents, intakeRegistry, sendXhr }) => {
+      await sendXhr('/headers')
+      await flushEvents()
+
+      const tracedResources = intakeRegistry.rumResourceEvents.filter(
+        (event) => event.resource.type === 'xhr' && event._dd?.trace_id
+      )
+      expect(tracedResources).toHaveLength(1)
+      expect(tracedResources[0]._dd.trace_id).toMatch(/\d+/)
+    })
+
+  createTest('override trace sample rate when bridge provides isTraceSampled false')
+    .withRum({ service: 'service', traceSampleRate: 100, allowedTracingUrls: ['LOCATION_ORIGIN'] })
+    .withEventBridge({ isTraceSampled: false })
+    .run(async ({ flushEvents, intakeRegistry, sendXhr }) => {
+      await sendXhr('/headers')
+      await flushEvents()
+
+      const xhrResources = intakeRegistry.rumResourceEvents.filter((event) => event.resource.type === 'xhr')
+      expect(xhrResources).toHaveLength(1)
+      expect(xhrResources[0]._dd?.trace_id).toBeUndefined()
+    })
+
   createTest('do not send records when the recording is stopped')
     .withRum()
     .withEventBridge()