feat: user tracking

packages/session-recorder/src/index.ts

@@ -196,10 +196,16 @@ const SplunkRumRecorder = {
 			debug,
 			headers,
 			getResourceAttributes() {
-				return {
+				const newAttributes = {
 					...resource.attributes,
 					'splunk.rumSessionId': SplunkRum.getSessionId(),
 				}
+				const anonymousId = SplunkRum.getAnonymousId()
+				if (anonymousId) {
+					newAttributes['user.anonymousId'] = anonymousId
+				}
+
+				return newAttributes
 			},
 		})
 		const processor = new BatchLogProcessor(exporter, {})

packages/web/src/SplunkSpanAttributesProcessor.ts

@@ -19,13 +19,16 @@
 import { Attributes } from '@opentelemetry/api'
 import { Span, SpanProcessor } from '@opentelemetry/sdk-trace-base'
 import { getRumSessionId } from './session'
+import { forgetAnonymousId, getOrCreateAnonymousId } from './user-tracking'
+import { SplunkOtelWebConfig } from './types/config'
 
 export class SplunkSpanAttributesProcessor implements SpanProcessor {
 	private readonly _globalAttributes: Attributes
 
 	constructor(
 		globalAttributes: Attributes,
 		private useLocalStorageForSessionMetadata: boolean,
+		private getUserTracking: () => SplunkOtelWebConfig['user']['trackingMode'],
 	) {
 		this._globalAttributes = globalAttributes ?? {}
 	}
@@ -49,6 +52,13 @@ export class SplunkSpanAttributesProcessor implements SpanProcessor {
 			'splunk.rumSessionId',
 			getRumSessionId({ useLocalStorage: this.useLocalStorageForSessionMetadata }),
 		)
+		if (this.getUserTracking() === 'anonymousTracking') {
+			span.setAttribute(
+				'user.anonymousId',
+				getOrCreateAnonymousId({ useLocalStorage: this.useLocalStorageForSessionMetadata }),
+			)
+		}
+
 		span.setAttribute('browser.instance.visibility_state', document.visibilityState)
 	}
 
@@ -63,6 +73,7 @@ export class SplunkSpanAttributesProcessor implements SpanProcessor {
 	}
 
 	shutdown(): Promise<void> {
+		forgetAnonymousId()
 		return Promise.resolve()
 	}
 }

packages/web/src/index.ts

@@ -66,6 +66,7 @@ import { registerGlobal, unregisterGlobal } from './global-utils'
 import { BrowserInstanceService } from './services/BrowserInstanceService'
 import { SessionId } from './session'
 import { SplunkOtelWebConfig, SplunkOtelWebExporterOptions, SplunkOtelWebOptionsInstrumentations } from './types'
+import { forgetAnonymousId, getOrCreateAnonymousId } from './user-tracking'
 import { isBot } from './utils/is-bot'
 
 export { type SplunkExporterConfig } from './exporters/common'
@@ -220,6 +221,8 @@ export interface SplunkOtelWebType extends SplunkOtelWebEventTarget {
 
 	error: (...args: Array<any>) => void
 
+	getAnonymousId: () => string | undefined
+
 	/**
 	 * This method provides access to computed, final value of global attributes, which are applied to all created spans.
 	 */
@@ -239,9 +242,12 @@ export interface SplunkOtelWebType extends SplunkOtelWebEventTarget {
 	readonly resource?: Resource
 
 	setGlobalAttributes: (attributes: Attributes) => void
+
+	setUserTrackingMode: (mode: SplunkOtelWebConfig['user']['trackingMode']) => void
 }
 
 let inited = false
+let userTrackingMode: SplunkOtelWebConfig['user']['trackingMode'] = 'noTracking'
 let _deregisterInstrumentations: () => void | undefined
 let _deinitSessionTracking: () => void | undefined
 let _errorInstrumentation: SplunkErrorInstrumentation | undefined
@@ -271,6 +277,7 @@ export const SplunkRum: SplunkOtelWebType = {
 	},
 
 	init: function (options) {
+		userTrackingMode = options.user?.trackingMode ?? 'noTracking'
 		// "env" based config still a bad idea for web
 		if (!('OTEL_TRACES_EXPORTER' in _globalThis)) {
 			_globalThis.OTEL_TRACES_EXPORTER = 'none'
@@ -426,6 +433,7 @@ export const SplunkRum: SplunkOtelWebType = {
 				...(processedOptions.globalAttributes || {}),
 			},
 			this._processedOptions.persistence === 'localStorage',
+			() => userTrackingMode,
 		)
 		provider.addSpanProcessor(this.attributesProcessor)
 
@@ -496,6 +504,7 @@ export const SplunkRum: SplunkOtelWebType = {
 		unregisterGlobal('splunk.rum')
 		unregisterGlobal('splunk.rum.version')
 
+		forgetAnonymousId()
 		inited = false
 	},
 
@@ -544,6 +553,16 @@ export const SplunkRum: SplunkOtelWebType = {
 		return this.removeEventListener(name, callback)
 	},
 
+	setUserTrackingMode(mode: SplunkOtelWebConfig['user']['trackingMode']) {
+		userTrackingMode = mode
+	},
+
+	getAnonymousId() {
+		if (userTrackingMode === 'anonymousTracking') {
+			return getOrCreateAnonymousId({ useLocalStorage: this._processedOptions.persistence === 'localStorage' })
+		}
+	},
+
 	getSessionId() {
 		if (!inited) {
 			return undefined

packages/web/src/types/config.ts

@@ -172,6 +172,11 @@ export interface SplunkOtelWebConfig {
 	 */
 	tracer?: WebTracerConfig
 
+	user?: {
+		/** Sets tracking mode of user. Defaults to 'noTracking'. */
+		trackingMode?: 'noTracking' | 'anonymousTracking'
+	}
+
 	/**
 	 * Sets a value for the 'app.version' attribute
 	 */

packages/web/src/user-tracking/index.ts

@@ -0,0 +1,69 @@
+/**
+ *
+ * Copyright 2020-2025 Splunk Inc.
+ *
+ * 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 { generateId } from '../utils'
+import { safelyGetLocalStorage } from '../utils/storage'
+
+const KEY = 'splunk.anonymousId'
+let anonymousId: string | undefined
+
+export const getOrCreateAnonymousId = ({ useLocalStorage }: { useLocalStorage: boolean }) => {
+	if (anonymousId) {
+		return anonymousId
+	}
+
+	const id = useLocalStorage ? getAnonymousIdFromLocalStorage() : getAnonymousIdFromCookie()
+	anonymousId = id
+	return id
+}
+
+export const forgetAnonymousId = () => {
+	anonymousId = undefined
+}
+
+const getAnonymousIdFromLocalStorage = () => {
+	const lsValue = safelyGetLocalStorage(KEY)
+	if (lsValue) {
+		return lsValue
+	}
+
+	const newId = generateAnonymousId()
+	localStorage.setItem(KEY, newId)
+	return newId
+}
+
+const getAnonymousIdFromCookie = () => {
+	const cookieValue = document.cookie
+		.split('; ')
+		.find((row) => row.startsWith(KEY + '='))
+		?.split('=')[1]
+
+	if (cookieValue) {
+		setCookie(cookieValue)
+		return cookieValue
+	}
+
+	const newId = generateAnonymousId()
+	setCookie(newId)
+	return newId
+}
+
+const generateAnonymousId = () => generateId(128)
+
+const setCookie = (newId: string) => {
+	document.cookie = `${KEY}=${newId}; max-age=${60 * 60 * 24 * 400}`
+}

packages/web/tests/SplunkSpanAttributesProcessor.test.ts

@@ -27,6 +27,7 @@ describe('SplunkSpanAttributesProcessor', () => {
 					key1: 'value1',
 				},
 				false,
+				() => false,
 			)
 
 			expect(processor.getGlobalAttributes()).toStrictEqual({
@@ -41,6 +42,7 @@ describe('SplunkSpanAttributesProcessor', () => {
 					key2: 'value2',
 				},
 				false,
+				() => false,
 			)
 
 			processor.setGlobalAttributes({

packages/web/tests/user-tracking.test.ts

@@ -0,0 +1,102 @@
+/**
+ *
+ * Copyright 2020-2025 Splunk Inc.
+ *
+ * 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 SplunkRum from '../src/index'
+import * as tracing from '@opentelemetry/sdk-trace-base'
+import { describe, it, expect, afterEach } from 'vitest'
+import { deinit, initWithDefaultConfig, SpanCapturer } from './utils'
+
+const createSpan = (tracer: tracing.Tracer) => {
+	const span = tracer.startSpan('testSpan')
+	span.end()
+	return span as tracing.Span
+}
+
+const getLocalStorage = () => localStorage.getItem('splunk.anonymousId')
+
+const getCookie = () =>
+	document.cookie
+		.split('; ')
+		.find((row) => row.startsWith('splunk.anonymousId='))
+		?.split('=')[1]
+
+describe('userTracking is reflected', () => {
+	const capturer = new SpanCapturer()
+
+	afterEach(() => {
+		deinit(true)
+	})
+
+	it('cookies/userTrackingMode is default, then anonymousTracking', () => {
+		initWithDefaultConfig(capturer)
+
+		const tracer = SplunkRum.provider.getTracer('test')
+		const spanWithoutAnonymousId = createSpan(tracer)
+		expect(spanWithoutAnonymousId.attributes['user.anonymousId'], 'Checking user.anonymousId').toBeUndefined()
+
+		SplunkRum.setUserTrackingMode('anonymousTracking')
+
+		const spanWithAnonymousId = createSpan(tracer)
+		const anonymousId = spanWithAnonymousId.attributes['user.anonymousId']
+		expect(anonymousId, 'Checking user.anonymousId').toBeDefined()
+		expect(getCookie(), 'Checking cookie value').equal(anonymousId)
+	})
+
+	it('cookies/userTrackingMode is anonymousTracking, then noTracking', () => {
+		initWithDefaultConfig(capturer, { user: { trackingMode: 'anonymousTracking' } })
+
+		const tracer = SplunkRum.provider.getTracer('test')
+		const spanWithAnonymousId = createSpan(tracer)
+		const anonymousId = spanWithAnonymousId.attributes['user.anonymousId']
+		expect(anonymousId, 'Checking user.anonymousId').toBeDefined()
+		expect(getCookie(), 'Checking cookie value').equal(anonymousId)
+
+		SplunkRum.setUserTrackingMode('noTracking')
+
+		const spanWithoutAnonymousId = createSpan(tracer)
+		expect(spanWithoutAnonymousId.attributes['user.anonymousId'], 'Checking user.anonymousId').toBeUndefined()
+	})
+
+	it('localStorage/userTrackingMode is anonymousTracking, then noTracking', () => {
+		initWithDefaultConfig(capturer, { user: { trackingMode: 'anonymousTracking' }, persistence: 'localStorage' })
+
+		const tracer = SplunkRum.provider.getTracer('test')
+		const spanWithAnonymousId = createSpan(tracer)
+		const anonymousId = spanWithAnonymousId.attributes['user.anonymousId']
+		expect(anonymousId, 'Checking user.anonymousId').toBe(getLocalStorage())
+
+		SplunkRum.setUserTrackingMode('noTracking')
+
+		const spanWithoutAnonymousId = createSpan(tracer)
+		expect(spanWithoutAnonymousId.attributes['user.anonymousId'], 'Checking user.anonymousId').toBeUndefined()
+	})
+
+	it('localStorage/userTrackingMode is default, then anonymousTracking', () => {
+		initWithDefaultConfig(capturer, { persistence: 'localStorage' })
+
+		const tracer = SplunkRum.provider.getTracer('test')
+		const spanWithoutAnonymousId = createSpan(tracer)
+		expect(spanWithoutAnonymousId.attributes['user.anonymousId'], 'Checking user.anonymousId').toBeUndefined()
+
+		SplunkRum.setUserTrackingMode('anonymousTracking')
+
+		const spanWithAnonymousId = createSpan(tracer)
+		const anonymousId = spanWithAnonymousId.attributes['user.anonymousId']
+		expect(anonymousId, 'Checking user.anonymousId').toBe(getLocalStorage())
+	})
+})