From a96eaf8eb36af8f60e0ad2dce154f023cd4cef69 Mon Sep 17 00:00:00 2001
From: Oscar Reyes <oscar-rreyes1@hotmail.com>
Date: Thu, 7 Dec 2023 09:51:13 -0600
Subject: [PATCH] feat: adding traceparent from meta tag

---
 .../src/instrumentation.ts                    | 21 ++++++++++++---
 .../test/userInteraction.test.ts              | 26 +++++++++++++++++++
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/plugins/web/opentelemetry-instrumentation-user-interaction/src/instrumentation.ts b/plugins/web/opentelemetry-instrumentation-user-interaction/src/instrumentation.ts
index e8be5e3fc5..e1bd5a44f1 100644
--- a/plugins/web/opentelemetry-instrumentation-user-interaction/src/instrumentation.ts
+++ b/plugins/web/opentelemetry-instrumentation-user-interaction/src/instrumentation.ts
@@ -19,7 +19,7 @@
 import { isWrapped, InstrumentationBase } from '@opentelemetry/instrumentation';
 
 import * as api from '@opentelemetry/api';
-import { hrTime } from '@opentelemetry/core';
+import { TRACE_PARENT_HEADER, hrTime } from '@opentelemetry/core';
 import { getElementXPath } from '@opentelemetry/sdk-trace-web';
 import { AttributeNames } from './enums/AttributeNames';
 import {
@@ -132,6 +132,7 @@ export class UserInteractionInstrumentation extends InstrumentationBase<unknown>
     }
     const xpath = getElementXPath(element, true);
     try {
+      const context = this._getContext();
       const span = this.tracer.startSpan(
         eventName,
         {
@@ -143,8 +144,8 @@ export class UserInteractionInstrumentation extends InstrumentationBase<unknown>
           },
         },
         parentSpan
-          ? api.trace.setSpan(api.context.active(), parentSpan)
-          : undefined
+          ? api.trace.setSpan(context, parentSpan)
+          : context
       );
 
       if (this._shouldPreventSpanCreation(eventName, element, span) === true) {
@@ -177,6 +178,20 @@ export class UserInteractionInstrumentation extends InstrumentationBase<unknown>
     }
   }
 
+  /**
+   * 
+   * Returns the current context from meta tag
+   */
+  private _getContext(): api.Context {
+    const metaElement = Array.from(document.getElementsByTagName('meta')).find(
+      e => e.getAttribute('name') === TRACE_PARENT_HEADER
+    );
+    const traceparent = (metaElement && metaElement.content) || '';
+    const context = api.propagation.extract(api.context.active(), { traceparent });
+
+    return context;
+  }
+
   /**
    * Return the current span
    * @param zone
diff --git a/plugins/web/opentelemetry-instrumentation-user-interaction/test/userInteraction.test.ts b/plugins/web/opentelemetry-instrumentation-user-interaction/test/userInteraction.test.ts
index 792387e8c5..d60712f88b 100644
--- a/plugins/web/opentelemetry-instrumentation-user-interaction/test/userInteraction.test.ts
+++ b/plugins/web/opentelemetry-instrumentation-user-interaction/test/userInteraction.test.ts
@@ -38,6 +38,7 @@ import {
   fakeEventInteraction,
   getData,
 } from './helper.test';
+import { TRACE_PARENT_HEADER } from '@opentelemetry/core';
 
 const FILE_URL =
   'https://raw.githubusercontent.com/open-telemetry/opentelemetry-js/main/package.json';
@@ -621,5 +622,30 @@ describe('UserInteractionInstrumentation', () => {
         'go should be unwrapped'
       );
     });
+
+    it('should use the traceparent trace id as parent id', () => {
+      registerTestInstrumentations({
+        eventNames: ['click'],
+      });
+
+      const version = '00';
+      const idGenerator = new tracing.RandomIdGenerator();
+      const traceId = idGenerator.generateTraceId();
+      const spanId = idGenerator.generateSpanId();
+      const samplingFlags = '01';
+
+      const traceparent = `${version}-${traceId}-${spanId}-${samplingFlags}`;
+
+      const metaElement = document.createElement('meta');
+      metaElement.setAttribute('name', TRACE_PARENT_HEADER);
+      metaElement.setAttribute('content', traceparent);
+      document.head.appendChild(metaElement);
+
+      fakeEventInteraction('click');
+      assert.strictEqual(exportSpy.args.length, 1, 'should export one span');
+      const span = exportSpy.args[0][0][0];
+      assert.strictEqual(span.parentSpanId, spanId);
+      assertInteractionSpan(span, { name: 'click' });
+    });
   });
 });