use encoded value for tracestate in envelope header

Author: lobsterkatie

packages/core/src/request.ts

@@ -1,4 +1,5 @@
 import { Event, SdkInfo, SentryRequest, Session } from '@sentry/types';
+import { base64ToUnicode, logger } from '@sentry/utils';
 
 import { API } from './api';
 
@@ -66,26 +67,28 @@ export function eventToSentryRequest(event: Event, api: API): SentryRequest {
 export function transactionToSentryRequest(event: Event, api: API): SentryRequest {
   const sdkInfo = getSdkMetadataForEnvelopeHeader(api);
 
-  const { transactionSampling, ...metadata } = event.debug_meta || {};
+  const { transactionSampling, tracestate: encodedTracestate, ...metadata } = event.debug_meta || {};
   const { method: samplingMethod, rate: sampleRate } = transactionSampling || {};
   if (Object.keys(metadata).length === 0) {
     delete event.debug_meta;
   } else {
     event.debug_meta = metadata;
   }
 
+  // the tracestate is stored in bas64-encoded JSON, but envelope header values are expected to be full JS values,
+  // so we have to decode and reinflate it
+  let tracestate;
+  try {
+    tracestate = JSON.parse(base64ToUnicode(encodedTracestate as string));
+  } catch (err) {
+    logger.warn(err);
+  }
+
   const envelopeHeaders = JSON.stringify({
     event_id: event.event_id,
     sent_at: new Date().toISOString(),
     ...(sdkInfo && { sdk: sdkInfo }),
-
-    // trace context for dynamic sampling on relay
-    trace: {
-      trace_id: event.contexts?.trace?.trace_id,
-      public_key: api.getDsn().publicKey,
-      environment: event.environment || null,
-      release: event.release || null,
-    },
+    ...(tracestate && { trace: tracestate }), // trace context for dynamic sampling on relay
   });
 
   const itemHeaders = JSON.stringify({

packages/core/test/lib/request.test.ts

@@ -58,7 +58,20 @@ describe('eventToSentryRequest', () => {
     beforeEach(() => {
       transactionEvent = {
         ...eventBase,
-        debug_meta: { transactionSampling: { method: TransactionSamplingMethod.Rate, rate: 0.1121 } },
+        debug_meta: {
+          transactionSampling: { method: TransactionSamplingMethod.Rate, rate: 0.1121 },
+          // This value is hardcoded in its base64 form to avoid a dependency on @sentry/tracing, where the method to
+          // compute the value lives. It's equivalent to
+          // computeTracestateValue({
+          //   trace_id: '1231201211212012',
+          //   environment: 'dogpark',
+          //   release: 'off.leash.park',
+          //   public_key: 'dogsarebadatkeepingsecrets',
+          // }),
+          tracestate:
+            'eyJ0cmFjZV9pZCI6IjEyMzEyMDEyMTEyMTIwMTIiLCJlbnZpcm9ubWVudCI6ImRvZ3BhcmsiLCJyZWxlYXNlIjoib2ZmLmxlYXNo' +
+            'LnBhcmsiLCJwdWJsaWNfa2V5IjoiZG9nc2FyZWJhZGF0a2VlcGluZ3NlY3JldHMifQ',
+        },
         spans: [],
         transaction: '/dogs/are/great/',
         type: 'transaction',
@@ -77,7 +90,7 @@ describe('eventToSentryRequest', () => {
     });
 
     describe('envelope header', () => {
-      it('adds correct data to envelope header', () => {
+      it('adds correct entries to envelope header', () => {
         jest.spyOn(Date.prototype, 'toISOString').mockReturnValueOnce('2012-12-31T09:08:13.000Z');
 
         const result = eventToSentryRequest(transactionEvent, api);
@@ -155,7 +168,7 @@ describe('eventToSentryRequest', () => {
     });
 
     describe('item header', () => {
-      it('adds correct data to item header', () => {
+      it('adds correct entries to item header', () => {
         const result = eventToSentryRequest(transactionEvent, api);
         const envelope = parseEnvelopeRequest(result);