feat(tracing): Add dynamic sampling correlation context data to envelope header (#3062)

Author: lobsterkatie

packages/core/src/request.ts

@@ -42,7 +42,17 @@ export function eventToSentryRequest(event: Event, api: API): SentryRequest {
     const envelopeHeaders = JSON.stringify({
       event_id: event.event_id,
       sent_at: new Date().toISOString(),
+
+      // trace context for dynamic sampling on relay
+      trace: {
+        trace_id: event.contexts?.trace?.trace_id,
+        // TODO: any reason we can't change this property to be called publicKey, since that's what it is?
+        public_key: api.getDsn().user,
+        environment: event.environment || 'no environment specified',
+        release: event.release || 'no release specified',
+      },
     });
+
     const itemHeaders = JSON.stringify({
       type: event.type,
 
@@ -64,6 +74,7 @@ export function eventToSentryRequest(event: Event, api: API): SentryRequest {
       //
       // length: new TextEncoder().encode(req.body).length,
     });
+
     // The trailing newline is optional. We intentionally don't send it to avoid
     // sending unnecessary bytes.
     //

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

@@ -16,14 +16,74 @@ describe('eventToSentryRequest', () => {
     user: { id: '1121', username: 'CharlieDog', ip_address: '11.21.20.12' },
   };
 
+  it('injects correct data for error/message events', () => {
+    const event = {
+      event_id: '1231201211212012',
+      exception: { values: [{ type: 'PuppyProblemsError', value: 'Charlie ate the flip-flops :-(' }] },
+      user: { id: '1121', username: 'CharlieDog', ip_address: '11.21.20.12' },
+    };
+
+    const result = eventToSentryRequest(event, api);
+    expect(result.type).toEqual('event');
+    expect(result.url).toEqual(
+      'https://squirrelchasers.ingest.sentry.io/api/12312012/store/?sentry_key=dogsarebadatkeepingsecrets&sentry_version=7',
+    );
+    expect(result.body).toEqual(JSON.stringify(event));
+  });
+
+  it('injects correct data for transaction events', () => {
+    const eventId = '1231201211212012';
+    const traceId = '0908201304152013';
+    const event = {
+      contexts: { trace: { trace_id: traceId, span_id: '12261980', op: 'pageload' } },
+      environment: 'dogpark',
+      event_id: eventId,
+      release: 'off.leash.park',
+      spans: [],
+      transaction: '/dogs/are/great/',
+      type: 'transaction',
+      user: { id: '1121', username: 'CharlieDog', ip_address: '11.21.20.12' },
+    };
+
+    const result = eventToSentryRequest(event as Event, api);
+
+    const [envelopeHeaderString, itemHeaderString, eventString] = result.body.split('\n');
+
+    const envelope = {
+      envelopeHeader: JSON.parse(envelopeHeaderString),
+      itemHeader: JSON.parse(itemHeaderString),
+      event: JSON.parse(eventString),
+    };
+
+    expect(result.type).toEqual('transaction');
+    expect(result.url).toEqual(
+      'https://squirrelchasers.ingest.sentry.io/api/12312012/envelope/?sentry_key=dogsarebadatkeepingsecrets&sentry_version=7',
+    );
+    expect(envelope.envelopeHeader).toEqual({
+      event_id: eventId,
+      sent_at: expect.any(String),
+      trace: {
+        environment: 'dogpark',
+        public_key: 'dogsarebadatkeepingsecrets',
+        release: 'off.leash.park',
+        trace_id: traceId,
+      },
+    });
+    expect(envelope.itemHeader).toEqual({
+      type: 'transaction',
+      sample_rates: expect.any(Array),
+    });
+    expect(envelope.event).toEqual(event);
+  });
+
   [
     { method: TransactionSamplingMethod.Rate, rate: '0.1121', dog: 'Charlie' },
     { method: TransactionSamplingMethod.Sampler, rate: '0.1231', dog: 'Maisey' },
     { method: TransactionSamplingMethod.Inheritance, dog: 'Cory' },
     { method: TransactionSamplingMethod.Explicit, dog: 'Bodhi' },
 
-    // this shouldn't ever happen (at least the method should always be included in tags), but good to know that things
-    // won't blow up if it does
+    // this shouldn't ever happen (tags should always include at least the sampling method), but good to know that
+    // things won't blow up if it does happen
     { dog: 'Lucy' },
   ].forEach(({ method, rate, dog }) => {
     it(`adds transaction sampling information to item header - ${method}, ${rate}, ${dog}`, () => {