fix(core): Remove sampled flag from dynamic sampling context in Tra…

…cing without Performance mode (#13753)

Fix a bug in Core that surfaced in Node apps configured for
Tracing without Performance.

Previously, we'd incorrectly add `sampled: false` flag when creating the
DSC from an active span if the application was configured for TwP. This
is possible because in TwP, Otel still emits non-recording spans for the
incoming requests. Our implementation in Core didn't account for this
edge case yet.

dev-packages/node-integration-tests/suites/tracing/meta-tags-twp-errors/server.js

@@ -4,25 +4,22 @@ const Sentry = require('@sentry/node');
 Sentry.init({
  dsn: 'https://public@dsn.ingest.sentry.io/1337',
  transport: loggingTransport,
- beforeSend(event) {
- event.contexts = {
- ...event.contexts,
- traceData: {
- ...Sentry.getTraceData(),
- metaTags: Sentry.getTraceMetaTags(),
- },
- };
- return event;
- },
 });
 
 // express must be required after Sentry is initialized
 const express = require('express');
 
 const app = express();
 
-app.get('/test', () => {
- throw new Error('test error');
+app.get('/test', (_req, res) => {
+ Sentry.withScope(scope => {
+ scope.setContext('traceData', {
+ ...Sentry.getTraceData(),
+ metaTags: Sentry.getTraceMetaTags(),
+ });
+ Sentry.captureException(new Error('test error 2'));
+ });
+ res.status(200).send();
 });
 
 Sentry.setupExpressErrorHandler(app);

dev-packages/node-integration-tests/suites/tracing/meta-tags-twp-errors/test.ts

@@ -5,7 +5,7 @@ describe('errors in TwP mode have same trace in trace context and getTraceData()
  cleanupChildProcesses();
  });
 
- test('in incoming request', async () => {
+ test('in incoming request', done => {
  createRunner(__dirname, 'server.js')
  .expect({
  event: event => {
@@ -17,14 +17,16 @@ describe('errors in TwP mode have same trace in trace context and getTraceData()
  const traceData = contexts?.traceData || {};
 
  expect(traceData['sentry-trace']).toEqual(`${trace_id}-${span_id}`);
+
  expect(traceData.baggage).toContain(`sentry-trace_id=${trace_id}`);
+ expect(traceData.baggage).not.toContain('sentry-sampled=');
 
  expect(traceData.metaTags).toContain(`<meta name="sentry-trace" content="${trace_id}-${span_id}"/>`);
- expect(traceData.metaTags).toContain(`sentr y-trace_id=${trace_id}`);
+ expect(traceData.metaTags).toContain(`sentry-trace_id=${trace_id}`);
  expect(traceData.metaTags).not.toContain('sentry-sampled=');
  },
  })
- .start()
+ .start(done)
  .makeRequest('get', '/test');
  });
 
@@ -41,6 +43,7 @@ describe('errors in TwP mode have same trace in trace context and getTraceData()
 
  expect(traceData['sentry-trace']).toEqual(`${trace_id}-${span_id}`);
  expect(traceData.baggage).toContain(`sentry-trace_id=${trace_id}`);
+ expect(traceData.baggage).not.toContain('sentry-sampled=');
 
  expect(traceData.metaTags).toContain(`<meta name="sentry-trace" content="${trace_id}-${span_id}"/>`);
  expect(traceData.metaTags).toContain(`sentry-trace_id=${trace_id}`);

dev-packages/node-integration-tests/suites/tracing/meta-tags-twp/test.ts

@@ -27,5 +27,6 @@ describe('getTraceMetaTags', () => {
  expect(sentryBaggageContent).toContain('sentry-environment=production');
  expect(sentryBaggageContent).toContain('sentry-public_key=public');
  expect(sentryBaggageContent).toContain(`sentry-trace_id=${traceId}`);
+ expect(sentryBaggageContent).not.toContain('sentry-sampled=');
  });
 });

packages/core/src/tracing/dynamicSamplingContext.ts

@@ -9,6 +9,7 @@ import {
 import { DEFAULT_ENVIRONMENT } from '../constants';
 import { getClient } from '../currentScopes';
 import { SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE, SEMANTIC_ATTRIBUTE_SENTRY_SOURCE } from '../semanticAttributes';
+import { hasTracingEnabled } from '../utils/hasTracingEnabled';
 import { getRootSpan, spanIsSampled, spanToJSON } from '../utils/spanUtils';
 
 /**
@@ -103,7 +104,12 @@ export function getDynamicSamplingContextFromSpan(span: Span): Readonly<Partial<
  dsc.transaction = name;
  }
 
- dsc.sampled = String(spanIsSampled(rootSpan));
+ // How can we even land here with hasTracingEnabled() returning false?
+ // Otel creates a Non-recording span in Tracing Without Performance mode when handling incoming requests
+ // So we end up with an active span that is not sampled (neither positively nor negatively)
+ if (hasTracingEnabled()) {
+ dsc.sampled = String(spanIsSampled(rootSpan));
+ }
 
  client.emit('createDsc', dsc, rootSpan);
 

packages/core/test/lib/tracing/dynamicSamplingContext.test.ts

@@ -2,6 +2,7 @@ import type { Span, SpanContextData, TransactionSource } from '@sentry/types';
 import {
  SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
  SEMANTIC_ATTRIBUTE_SENTRY_SOURCE,
+ getClient,
  setCurrentClient,
 } from '../../../src';
 import { SentrySpan, getDynamicSamplingContextFromSpan, startInactiveSpan } from '../../../src/tracing';
@@ -68,7 +69,7 @@ describe('getDynamicSamplingContextFromSpan', () => {
  environment: 'production',
  sampled: 'true',
  sample_rate: '0.56',
- trace_id: expect.any(String),
+ trace_id: expect.stringMatching(/^[a-f0-9]{32}$/),
  transaction: 'tx',
  });
  });
@@ -85,7 +86,7 @@ describe('getDynamicSamplingContextFromSpan', () => {
  environment: 'production',
  sampled: 'true',
  sample_rate: '1',
- trace_id: expect.any(String),
+ trace_id: expect.stringMatching(/^[a-f0-9]{32}$/),
  transaction: 'tx',
  });
  });
@@ -107,7 +108,7 @@ describe('getDynamicSamplingContextFromSpan', () => {
  environment: 'production',
  sampled: 'true',
  sample_rate: '0.56',
- trace_id: expect.any(String),
+ trace_id: expect.stringMatching(/^[a-f0-9]{32}$/),
  transaction: 'tx',
  });
  });
@@ -144,4 +145,23 @@ describe('getDynamicSamplingContextFromSpan', () => {
  expect(dsc.transaction).toEqual('tx');
  });
  });
+
+ it("doesn't return the sampled flag in the DSC if in Tracing without Performance mode", () => {
+ const rootSpan = new SentrySpan({
+ name: 'tx',
+ sampled: undefined,
+ });
+
+ // Simulate TwP mode by deleting the tracesSampleRate option set in beforeEach
+ delete getClient()?.getOptions().tracesSampleRate;
+
+ const dynamicSamplingContext = getDynamicSamplingContextFromSpan(rootSpan);
+
+ expect(dynamicSamplingContext).toStrictEqual({
+ release: '1.0.1',
+ environment: 'production',
+ trace_id: expect.stringMatching(/^[a-f0-9]{32}$/),
+ transaction: 'tx',
+ });
+ });
 });