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feat(browser): Add option to sample linked traces consistently#16037

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Merged
Lms24 merged 9 commits into from
May 5, 2025
Merged

feat(browser): Add option to sample linked traces consistently #16037

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7154f69
feat(browser): Add option to sample linked traces consistently
Lms24 Apr 11, 2025
fdb6cdd
add integration tests
Lms24 Apr 11, 2025
677cbb9
Update packages/core/src/tracing/dynamicSamplingContext.ts
Lms24 Apr 11, 2025
f06a051
fix meta tag precedence, add more tests, move some files and code around
Lms24 Apr 30, 2025
45b7e75
fix lint and size-limit
Lms24 Apr 30, 2025
9aae9b8
finally fix lint??
Lms24 Apr 30, 2025
02f7e7e
size limit once more :(
Lms24 Apr 30, 2025
9a81cd0
fix test flakiness
Lms24 May 2, 2025
d5bab06
swap linkTraces arguments, adjust comment
Lms24 May 5, 2025
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4 changes: 2 additions & 2 deletions .size-limit.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
path: 'packages/browser/build/npm/esm/index.js',
import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
gzip: true,
limit: '76 KB',
limit: '77 KB',
},
{
name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
import: createImport('init'),
ignore: ['$app/stores'],
gzip: true,
limit: '38.5 KB',
limit: '39 KB',
},
// Node SDK (ESM)
{
Expand Down
21 changes: 21 additions & 0 deletions ...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js
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@@ -0,0 +1,21 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
dsn: 'https://public@dsn.ingest.sentry.io/1337',
integrations: [
Sentry.browserTracingIntegration({
linkPreviousTrace: 'in-memory',
consistentTraceSampling: true,
}),
],
tracePropagationTargets: ['someurl.com'],
tracesSampler: ctx => {
if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
return 1;
}
return ctx.inheritOrSampleWith(0);
},
debug: true,
});
17 changes: 17 additions & 0 deletions ...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js
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@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
Sentry.startNewTrace(() => {
Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
});
});

btn2.addEventListener('click', () => {
Sentry.startNewTrace(() => {
Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
await fetch('https://someUrl.com');
});
});
});
10 changes: 10 additions & 0 deletions ...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html
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@@ -0,0 +1,10 @@
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<button id="btn1">
</button>
<button id="btn2">
</button>
</html>
153 changes: 153 additions & 0 deletions ...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts
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import { expect } from '@playwright/test';
import {
extractTraceparentData,
parseBaggageHeader,
SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
eventAndTraceHeaderRequestParser,
shouldSkipTracingTest,
waitForTracingHeadersOnUrl,
waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
if (shouldSkipTracingTest()) {
sentryTest.skip();
}

const url = await getLocalTestUrl({ testDir: __dirname });

const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
return evt.contexts?.trace?.op === 'pageload';
});
await page.goto(url);

const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
const pageloadSampleRand = Number(res[1]?.sample_rand);
const pageloadTraceContext = res[0].contexts?.trace;

expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
});

const customTraceContext = await sentryTest.step('Custom trace', async () => {
const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
await page.locator('#btn1').click();
const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
await customTrace1RequestPromise,
);

const customTraceContext = customTrace1Event.contexts?.trace;

expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
// although we "continue the trace" from pageload, this is actually a root span,
// so there must not be a parent span id
expect(customTraceContext?.parent_span_id).toBeUndefined();

expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

return customTraceContext;
});

await sentryTest.step('Navigation', async () => {
const navigation1RequestPromise = waitForTransactionRequest(
page,
evt => evt.contexts?.trace?.op === 'navigation',
);
await page.goto(`${url}#foo`);
const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
await navigation1RequestPromise,
);
const navTraceContext = navigationEvent.contexts?.trace;

expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

expect(navTraceContext?.links).toEqual([
{
trace_id: customTraceContext?.trace_id,
span_id: customTraceContext?.span_id,
sampled: true,
attributes: {
[SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
},
},
]);
expect(navTraceContext?.parent_span_id).toBeUndefined();

expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
});
});

sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
if (shouldSkipTracingTest()) {
sentryTest.skip();
}

const url = await getLocalTestUrl({ testDir: __dirname });

const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
await page.goto(url);

const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
const pageloadSampleRand = Number(res[1]?.sample_rand);

expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

const pageloadTraceContext = res[0].contexts?.trace;

expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
});

await sentryTest.step('Make fetch request', async () => {
const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

await page.locator('#btn2').click();

const { baggage, sentryTrace } = await tracingHeadersPromise;

const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
);
expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

expect(sentryTrace).toBeDefined();
expect(baggage).toBeDefined();

expect(extractTraceparentData(sentryTrace)).toEqual({
traceId: fetchTraceTraceContext?.trace_id,
parentSpanId: httpClientSpan?.span_id,
parentSampled: true,
});

expect(parseBaggageHeader(baggage)).toEqual({
'sentry-environment': 'production',
'sentry-public_key': 'public',
'sentry-sample_rand': `${pageloadSampleRand}`,
'sentry-sample_rate': '1',
'sentry-sampled': 'true',
'sentry-trace_id': fetchTraceTraceContext?.trace_id,
'sentry-transaction': 'custom root span 2',
});
});
});
});
17 changes: 17 additions & 0 deletions ...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js
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@@ -0,0 +1,17 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
dsn: 'https://public@dsn.ingest.sentry.io/1337',
integrations: [
Sentry.browserTracingIntegration({
linkPreviousTrace: 'in-memory',
consistentTraceSampling: true,
}),
],
tracePropagationTargets: ['someurl.com'],
tracesSampleRate: 1,
debug: true,
sendClientReports: true,
});
17 changes: 17 additions & 0 deletions ...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js
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@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
Sentry.startNewTrace(() => {
Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
});
});

btn2.addEventListener('click', () => {
Sentry.startNewTrace(() => {
Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
await fetch('https://someUrl.com');
});
});
});
13 changes: 13 additions & 0 deletions ...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html
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@@ -0,0 +1,13 @@
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
<meta
name="baggage"
content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
/>
</head>
<button id="btn1">Custom Trace</button>
<button id="btn2">fetch request</button>
</html>
100 changes: 100 additions & 0 deletions ...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts
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import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
envelopeRequestParser,
getMultipleSentryEnvelopeRequests,
hidePage,
shouldSkipTracingTest,
waitForClientReportRequest,
waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
sentryTest(
'Continues negative sampling decision from meta tag across all traces and downstream propagations',
async ({ getLocalTestUrl, page }) => {
if (shouldSkipTracingTest()) {
sentryTest.skip();
}

const url = await getLocalTestUrl({ testDir: __dirname });

let txnsReceived = 0;
// @ts-expect-error - no need to return something valid here
getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
++txnsReceived;
return {};
});

const clientReportPromise = waitForClientReportRequest(page);

await sentryTest.step('Initial pageload', async () => {
await page.goto(url);
expect(txnsReceived).toEqual(0);
});

await sentryTest.step('Custom instrumented button click', async () => {
await page.locator('#btn1').click();
expect(txnsReceived).toEqual(0);
});

await sentryTest.step('Navigation', async () => {
await page.goto(`${url}#foo`);
expect(txnsReceived).toEqual(0);
});

await sentryTest.step('Make fetch request', async () => {
const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

await page.locator('#btn2').click();
const { baggage, sentryTrace } = await tracingHeadersPromise;

expect(sentryTrace).toBeDefined();
expect(baggage).toBeDefined();

expect(extractTraceparentData(sentryTrace)).toEqual({
traceId: expect.not.stringContaining(metaTagTraceId),
parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
parentSampled: false,
});

expect(parseBaggageHeader(baggage)).toEqual({
'sentry-environment': 'production',
'sentry-public_key': 'public',
'sentry-sample_rand': `${metaTagSampleRand}`,
'sentry-sample_rate': `${metaTagSampleRate}`,
'sentry-sampled': 'false',
'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
'sentry-transaction': 'custom root span 2',
});
});

await sentryTest.step('Client report', async () => {
await hidePage(page);
const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
expect(clientReport).toEqual({
timestamp: expect.any(Number),
discarded_events: [
{
category: 'transaction',
quantity: 4,
reason: 'sample_rate',
},
],
});
});

await sentryTest.step('Wait for transactions to be discarded', async () => {
// give it a little longer just in case a txn is pending to be sent
await page.waitForTimeout(1000);
expect(txnsReceived).toEqual(0);
});
},
);
});
19 changes: 19 additions & 0 deletions ...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js
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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
dsn: 'https://public@dsn.ingest.sentry.io/1337',
integrations: [
Sentry.browserTracingIntegration({
linkPreviousTrace: 'session-storage',
consistentTraceSampling: true,
}),
],
tracePropagationTargets: ['someurl.com'],
tracesSampler: ({ inheritOrSampleWith }) => {
return inheritOrSampleWith(0);
},
debug: true,
sendClientReports: true,
});
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
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feat(browser): Add option to sample linked traces consistently#16037

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 Merged

Lms24
merged 9 commits into

from

May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
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7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

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4 changes: 2 additions & 2 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
Expand Down

21 changes: 21 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

17 changes: 17 additions & 0 deletions
...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

10 changes: 10 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

153 changes: 153 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,153 @@
import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

17 changes: 17 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

17 changes: 17 additions & 0 deletions
...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

13 changes: 13 additions & 0 deletions
...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

100 changes: 100 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

19 changes: 19 additions & 0 deletions
...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
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';
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})();
}
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try {
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feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
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 Merged

Lms24
merged 9 commits into

from

May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
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7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

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4 changes: 2 additions & 2 deletions
.size-limit.js

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Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
Expand Down

21 changes: 21 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

17 changes: 17 additions & 0 deletions
...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

10 changes: 10 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

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<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

153 changes: 153 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

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import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

17 changes: 17 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

17 changes: 17 additions & 0 deletions
...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

13 changes: 13 additions & 0 deletions
...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

100 changes: 100 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

19 changes: 19 additions & 0 deletions
...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
Skip to content
feat(browser): Add option to sample linked traces consistently#16037

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 Merged

Lms24
merged 9 commits into

from

May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
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7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

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4 changes: 2 additions & 2 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
Expand Down

21 changes: 21 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

17 changes: 17 additions & 0 deletions
...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

10 changes: 10 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

153 changes: 153 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,153 @@
import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

17 changes: 17 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

17 changes: 17 additions & 0 deletions
...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

13 changes: 13 additions & 0 deletions
...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

100 changes: 100 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,100 @@
import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

19 changes: 19 additions & 0 deletions
...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
Skip to content
feat(browser): Add option to sample linked traces consistently#16037

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Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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to your account

 Merged

Lms24
merged 9 commits into

from

May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
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Hold shift + click to select a range
7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

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4 changes: 2 additions & 2 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
Expand Down

21 changes: 21 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

17 changes: 17 additions & 0 deletions
...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

10 changes: 10 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

153 changes: 153 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,153 @@
import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

17 changes: 17 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

17 changes: 17 additions & 0 deletions
...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

13 changes: 13 additions & 0 deletions
...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

100 changes: 100 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

19 changes: 19 additions & 0 deletions
...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
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feat(browser): Add option to sample linked traces consistently#16037

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 Merged

Lms24
merged 9 commits into

from

May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
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7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

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4 changes: 2 additions & 2 deletions
.size-limit.js

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Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
Expand Down

21 changes: 21 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

17 changes: 17 additions & 0 deletions
...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

10 changes: 10 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

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<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

153 changes: 153 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

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import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

17 changes: 17 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

17 changes: 17 additions & 0 deletions
...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

13 changes: 13 additions & 0 deletions
...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

100 changes: 100 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

19 changes: 19 additions & 0 deletions
...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
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feat(browser): Add option to sample linked traces consistently#16037

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 Merged

Lms24
merged 9 commits into

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May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
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7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

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4 changes: 2 additions & 2 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
Expand Down

21 changes: 21 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

17 changes: 17 additions & 0 deletions
...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

10 changes: 10 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

153 changes: 153 additions & 0 deletions
...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

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Original file line numberDiff line numberDiff line change
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import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

17 changes: 17 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

17 changes: 17 additions & 0 deletions
...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

13 changes: 13 additions & 0 deletions
...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

100 changes: 100 additions & 0 deletions
...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,100 @@
import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

19 changes: 19 additions & 0 deletions
...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
feat(browser): Add option to sample linked traces consistently by Lms24 · Pull Request #16037 · getsentry/sentry-javascript · GitHub
Skip to content
feat(browser): Add option to sample linked traces consistently#16037

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privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

Lms24
merged 9 commits into

from

May 5, 2025
 Merged


feat(browser): Add option to sample linked traces consistently
#16037
Show file tree
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 Changes from all commits
Commits

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9 commits


Select commit
Hold shift + click to select a range
7154f69

feat(browser): Add option to sample linked traces consistently


Lms24 Apr 11, 2025
fdb6cdd

add integration tests


Lms24 Apr 11, 2025
677cbb9

Update packages/core/src/tracing/dynamicSamplingContext.ts


Lms24 Apr 11, 2025
f06a051

fix meta tag precedence, add more tests, move some files and code around


Lms24 Apr 30, 2025
45b7e75

fix lint and size-limit


Lms24 Apr 30, 2025
9aae9b8

finally fix lint??


Lms24 Apr 30, 2025
02f7e7e

size limit once more :(


Lms24 Apr 30, 2025
9a81cd0

fix test flakiness


Lms24 May 2, 2025
d5bab06

swap linkTraces arguments, adjust comment


Lms24 May 5, 2025

File filter

Filter by extension
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Conversations

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4 changes: 2 additions & 2 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -47,7 +47,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/index.js',
 import: createImport('init', 'browserTracingIntegration', 'replayIntegration'),
 gzip: true,
 limit: '76 KB',
 limit: '77 KB',
 },
 {
 name: '@sentry/browser (incl. Tracing, Replay) - with treeshaking flags',
Expand DownExpand Up@@ -219,7 +219,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '38.5 KB',
 limit: '39 KB',
 },
 // Node SDK (ESM)
 {
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...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ctx => {
 if (ctx.attributes && ctx.attributes['sentry.origin'] === 'auto.pageload.browser') {
 return 1;
 }
 return ctx.inheritOrSampleWith(0);
 },
 debug: true,
});

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...es/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

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...tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/template.html

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<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8" />
 </head>
 <button id="btn1">
 </button>
 <button id="btn2">
 </button>
</html>

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...uites/tracing/browserTracingIntegration/linked-traces/consistent-sampling/default/test.ts

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import { expect } from '@playwright/test';
import {
 extractTraceparentData,
 parseBaggageHeader,
 SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE,
 SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE,
} from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 eventAndTraceHeaderRequestParser,
 shouldSkipTracingTest,
 waitForTracingHeadersOnUrl,
 waitForTransactionRequest,
} from '../../../../../../utils/helpers';

sentryTest.describe('When `consistentTraceSampling` is `true`', () => {
 sentryTest('Continues sampling decision from initial pageload', async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => {
 return evt.contexts?.trace?.op === 'pageload';
 });
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);
 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);
 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 return { pageloadTraceContext: res[0].contexts?.trace, pageloadSampleRand };
 });

 const customTraceContext = await sentryTest.step('Custom trace', async () => {
 const customTrace1RequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 await page.locator('#btn1').click();
 const [customTrace1Event, customTraceTraceHeader] = eventAndTraceHeaderRequestParser(
 await customTrace1RequestPromise,
 );

 const customTraceContext = customTrace1Event.contexts?.trace;

 expect(customTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);
 // although we "continue the trace" from pageload, this is actually a root span,
 // so there must not be a parent span id
 expect(customTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(customTraceTraceHeader?.sample_rand));

 return customTraceContext;
 });

 await sentryTest.step('Navigation', async () => {
 const navigation1RequestPromise = waitForTransactionRequest(
 page,
 evt => evt.contexts?.trace?.op === 'navigation',
 );
 await page.goto(`${url}#foo`);
 const [navigationEvent, navigationTraceHeader] = eventAndTraceHeaderRequestParser(
 await navigation1RequestPromise,
 );
 const navTraceContext = navigationEvent.contexts?.trace;

 expect(navTraceContext?.trace_id).not.toEqual(customTraceContext?.trace_id);
 expect(navTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(navTraceContext?.links).toEqual([
 {
 trace_id: customTraceContext?.trace_id,
 span_id: customTraceContext?.span_id,
 sampled: true,
 attributes: {
 [SEMANTIC_LINK_ATTRIBUTE_LINK_TYPE]: 'previous_trace',
 },
 },
 ]);
 expect(navTraceContext?.parent_span_id).toBeUndefined();

 expect(pageloadSampleRand).toEqual(Number(navigationTraceHeader?.sample_rand));
 });
 });

 sentryTest('Propagates continued sampling decision to outgoing requests', async ({ page, getLocalTestUrl }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 const { pageloadTraceContext, pageloadSampleRand } = await sentryTest.step('Initial pageload', async () => {
 const pageloadRequestPromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'pageload');
 await page.goto(url);

 const res = eventAndTraceHeaderRequestParser(await pageloadRequestPromise);
 const pageloadSampleRand = Number(res[1]?.sample_rand);

 expect(pageloadSampleRand).toBeGreaterThanOrEqual(0);

 const pageloadTraceContext = res[0].contexts?.trace;

 expect(pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toBe(1);

 return { pageloadTraceContext: pageloadTraceContext, pageloadSampleRand };
 });

 await sentryTest.step('Make fetch request', async () => {
 const fetchTracePromise = waitForTransactionRequest(page, evt => evt.contexts?.trace?.op === 'custom');
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();

 const { baggage, sentryTrace } = await tracingHeadersPromise;

 const [fetchTraceEvent, fetchTraceTraceHeader] = eventAndTraceHeaderRequestParser(await fetchTracePromise);

 const fetchTraceSampleRand = Number(fetchTraceTraceHeader?.sample_rand);
 const fetchTraceTraceContext = fetchTraceEvent.contexts?.trace;
 const httpClientSpan = fetchTraceEvent.spans?.find(span => span.op === 'http.client');

 expect(fetchTraceSampleRand).toEqual(pageloadSampleRand);

 expect(fetchTraceTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE]).toEqual(
 pageloadTraceContext?.data?.[SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE],
 );
 expect(fetchTraceTraceContext?.trace_id).not.toEqual(pageloadTraceContext?.trace_id);

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: fetchTraceTraceContext?.trace_id,
 parentSpanId: httpClientSpan?.span_id,
 parentSampled: true,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${pageloadSampleRand}`,
 'sentry-sample_rate': '1',
 'sentry-sampled': 'true',
 'sentry-trace_id': fetchTraceTraceContext?.trace_id,
 'sentry-transaction': 'custom root span 2',
 });
 });
 });
});

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...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'in-memory',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampleRate: 1,
 debug: true,
 sendClientReports: true,
});

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...cing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/subject.js

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const btn1 = document.getElementById('btn1');

const btn2 = document.getElementById('btn2');

btn1.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 1', op: 'custom' }, () => {});
 });
});

btn2.addEventListener('click', () => {
 Sentry.startNewTrace(() => {
 Sentry.startSpan({ name: 'custom root span 2', op: 'custom' }, async () => {
 await fetch('https://someUrl.com');
 });
 });
});

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...g/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/template.html

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<!doctype html>
<html>
 <head>
 <meta charset="utf-8" />
 <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-0" />
 <meta
 name="baggage"
 content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=false,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.9"
 />
 </head>
 <button id="btn1">Custom Trace</button>
 <button id="btn2">fetch request</button>
</html>

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...tracing/browserTracingIntegration/linked-traces/consistent-sampling/meta-negative/test.ts

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import { expect } from '@playwright/test';
import type { ClientReport } from '@sentry/core';
import { extractTraceparentData, parseBaggageHeader } from '@sentry/core';
import { sentryTest } from '../../../../../../utils/fixtures';
import {
 envelopeRequestParser,
 getMultipleSentryEnvelopeRequests,
 hidePage,
 shouldSkipTracingTest,
 waitForClientReportRequest,
 waitForTracingHeadersOnUrl,
} from '../../../../../../utils/helpers';

const metaTagSampleRand = 0.9;
const metaTagSampleRate = 0.2;
const metaTagTraceId = '12345678901234567890123456789012';

sentryTest.describe('When `consistentTraceSampling` is `true` and page contains <meta> tags', () => {
 sentryTest(
 'Continues negative sampling decision from meta tag across all traces and downstream propagations',
 async ({ getLocalTestUrl, page }) => {
 if (shouldSkipTracingTest()) {
 sentryTest.skip();
 }

 const url = await getLocalTestUrl({ testDir: __dirname });

 let txnsReceived = 0;
 // @ts-expect-error - no need to return something valid here
 getMultipleSentryEnvelopeRequests<Event>(page, 1, { envelopeType: 'transaction' }, () => {
 ++txnsReceived;
 return {};
 });

 const clientReportPromise = waitForClientReportRequest(page);

 await sentryTest.step('Initial pageload', async () => {
 await page.goto(url);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Custom instrumented button click', async () => {
 await page.locator('#btn1').click();
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Navigation', async () => {
 await page.goto(`${url}#foo`);
 expect(txnsReceived).toEqual(0);
 });

 await sentryTest.step('Make fetch request', async () => {
 const tracingHeadersPromise = waitForTracingHeadersOnUrl(page, 'https://someUrl.com');

 await page.locator('#btn2').click();
 const { baggage, sentryTrace } = await tracingHeadersPromise;

 expect(sentryTrace).toBeDefined();
 expect(baggage).toBeDefined();

 expect(extractTraceparentData(sentryTrace)).toEqual({
 traceId: expect.not.stringContaining(metaTagTraceId),
 parentSpanId: expect.stringMatching(/^[0-9a-f]{16}$/),
 parentSampled: false,
 });

 expect(parseBaggageHeader(baggage)).toEqual({
 'sentry-environment': 'production',
 'sentry-public_key': 'public',
 'sentry-sample_rand': `${metaTagSampleRand}`,
 'sentry-sample_rate': `${metaTagSampleRate}`,
 'sentry-sampled': 'false',
 'sentry-trace_id': expect.not.stringContaining(metaTagTraceId),
 'sentry-transaction': 'custom root span 2',
 });
 });

 await sentryTest.step('Client report', async () => {
 await hidePage(page);
 const clientReport = envelopeRequestParser<ClientReport>(await clientReportPromise);
 expect(clientReport).toEqual({
 timestamp: expect.any(Number),
 discarded_events: [
 {
 category: 'transaction',
 quantity: 4,
 reason: 'sample_rate',
 },
 ],
 });
 });

 await sentryTest.step('Wait for transactions to be discarded', async () => {
 // give it a little longer just in case a txn is pending to be sent
 await page.waitForTimeout(1000);
 expect(txnsReceived).toEqual(0);
 });
 },
 );
});

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...acing/browserTracingIntegration/linked-traces/consistent-sampling/meta-precedence/init.js

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import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 integrations: [
 Sentry.browserTracingIntegration({
 linkPreviousTrace: 'session-storage',
 consistentTraceSampling: true,
 }),
 ],
 tracePropagationTargets: ['someurl.com'],
 tracesSampler: ({ inheritOrSampleWith }) => {
 return inheritOrSampleWith(0);
 },
 debug: true,
 sendClientReports: true,
});
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