fix(cloudflare): Use TransformStream to keep track of streams - #20452

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JPeer264 merged 2 commits into
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jp/cloudflare-streaming-span-fix
Apr 22, 2026
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fix(cloudflare): Use TransformStream to keep track of streams#20452
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closes#20409
closes JS-2233

Problem

The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.

Solution

By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.

There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.

I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).

Some evidence

repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409

cloudflare logs before:

image

cloudflare logs after:

image

Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/

Screenshot 2026-04-22 at 15 03 32

@JPeer264
JPeer264 requested review from logaretm and s1gr1dApril 22, 2026 13:07
@JPeer264JPeer264 self-assigned this Apr 22, 2026
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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)

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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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size-limit report 📦

PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺

View base workflow run

@JPeer264
JPeer264force-pushed the jp/cloudflare-streaming-span-fix branch from 75e9262 to 6de2693CompareApril 22, 2026 14:52
sentry[bot]
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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
@JPeer264
JPeer264force-pushed the jp/cloudflare-streaming-span-fix branch 2 times, most recently from 6de2693 to 339219aCompareApril 22, 2026 15:19
sentry[bot]
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Comment threadpackages/cloudflare/src/request.ts
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Way cleaner, that's very cool!

@JPeer264
JPeer264 merged commit 7569b10 into developApr 22, 2026
119 of 121 checks passed
@JPeer264
JPeer264 deleted the jp/cloudflare-streaming-span-fix branch April 22, 2026 17:31
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@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)

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@JPeer264@logaretm
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n 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;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
Merged
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Conversation
@JPeer264
@JPeer264JPeer264
commented
Apr 22, 2026

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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
@JPeer264
JPeer264
requested review from
logaretm and s1gr1dApril 22, 2026 13:07
@JPeer264JPeer264
self-assigned this
Apr 22, 2026
@linear-code
linear-codeBot
commented
Apr 22, 2026

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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
sentry[bot]
sentryBot
reviewed
Apr 22, 2026
View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
@github-actions
github-actionsBot
commented
Apr 22, 2026•

edited

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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
@JPeer264
JPeer264force-pushed
the
jp/cloudflare-streaming-span-fix
branch
from
75e9262 to
6de2693CompareApril 22, 2026 14:52
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reviewed
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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
@JPeer264
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from
6de2693 to
339219aCompareApril 22, 2026 15:19
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Comment threadpackages/cloudflare/src/request.ts
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Way cleaner, that's very cool!
@JPeer264
JPeer264
merged commit 7569b10
into
developApr 22, 2026

119 of 121 checks passed

@JPeer264
JPeer264
deleted the

jp/cloudflare-streaming-span-fix

branch
April 22, 2026 17:31
@sentry-release-botsentry-release-botBot
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Apr 23, 2026

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@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


2 participants

@JPeer264@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
Merged
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Conversation
@JPeer264
@JPeer264JPeer264
commented
Apr 22, 2026

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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
@JPeer264
JPeer264
requested review from
logaretm and s1gr1dApril 22, 2026 13:07
@JPeer264JPeer264
self-assigned this
Apr 22, 2026
@linear-code
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commented
Apr 22, 2026

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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
sentry[bot]
sentryBot
reviewed
Apr 22, 2026
View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
@JPeer264
JPeer264force-pushed
the
jp/cloudflare-streaming-span-fix
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6de2693CompareApril 22, 2026 14:52
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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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Way cleaner, that's very cool!
@JPeer264
JPeer264
merged commit 7569b10
into
developApr 22, 2026

119 of 121 checks passed

@JPeer264
JPeer264
deleted the

jp/cloudflare-streaming-span-fix

branch
April 22, 2026 17:31
@sentry-release-botsentry-release-botBot
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Apr 23, 2026

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46 tasks
@github-actionsgithub-actionsBot
mentioned this pull request
Apr 23, 2026

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Successfully merging this pull request may close these issues.

@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


2 participants

@JPeer264@logaretm

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

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
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JPeer264 merged 2 commits into
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jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
JPeer264 merged 2 commits into
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jp/cloudflare-streaming-span-fix
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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
@JPeer264
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requested review from
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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
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View reviewed changes
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
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Way cleaner, that's very cool!
@JPeer264
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@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


2 participants

@JPeer264@logaretm

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

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
Merged
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Conversation
@JPeer264
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Apr 22, 2026

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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
@JPeer264
JPeer264
requested review from
logaretm and s1gr1dApril 22, 2026 13:07
@JPeer264JPeer264
self-assigned this
Apr 22, 2026
@linear-code
linear-codeBot
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Apr 22, 2026

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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
sentry[bot]
sentryBot
reviewed
Apr 22, 2026
View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
@github-actions
github-actionsBot
commented
Apr 22, 2026•

edited

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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
@JPeer264
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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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Comment threadpackages/cloudflare/src/request.ts
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Way cleaner, that's very cool!
@JPeer264
JPeer264
merged commit 7569b10
into
developApr 22, 2026

119 of 121 checks passed

@JPeer264
JPeer264
deleted the

jp/cloudflare-streaming-span-fix

branch
April 22, 2026 17:31
@sentry-release-botsentry-release-botBot
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Apr 23, 2026

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@sentrysentry[bot]sentry[bot] left review comments
@logaretmlogaretmlogaretm approved these changes
@s1gr1ds1gr1dAwaiting requested review from s1gr1d

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Successfully merging this pull request may close these issues.

@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


2 participants

@JPeer264@logaretm

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
Merged
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Conversation
@JPeer264
@JPeer264JPeer264
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Apr 22, 2026

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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
@JPeer264
JPeer264
requested review from
logaretm and s1gr1dApril 22, 2026 13:07
@JPeer264JPeer264
self-assigned this
Apr 22, 2026
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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
sentry[bot]
sentryBot
reviewed
Apr 22, 2026
View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
@JPeer264
JPeer264force-pushed
the
jp/cloudflare-streaming-span-fix
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Way cleaner, that's very cool!
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@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
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jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
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jp/cloudflare-streaming-span-fix
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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
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Comment threadpackages/cloudflare/src/request.ts
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
@JPeer264
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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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Comment threadpackages/cloudflare/src/request.ts
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Way cleaner, that's very cool!
@JPeer264
JPeer264
merged commit 7569b10
into
developApr 22, 2026

119 of 121 checks passed

@JPeer264
JPeer264
deleted the

jp/cloudflare-streaming-span-fix

branch
April 22, 2026 17:31
@sentry-release-botsentry-release-botBot
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Apr 23, 2026

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46 tasks
@github-actionsgithub-actionsBot
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Apr 23, 2026

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@sentrysentry[bot]sentry[bot] left review comments
@logaretmlogaretmlogaretm approved these changes
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Successfully merging this pull request may close these issues.

@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


2 participants

@JPeer264@logaretm

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

Skip to content
fix(cloudflare): Use TransformStream to keep track of streams - #20452
Merged
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Apr 22, 2026
Merged
fix(cloudflare): Use TransformStream to keep track of streams#20452
JPeer264 merged 2 commits into
developfrom 
jp/cloudflare-streaming-span-fix
Conversation
@JPeer264
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Apr 22, 2026

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closes#20409

closes JS-2233
Problem
The issue is that we had a waitUntil?.(streamMonitor); that waited until the stream was done. streamMonitor could potentially live forever, while waitUntil has a limit of 30 seconds until it is getting cancelled. With the current approach we allow streams only being open for 30 seconds - then the waitUntil would cancel the request. This can only be reproduced when deployed, that is the reason why we didn't notice in our test cases.
Solution
By removing the waitUntil there is no hard limit, but we still have to wait until the stream is over in order to end our spans and flush accordingly. This can be achieved with TransformStream, where we simply use the stream body from the client and pipe it through our transformer. With flush and cancel we know exactly when the stream would end or be cancelled - which is the only thing we need.
There is btw no reason to add integration of E2E tests, as miniflare doesn't have this limitation and it couldn't be reproduced, so the tests would always succeed. The unit tests are kinda simulating that by checking if waitUntil is getting called or not.
I also figured that the client isn't getting disposed and would leak memory - this PR is also fixing that (see screenshots).
Some evidence
repro: https://github.com/JPeer264/sentry-repros/tree/issue-20409
cloudflare logs before:
image
cloudflare logs after:
image
Sentry trace: https://sentry-sdks.sentry.io/explore/traces/trace/29a307b1272e48dbb3a87c270c487e5a/
Screenshot 2026-04-22 at 15 03 32
@JPeer264
JPeer264
requested review from
logaretm and s1gr1dApril 22, 2026 13:07
@JPeer264JPeer264
self-assigned this
Apr 22, 2026
@linear-code
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Apr 22, 2026

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JS-2233 @sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)
sentry[bot]
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reviewed
Apr 22, 2026
View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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size-limit report 📦
PathSize% ChangeChange
@sentry/browser25.88 kB--
@sentry/browser - with treeshaking flags24.35 kB--
@sentry/browser (incl. Tracing)43.81 kB--
@sentry/browser (incl. Tracing + Span Streaming)45.5 kB--
@sentry/browser (incl. Tracing, Profiling)48.73 kB--
@sentry/browser (incl. Tracing, Replay)82.98 kB--
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags72.5 kB--
@sentry/browser (incl. Tracing, Replay with Canvas)87.67 kB--
@sentry/browser (incl. Tracing, Replay, Feedback)99.93 kB--
@sentry/browser (incl. Feedback)42.7 kB--
@sentry/browser (incl. sendFeedback)30.55 kB--
@sentry/browser (incl. FeedbackAsync)35.55 kB--
@sentry/browser (incl. Metrics)27.16 kB--
@sentry/browser (incl. Logs)27.29 kB--
@sentry/browser (incl. Metrics & Logs)27.98 kB--
@sentry/react27.62 kB--
@sentry/react (incl. Tracing)46.05 kB--
@sentry/vue30.71 kB--
@sentry/vue (incl. Tracing)45.62 kB--
@sentry/svelte25.89 kB--
CDN Bundle28.57 kB--
CDN Bundle (incl. Tracing)46.08 kB--
CDN Bundle (incl. Logs, Metrics)29.95 kB--
CDN Bundle (incl. Tracing, Logs, Metrics)47.12 kB--
CDN Bundle (incl. Replay, Logs, Metrics)68.92 kB--
CDN Bundle (incl. Tracing, Replay)83.14 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)84.17 kB--
CDN Bundle (incl. Tracing, Replay, Feedback)88.61 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)89.69 kB--
CDN Bundle - uncompressed83.59 kB--
CDN Bundle (incl. Tracing) - uncompressed137.62 kB--
CDN Bundle (incl. Logs, Metrics) - uncompressed87.73 kB--
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed141.03 kB--
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed211.31 kB--
CDN Bundle (incl. Tracing, Replay) - uncompressed255.06 kB--
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed258.46 kB--
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed267.97 kB--
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed271.36 kB--
@sentry/nextjs (client)48.58 kB--
@sentry/sveltekit (client)44.22 kB--
@sentry/node-core58.35 kB+0.02%+8 B 🔺
@sentry/node175.66 kB+0.01%+13 B 🔺
@sentry/node - without tracing98.3 kB+0.02%+12 B 🔺
@sentry/aws-serverless115.33 kB+0.01%+10 B 🔺
View base workflow run
@JPeer264
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View reviewed changes
Comment threadpackages/cloudflare/src/request.ts
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Way cleaner, that's very cool!
@JPeer264
JPeer264
merged commit 7569b10
into
developApr 22, 2026

119 of 121 checks passed

@JPeer264
JPeer264
deleted the

jp/cloudflare-streaming-span-fix

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April 22, 2026 17:31
@sentry-release-botsentry-release-botBot
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@sentrysentry[bot]sentry[bot] left review comments
@logaretmlogaretmlogaretm approved these changes
@s1gr1ds1gr1dAwaiting requested review from s1gr1d

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Successfully merging this pull request may close these issues.

@sentry/cloudflare: root http.server span lost on streaming responses exceeding ctx.waitUntil 30s budget (regression since 10.28.0)


2 participants

@JPeer264@logaretm