✨ [RUM-10145] collect errors on module evaluation #3622

BenoitZugmeyer · 2025-06-11T15:44:08Z

Motivation

Currently, the RUM and Logs Browser SDK are starting to collect errors when the following conditions are met:

the SDK is loaded
init() was called
tracking consent was granted (either via the trackingConsent init parameter or when setTrackingConsent(‘granted’) is called)
a RUM View was created (RUM only, in case trackViewsManually is used)
the Remote Configuration is fetched

To improve observability coverage, we want to collect errors earlier, and the easiest way to do so is to start collecting errors on module evaluation, buffer them, and send them when RUM is ready.

This is a first step. We chose to start with runtime errors first as it was deemed to be the most valuable without much drawback, but our approach needs to be easily extendable to collect other kind of values.

Also, in the future this mechanism could be separated from the main SDK to allow customer inline this code in their HTML to cover even more ground, mitigating the performance impact of inlining the whole SDK entirely.

Changes

Please review commit by commit.

We start by introducing a BufferedObserver, which is intended to be used for other purposes and eventually replace BoundedBuffer.

After a bit of refactoring in tests, we implement early runtime error collection in RUM and Logs by tracking runtime errors and putting them in a BufferedObserver instance.

Test instructions

In the sandbox (which uses a sync CDN setup), throw an exception before calling init, ex:

throw new Error('test')
setTimeout(() => {
  DD_RUM.init(...)
  DD_LOGS.init(...)
})

The error should be collected.

Checklist

Tested locally
Tested on staging
Added unit tests for this change.
Added e2e/integration tests for this change.

codecov-commenter · 2025-06-11T15:50:18Z

Codecov Report

Attention: Patch coverage is 96.20253% with 3 lines in your changes missing coverage. Please review.

Project coverage is 92.21%. Comparing base (2650637) to head (cafe16b).

Files with missing lines	Patch %	Lines
...kages/rum-core/src/domain/error/errorCollection.ts	50.00%	2 Missing ⚠️
packages/core/src/tools/queueMicrotask.ts	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3622      +/-   ##
==========================================
- Coverage   92.21%   92.21%   -0.01%     
==========================================
  Files         329      331       +2     
  Lines        8209     8257      +48     
  Branches     1856     1864       +8     
==========================================
+ Hits         7570     7614      +44     
- Misses        639      643       +4

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packages/core/src/tools/observable.ts

amortemousque · 2025-06-13T09:49:48Z

packages/core/src/domain/error/trackRuntimeError.ts

-  }
-  const { stop: stopInstrumentingOnError } = instrumentOnError(handleRuntimeError)
-  const { stop: stopInstrumentingOnUnhandledRejection } = instrumentUnhandledRejection(handleRuntimeError)
+export function trackRuntimeError() {


💬 suggestion: ‏Why not using BufferedObservable directly in here.

I tried, but:

It makes a circular dependency between trackRuntimeError and bufferedData

The "Buffered Data" concept leaks everywhere in trackRuntimeError. It makes it more complex as it's not scoped to rawError anymore.

Hum, fine by me! Let’s move forward and maybe refine the design later as this pattern is used more widely :)

packages/core/src/domain/earlyDataCollection.ts

cit-pr-commenter · 2025-07-02T17:11:56Z

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	149.01 KiB	149.92 KiB	936 B	+0.61%	✅
Rum Recorder	17.91 KiB	17.91 KiB	0 B	0.00%	✅
Rum Profiler	4.98 KiB	4.98 KiB	0 B	0.00%	✅
Logs	52.87 KiB	53.62 KiB	769 B	+1.42%	✅
Flagging	0 B	931 B	931 B	N/A%	✅
Rum Slim	107.71 KiB	108.54 KiB	854 B	+0.77%	✅
Worker	23.60 KiB	23.60 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base Average Cpu Time (ms)	Local Average Cpu Time (ms)	𝚫
addglobalcontext	0.020	0.012	-0.007
addaction	0.049	0.027	-0.022
addtiming	0.009	0.006	-0.003
adderror	0.045	0.026	-0.019
startstopsessionreplayrecording	0.008	0.004	-0.003
startview	0.016	0.009	-0.007
logmessage	0.060	0.026	-0.034

🧠 Memory Performance

Action Name	Base Consumption Memory (bytes)	Local Consumption Memory (bytes)	𝚫 (bytes)
addglobalcontext	26.34 KiB	27.79 KiB	1.45 KiB
addaction	52.99 KiB	55.23 KiB	2.24 KiB
addtiming	25.50 KiB	26.99 KiB	1.49 KiB
adderror	60.10 KiB	63.11 KiB	3.00 KiB
startstopsessionreplayrecording	24.86 KiB	25.65 KiB	807 B
startview	429.65 KiB	429.11 KiB	-555 B
logmessage	53.27 KiB	61.24 KiB	7.97 KiB

🔗 RealWorld

BenoitZugmeyer · 2025-07-03T12:56:24Z

/to-staging

dd-devflow · 2025-07-03T12:56:28Z

View all feedbacks in Devflow UI.

2025-07-03 12:56:28 UTC ℹ️ Start processing command /to-staging

2025-07-03 12:56:39 UTC ℹ️ Branch Integration: starting soon, merge expected in approximately 12m46s (p90)

Commit a4f4d328cc will soon be integrated into staging-27.

2025-07-03 13:08:36 UTC ℹ️ Branch Integration: This commit was successfully integrated

Commit a4f4d328cc has been merged into staging-27 in merge commit 2da91af4e6.

Check out the triggered pipeline on Gitlab 🦊

If you need to revert this integration, you can use the following command: /code revert-integration -b staging-27

Integrated commit sha: a4f4d32 Co-authored-by: BenoitZugmeyer <[email protected]>

packages/core/src/tools/observable.ts

rgaignault · 2025-07-03T14:42:16Z

packages/core/src/domain/bufferedData.ts

+import type { RawError } from './error/error.types'
+import { trackRuntimeError } from './error/trackRuntimeError'
+
+const BUFFER_LIMIT = 500


💭 suggestion : Could we put a single const for the buffer limit or is it expected since the other is deprecated?
(see boundedBuffer.ts)

I'd like to keep BufferedObservable as generic as possible to encourage using it in more places. But I could add a default value in the BufferedObservable constructor, to keep it configurable while not having to define a limit every single time when it doesn't matter much. WDYT?

bcaudan · 2025-07-11T13:30:50Z

packages/core/src/tools/observable.ts

+   * work even if this method isn't called, but still useful to clarify our intent and lowering our
+   * memory impact.
+   */
+  unbuffer() {


❓ question: ‏could the unbuffer be done without an explicit call after the first subscribe?

It could for now, as it is subscribed only once. But in the future I expect this observable to be used in multiple places where the buffer is leveraged (ex: we could imagine using the observable to generate resources, actions... not just errors).

bcaudan

Great work!

…lection-2

BenoitZugmeyer · 2025-07-17T09:12:37Z

/to-staging

dd-devflow-routing-codex · 2025-07-17T09:12:41Z

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2025-07-17 09:12:40 UTC ℹ️ Start processing command /to-staging

2025-07-17 09:12:48 UTC ℹ️ Branch Integration: starting soon, merge expected in approximately 7m42s (p90)

Commit cafe16b8e6 will soon be integrated into staging-29.

2025-07-17 09:12:56 UTC ⚠️ Branch Integration: This commit was already integrated

Commit cafe16b8e6 had already been merged into staging-29

If you need to revert this integration, you can use the following command: /code revert-integration -b staging-29

BenoitZugmeyer · 2025-07-17T13:02:39Z

/merge

dd-devflow-routing-codex · 2025-07-17T13:02:43Z

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2025-07-17 13:02:43 UTC ℹ️ Start processing command /merge

2025-07-17 13:02:58 UTC ℹ️ MergeQueue: pull request added to the queue

The expected merge time in main is approximately 25m (p90).

2025-07-17 13:29:58 UTC ℹ️ MergeQueue: This merge request was merged

BenoitZugmeyer force-pushed the benoit/early-data-collection-2 branch from 8a8b156 to fbe5f7b Compare June 11, 2025 15:47

BenoitZugmeyer force-pushed the benoit/early-data-collection-2 branch 2 times, most recently from b25932e to 80e46f3 Compare June 11, 2025 15:59

amortemousque reviewed Jun 13, 2025

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BenoitZugmeyer force-pushed the benoit/early-data-collection-2 branch from 80e46f3 to 8db9e24 Compare July 2, 2025 17:01

BenoitZugmeyer added 8 commits July 3, 2025 11:37

✨ implement a buffered observable

4bad010

📝 deprecate BoundedBuffer

e3b52bc

♻️ make trackRuntimeError return an Observable

a024b45

✅ refactor logs runtimeErrorCollection.spec

d14a29f

✅ refactor startLogs.spec

f6d52ef

✨ implement early data collection

e05fedd

✨ use early data collection in Logs

7b19999

✨ use early data collection in RUM

3068ee7

BenoitZugmeyer force-pushed the benoit/early-data-collection-2 branch from 8db9e24 to bd3bfb1 Compare July 3, 2025 10:47

✅ add e2e tests

a4f4d32

BenoitZugmeyer force-pushed the benoit/early-data-collection-2 branch from bd3bfb1 to a4f4d32 Compare July 3, 2025 12:18

BenoitZugmeyer marked this pull request as ready for review July 3, 2025 12:56

BenoitZugmeyer requested a review from a team as a code owner July 3, 2025 12:56

dd-mergequeue bot added a commit that referenced this pull request Jul 3, 2025

Integrate benoit/early-data-collection-2 (#3622) into staging-27

2da91af

Integrated commit sha: a4f4d32 Co-authored-by: BenoitZugmeyer <[email protected]>

dd-devflow bot added the staging-27 label Jul 3, 2025

rgaignault reviewed Jul 3, 2025

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👌 fix typo comment

555d660

amortemousque approved these changes Jul 7, 2025

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thomas-lebeau approved these changes Jul 10, 2025

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bcaudan reviewed Jul 11, 2025

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bcaudan approved these changes Jul 11, 2025

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BenoitZugmeyer added 2 commits July 17, 2025 10:08

Merge remote-tracking branch 'origin/main' into benoit/early-data-col…

b1cd3b6

…lection-2

🚨 fix lint

cafe16b

dd-devflow bot added the staging-29 label Jul 17, 2025

dd-devflow bot added mergequeue-status: queued mergequeue-status: in_progress and removed mergequeue-status: queued labels Jul 17, 2025

dd-mergequeue bot merged commit 3d4cda8 into main Jul 17, 2025
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dd-mergequeue bot deleted the benoit/early-data-collection-2 branch July 17, 2025 13:29

dd-devflow bot added mergequeue-status: done and removed mergequeue-status: in_progress labels Jul 17, 2025

✨ [RUM-10145] collect errors on module evaluation #3622

✨ [RUM-10145] collect errors on module evaluation #3622

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Motivation

Changes

Test instructions

Checklist

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