[Profiling] Add action and vital metadata to profiles by MandragoreVR · Pull Request #4148 · DataDog/browser-sdk

MandragoreVR · 2026-02-06T15:34:10Z

Motivation

To enable profiling aggregation on the backend for vitals and actions, we want to add vitals and actions data to the metadata of profiling events.

This PR adds these entries to the profiling events metadata.

Changes

Create a vitalHistory next to the profiler that catches vital events from the life cycle and stores them in the history
- Vital events are currently only sent in the lifecycle when they end. However, one vital event might span over multiple profiles, so the profile where this vital event starts must be tagged with this vital event too.
  - This PR defines the id of duration vitals when they start instead of when they end, and adds a new lifecycle event to broadcast vitals when they start
  - Note: this will not cause issues if the vital doesn't end, because this is only used to tag profile events, so in the worst case, the id of this vital will not be used
Same thing for the actions: creation of an actionHistory
- the id of the action was created on action start, but not returned by the event tracker, so I changed that to make the start method of the event tracker return the stored data
Update the build of a profile's attributes to add actions and vitals
- update profiler's tests to make sure vitals and actions are collected

Test instructions

In the file sandbox/react-app/main.tsx, add:

profilingSampleRate: 100,
  site: 'datadoghq.com',
  service: 'sandbox-react-app',
  env: 'development',
  beforeSend: () => false,

to the SDK configuration, and add

  useEffect(() => {
    datadogRum.startDurationVital('test vital')

    const timeout = setTimeout(() => {
      datadogRum.stopDurationVital('test vital')
    }, 1000)

    return () => {
      clearTimeout(timeout)
    }
  }, [])

before the return of the Layout function to have a vital that will be displayed in the collected ones.

Run yarn dev and go to localhost:8080/react-app
Wait for a request to https://browser-intake-datadoghq.com/api/v2/profile in the network tab (profiles usually last one minute, so this might not come instantly, but you can also edit the constant collectIntervalMs in profiler.ts to make it faster)
Look at the payload, that contains two big objects.
- The first one should contain the fields "action" and "vital", both with an object of the shape { "id": string[], "label": string[] }
- The second one should contain the fields "action" and "vitals" with the following shape:

Checklist

Tested locally
Added unit tests for this change.
Added e2e/integration tests for this change.
Updated documentation and/or relevant AGENTS.md file

github-actions · 2026-02-06T15:34:23Z

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

cit-pr-commenter-54b7da · 2026-02-06T15:35:04Z

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	171.96 KiB	172.07 KiB	+110 B	+0.06%	✅
Rum Profiler	4.67 KiB	6.20 KiB	+1.53 KiB	+32.78%	✅
Rum Recorder	24.72 KiB	24.72 KiB	0 B	0.00%	✅
Logs	56.29 KiB	56.29 KiB	0 B	0.00%	✅
Flagging	944 B	944 B	0 B	0.00%	✅
Rum Slim	127.73 KiB	127.84 KiB	+112 B	+0.09%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base CPU Time (ms)	Local CPU Time (ms)	𝚫%
addglobalcontext	N/A	0.005	N/A
addaction	N/A	0.0141	N/A
adderror	N/A	0.0135	N/A
addtiming	N/A	0.0027	N/A
startview	N/A	0.0136	N/A
startstopsessionreplayrecording	N/A	0.0007	N/A
logmessage	N/A	0.0188	N/A

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
addglobalcontext	N/A	26.57 KiB	N/A
addaction	N/A	110.66 KiB	N/A
addtiming	N/A	26.99 KiB	N/A
adderror	N/A	118.54 KiB	N/A
startstopsessionreplayrecording	N/A	25.68 KiB	N/A
startview	N/A	510.12 KiB	N/A
logmessage	N/A	44.74 KiB	N/A

🔗 RealWorld

datadog-official · 2026-02-12T13:35:41Z

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage (details)
• Patch Coverage: 88.06%
• Overall Coverage: 77.21% (+0.03%)

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: 5e88cac | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

…id on start instead of stop

…fined

thomasbertet

Looks good to me!

I believe we could have a more generic history combining all of the profiler's tracked events in one place, it would be slightly less code.

thomasbertet · 2026-02-18T17:31:44Z

packages/rum/src/domain/profiling/vitalHistory.ts

+      {
+        id: vitalStart.id,
+        startClocks: vitalStart.startClocks,
+        duration: 0 as Duration,


I wonder if we should have another value for "non-stopped" events 🤔
Relying on 0 seems like it could be error prone and the BE that process should be aware 0 means "not stopped".
Maybe just undefined would work instead ? WDYT ?

Good question... could we maybe settle for something like -1, though, to not have to re-do a rum-events-format PR to allow undefined here?

Yes, but we will need to adjust the logic, I kinda forgot about this when I did the BE logic : https://github.com/DataDog/profiling-backend/pull/7969/changes#diff-fe24f465d52fe19d3a52bfd86ac3eaa5e441e710eca6bb9c26a14cac5ce169e4R339-R346

You can see I'm just using the duration field without taking into account if the duration is 0 or undefined.
Let's have -1 as signal for unfinished events. I'll prepare the BE to support that value.

Actually maybe that's cleaner if that's undefined, even if we have to do another PR for the format, WDYT ?

Works for me, I just updated!

MandragoreVR · 2026-02-23T16:01:43Z

/to-staging

gh-worker-devflow-routing-ef8351 · 2026-02-23T16:01:47Z

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2026-02-23 16:01:53 UTC ℹ️ Branch Integration: starting soon, merge expected in approximately 14m (p90)

Commit 65b99121e9 will soon be integrated into staging-09.

2026-02-23 16:16:03 UTC ℹ️ Branch Integration: this commit was successfully integrated

Commit 65b99121e9 has been merged into staging-09 in merge commit 848b6b79d7.

Check out the triggered DDCI request.

If you need to revert this integration, you can use the following command: /code revert-integration -b staging-09

…a-to-profiles (#4148) into staging-09 Integrated commit sha: 65b9912 Co-authored-by: MandragoreVR <teo.chaillou@datadoghq.com>

MandragoreVR · 2026-02-24T09:32:51Z

/to-staging

gh-worker-devflow-routing-ef8351 · 2026-02-24T09:32:53Z

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2026-02-24 09:33:01 UTC ℹ️ Branch Integration: starting soon, merge expected in approximately 14m (p90)

Commit a68787a74c will soon be integrated into staging-09.

2026-02-24 09:46:05 UTC ℹ️ Branch Integration: this commit was successfully integrated

Commit a68787a74c has been merged into staging-09 in merge commit 661ba0a622.

Check out the triggered DDCI request.

If you need to revert this integration, you can use the following command: /code revert-integration -b staging-09

MandragoreVR · 2026-02-24T09:45:36Z

/to-staging -c

…a-to-profiles (#4148) into staging-09 Integrated commit sha: a68787a Co-authored-by: MandragoreVR <teo.chaillou@datadoghq.com>

gh-worker-devflow-routing-ef8351 · 2026-02-24T09:45:44Z

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2026-02-24 09:45:42 UTC ❌ Devflow: /to-staging -c

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amortemousque · 2026-02-25T13:56:30Z

packages/rum/src/domain/profiling/actionHistory.ts

+
+  lifeCycle.subscribe(LifeCycleEventType.RAW_RUM_EVENT_COLLECTED, ({ rawRumEvent, startClocks, duration }) => {
+    if (rawRumEvent.type === 'action') {
+      const durationForEntry = duration ?? (0 as Duration)


You can use duration! like we do in longTaskHistory

amortemousque · 2026-02-25T13:56:56Z

packages/rum/src/domain/profiling/actionHistory.ts

+          .add(
+            {
+              id: rawRumEvent.action.id,
+              label: '',


❓ question: ‏Is it expected not to have a label? Shouldn't it be the action name?

amortemousque · 2026-02-25T14:26:13Z

packages/rum/src/domain/profiling/actionHistory.ts

+    expireDelay: ACTION_ID_HISTORY_TIME_OUT_DELAY,
+  })
+
+  const startedActions = new Map<string, ValueHistoryEntry<ActionContext>>()


💬 suggestion: You can use only the history and do history.findAll(startClocks.relative).find((action) => action.id === rawRumEvent.action.id)to locate the startedAction you want to update.

amortemousque · 2026-02-25T15:04:52Z

packages/rum-core/src/domain/action/trackManualActions.ts

      { isChildEvent: isActionChildEvent }
    )
+
+    lifeCycle.notify(LifeCycleEventType.ACTION_STARTED, startedManualAction)


💬 suggestion: ‏You could make this part of eventTracker so you have the lifecycle event for click and manual actions. We also are planning to use eventTracker for vitals.

MandragoreVR self-assigned this Feb 6, 2026

MandragoreVR force-pushed the teo.chaillou/RUM-14305-browser-add-action-and-vital-metadata-to-profiles branch 2 times, most recently from 59aa5b7 to f709051 Compare February 12, 2026 13:32

MandragoreVR marked this pull request as ready for review February 12, 2026 13:33

MandragoreVR requested a review from a team as a code owner February 12, 2026 13:33

MandragoreVR marked this pull request as draft February 17, 2026 15:51

MandragoreVR force-pushed the teo.chaillou/RUM-14305-browser-add-action-and-vital-metadata-to-profiles branch from f709051 to 2d17fef Compare February 17, 2026 22:25

MandragoreVR added 3 commits February 18, 2026 18:12

feat(vitals): add vital metadata to profile events, and create vital …

b30b272

…id on start instead of stop

feat(actions): add action metadata to profile events

52c4fbc

fix(vital): only access lifecycle in startDurationVital when it is de…

ac62ddd

…fined

MandragoreVR force-pushed the teo.chaillou/RUM-14305-browser-add-action-and-vital-metadata-to-profiles branch from 5059362 to ac62ddd Compare February 18, 2026 17:14

MandragoreVR marked this pull request as ready for review February 18, 2026 17:28

thomasbertet approved these changes Feb 18, 2026

View reviewed changes

fix(vital/action): make duration undefined when event is still ongoing

84bcf8d

MandragoreVR force-pushed the teo.chaillou/RUM-14305-browser-add-action-and-vital-metadata-to-profiles branch from ade4eac to 65b9912 Compare February 23, 2026 15:56

gh-worker-dd-devflow-36fce6 bot added the staging-09 label Feb 23, 2026

MandragoreVR force-pushed the teo.chaillou/RUM-14305-browser-add-action-and-vital-metadata-to-profiles branch from 65b9912 to a68787a Compare February 24, 2026 09:32

fix(pipeline): add rum-events-format and fix e2e tests

5e88cac

MandragoreVR force-pushed the teo.chaillou/RUM-14305-browser-add-action-and-vital-metadata-to-profiles branch from a68787a to 5e88cac Compare February 24, 2026 09:44

amortemousque reviewed Feb 25, 2026

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