add s/s action #4038

BeltranBulbarellaDD · 2025-12-17T15:34:38Z

Motivation

Discussed in this RFC

Tldr: addEvent does not cover all the cases needed for complete action collection in frameworks like Flutter.
This PR adds Start and Stop action.

Changes

Added telemetry event type to test locally (For CI to pass, need to add in RumEventsFormat PR)

Added FF: START_STOP_ACTION

Expanded ActionType

Created expanded startActionCollection, created startCustomActionInternal and stopCustomActionInternal

Test instructions

I used this HTML file to test locally.
Should be able to start an action, generate events and stop the action. When in RUM explorer Attributes for each Event should have the Action.ID.
Example action with error, long_task and resource.

Example in Flutter web.

Checklist

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

cit-pr-commenter · 2025-12-17T15:36:52Z

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	164.35 KiB	166.38 KiB	+2.04 KiB	+1.24%	✅
Rum Profiler	4.33 KiB	4.33 KiB	0 B	0.00%	✅
Rum Recorder	20.04 KiB	20.04 KiB	0 B	0.00%	✅
Logs	56.14 KiB	56.18 KiB	+40 B	+0.07%	✅
Flagging	944 B	944 B	0 B	0.00%	✅
Rum Slim	121.57 KiB	123.43 KiB	+1.86 KiB	+1.53%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base CPU Time (ms)	Local CPU Time (ms)	𝚫%
RUM - add global context	0.0048	0.0045	-6.25%
RUM - add action	0.0146	0.0124	-15.07%
RUM - add error	0.0134	0.0125	-6.72%
RUM - add timing	0.0031	0.0028	-9.68%
RUM - start view	0.0036	0.0034	-5.56%
RUM - start/stop session replay recording	0.0008	0.0007	-12.50%
Logs - log message	0.0151	0.0135	-10.60%

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
RUM - add global context	26.64 KiB	26.48 KiB	-160 B
RUM - add action	50.13 KiB	49.52 KiB	-624 B
RUM - add timing	26.76 KiB	26.69 KiB	-66 B
RUM - add error	56.21 KiB	54.87 KiB	-1.34 KiB
RUM - start/stop session replay recording	25.57 KiB	25.49 KiB	-84 B
RUM - start view	424.67 KiB	425.59 KiB	+946 B
Logs - log message	47.45 KiB	45.89 KiB	-1.56 KiB

🔗 RealWorld

datadog-datadog-prod-us1 · 2025-12-17T15:48:06Z

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage
• Patch Coverage: 89.87%
• Overall Coverage: 77.36% (+0.07%)

View detailed report

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

🔗 Commit SHA: 66ce586 | Docs | Datadog PR Page | Was this helpful? Give us feedback!}

BeltranBulbarellaDD · 2025-12-18T14:12:48Z

@codex

chatgpt-codex-connector · 2025-12-18T14:13:49Z

Thanks for the ping—current CI is all green and bundle size deltas are small (≈+0.8% on Rum/Rum Slim, others unchanged). Patch coverage on the new lines is ~85% with overall coverage unchanged aside from reported delta. Let me know if you want me to tackle any follow-ups.

View task →

BeltranBulbarellaDD · 2025-12-31T08:14:31Z

@codex pls review

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

BeltranBulbarellaDD · 2026-01-02T15:02:03Z

@codex review pls

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

BeltranBulbarellaDD · 2026-01-05T13:05:00Z

@codex review pls

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

BeltranBulbarellaDD · 2026-01-05T13:31:37Z

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

  configuration: RumConfiguration
 ) {
+  const customActionHistory = createValueHistory<string>({ expireDelay: ACTION_CONTEXT_TIME_OUT_DELAY })
+  const activeCustomActions = new Map<string, ActiveCustomAction>()


I wonder if this should be a weakMap like in VitalCollection so it gets garbage collected

You can't have a weakmap with primitive types like string as key. So no, that won't be an option. This is why FeatureOperation uses an object as "key" instead of a string.

BeltranBulbarellaDD · 2026-01-05T13:32:54Z

@codex review pls

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packages/rum-core/src/boot/preStartRum.ts

BeltranBulbarellaDD · 2026-01-13T10:44:22Z

@codex pls review

chatgpt-codex-connector · 2026-01-13T10:57:10Z

Codex Review: Didn't find any major issues. Another round soon, please!

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

packages/rum-core/src/boot/rumPublicApi.ts

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

packages/rum-core/src/boot/rumPublicApi.ts

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

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

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

BenoitZugmeyer · 2026-01-13T17:27:04Z

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

+function getActionLookupKey(name: string, actionKey?: string): string {
+  return JSON.stringify({ name, actionKey })


thought: I'm not sure we need to care if the same action key is used with different name... do we?

Not really, I added it just to be safe. But agreed to remove it.

…tion. Change stop and discard signatures.

BeltranBulbarellaDD · 2026-01-14T10:18:07Z

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

+        return duration
+      },
+      get counts() {
+        const { errorCount, longTaskCount, resourceCount } = eventCountsSubscription.eventCounts


Going to ask an agent how to try to reduce bundle size. For example here.

BeltranBulbarellaDD · 2026-01-14T13:48:19Z

@codex can you give a review and suggest where we could save on bundle size? Is there room for improvement?

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chatgpt-codex-connector · 2026-01-14T14:01:30Z

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

    HookNames.AssembleTelemetry,
    ({ startTime }): DefaultTelemetryEventAttributes => ({
      action: { id: actionContexts.findActionId(startTime) as string },
    })


Avoid array action.id in telemetry events

With start/stop actions, multiple concurrent custom actions are supported (via actionKey), so actionContexts.findActionId() can return a string[]. In AssembleTelemetry this value is written directly to action.id, but telemetry schemas define action.id as a single string (see packages/core/src/domain/telemetry/telemetryEvent.types.ts). During overlapping actions, any telemetry event emitted in that window will carry an array and can be rejected or dropped by downstream validation. Consider selecting one id (e.g., most recent) or omitting the action context when multiple ids are active.

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chatgpt-codex-connector · 2026-01-14T14:01:30Z

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

+  const customActions = trackCustomActions(lifeCycle, actionTracker, (action) => {
+    lifeCycle.notify(LifeCycleEventType.RAW_RUM_EVENT_COLLECTED, processAction(action))
+  })


Gate custom action tracking to avoid bundle/runtime overhead

Custom action tracking is instantiated unconditionally, even when START_STOP_ACTION is disabled or never used. This means the extra tracker code and lifecycle subscriptions are included and executed for all builds, increasing bundle size and baseline work. If this feature is meant to be experimental/opt‑in, consider lazily initializing trackCustomActions (and its shared tracker) behind the feature flag or on first startAction call to keep the default bundle smaller.

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add s/s action

2f11566

BeltranBulbarellaDD added 4 commits December 17, 2025 16:24

Add unit tests for startAction and stopAction

065a6fe

Linting fixes

aec81c6

cleanup

270c0cb

fix leaked listener

b0bc642

BeltranBulbarellaDD added 7 commits December 30, 2025 13:23

Integrated trackEventCounts and integrate with startActionCollection.

a06410a

Merge branch 'main' into beltran.bulbarella/start-stopAction

2080477

merged rum-events-format

b4af4f6

Fix format

3e88bd7

sync schemas

f129855

fix comma

2259509

Add telemetry type (remove after merge in R-E-F)

446390e

chatgpt-codex-connector bot reviewed Dec 31, 2025

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packages/rum-core/src/domain/action/actionCollection.ts Outdated Show resolved Hide resolved

BeltranBulbarellaDD added 4 commits December 31, 2025 10:12

Add loading_time to custom actions

efe5ffc

wait for fetch to complete in e2e test so to avoid flaky test

2c95977

revert test

546fdde

wait for requests to complete in e2e test so to avoid flaky test

d7a7e14

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packages/rum-core/src/domain/action/actionCollection.ts Outdated Show resolved Hide resolved

Update activeCustomActions to track existing actions

e8725ba

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packages/rum-core/src/domain/action/actionCollection.ts Outdated Show resolved Hide resolved

Clean up activeCustomActions on session renewal

9864c12

BeltranBulbarellaDD commented Jan 5, 2026

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BeltranBulbarellaDD marked this pull request as ready for review January 12, 2026 14:33

BeltranBulbarellaDD requested a review from a team as a code owner January 12, 2026 14:33

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packages/rum-core/src/boot/preStartRum.ts Show resolved Hide resolved

BeltranBulbarellaDD added 2 commits January 13, 2026 09:26

Merge branch 'main' into beltran.bulbarella/start-stopAction

573cb0a

run format

ee43b93

BeltranBulbarellaDD force-pushed the beltran.bulbarella/start-stopAction branch 2 times, most recently from 0cdbbeb to ee43b93 Compare January 13, 2026 09:14

BeltranBulbarellaDD added 2 commits January 13, 2026 11:36

support start time for pre init action tracking

7946916

Merge branch 'main' into beltran.bulbarella/start-stopAction

4227e82

modify to test that the clocks are captured at call time

1b690e5

BeltranBulbarellaDD marked this pull request as draft January 13, 2026 13:20

BeltranBulbarellaDD marked this pull request as ready for review January 13, 2026 14:05

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packages/rum-core/src/domain/action/actionCollection.ts Outdated Show resolved Hide resolved

BenoitZugmeyer reviewed Jan 13, 2026

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BeltranBulbarellaDD added 4 commits January 14, 2026 10:13

Remove actionKey, make experimental docs, pass clocks to actionCollec…

3e0bbd9

…tion. Change stop and discard signatures.

Created trackCustomActions, revamp processAction, edit clickAction.

40e8331

remove actionKey, run formatter.

8e6763f

Linting fixes

feead72

BeltranBulbarellaDD commented Jan 14, 2026

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BeltranBulbarellaDD added 4 commits January 14, 2026 11:27

Linting fixes.

d6a11c0

Re add actionKey, created TrackedActionMetadata.

02fa207

Fix typecheck

c28599f

Change getActionLookupKey

20019e3

TEST REDUCE BUNDLE SIZE

0dc0e6a

chatgpt-codex-connector bot reviewed Jan 14, 2026

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BeltranBulbarellaDD added 2 commits January 14, 2026 15:31

SECOND TEST REDUCE BUNDLE SIZE

53b70d9

Add back action types

66ce586

		function getActionLookupKey(name: string, actionKey?: string): string {
		return JSON.stringify({ name, actionKey })

add s/s action #4038

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add s/s action #4038

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Motivation

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Test instructions

Checklist

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BeltranBulbarellaDD commented Dec 17, 2025 •

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