[RUM Profiler] Add `profiling` context to Long Task and View events #3583

thomasbertet · 2025-06-02T13:48:35Z

Motivation

In the RUM x Profiling integration, we would like to explain why there is no Profiling data on a specific Long Tasks. It would be super useful to have a detailed profiling status to be able to help users understand why. There could be a bunch of different reasons and this status tries to reflects all of them.

This PR is based on work done in DataDog/rum-events-format#274 defining the context.

Changes

new _dd.profiling field on RumViewEvent, RumLongTaskEvent (updated the rum-events-format PR)
This new status describes what is the current state of the Profiling at a "high level".

View emitted now has a profiling field in _dd:

Long Task emitted also has a profiling field in _dd:

These status have been designed so that it will be possible to aggregate them when a single view is receiving multiple of them
For Long Tasks, there is no aggregation so it's easier and the exact status of the Profiler that is collected on Long Task collection is the one used, always.

Test instructions

Open the Browser SDK Browser Extension, and assert you can now see _dd.profiling.status field on top level of both Views and Long Task events, with a meaningful status.

Checklist

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

packages/rum-core/src/rawRumEvent.types.ts

bcaudan · 2025-06-02T14:53:49Z

packages/rum-core/src/rawRumEvent.types.ts

+ * - failed-to-lazy-load: The Profiler script failed to be loaded by the Browser. (may be connection issue or the chunk was not found)
+ * - failed-to-start: The Profiler failed to start. (most probable cause if when the web server did not return the `Document-Policy: js-profiling` HTTP Response header)
+ * - running: The Profiler is running.
+ * - stopped: The Profiler is stopped.


🥜 nitpick: ‏not sure exactly how this status is planned to be used but from an end-user perspective, looking for events with profiles by searching @profiling_status: stopped seems a bit odd to me.

I don't expect a lot of View or Long Tasks will have this stopped but overall it will be used by us on the UI to be able to let users know why there is no Profiling data.

bcaudan · 2025-06-02T14:56:01Z

packages/rum-core/src/rawRumEvent.types.ts

+export type ProfilingStatus =
+  | 'not-available-in-slim-bundle'
+  | 'initializing'
+  | 'missing-profiling-experimental-feature'


💬 suggestion: ‏we'll probably won't provide a version with experimental flag to customers, so not sure if this case need to be handled

As long as we have an experimental version, I think we should keep it. It will help us identify issues with potential design partners.

afaik, we don't want to communicate experimental flag to external parties.

bcaudan · 2025-06-02T15:00:02Z

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

      cleanupTasks.push(stopLongAnimationFrameCollection)
    } else {
-      startLongTaskCollection(lifeCycle, configuration)
+      startLongTaskCollection(lifeCycle, configuration, profilerApi)


💬 suggestion: ‏instead of passing profilerApi around, it could be interesting to see if you could subscribe to the assemble hook instead.
look at hooks.register(HookNames.Assemble usages.

I did just that in the last commit. PTAL and let me know if that's what you envisioned.

codecov-commenter · 2025-06-03T11:55:39Z

Codecov Report

Attention: Patch coverage is 73.68421% with 5 lines in your changes missing coverage. Please review.

Project coverage is 92.41%. Comparing base (c947b2d) to head (c609a63).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/rum/src/domain/profiling/profiler.ts	28.57%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3583      +/-   ##
==========================================
- Coverage   92.44%   92.41%   -0.04%     
==========================================
  Files         322      323       +1     
  Lines        8129     8147      +18     
  Branches     1838     1839       +1     
==========================================
+ Hits         7515     7529      +14     
- Misses        614      618       +4

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cit-pr-commenter · 2025-06-03T12:03:39Z

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	146.84 KiB	147.37 KiB	544 B	+0.36%	✅
Rum Recorder	18.02 KiB	18.02 KiB	0 B	0.00%	✅
Rum Profiler	4.63 KiB	5.06 KiB	441 B	+9.30%	⚠️
Logs	51.72 KiB	51.72 KiB	0 B	0.00%	✅
Flagging	0 B	935 B	935 B	N/A%	✅
Rum Slim	106.46 KiB	106.63 KiB	179 B	+0.16%	✅
Worker	23.59 KiB	23.59 KiB	0 B	0.00%	✅

⚠️ The increase is particularly high and exceeds 5%. Please check the changes.

🚀 CPU Performance

Action Name	Base Average Cpu Time (ms)	Local Average Cpu Time (ms)	𝚫
addglobalcontext	0.013	0.009	-0.004
addaction	0.041	0.033	-0.008
addtiming	0.010	0.007	-0.002
adderror	0.037	0.035	-0.003
startstopsessionreplayrecording	0.002	0.001	-0.000
startview	0.011	0.007	-0.003
logmessage	0.056	0.035	-0.022

🧠 Memory Performance

Action Name	Base Consumption Memory (bytes)	Local Consumption Memory (bytes)	𝚫 (bytes)
addglobalcontext	28.96 KiB	25.88 KiB	-3162 B
addaction	57.46 KiB	54.05 KiB	-3494 B
addtiming	25.91 KiB	26.21 KiB	300 B
adderror	56.69 KiB	60.64 KiB	3.96 KiB
startstopsessionreplayrecording	23.70 KiB	24.71 KiB	1.01 KiB
startview	429.04 KiB	425.41 KiB	-3721 B
logmessage	56.65 KiB	58.24 KiB	1.59 KiB

🔗 RealWorld

thomasbertet · 2025-06-03T12:42:57Z

packages/rum-core/src/domain/contexts/profilingContext.ts

+    HookNames.Assemble,
+    ({ eventType }): DefaultRumEventAttributes => ({
+      type: eventType,
+      profiling: profilerApi.getProfilingContext(),


My guess is that I should filter on the eventType I'm interested in before actually appending the profiling context. WDYT ? I kinda expected the typechecker to yell at me 🤔

…ent field

…zing status

…tatus

… rum-event-format types for Profiler

thomasbertet · 2025-06-13T09:53:20Z

package.json

@@ -33,7 +33,8 @@
    "test:e2e:ci:bs": "yarn build && yarn build:apps && yarn test:e2e:bs",
    "test:compat:tsc": "node scripts/check-typescript-compatibility.js",
    "test:compat:ssr": "scripts/cli check_server_side_rendering_compatibility",
-    "rum-events-format:sync": "scripts/cli update_submodule && scripts/cli build_json2type && node scripts/generate-schema-types.js",
+    "rum-events-format:sync": "scripts/cli update_submodule && yarn rum-events-format:generate",
+    "rum-events-format:generate": "scripts/cli build_json2type && node scripts/generate-schema-types.js",


I found it useful to generate locally the files I had checked-out in the rum-events-format submodule, mainly to confirm everything works as expected.
It's slightly different from rum-events-format:sync because there is no sync, on the file generation taken from the submodule.

thomasbertet changed the title ~~[RUM Profiler] new ProfilingStatusManager to add profiling_status to Long Task and View events~~ [RUM Profiler] Add profiling_status to Long Task and View events Jun 2, 2025

bcaudan reviewed Jun 2, 2025

View reviewed changes

thomasbertet force-pushed the thomas.bertet/rum-profiler-add-profiling-status-to-events branch from bec3ff0 to 7944d6f Compare June 3, 2025 11:53

thomasbertet changed the title ~~[RUM Profiler] Add profiling_status to Long Task and View events~~ [RUM Profiler] Add profiling context to Long Task and View events Jun 3, 2025

thomasbertet commented Jun 3, 2025

View reviewed changes

thomasbertet mentioned this pull request Jun 4, 2025

[RUM Profiler] Add Profiling context to Long Task, View and Configuration DataDog/rum-events-format#274

Merged

thomasbertet force-pushed the thomas.bertet/rum-profiler-add-profiling-status-to-events branch from 29ed0f3 to 1ffc8d9 Compare June 6, 2025 13:11

thomasbertet added 11 commits June 11, 2025 15:55

[RUM Profiler] new ProfilingStatusManaget to fill profiling_status ev…

642581a

…ent field

[RUM Profiler] Add profiling_status to Long Task events, add initiali…

910de99

…zing status

[RUM Profiler] Add profiling_status to LoAF. Add slim stub with new s…

442940d

…tatus

[RUM Profiler] Use hooks.register instead of invasive profilerApi Use…

7ec58eb

… rum-event-format types for Profiler

[RUM Profiler] Remove leftovers from previous iteration

e834de5

[RUM Profiler] remove unecessary changes

e0d31b5

[RUM Profiler] move Profiling context to _dd

70fe791

[RUM Profiler] Update formatting

0206044

[RUM Profiler] update context based on latest rum-events-format

8aa4819

[RUM Proflier] set context to undefined for slim bundle

01b8992

[RUM Profiler] sync rum-events-format, update previous iteration

6b6bb99

thomasbertet force-pushed the thomas.bertet/rum-profiler-add-profiling-status-to-events branch from 1ffc8d9 to 6b6bb99 Compare June 11, 2025 13:57

thomasbertet added 2 commits June 11, 2025 16:25

[RUM Profiler] update test following Profiling context typing update

e29dc04

[RUM Profiler] format, fix import type

16ff3a9

thomasbertet commented Jun 13, 2025

View reviewed changes

[RUM Profiler] Separate exports for type and non-type exports

c609a63

thomasbertet marked this pull request as ready for review June 13, 2025 11:49

thomasbertet requested a review from a team as a code owner June 13, 2025 11:49

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[RUM Profiler] Add `profiling` context to Long Task and View events #3583

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