[UI Telemetry] Implement SharedWorker for batching frontend logs by daniellok-db · Pull Request #19292 · mlflow/mlflow

daniellok-db · 2025-12-09T07:55:55Z

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stack/server-handlers-2 [Files changed]
- stack/service-worker [Files changed]
  - stack/fe-client [Files changed]
    - stack/settings [Files changed]
      - stack/documentation [Files changed]

Related Issues/PRs

#xxx

What changes are proposed in this pull request?

This PR implements the SharedWorker code that runs in the browser. The next PR contains the client code that is actually used by the frontend.

The worker is fairly simple, it receives logs via postMessage from the client, does a few validation checks, enriches the data with session ID, and then queues up the logs to be dispatched periodically.

How is this PR tested?

Existing unit/integration tests
New unit/integration tests
Manual tests

Bug bashed manually

Does this PR require documentation update?

Release Notes

Is this a user-facing change?

No. You can skip the rest of this section.
Yes. Give a description of this change to be included in the release notes for MLflow users.

What component(s), interfaces, languages, and integrations does this PR affect?

Components

How should the PR be classified in the release notes? Choose one:

rn/none - No description will be included. The PR will be mentioned only by the PR number in the "Small Bugfixes and Documentation Updates" section
rn/breaking-change - The PR will be mentioned in the "Breaking Changes" section
rn/feature - A new user-facing feature worth mentioning in the release notes
rn/bug-fix - A user-facing bug fix worth mentioning in the release notes
rn/documentation - A user-facing documentation change worth mentioning in the release notes

Should this PR be included in the next patch release?

Yes should be selected for bug fixes, documentation updates, and other small changes. No should be selected for new features and larger changes. If you're unsure about the release classification of this PR, leave this unchecked to let the maintainers decide.

What is a minor/patch release?

Minor release: a release that increments the second part of the version number (e.g., 1.2.0 -> 1.3.0).
Bug fixes, doc updates and new features usually go into minor releases.
Patch release: a release that increments the third part of the version number (e.g., 1.2.0 -> 1.2.1).
Bug fixes and doc updates usually go into patch releases.

Yes (this PR will be cherry-picked and included in the next patch release)
No (this PR will be included in the next minor release)

github-actions · 2025-12-10T05:11:30Z

@daniellok-db Thank you for the contribution! Could you fix the following issue(s)?

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The DCO check failed. Please sign off your commit(s) by following the instructions here. See https://github.com/mlflow/mlflow/blob/master/CONTRIBUTING.md#sign-your-work for more details.

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Pull request overview

This PR implements a SharedWorker-based system for batching and uploading frontend telemetry logs in MLflow. The implementation includes:

Backend handlers for fetching telemetry configuration and receiving batched telemetry records
Frontend SharedWorker that batches events and uploads them every 15 seconds
Configuration management with caching and fallback values
Proto definitions for UI telemetry messages

Key Changes

Added UI-specific telemetry configuration endpoints with caching
Implemented SharedWorker for cross-tab telemetry batching
Extended telemetry Record schema to support custom session/installation IDs
Added comprehensive test coverage for new functionality

Reviewed changes

Copilot reviewed 16 out of 18 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
`mlflow/telemetry/utils.py`	Added `fetch_ui_telemetry_config()` function with fallback support
`mlflow/telemetry/constant.py`	Added UI config URLs and fallback config constant
`mlflow/telemetry/schemas.py`	Extended Record to support optional installation_id and session_id
`mlflow/server/handlers.py`	Added GET/POST handlers for UI telemetry with TTL caching
`mlflow/server/__init__.py`	Registered new telemetry routes
`mlflow/server/js/src/telemetry/worker/TelemetryLogger.worker.ts`	Implemented SharedWorker for batching telemetry
`mlflow/server/js/src/telemetry/worker/LogQueue.ts`	Implemented queue with 15-second flush interval
`mlflow/server/js/craco.config.js`	Configured webpack to build worker as separate entry point
`tests/telemetry/test_*.py`	Added comprehensive tests for new functionality
`tests/server/test_handlers.py`	Added tests for GET/POST telemetry handlers

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github-actions · 2025-12-10T05:19:40Z

Documentation preview for d06c455 is available at:

https://pr-19292--mlflow-docs-preview.netlify.app/docs/latest/

More info

Ignore this comment if this PR does not change the documentation.
The preview is updated when a new commit is pushed to this PR.
This comment was created by this workflow run.
The documentation was built by this workflow run.

daniellok-db · 2025-12-10T09:33:58Z

mlflow/server/js/craco.config.js

+              // serve SharedWorker file at top-level, it seems to be more
+              // stable than if it's contained in `static/js/...`. previously
+              // i was running into issues with webpack path resolution
+              return 'TelemetryLogger.[name].[contenthash].worker.js';


i think it is possible not to include contenthash here so that the file can be stable across hot reloads, but i was running into some issue where the yarn dev server was OOMing. i assume there were a lot of references that could not be cleaned up.

this way when the hash changes, we can manually terminate the orphaned workers. anyway it is a dev only issue as the bundle is static post-build.

daniellok-db · 2025-12-10T09:36:21Z

mlflow/server/js/src/telemetry/worker/LogQueue.ts

+import { UI_TELEMETRY_ENDPOINT } from './constants';
+import { type TelemetryRecord } from './types';
+
+const FLUSH_INTERVAL_MS = 15000; // 15 seconds


to be discussed: what's the right flush interval? UI sessions can be longer lived, 15 seconds may be a bit too short. the tradeoff here is log fidelity vs. request volume. the longer the interval, the more logs are lost when the browser is closed, but we can save some request overhead.

Could we start with 60 seconds? cc @B-Step62

daniellok-db · 2025-12-10T09:37:23Z

mlflow/server/js/src/telemetry/worker/TelemetryLogger.worker.ts

+    if (!config || (config.disable_ui_telemetry ?? true)) {
+      return;
+    }


if config couldn't be fetched, or if for some reason we cannot read the disable_ui_telemetry field, then drop the log

daniellok-db · 2025-12-10T09:38:23Z

mlflow/server/js/src/telemetry/worker/TelemetryLogger.worker.ts

+  private config: Promise<TelemetryConfig | null> = fetchConfig();
+  private sessionId = crypto.randomUUID();
+  private logQueue: LogQueue = new LogQueue();
+  private samplingValue: number = Math.random() * 100;


Math.random() generates a random float between 0 - 1, so we can specify a pretty granular ui_rollout_percent in the config, like 12.345678.

…low#19292)

)

This was referenced Dec 9, 2025

[UI Telemetry] Allow session_id and installation_id to be overridden in TelemetryRecord #19240

Merged

[UI Telemetry] Add utils to fetch UI config #19291

Merged

[UI Telemetry] Protos for server handler #19275

Closed

daniellok-db force-pushed the stack/service-worker branch 3 times, most recently from c2cc1fe to 53c8f83 Compare December 9, 2025 14:15

daniellok-db mentioned this pull request Dec 9, 2025

[UI Telemetry] Add server handlers #19303

Merged

29 tasks

daniellok-db force-pushed the stack/service-worker branch 2 times, most recently from f0fb458 to 3bc5eb5 Compare December 10, 2025 04:02

daniellok-db mentioned this pull request Dec 10, 2025

[UI Telemetry] Add logging client and hook into design system provider #19312

Merged

29 tasks

daniellok-db changed the title ~~full-ui~~ [UI Telemetry] Implement SharedWorker for batching frontend logs Dec 10, 2025

daniellok-db marked this pull request as ready for review December 10, 2025 05:11

Copilot AI review requested due to automatic review settings December 10, 2025 05:11

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daniellok-db force-pushed the stack/service-worker branch 3 times, most recently from 05a93cb to 19de120 Compare December 10, 2025 09:24

daniellok-db commented Dec 10, 2025

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github-actions bot added area/uiux Front-end, user experience, plotting, JavaScript, JavaScript dev server rn/none List under Small Changes in Changelogs. labels Dec 10, 2025

daniellok-db requested review from B-Step62, TomeHirata, hubertzub-db and serena-ruan December 10, 2025 09:41

daniellok-db added 21 commits December 18, 2025 09:41

unproto

81e1edd

fix

2fdc384

fix

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address comments

0e6048a

fix

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edit add_records

d35739c

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0566bb8

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5e1298e

3 hours

ebdce9a

3.0

3839eec

full-ui

e62ce8d

js

8fc4cfd

fix

dfc2b89

telemetry

e27d6cf

fix

b5da957

remove

da54e84

fix

5ec18ff

settimeout and change interval to 30s

cd3f170

3.0

1d94ccf

return

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add shutdown

d06c455

daniellok-db force-pushed the stack/service-worker branch from 121fb44 to d06c455 Compare December 18, 2025 00:41

TomeHirata approved these changes Dec 18, 2025

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daniellok-db added this pull request to the merge queue Dec 18, 2025

Merged via the queue into mlflow:master with commit 712cd0c Dec 18, 2025
63 of 65 checks passed

daniellok-db deleted the stack/service-worker branch December 18, 2025 02:45

daniellok-db added the v3.8.0 label Dec 18, 2025

WeichenXu123 pushed a commit to WeichenXu123/mlflow that referenced this pull request Dec 19, 2025

[UI Telemetry] Implement SharedWorker for batching frontend logs (mlf…

8e72912

…low#19292)

WeichenXu123 pushed a commit that referenced this pull request Dec 19, 2025

[UI Telemetry] Implement SharedWorker for batching frontend logs (#19292

b6a774d

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[UI Telemetry] Implement SharedWorker for batching frontend logs#19292

[UI Telemetry] Implement SharedWorker for batching frontend logs#19292
daniellok-db merged 26 commits intomlflow:masterfrom
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