MetricsPlatform: Enable experiment config fetching
Closed, ResolvedPublic1 Estimated Story Points
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	phuedx
	Jun 17 2025, 9:26 AM

Description

Background

The Experiment Platform team would like to run a series of tests on logged-in users only. To do this, the MetricsPlatform extension needs to fetch experiment configs from xLab.

AC

Set $wgMetricsPlatformEnableExperimentConfigsFetching to true in production
Monitor xLab after the deployment
Monitor the WANObjectCache Key Group dashboard for the MetricsPlatform key group

Details

Related Changes in Gerrit:

	Subject	Repo	Branch	Lines +/-
	Enable experiment configs fetching for group 0	operations/mediawiki-config	master	+6 -0

Customize query in gerrit

Related Objects
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Status	Assigned	Task
Resolved	JVanderhoop-WMF	T397337 [Epic] Verification of Experimentation Lab Closed Beta capabilities
Resolved	None	T397140 Run a logged-in synthetic A/A test using the JS SDK
Resolved	Sfaci	T397143 Run a logged-in synthetic A/A test using the PHP SDK
Resolved	Kgraessle	T396789 [Epic] Run and analyse an experiment for the group by toggle for Watchlist/RecentChanges/RelatedChanges
Resolved	cjming	T397144 MetricsPlatform: Enable experiment config fetching

Event Timeline

phuedx created this task.Jun 17 2025, 9:26 AM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptJun 17 2025, 9:26 AM

phuedx added a subtask: T397140: Run a logged-in synthetic A/A test using the JS SDK.Jun 17 2025, 9:26 AM

phuedx added a subtask: T397143: Run a logged-in synthetic A/A test using the PHP SDK.

phuedx removed a subtask: T397140: Run a logged-in synthetic A/A test using the JS SDK.

phuedx added a parent task: T397140: Run a logged-in synthetic A/A test using the JS SDK.

phuedx removed a subtask: T397143: Run a logged-in synthetic A/A test using the PHP SDK.Jun 17 2025, 9:29 AM

phuedx added a parent task: T397143: Run a logged-in synthetic A/A test using the PHP SDK.

phuedx set the point value for this task to 1.Jun 17 2025, 9:35 AM

Set $wgMetricsPlatformEnableExperimentConfigsFetching to true for enwiki in production

@phuedx: Why is this specific to enwiki, could we not make this true as default? (Our would that bring xLab down from all the wikis fetching the config?) Is the implication that Moderator Tools will need this done for all the specific wikis they plan to conduct their upcoming experiment (T396789) on?

phuedx updated the task description. (Show Details)Jun 17 2025, 12:49 PM

In T397144#10922644, @mpopov wrote:

Set $wgMetricsPlatformEnableExperimentConfigsFetching to true for enwiki in production

@phuedx: Why is this specific to enwiki, could we not make this true as default? (Our would that bring xLab down from all the wikis fetching the config?)

Mibad. Nope. xLab returns config for all active experiments for all wikis. We cache that per DC for 1 minute. So we should expect 1 request per minute per DC. I've updated the AC to remove the "for enwiki" bit but I'll also add an AC to monitor xLab after the change is deployed.

Awesome, thank you!

phuedx updated the task description. (Show Details)Jun 17 2025, 12:54 PM

Kgraessle added a parent task: T396789: [Epic] Run and analyse an experiment for the group by toggle for Watchlist/RecentChanges/RelatedChanges.Jun 17 2025, 2:03 PM

Milimetric assigned this task to cjming.Jun 30 2025, 3:17 PM

Milimetric triaged this task as High priority.

Milimetric moved this task from Incoming to Backlog on the Test Kitchen board.

Milimetric edited projects, added Test Kitchen (Experiment Platform Sprint 8); removed Test Kitchen.

Milimetric moved this task from Ready for Development to In Progress on the Test Kitchen (Experiment Platform Sprint 8) board.

Change #1165060 had a related patch set uploaded (by Clare Ming; author: Clare Ming):

[operations/mediawiki-config@master] Enable experiment configs fetching

https://gerrit.wikimedia.org/r/1165060

gerritbot added a project: Patch-For-Review.Jun 30 2025, 4:24 PM

cjming moved this task from In Progress to Needs Review on the Test Kitchen (Experiment Platform Sprint 8) board.Jun 30 2025, 5:09 PM

Change #1165060 merged by jenkins-bot:

[operations/mediawiki-config@master] Enable experiment configs fetching for group 0

https://gerrit.wikimedia.org/r/1165060

Mentioned in SAL (#wikimedia-operations) [2025-06-30T20:09:30Z] <cjming@deploy1003> Started scap sync-world: Backport for [[gerrit:1159568|Revert "Add scrambled: password class" (T395360 T395372)]], [[gerrit:1165060|Enable experiment configs fetching for group 0 (T397144)]]

Mentioned in SAL (#wikimedia-operations) [2025-06-30T20:11:27Z] <cjming@deploy1003> cjming, tgr: Backport for [[gerrit:1159568|Revert "Add scrambled: password class" (T395360 T395372)]], [[gerrit:1165060|Enable experiment configs fetching for group 0 (T397144)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.

Mentioned in SAL (#wikimedia-operations) [2025-06-30T20:19:27Z] <cjming@deploy1003> Finished scap sync-world: Backport for [[gerrit:1159568|Revert "Add scrambled: password class" (T395360 T395372)]], [[gerrit:1165060|Enable experiment configs fetching for group 0 (T397144)]] (duration: 09m 57s)