MWPW-159555 Add support for lana-sample query param

[chrischrischris]

The lana-sample query param will override any sample rate defined elsewhere. Setting it to "100" will force lana to send everything to splunk.

Resolves: MWPW-159555

Test URLs:

• Before: https://main--milo--adobecom.hlx.page/?martech=off
• After: https://mwpw-159555--milo--adobecom.hlx.page/?martech=off

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Commits

• a18ae2d ✅ (latest)
• 4914104 ✅
• 7672f03 ✅
• 218294e ✅
• 86a6d73 ❌

[aem-code-sync]

	Page	Scores	Audits	Google
📱	/?martech=off
🖥️	/?martech=off

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.34%. Comparing base (ec48f3c) to head (a18ae2d).
Report is 45 commits behind head on stage.

Additional details and impacted files

@@           Coverage Diff           @@
##            stage    #3045   +/-   ##
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  Coverage   96.34%   96.34%           
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  Files         243      243           
  Lines       55284    55288    +4     
=======================================
+ Hits        53261    53265    +4     
  Misses       2023     2023           

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[github-actions]

This pull request is not passing all required checks. Please see this discussion for information on how to get all checks passing. Inconsistent checks can be manually retried. If a test absolutely can not pass for a good reason, please add a comment with an explanation to the PR.

[SilviuLCF]

Hi @chrischrischris can you provide some guidance on how testing should be performed for this change?

thank you

[overmyheadandbody]

Seems the new unit test is failing - ❌ LANA > The lana-sample query param overrides existing sampleRate

[github-actions]

Reminder to set the Ready for Stage label - to queue this to get merged to stage & production.

[thedoc31]

Assuming someone will always send in a valid integer between 0 and 100 is dangerous without any (apparent) input validation or error handling. What happens if I send in an invalid number or a value long enough to be a BigInt? Would lana know what to do if it got a NaN in this param?

[chrischrischris]

@thedoc31 The parseInt handles the sanitization of the input. If the lana-sample param is invalid it will be NaN and the next line will ignore it:

const sampleRateParam = parseInt(new URL(window.location).searchParams.get('lana-sample'), 10);
const sampleRate = sampleRateParam || (o.errorType === 'i' ? o.implicitSampleRate : o.sampleRate);

It's fine if the param is negative or a gigantic number. Negative will behave like 0, anything over 100 behaves like 100.

I've added a test case for an invalid param value.

[SilviuLCF]

Verified, ready to STAGE

The parseInt and existing code provide sufficient validation and the extra test case will validate that. Closing objection