[analytics] Add browser request accept-language

[imnasnainaec]

Enables browser language analytics, non-PII analytics requested by SIL leadership.

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This change is 

Summary by CodeRabbit

• New Features

  • Recognizes and tags the Accept-Language header in HTTP requests.

• Refactor

  • Simplified and optimized query string handling for cleaner, more reliable URL tagging.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

Modified Backend/Otel/OtelKernel.cs to tag Accept-Language headers as http.request.header.accept_language for AspNetCore requests and to simplify HttpClient query tagging using a single null-safe query check.

Changes

Cohort / File(s)	Summary
HTTP request telemetry enrichment Backend/Otel/OtelKernel.cs	Added tagging of the Accept-Language header as http.request.header.accept_language for AspNetCore. Simplified HttpClient query-tagging by replacing nested null checks with a single null-safe check that sets url.query when a query exists.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Single-file change with small, local logic additions and simplifications
• Areas to check:
  • Correct header name and casing for tagging (http.request.header.accept_language)
  • Null-safe query check covers all HttpClient URI edge cases (empty vs null query)

Poem

🐰 I sniffed the headers, found a tongue to name,

I tucked the query tidy, no nested checks to blame,
Telemetry twinkles, small changes, bright and neat,
One file hopped forward on quick, clever feet,
nibble-nudge celebration in every beat.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly describes the main change: adding Accept-Language header tagging for analytics purposes.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch otel-accept-lang

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

Backend/Otel/OtelKernel.cs (1)

85-88: Accept-Language enrichment is solid; consider avoiding magic string and double-check consent expectations

The new Accept-Language tagging is implemented safely with TryGetValue and produces a sensible string via langs.ToString(). Two minor follow-ups to consider:

• Use a constant (e.g., Microsoft.Net.Http.Headers.HeaderNames.AcceptLanguage) instead of the raw "Accept-Language" literal to avoid typos and ease reuse.
• Today this tag is added for all requests, regardless of analyticsOn/consent. If your privacy/analytics policy expects all analytics-related attributes (even “non-PII” ones) to be gated by consent, you may want to condition this on the same consent signal used elsewhere; if Accept-Language is explicitly allowed outside consent, current behavior is fine.

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 16e96db and ff48c31.

📒 Files selected for processing (1)

• Backend/Otel/OtelKernel.cs (2 hunks)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (4)

• GitHub Check: docker_build
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• GitHub Check: Analyze (csharp)

🔇 Additional comments (1)

Backend/Otel/OtelKernel.cs (1)

101-103: Null-safe query check refactor looks good

The new if (!string.IsNullOrEmpty(request.RequestUri?.Query)) keeps prior behavior while simplifying the null checks and still avoids NullReferenceException when RequestUri is unset. No further changes needed from my side.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.66%. Comparing base (16e96db) to head (38e17db).
⚠️ Report is 17 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #4060       +/-   ##
===========================================
+ Coverage   74.55%   85.66%   +11.10%     
===========================================
  Files         294       54      -240     
  Lines       10897     4763     -6134     
  Branches     1366      587      -779     
===========================================
- Hits         8124     4080     -4044     
+ Misses       2378      539     -1839     
+ Partials      395      144      -251     

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[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

Backend/Otel/OtelKernel.cs (1)

80-86: Avoid setting empty Accept-Language tag; consider consent alignment

request.Headers.AcceptLanguage is a valid typed property on IHeaderDictionary and will compile. However, calling .ToString() on a missing header returns an empty string rather than skipping the tag. Consider checking for presence before tagging:

-                TrackSession(activity, request);
-                activity.SetTag("http.request.header.accept_language", request.Headers.AcceptLanguage.ToString());
+                TrackSession(activity, request);
+                var acceptLanguage = request.Headers.AcceptLanguage;
+                if (!StringValues.IsNullOrEmpty(acceptLanguage))
+                {
+                    activity.SetTag("http.request.header.accept_language", acceptLanguage.ToString());
+                }

Additionally, if product requirements mandate that this header should only be captured when analytics consent is enabled, gate this on the same consent signal already checked in TrackConsent().

🧹 Nitpick comments (1)

Backend/Otel/OtelKernel.cs (1)

95-101: HttpClient query tagging change looks good; keep an eye on PII in queries

The simplified null/empty check for request.RequestUri?.Query is correct and keeps the behavior (only tag when a non-empty query exists) while reducing nesting. request is non-null in this callback, so the remaining null-conditional on RequestUri is sufficient.

Given you are tagging the full url.query, just ensure that upstream callers don’t place secrets or sensitive PII in query strings, or consider redaction if that’s a risk.

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between ff48c31 and 38e17db.

📒 Files selected for processing (1)

• Backend/Otel/OtelKernel.cs (2 hunks)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (4)

• GitHub Check: docker_build
• GitHub Check: test_build (8.0.x)
• GitHub Check: Analyze (csharp)
• GitHub Check: tox (3.12)

[jasonleenaylor]

@jasonleenaylor reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)