fix: prevent request ID collisions and preserve session log grouping

[StrangeXin]

What changed

• Normalize missing or all-zero x-request-id values before tracing and context conversion.
• Propagate the normalized request ID to downstream middleware and response headers.
• Populate BifrostContextKeyParentRequestID from session correlation headers using this precedence:
  1. W3C baggage member session-id
  2. Bifrost x-bf-session-id
  3. Compatibility header x-conversation-id
• Add regression coverage for request ID normalization and session-header precedence.

Why

Some OpenAI-compatible clients emit 00000000000000000000000000000000 as a placeholder x-request-id. Bifrost currently treats it as a valid ID, so unrelated requests can collide in the logging store and appear missing or overwritten.

Separately, Bifrost's logging plugin groups requests through BifrostContextKeyParentRequestID, while x-bf-session-id previously populated only the key-stickiness context value. Clients that provide a stable conversation/session header therefore produce complete individual records but no session grouping in LLM Logs.

Impact

• Placeholder request IDs no longer collapse unrelated log records.
• Bifrost's native session header now also drives LLM log grouping.
• Clients using x-conversation-id retain conversation grouping without a separate proxy or transport plugin.
• Existing valid caller-supplied request IDs remain unchanged.

Validation

• go test ./bifrost-http/handlers
• go test ./bifrost-http/handlers -run TestTracingMiddleware_SetsCorrelationHeaders -count=1 -timeout=90s
• go test ./bifrost-http/lib -run 'TestNormalizeRequestID|TestConvertToBifrostContext_(BaggageSessionIDSetsGrouping|EmptyBaggageSessionIDIgnored|SessionHeaderPrecedence|ReplacesAllZeroRequestID)' -count=1 -timeout=90s

The full bifrost-http/lib package run was stopped after its unrelated integration-style tests continued for several minutes; all directly affected tests passed.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
5 out of 7 committers have signed the CLA.

✅ akshaydeo
✅ roroghost17
✅ Madhuvod
✅ StrangeXin
✅ devonpmack
❌ TejasGhatte
❌ Pratham-Mishra04
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 676c69d5-c262-4aac-a676-44ad7a876595

📥 Commits

Reviewing files that changed from the base of the PR and between cda044b and ec2ffcb.

📒 Files selected for processing (2)

• transports/bifrost-http/lib/ctx.go
• transports/bifrost-http/lib/ctx_test.go

🚧 Files skipped from review as they are similar to previous changes (2)

• transports/bifrost-http/lib/ctx.go
• transports/bifrost-http/lib/ctx_test.go

---

📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes

  • Improved request ID handling by normalizing whitespace-only and all-zero values to unique, valid identifiers.
  • Ensured normalized request IDs are consistently propagated via correlation headers in both request handling and responses.
  • Improved parent-request/session identification when multiple session-related headers are present, using a clear precedence order.

• Tests

  • Added unit tests covering request ID normalization (including all-zero replacement).
  • Added tests validating session/parent-request precedence and downstream propagation behavior.

Walkthrough

Request ID normalization is centralized and applied by tracing middleware and Bifrost context conversion. Parent request ID selection now follows explicit session, baggage, and conversation-header precedence, with tests covering sentinel replacement and propagation.

Changes

Request ID and context handling

Layer / File(s)	Summary
Request ID normalization utility transports/bifrost-http/lib/requestid.go, transports/bifrost-http/lib/requestid_test.go	Adds NormalizeRequestID and tests preservation of valid IDs plus replacement of blank, whitespace-only, and all-zero values.
Bifrost context request and parent IDs transports/bifrost-http/lib/ctx.go, transports/bifrost-http/lib/ctx_test.go	Normalizes context request IDs and applies parent request ID precedence across x-bf-session-id, baggage, and x-conversation-id, with corresponding tests.
Tracing middleware propagation transports/bifrost-http/handlers/middlewares.go, transports/bifrost-http/handlers/middlewares_test.go	Normalizes incoming request IDs and propagates normalized values downstream and in responses, including all-zero inputs.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers: pratham-mishra04, akshaydeo, bearts

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly matches the main change: fixing request ID collisions and preserving session log grouping.
Description check	✅ Passed	The description covers the summary, rationale, impact, and validation, but several template sections are omitted.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.2)

level=error msg="[linters_context] typechecking error: pattern ./...: directory prefix . does not contain main module or its selected dependencies"

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[greptile-apps]

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.

Important Files Changed

Filename	Overview
transports/bifrost-http/handlers/middlewares.go	Normalizes request IDs before tracing and propagates the result through request and response headers.
transports/bifrost-http/handlers/middlewares_test.go	Adds middleware coverage for replacing an all-zero request ID.
transports/bifrost-http/lib/ctx.go	Normalizes context request IDs and adds session-header precedence for log grouping.
transports/bifrost-http/lib/ctx_test.go	Adds coverage for session grouping precedence and all-zero request IDs.
transports/bifrost-http/lib/requestid.go	Introduces the shared request-ID normalization helper.
transports/bifrost-http/lib/requestid_test.go	Covers valid, empty, whitespace-only, and all-zero request IDs.

_{Reviews (2): Last reviewed commit: "Merge remote-tracking branch 'origin/dev..." | Re-trigger Greptile}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@transports/bifrost-http/lib/ctx.go`:
- Around line 240-253: Update parentRequestID selection in
transports/bifrost-http/lib/ctx.go:240-253 to evaluate x-bf-session-id first,
then fall back to baggage and finally x-conversation-id, while preserving
trimming and length validation. Update the related assertions in
transports/bifrost-http/lib/ctx_test.go:300-328 to verify x-bf-session-id takes
precedence over baggage.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 4f9d7813-179f-458d-8855-c93d76115173

📥 Commits

Reviewing files that changed from the base of the PR and between 493bff0 and cda044b.

📒 Files selected for processing (6)

• transports/bifrost-http/handlers/middlewares.go
• transports/bifrost-http/handlers/middlewares_test.go
• transports/bifrost-http/lib/ctx.go
• transports/bifrost-http/lib/ctx_test.go
• transports/bifrost-http/lib/requestid.go
• transports/bifrost-http/lib/requestid_test.go

The merge-base changed after approval.

[akshaydeo]

Hi @StrangeXin — thanks for the contribution! This PR is currently blocked because our CLA bot shows the Contributor License Agreement as not yet signed. Could you sign it here so we can move this forward: https://cla-assistant.io/maximhq/bifrost?pullRequest=5348

Let us know if you run into any issues signing.