perf: add SetTraceIdWithValue, cache OTEL span lookup

[ankurs]

Summary

• Add SetTraceIdWithValue returning (context.Context, string) to avoid a separate GetTraceId call after SetTraceId — eliminates redundant context lookups on the hot path
• SetTraceId delegates to SetTraceIdWithValue — existing callers are unaffected (public API preserved)
• Cache oteltrace.SpanFromContext(ctx) result: called once instead of up to 3 times per invocation

Ref: ROADMAP items 1.2, 1.3

Test plan

• Existing TestSetTraceId_* tests pass unchanged (public API preserved)
• New TestSetTraceIdWithValue_* tests verify returned trace ID matches GetTraceId
• OTEL span attribute test for SetTraceIdWithValue
• go test -race ./notifier/... passes

[coderabbitai]

📝 Walkthrough

Walkthrough

The notifier package's trace ID handling was refactored by introducing SetTraceIdWithValue that resolves trace IDs (from options, gRPC metadata, OTEL span, or UUID) and returns both the updated context and the resolved trace ID string. The original SetTraceId function was reintroduced as a wrapper for backward compatibility. Three test cases verify the new function's behavior with various trace ID scenarios and OTEL span attribute setting.

Changes

Cohort / File(s)	Summary
Trace ID Resolution Refactor notifier/notifier.go	Introduced SetTraceIdWithValue to resolve and cache trace IDs while returning the string value; refactored SetTraceId as a wrapper that discards the returned string, preserving the original API.
Test Coverage notifier/notifier_test.go	Added three test cases for SetTraceIdWithValue covering non-empty trace ID generation, preservation of existing trace IDs, and verification of OTEL span attribute coldbrew.trace_id setting.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related issues

• Add test: verify coldbrew.trace_id OTEL span attribute in SetTraceId #23: Related due to overlapping changes in SetTraceId behavior and OTEL span attribute (coldbrew.trace_id) handling that both issues address.

Possibly related PRs

• feat: migrate notifier from OpenTracing to OTEL trace context #18: Modifies trace-ID handling in notifier to integrate OpenTelemetry span context for trace extraction and resolution.
• feat: link ColdBrew trace ID to OTEL span as attribute #22: Updates SetTraceId logic to resolve ColdBrew trace IDs and set them as OTEL span attributes.
• test: verify coldbrew.trace_id OTEL span attribute in SetTraceId #24: Adds test coverage for OTEL span attribute behavior in trace-ID resolution logic.

Poem

🐰 A trace ID returns with grace,
OpenTelemetry's embrace,
Split the logic, keep it light,
Wrapped with backward-compat might,
OTEL attributes shining bright! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 42.86% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main changes: introducing SetTraceIdWithValue function and caching OTEL span lookup for performance improvements.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch perf/set-trace-id-with-value

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[Copilot]

Pull request overview

This PR optimizes trace ID resolution on the notifier hot path by adding a new API that returns the resolved trace ID alongside the updated context, and by reducing repeated OpenTelemetry span lookups.

Changes:

• Add SetTraceIdWithValue(ctx) (context.Context, string) to return the resolved trace ID without requiring a follow-up GetTraceId call.
• Refactor SetTraceId to delegate to SetTraceIdWithValue.
• Add unit tests covering the new API and OTEL attribute behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
notifier/notifier.go	Introduces SetTraceIdWithValue, caches span lookup, and refactors SetTraceId to delegate.
notifier/notifier_test.go	Adds tests for SetTraceIdWithValue (returned value, existing trace ID, OTEL attribute).

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@notifier/notifier.go`:
- Line 580: Remove the invalid compiler directive "//go:inline"—locate the
literal comment "//go:inline" in notifier.go and delete it (do not replace with
any nonstandard directive); if you intended to control inlining behavior use
supported directives like "//go:noinline" or "//go:noescape" instead, but
otherwise just remove the "//go:inline" line so the code relies on the
compiler's automatic inlining.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6163925c-9912-45be-8679-5d5acdb3eaf5

📥 Commits

Reviewing files that changed from the base of the PR and between d378bec and f3d083f.

📒 Files selected for processing (2)

• notifier/notifier.go
• notifier/notifier_test.go

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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