docs: correct workers tracing sampling description

[ankurs]

Summary

The workers tracing docs claimed worker spans are "always sampled regardless of the global sampler" — this is no longer accurate. The current middleware.Tracing() implementation uses tracing.NewInternalSpan which respects the global sampler.

Updated the description to reflect actual behavior: worker spans are typically trace roots, so sampling follows the global TracerProvider's sampler. If using ParentBased(TraceIDRatioBased(...)) with a low ratio, worker spans may be dropped — users should configure AlwaysSample() if needed.

Test plan

• Visual review — wording matches actual workers/middleware/tracing.go behavior

Summary by CodeRabbit

• Documentation
  • Updated tracing documentation to clarify how worker spans are sampled by the global TracerProvider and provided guidance on configuring sampling strategies for worker cycles to ensure consistent tracing behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 8b46a22d-46f0-44f6-94e0-76d16ce82f6c

📥 Commits

Reviewing files that changed from the base of the PR and between 92e8140 and 365dde4.

📒 Files selected for processing (1)

• howto/workers.md

---

📝 Walkthrough

Walkthrough

Updated worker tracing documentation to clarify that worker:<name>:cycle spans are typically trace roots whose sampling follows the global TracerProvider sampler, with added guidance on sampler configuration options.

Changes

Cohort / File(s)	Summary
Worker Tracing Documentation howto/workers.md	Revised description of worker:<name>:cycle span sampling behavior. Now clarifies these are trace roots following global sampler behavior rather than always being independently sampled. Added guidance on using AlwaysSample() when all cycles should be traced and noted that ParentBased(TraceIDRatioBased(...)) with low ratios may drop worker spans.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

🐰 A worker's span now clearly traced,
Where sampler rules are now embraced,
No more mystery in the light,
Global guidance shining bright! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: correcting the documentation about workers tracing sampling behavior to accurately reflect how the middleware respects the global sampler.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch docs/fix-workers-tracing-sampling

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[Copilot]

Pull request overview

Updates the workers tracing documentation to reflect that worker cycle spans are sampled according to the global OpenTelemetry TracerProvider sampler (rather than being force-sampled), clarifying how root-span sampling can drop worker traces under low sampling ratios.

Changes:

• Corrects the tracing section to state worker spans typically have no parent and therefore follow the global sampler.
• Adds guidance that low ParentBased(TraceIDRatioBased(...)) ratios can probabilistically drop worker spans and suggests using AlwaysSample() when full coverage is required.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.