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feat: extract trace context from MSK events - #830

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lucassarcanjo:feat/msk-trace-extraction
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feat: extract trace context from MSK events#830
lucassarcanjo wants to merge 3 commits into
DataDog:mainfrom
lucassarcanjo:feat/msk-trace-extraction

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@lucassarcanjo

@lucassarcanjo lucassarcanjo commented Sep 8, 2026 •
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What does this PR do?

Adds automatic trace context extraction for MSK-triggered Lambdas. Kafka header byte arrays are decoded as UTF-8 and passed to the existing tracer, preserving Datadog and W3C propagation context.

For batches, the Lambda span uses the first record with valid trace context across the topic-partition groups. Malformed headers are skipped, and headers from different records are never combined.

Motivation

Fixes #829. An instrumented producer's trace headers reach the Lambda event, but the existing dispatcher does not extract them, so the Lambda starts a separate trace.

Testing Guidelines

  • yarn test --runInBand: 691 tests and 3 snapshots passed on Node.js 22.
  • yarn lint and formatting checks passed.
  • Local Node.js 24 check with real dd-trace@5.118.0: the Lambda tracing lifecycle preserves the producer parent ID, sampling priority, and 128-bit trace ID with Datadog-only, W3C-only, and combined headers. The same reproduction fails with the original dispatcher.
  • Live AWS/MSK and Docker integration validation are pending.

Types of Changes

  • New feature

Check all that apply

  • This PR's description is comprehensive
  • This PR's changes are covered by the automated tests
  • This PR passes the integration tests (ask a Datadog member to run the tests)

purple4reina
purple4reina reviewed Sep 8, 2026
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Comment thread src/trace/context/extractors/msk.ts
@lucassarcanjo
lucassarcanjo marked this pull request as ready for review September 9, 2026 12:11
@lucassarcanjo
lucassarcanjo requested review from a team as code owners September 9, 2026 12:11
@lucassarcanjo
lucassarcanjo requested a review from lym953 September 9, 2026 12:11
BridgeAR
BridgeAR reviewed Sep 10, 2026
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Thank you for the PR! I just left a few suggestions to make the code a bit faster :)

Comment thread src/trace/context/extractors/msk.ts Outdated
Comment thread src/trace/context/extractors/msk.ts Outdated
Comment thread src/trace/context/extractors/msk.ts Outdated
Comment thread src/trace/context/extractors/msk.ts Outdated
@lucassarcanjo
lucassarcanjo force-pushed the feat/msk-trace-extraction branch from 34ffa90 to c552877 Compare September 10, 2026 17:20
BridgeAR
BridgeAR reviewed Sep 10, 2026
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Thank you for the quick follow-ups!

Code wise it seems fine to me.

@lucassarcanjo

lucassarcanjo commented Sep 11, 2026

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Hi @lym953, could you take a look at this PR?

@jcstorms1

jcstorms1 commented Sep 15, 2026

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@codex review

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chatgpt-codex-connector Bot commented Sep 15, 2026

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To use Codex here, create a Codex account and connect to github.

@jcstorms1

jcstorms1 commented Sep 15, 2026

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@codex review

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chatgpt-codex-connector Bot commented Sep 15, 2026 •
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Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review Status Commit Review trigger
📝 Code Review ✅ Completed 2026-09-15T19:58:31.341873Z c552877 Manual request
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@chatgpt-codex-connector

chatgpt-codex-connector Bot commented Sep 15, 2026

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Codex Review: Didn't find any major issues. You're on a roll.

Reviewed commit: c552877bb5

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@jcstorms1

jcstorms1 commented Sep 15, 2026

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LGTM 👍

@zarirhamza

zarirhamza commented Sep 15, 2026

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Thanks @lucassarcanjo! This looks good to us but we need you to rebase onto the original main branch instead of a fork. If you'd rather us take care of it, please enable allow edits from maintainers so we can rebase and merge

@lucassarcanjo
lucassarcanjo force-pushed the feat/msk-trace-extraction branch from c552877 to b6dd184 Compare September 15, 2026 23:44
@lucassarcanjo

lucassarcanjo commented Sep 15, 2026

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Hi @zarirhamza, done!

@jeastham1993 jeastham1993 mentioned this pull request Sep 16, 2026
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8 tasks
@lucassarcanjo @zarirhamza
feat: extract trace context from MSK events
9d0b27a
@lucassarcanjo @zarirhamza
fix: log MSK trace context extraction outcomes
02510e4
@lucassarcanjo @zarirhamza
refactor: simplify MSK header parsing per review
b98fe61 
- Guard event.records with an early return instead of an empty fallback
- Wrap the record loop in a single try/catch so errors log once
- Return null from getParsedRecordHeaders when nothing decodes, lazily
  creating the headers map
- Drop per-byte validation and rely on Buffer.from
@zarirhamza
zarirhamza force-pushed the feat/msk-trace-extraction branch from b6dd184 to b98fe61 Compare September 16, 2026 15:10
@jcstorms1 jcstorms1 mentioned this pull request Sep 16, 2026
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@zarirhamza

zarirhamza commented Sep 17, 2026

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/remove

@gh-worker-devflow-routing-ef8351

gh-worker-devflow-routing-ef8351 Bot commented Sep 17, 2026 •
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View all feedbacks in Devflow UI.

2026-09-17 13:15:41 UTC ℹ️ Start processing command /remove

2026-09-17 13:15:49 UTC ℹ️ Devflow: /remove

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@BridgeAR BridgeAR BridgeAR left review comments
@jcstorms1 jcstorms1 jcstorms1 approved these changes
@lym953 lym953 Awaiting requested review from lym953 lym953 is a code owner automatically assigned from DataDog/serverless-aws
@purple4reina purple4reina Awaiting requested review from purple4reina

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Built-in trace context extraction for MSK-triggered Lambdas

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@lucassarcanjo @jcstorms1 @zarirhamza @purple4reina @BridgeAR