[APMSVLS-464][APMSVLS-463] fix: Configure span kind and peer tag stats by lucaspimentel · Pull Request #1189 · DataDog/datadog-lambda-extension

lucaspimentel · 2026-04-16T21:07:53Z

Overview

Configure SpanConcentrator in bottlecap with the Go agent's default ComputeStatsBySpanKind span kinds and basePeerTags peer tag keys, fixing two gaps in agent-side trace stats computation:

APMSVLS-464: span_kinds_stats_computed was empty, so non-top-level, non-measured spans with span.kind = server/client/producer/consumer) were silently excluded from stats.
APMSVLS-463: peer_tag_keys was empty, so client/producer/consumer spans had no per-dependency granularity in stats output (e.g., all S3 buckets, DynamoDB tables, Kafka topics lumped together).

Changes

Add STATS_ELIGIBLE_SPAN_KINDS constant (4 span kinds matching the Go agent's KindsComputed)
Add DEFAULT_PEER_TAG_KEYS constant (43 peer tag keys matching the Go agent's basePeerTags from mappings.json)
Pass both to SpanConcentrator::new() instead of empty vecs
Add tests that exercise the full StatsConcentratorService pipeline for both features

Follow-up

Both constants are hand-copied from the Go agent (KindsComputed and basePeerTags), which is the source of truth, and the same lists are also duplicated in serverless-components. A future refactor should keep the Rust agents in sync with the Go agent rather than each maintaining its own copy.

Testing

test_span_kind_stats_computed: sends a non-root, non-measured client span through the service, verifies stats are produced with span_kind="client"
test_peer_tags_populated: sends a client span with db.instance and db.system meta, verifies peer_tags contains both in the stats output
Tests were written first and confirmed failing before the fix was applied
Full test suite still passes

"Turns out an empty vec is a great way to compute stats on absolutely nothing. Efficient, but not very useful." — Claude 🤖

Tests verify that StatsConcentratorService computes stats for spans with span.kind and populates peer_tags in output. Both tests currently fail due to empty span_kinds_stats_computed and peer_tag_keys vecs passed to SpanConcentrator::new(). 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

Pass STATS_ELIGIBLE_SPAN_KINDS and DEFAULT_PEER_TAG_KEYS to SpanConcentrator::new() to match the Go agent defaults. This enables stats for OTel spans with span.kind and adds per-dependency granularity via peer tags for client/producer/consumer spans. 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

datadog-datadog-prod-us1 · 2026-06-10T18:01:25Z

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 3 Pipeline jobs failed

DataDog/datadog-lambda-extension | e2e-test-status (amd64)

DataDog/datadog-lambda-extension | bottlecap (arm64, fips, alpine)

DataDog/datadog-lambda-extension | integration-suite: [on-demand]

Useful? React with 👍 / 👎

_{This comment will be updated automatically if new data arrives.

🔗 Commit SHA: 311feb7 | Docs | Datadog PR Page | Give us feedback!}

🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

Copilot

Pull request overview

This PR configures Bottlecap’s SpanConcentrator to match the Go agent defaults for (1) which span.kind values are eligible for stats computation and (2) which peer-related tag keys are used to populate per-dependency peer_tags, closing gaps in agent-side trace stats aggregation.

Changes:

Configure SpanConcentrator with the Go agent’s default computed span kinds (client, server, producer, consumer) instead of an empty list.
Configure SpanConcentrator with the Go agent’s default peer tag key set (basePeerTags) instead of an empty list.
Add end-to-end tests for span-kind-based stats eligibility and peer tag population in emitted stats.

lucaspimentel · 2026-06-11T19:22:09Z

+    /// A non-root, non-measured span with `span.kind`="client" should produce stats
+    /// when `ComputeStatsBySpanKind` is enabled (i.e. `span_kinds_stats_computed` is
+    /// populated). With the current empty vec, this span is silently dropped.


Fixed. Reworded doc comment to describe the current span-kind allowlist behavior.

lucaspimentel · 2026-06-11T19:22:11Z

+    /// A client span with peer tag meta keys (`db.instance`, `db.system`) should produce
+    /// stats with non-empty `peer_tags` when `peer_tag_keys` is configured. With the
+    /// current empty vec, `peer_tags` in the output will always be empty.


Fixed. Reworded doc comment to describe the current peer_tag_keys behavior.

lucaspimentel · 2026-06-11T19:22:13Z

+        assert!(
+            result.is_some(),
+            "Expected stats for a client span with peer tags, but got None. \
+             span.kind-based eligibility is not working."
+        );


Fixed. Removed the span.kind eligibility sentence from the failure message.

litianningdatadog · 2026-06-11T13:50:06Z

+/// TODO: The source of truth is the Go agent's `basePeerTags` (derived from
+/// pkg/trace/semantics/mappings.json); this list is hand-copied here and in other Rust repos.
+/// Refactor so they stay in sync with the Go agent instead of each keeping its own copy.
+const DEFAULT_PEER_TAG_KEYS: [&str; 43] = [


same as above

Fixed. Changed DEFAULT_PEER_TAG_KEYS to &[&str].

litianningdatadog · 2026-06-11T13:50:38Z

+/// TODO: The source of truth is the Go agent's `KindsComputed`; this list is hand-copied here
+/// and in other Rust repos. Refactor so they stay in sync with the Go agent instead of each
+/// keeping its own copy.
+const STATS_ELIGIBLE_SPAN_KINDS: [&str; 4] = ["client", "consumer", "producer", "server"];


nit: prefer &[&str] over [&str; 4] to make future update easier.

Fixed. Changed STATS_ELIGIBLE_SPAN_KINDS to &[&str].

lucaspimentel changed the title ~~[APMSVLS-464][APMSVLS-463] fix: Configure span kind and peer tag stats in bottlecap~~ [APMSVLS-464][APMSVLS-463] fix: Configure span kind and peer tag stats Apr 16, 2026

lucaspimentel mentioned this pull request May 7, 2026

feat: pass span_kinds_stats_computed and peer_tags to span concentrator DataDog/serverless-components#124

Merged

lucaspimentel added 4 commits June 10, 2026 13:58

Fix clippy and fmt lint issues

acb4904

🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

Fix doc_markdown clippy lints in test comments

2eb4403

🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

lucaspimentel force-pushed the lpimentel/fix-stats-span-kind-peer-tags branch from c06bc9b to 2eb4403 Compare June 10, 2026 17:58

lucaspimentel added 2 commits June 10, 2026 17:18

Point stats config TODOs at the Go agent source of truth

3a44e8f

🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

Fix cast_possible_truncation clippy lint in test helper

9e45de2

🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

lucaspimentel marked this pull request as ready for review June 10, 2026 21:49

lucaspimentel requested review from a team as code owners June 10, 2026 21:49

lucaspimentel requested review from Copilot and litianningdatadog June 10, 2026 21:49

Copilot started reviewing on behalf of lucaspimentel June 10, 2026 21:49 View session

Copilot AI reviewed Jun 10, 2026

View reviewed changes

litianningdatadog reviewed Jun 11, 2026

View reviewed changes

litianningdatadog approved these changes Jun 11, 2026

View reviewed changes

lucaspimentel added 4 commits June 11, 2026 13:21

Describe current behavior in span-kind test doc comment

4b456f1

Describe current behavior in peer-tags test doc comment

a8fc1d6

Simplify peer-tags test failure message

250d391

Use slices for stats span-kind and peer-tag constants

311feb7

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[APMSVLS-464][APMSVLS-463] fix: Configure span kind and peer tag stats#1189

[APMSVLS-464][APMSVLS-463] fix: Configure span kind and peer tag stats#1189
lucaspimentel wants to merge 10 commits into
mainfrom
lpimentel/fix-stats-span-kind-peer-tags

lucaspimentel commented Apr 16, 2026 •

edited

Loading

Uh oh!

datadog-datadog-prod-us1 Bot commented Jun 10, 2026 •

edited by datadog-datadog-prod-us1-2 Bot

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

lucaspimentel Jun 11, 2026

Uh oh!

lucaspimentel Jun 11, 2026

Uh oh!

lucaspimentel Jun 11, 2026

Uh oh!

litianningdatadog Jun 11, 2026 •

edited

Loading

Uh oh!

lucaspimentel Jun 11, 2026

Uh oh!

litianningdatadog Jun 11, 2026

Uh oh!

lucaspimentel Jun 11, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Conversation

lucaspimentel commented Apr 16, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Overview

Changes

Follow-up

Testing

Uh oh!

datadog-datadog-prod-us1 Bot commented Jun 10, 2026 • edited by datadog-datadog-prod-us1-2 Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

⚠️ Warnings

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Uh oh!

lucaspimentel Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

lucaspimentel Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

lucaspimentel Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

litianningdatadog Jun 11, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

lucaspimentel Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

litianningdatadog Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

lucaspimentel Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

lucaspimentel commented Apr 16, 2026 •

edited

Loading

datadog-datadog-prod-us1 Bot commented Jun 10, 2026 •

edited by datadog-datadog-prod-us1-2 Bot

Loading

litianningdatadog Jun 11, 2026 •

edited

Loading