[APMSVLS-497][APMSVLS-498] test: add fake-intake for APM payload-level tests by lucaspimentel · Pull Request #1194 · DataDog/datadog-lambda-extension

lucaspimentel · 2026-04-21T00:39:39Z

Summary of changes

Adds an in-process fake intake that lets bottlecap's integration tests decode and inspect real outgoing APM payloads.

The fake intake accepts both APM flush endpoints (/api/v0.2/stats and /api/v0.2/traces), decodes each request body on arrival, and exposes typed query methods so tests can assert on individual fields. Two new integration tests exercise the full StatsFlusher and TraceFlusher fake-intake round trip.

Reason for change

Allow integration tests to inspect APM payloads and catch regressions.

Implementation details

add an in-process axum server on a random local port that accepts POST /api/v0.2/stats and POST /api/v0.2/traces, decodes each body on arrival, and stores the results.
add two new integration tests covering the two APM flush paths end-to-end.
The module is deliberately free of bottlecap-internal types to allow extraction into a shared crate later.

Test coverage

Added 2 new tests that server that use the new fake intake and serve as POCs.

Other details

Implements APMSVLS-497 and APMSVLS-498.

After the fake intake is proven and the API is stable, phase 2 will extract fake_intake.rs into a shared crate consumed by both bottlecap and SCL.

"Finally, a way to ask our StatsPayloads how they're really feeling, and not just whether they showed up to work." — Claude 🤖

Copilot

Pull request overview

This PR introduces an in-process “fake Datadog intake” test harness for Bottlecap APM payload-level integration testing, enabling assertions on decoded stats/traces payload fields rather than only verifying that an HTTP request occurred.

Changes:

Add FakeIntake axum server that accepts /api/v0.2/stats and /api/v0.2/traces, decodes bodies, and stores pb::StatsPayload / pb::AgentPayload for tests.
Add new APM integration tests that exercise the stats and traces flush paths and assert on decoded payload fields.
Make StatsFlusher::new accept an explicit stats intake URL so tests can redirect it to the fake intake; update the production call site accordingly.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
bottlecap/tests/common/mod.rs	Adds a shared `tests/common` module exposing `fake_intake`.
bottlecap/tests/common/fake_intake.rs	Implements the in-process fake intake server with decoding and captured payload storage.
bottlecap/tests/apm_integration_test.rs	Adds payload-level integration tests for stats and traces flush paths.
bottlecap/src/traces/stats_flusher.rs	Accepts `stats_url` in the constructor and logs the actual endpoint used.
bottlecap/src/bin/bottlecap/main.rs	Passes `trace_stats_url(&config.site)` into `StatsFlusher::new`.
bottlecap/Cargo.toml	Adds dev-dependencies for msgpack and gzip decoding used by the fake intake.
bottlecap/Cargo.lock	Updates lockfile for the new dev-dependencies.

duncanista

Seems like the stats URL change is different to what this PR claims, do we really need them together?

lucaspimentel · 2026-04-24T17:48:18Z

@duncanista

Seems like the stats URL change is different to what this PR claims, do we really need them together?

I split that small refactor out into #1210 and stacked this PR on that one.

…tests Spawns an axum server on a random local port that accepts POSTs on /api/v0.2/stats (msgpack + gzip) and /api/v0.2/traces (protobuf, with zstd/gzip/identity decompression), decodes each body on arrival, and stores the decoded pb::StatsPayload / pb::AgentPayload for tests to query via typed methods. Two integration tests cover both flush paths: - stats_payload_roundtrip_through_fake_intake: drives StatsFlusher::send directly and asserts on decoded hit counts, span kind, peer tags, and HTTP metadata. - trace_payload_roundtrip_through_fake_intake: drives TraceFlusher::flush through the real aggregator and asserts on decoded trace/span IDs and service metadata. Tests redirect StatsFlusher at the fake-intake by passing FakeIntake::stats_url() to StatsFlusher::new, which was lifted to take the URL as a parameter in a prior commit. Prototype for APMSVLS-494 phase 1; extraction to a shared datadog/apm-agent-parity-rs crate is planned for phase 2. Co-Authored-By: Claude <noreply@anthropic.com>

service_source and span_derived_primary_tags were added in 2.0.0 (crates.io) but the workspace pins the git version (1.0.0). 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

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

- Return Result instead of panicking on bad decompression; axum converts handler panics to TCP aborts, not 500s, which produces opaque test failures - Warn on unrecognized Content-Encoding instead of silently treating as identity - Make base_url() private; stats_url()/traces_url() cover all uses 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

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

base_url() was private and never called; stats_url() and traces_url() accessed the field directly. Removing it also makes the blanket #![allow(dead_code)] in common/mod.rs unnecessary. 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

fake_intake was re-exported from tests/common/mod.rs, causing it to be compiled into every test binary. logs_integration_test and metrics_integration_test never use it, so the compiler emitted dead-code errors under RUSTFLAGS=-D warnings. Remove the re-export from common/mod.rs and include the module directly in apm_integration_test via #[path]. Remove the now-unused `mod common;` declarations from logs and metrics test files. 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

The Drop impl already sends the shutdown signal and aborts the task. The explicit shutdown() method was never called in any test. 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

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

lucaspimentel changed the title ~~[APMSVLS-494] test: add in-process fake-intake for APM payload-level tests~~ [APMSVLS-494] test: add fake-intake for APM payload-level tests Apr 21, 2026

lucaspimentel marked this pull request as ready for review April 21, 2026 03:12

lucaspimentel requested a review from a team as a code owner April 21, 2026 03:12

lucaspimentel requested review from Copilot and duncanista and removed request for Copilot April 21, 2026 03:12

Copilot started reviewing on behalf of lucaspimentel April 21, 2026 03:13 View session

Copilot AI reviewed Apr 21, 2026

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Comment thread bottlecap/tests/common/fake_intake.rs Outdated

Comment thread bottlecap/tests/common/fake_intake.rs

Comment thread bottlecap/tests/common/fake_intake.rs Outdated

Comment thread bottlecap/tests/common/mod.rs Outdated

lucaspimentel changed the title ~~[APMSVLS-494] test: add fake-intake for APM payload-level tests~~ [APMSVLS-497][APMSVLS-498] test: add fake-intake for APM payload-level tests Apr 21, 2026

lucaspimentel requested a review from a team as a code owner April 23, 2026 20:12

duncanista reviewed Apr 24, 2026

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lucaspimentel mentioned this pull request Apr 24, 2026

refactor(stats): take stats_url as a StatsFlusher::new parameter #1210

Merged

5 tasks

lucaspimentel force-pushed the lpimentel/fake-intake-phase-1 branch from 2b10774 to 2e77c12 Compare April 24, 2026 17:36

lucaspimentel changed the base branch from main to lpimentel/stats-flusher-url-param April 24, 2026 17:36

lucaspimentel force-pushed the lpimentel/stats-flusher-url-param branch from 8f52b41 to 6fbe14b Compare April 24, 2026 21:07

lucaspimentel force-pushed the lpimentel/fake-intake-phase-1 branch from 2e77c12 to 027f404 Compare April 24, 2026 21:11

lucaspimentel force-pushed the lpimentel/stats-flusher-url-param branch from 6fbe14b to 56162d9 Compare April 28, 2026 19:52

lucaspimentel force-pushed the lpimentel/fake-intake-phase-1 branch from f6f171f to c51ec4d Compare April 29, 2026 19:21

lucaspimentel mentioned this pull request Apr 29, 2026

[APMSVLS-501] feat(bottlecap): add bottlecap-test-mode binary #1216

Draft

4 tasks

lucaspimentel marked this pull request as draft May 1, 2026 16:41

lucaspimentel force-pushed the lpimentel/stats-flusher-url-param branch from 56162d9 to 1850777 Compare May 5, 2026 17:10

Base automatically changed from lpimentel/stats-flusher-url-param to main May 5, 2026 20:27

lucaspimentel and others added 6 commits May 5, 2026 17:00

fix: remove fields absent from libdd-trace-protobuf 1.0.0

be6f7fa

service_source and span_derived_primary_tags were added in 2.0.0 (crates.io) but the workspace pins the git version (1.0.0). 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

style: apply rustfmt to apm integration test files

69c64c0

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

style: replace em dashes with colons and commas in comments

b6c24b0

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

test: remove unnecessary clone in stats roundtrip test

044d86b

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

lucaspimentel and others added 8 commits May 5, 2026 17:00

docs: fix ticket reference in apm_integration_test

0a9b4ec

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

style: wrap long eprintln! in fake_intake decompress

ed49f1d

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

fix(fake-intake): propagate server task panic in shutdown

5bc1d9e

fix(fake-intake): propagate axum serve errors via expect

4ccbe3e

refactor(fake-intake): remove unused shutdown method

a860792

The Drop impl already sends the shutdown signal and aborts the task. The explicit shutdown() method was never called in any test. 🤖 Co-Authored-By: Claude Code <noreply@anthropic.com>

style(fake-intake): remove trailing blank line before closing brace

aff7b2f

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

lucaspimentel force-pushed the lpimentel/fake-intake-phase-1 branch from c51ec4d to aff7b2f Compare May 5, 2026 21:01

lucaspimentel marked this pull request as ready for review May 5, 2026 23:07

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[APMSVLS-497][APMSVLS-498] test: add fake-intake for APM payload-level tests#1194

[APMSVLS-497][APMSVLS-498] test: add fake-intake for APM payload-level tests#1194
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lucaspimentel commented Apr 21, 2026 •

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