enhancement(datadog encoder): support for metrics v3 protocol

[tobz]

Summary

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

How did you test this PR?

References

[tobz]

• enhancement(datadog encoder): support for metrics v3 protocol #1175 👈 (View in Graphite)
• main

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[pr-commenter]

Binary Size Analysis (Agent Data Plane)

Target: bb1575e (baseline) vs a9f5109 (comparison) diff
Analysis Type: Stripped binaries (debug symbols excluded)
Baseline Size: 26.19 MiB
Comparison Size: 26.35 MiB
Size Change: +160.83 KiB (+0.60%)
Pass/Fail Threshold: +5%
Result: PASSED ✅

Changes by Module

Module	File Size	Symbols
saluki_components::encoders::datadog	+69.19 KiB	325
core	+38.49 KiB	8803
[sections]	+10.27 KiB	9
anyhow	+9.12 KiB	1256
hashbrown	+7.45 KiB	347
saluki_common::task::instrument	+7.28 KiB	76
protobuf	+4.74 KiB	12
saluki_components::common::datadog	-4.20 KiB	325
http	+3.85 KiB	323
agent_data_plane::cli::run	+2.73 KiB	70
saluki_io::compression::Compressor<W>	+2.49 KiB	3
saluki_io::net::util	+2.24 KiB	130
serde_core	+2.10 KiB	339
[Unmapped]	+2.08 KiB	1
uuid	+1.85 KiB	4
agent_data_plane::components::apm_onboarding	-1.36 KiB	34
saluki_components::transforms::dogstatsd_mapper	-992 B	18
saluki_components::forwarders::datadog	+846 B	22
tokio	+715 B	2137
tracing_core	+582 B	438

Detailed Symbol Changes

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  [NEW] +1.79Mi  [NEW] +1.79Mi    std::thread::local::LocalKey<T>::with::hc561bb4887a44f4d
  +1.2%  +155Ki  +1.3%  +132Ki    [21844 Others]
  [NEW]  +117Ki  [NEW]  +117Ki    agent_data_plane::cli::run::create_topology::_{{closure}}::h0c5e4b739c354b02
  [NEW] +84.6Ki  [NEW] +84.5Ki    agent_data_plane::internal::control_plane::spawn_control_plane::_{{closure}}::h267c0964a8265cd5
  [NEW] +67.3Ki  [NEW] +67.1Ki    saluki_components::common::datadog::io::run_endpoint_io_loop::_{{closure}}::h80e57416e92ba565
  [NEW] +57.8Ki  [NEW] +57.6Ki    agent_data_plane::cli::run::handle_run_command::_{{closure}}::hf85552faa28dc230
  [NEW] +49.5Ki  [NEW] +49.4Ki    saluki_app::bootstrap::AppBootstrapper::bootstrap::_{{closure}}::hf7945539f2e082c3
  [NEW] +47.5Ki  [NEW] +47.3Ki    moka::sync::base_cache::Inner<K,V,S>::do_run_pending_tasks::h3d28faf021a45e28
  [NEW] +46.4Ki  [NEW] +46.3Ki    h2::proto::connection::Connection<T,P,B>::poll::hf6f3caab9d5e2ca4
  [NEW] +46.0Ki  [NEW] +45.8Ki    _<saluki_components::destinations::prometheus::Prometheus as saluki_core::components::destinations::Destination>::run::_{{closure}}::h68ed13bab47c1030
  [NEW] +45.7Ki  [NEW] +45.5Ki    _<saluki_components::forwarders::otlp::OtlpForwarder as saluki_core::components::forwarders::Forwarder>::run::_{{closure}}::h8d4dd2e684a12115
  [DEL] -46.0Ki  [DEL] -45.8Ki    _<saluki_components::destinations::prometheus::Prometheus as saluki_core::components::destinations::Destination>::run::_{{closure}}::hea5618e9afd08b63
  [DEL] -46.1Ki  [DEL] -45.9Ki    _<saluki_components::forwarders::otlp::OtlpForwarder as saluki_core::components::forwarders::Forwarder>::run::_{{closure}}::hb0c627893c271e2c
  [DEL] -46.4Ki  [DEL] -46.3Ki    h2::proto::connection::Connection<T,P,B>::poll::h100071ec98c95c21
  [DEL] -47.5Ki  [DEL] -47.3Ki    moka::sync::base_cache::Inner<K,V,S>::do_run_pending_tasks::hfd5cba4fa7f4623d
  [DEL] -49.5Ki  [DEL] -49.4Ki    saluki_app::bootstrap::AppBootstrapper::bootstrap::_{{closure}}::h15f926ef5659e580
  [DEL] -57.8Ki  [DEL] -57.7Ki    agent_data_plane::cli::run::handle_run_command::_{{closure}}::hebabd4c0d26708e2
  [DEL] -64.2Ki  [DEL] -64.0Ki    saluki_components::common::datadog::io::run_endpoint_io_loop::_{{closure}}::h1c7964dcd8ecbead
  [DEL] -84.6Ki  [DEL] -84.5Ki    agent_data_plane::internal::control_plane::spawn_control_plane::_{{closure}}::h78c38079d35f4f77
  [DEL]  -114Ki  [DEL]  -114Ki    agent_data_plane::cli::run::create_topology::_{{closure}}::h4a1b0b37b7e2d03e
  [DEL] -1.79Mi  [DEL] -1.79Mi    std::thread::local::LocalKey<T>::with::he517c09e5477efe1
  +0.6%  +160Ki  +0.6%  +138Ki    TOTAL

[pr-commenter]

Regression Detector (Agent Data Plane)

Regression Detector Results

Run ID: aa6bf323-7cb3-429c-97b3-5b385bda7173

Baseline: bb1575e
Comparison: a9f5109
Diff

Optimization Goals: ✅ Improvement(s) detected

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
✅	otlp_ingest_metrics_5mb_memory	memory utilization	-6.54	[-6.75, -6.33]	1	(metrics) (profiles) (logs)

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	otlp_ingest_logs_5mb_memory	memory utilization	+4.51	[+4.12, +4.91]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_throughput	ingress throughput	-0.00	[-0.13, +0.13]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_cpu	% cpu utilization	-0.46	[-5.66, +4.74]	1	(metrics) (profiles) (logs)

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	dsd_uds_512kb_3k_contexts_cpu	% cpu utilization	+7.70	[-50.11, +65.52]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_memory	memory utilization	+4.51	[+4.12, +4.91]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_cpu	% cpu utilization	+2.74	[-2.38, +7.86]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_5mb_cpu	% cpu utilization	+1.65	[-0.67, +3.98]	1	(metrics) (profiles) (logs)
➖	dsd_uds_1mb_3k_contexts_memory	memory utilization	+1.16	[+0.98, +1.34]	1	(metrics) (profiles) (logs)
➖	dsd_uds_500mb_3k_contexts_memory	memory utilization	+1.04	[+0.88, +1.21]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_ottl_5mb_memory	memory utilization	+1.03	[+0.69, +1.37]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_memory	memory utilization	+0.97	[+0.78, +1.17]	1	(metrics) (profiles) (logs)
➖	dsd_uds_512kb_3k_contexts_memory	memory utilization	+0.93	[+0.76, +1.10]	1	(metrics) (profiles) (logs)
➖	dsd_uds_1mb_3k_contexts_cpu	% cpu utilization	+0.92	[-51.73, +53.58]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_idle	memory utilization	+0.87	[+0.85, +0.90]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_low	memory utilization	+0.67	[+0.48, +0.86]	1	(metrics) (profiles) (logs)
➖	dsd_uds_10mb_3k_contexts_memory	memory utilization	+0.65	[+0.47, +0.84]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_medium	memory utilization	+0.62	[+0.41, +0.82]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_heavy	memory utilization	+0.19	[+0.05, +0.33]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_ultraheavy	memory utilization	+0.03	[-0.10, +0.15]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_throughput	ingress throughput	+0.01	[-0.05, +0.07]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_ottl_5mb_throughput	ingress throughput	+0.00	[-0.02, +0.02]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_5mb_throughput	ingress throughput	-0.00	[-0.02, +0.02]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_throughput	ingress throughput	-0.00	[-0.13, +0.13]	1	(metrics) (profiles) (logs)
➖	dsd_uds_1mb_3k_contexts_throughput	ingress throughput	-0.00	[-0.06, +0.06]	1	(metrics) (profiles) (logs)
➖	dsd_uds_512kb_3k_contexts_throughput	ingress throughput	-0.00	[-0.06, +0.05]	1	(metrics) (profiles) (logs)
➖	dsd_uds_10mb_3k_contexts_throughput	ingress throughput	-0.00	[-0.12, +0.11]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_metrics_5mb_throughput	ingress throughput	-0.01	[-0.14, +0.12]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_5mb_memory	memory utilization	-0.30	[-0.56, -0.04]	1	(metrics) (profiles) (logs)
➖	dsd_uds_500mb_3k_contexts_cpu	% cpu utilization	-0.44	[-1.89, +1.01]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_logs_5mb_cpu	% cpu utilization	-0.46	[-5.66, +4.74]	1	(metrics) (profiles) (logs)
➖	dsd_uds_500mb_3k_contexts_throughput	ingress throughput	-2.11	[-2.22, -1.99]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_traces_ottl_5mb_cpu	% cpu utilization	-2.35	[-4.90, +0.20]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_metrics_5mb_cpu	% cpu utilization	-2.38	[-10.23, +5.47]	1	(metrics) (profiles) (logs)
➖	dsd_uds_10mb_3k_contexts_cpu	% cpu utilization	-3.09	[-31.96, +25.78]	1	(metrics) (profiles) (logs)
✅	otlp_ingest_metrics_5mb_memory	memory utilization	-6.54	[-6.75, -6.33]	1	(metrics) (profiles) (logs)

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	quality_gates_rss_dsd_heavy	memory_usage	10/10	111.45MiB ≤ 140MiB	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_low	memory_usage	10/10	33.80MiB ≤ 50MiB	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_medium	memory_usage	10/10	53.11MiB ≤ 75MiB	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_ultraheavy	memory_usage	10/10	161.88MiB ≤ 200MiB	(metrics) (profiles) (logs)
✅	quality_gates_rss_idle	memory_usage	10/10	21.30MiB ≤ 40MiB	(metrics) (profiles) (logs)

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

[tobz]

This is temporarily blocked on there being a version of the Datadog Agent for us to test against in correctness tests that has up-to-date v3 metrics support.

Currently, we're hitting an issue related to rate intervals being delta encoded when they shouldn't be. That bug is fixed in DataDog/datadog-agent#45825 but won't be released until 7.77: roughly 2 weeks from now before an RC is available to use. We can potentially do a hacky image build or something for keep going in the meantime and then switch back to a proper Agent version once available, we'll see.

[tobz]

We've temporarily handled the issue of correctness tests by using a "dev" container image (datadoghq/agent-dev) based on the latest fix for V3 support in the Datadog Agent. With this in place, we're now currently passing for both dsd-plain (V2 payloads) and dsd-plain-v3 (new, V3 payloads only).

We can't merge this as-is: we need to wait for at least an RC build of Datadog Agent 7.77 so we can pin to a non-development image. In the meantime, I'm going to work on making sure we've integrated all of the same small fixes/changes that have been steadily being made upstream in the Datadog Agent repository for V3 support.