feat(agent-data-plane): add per-metric tag value filtering

[lukesteensen]

Summary

Note

This is an experimental proposal. In addition to implementation feedback, we are looking for
feedback on whether the configuration schema presents tag-value aggregation coherently.

Add per-metric tag-value filtering to metric_tag_filterlist before aggregation.

• Allow configured tag values and remove or replace mismatches with a sentinel.
• Require complete tag values to match a regular expression and replace non-matches.
• Reject invalid or conflicting rules at startup; retain the last valid rules after invalid runtime updates.
• Document current behavior and configuration-schema trade-offs.

Change Type

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

How did you test this PR?

• Ran all 51 tag-filterlist unit tests, including new coverage for allowlists, regular expressions, conflicts, origin tags, and dynamic updates.
• Ran all 17 configuration-system tests.
• Ran cargo check --workspace.
• Ran cargo check --workspace --tests.
• Ran workspace Clippy with warnings denied.
• Ran formatting and git diff --check.

References

N/A

[datadog-datadog-prod-us1-2]

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⚠️ Warnings

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[pr-commenter]

Binary Size Analysis (Agent Data Plane)

Baseline: 5e5efc9 · Comparison: 5ee7dad · diff
Analysis Configuration: stripped binaries · Pass/Fail Threshold: +5%
Sizes: 41.60 MiB (baseline) vs 41.75 MiB (comparison)
Size Change: +160.83 KiB (+0.38%)

✅ Binary size difference within threshold

Changes by Module

Module	File Size	Symbols
agent_data_plane::components::tag_filterlist	+38.75 KiB	54
core	+36.10 KiB	4117
figment	+27.83 KiB	134
hashbrown	+26.55 KiB	336
datadog_agent_commons::ipc::client	-19.71 KiB	5
http_body_util	-17.93 KiB	78
tonic	+17.77 KiB	230
anon.7982b035c2501c8c015ba477222e7e44.7.llvm.16557284064573298568	-17.53 KiB	1
anon.1ef370b01afc3c06002d6efb66f80e95.853.llvm.4556770598221099425	+17.53 KiB	1
backon	+16.62 KiB	2
alloc	+10.89 KiB	608
tracing	-10.08 KiB	13
saluki_common::resource_tracking::groups	+9.09 KiB	13
axum	+7.23 KiB	120
h2	+6.66 KiB	224
serde_json	+6.59 KiB	127
anyhow	+5.76 KiB	479
http	+5.61 KiB	103
agent_data_plane::components::ottl_transform_processor	-5.61 KiB	38
std	-5.06 KiB	82

Detailed Symbol Changes

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +2.1%  +159Ki  +2.8%  +158Ki    [12859 Others]
  [NEW] +44.5Ki  [NEW] +44.4Ki    agent_data_plane::cli::run::handle_run_command::_{{closure}}::h3f138673993c17a5
  [NEW] +29.9Ki  [NEW] +29.8Ki    agent_data_plane::cli::dogstatsd::handle_dogstatsd_command::_{{closure}}::ha6527156150104f8
  [NEW] +28.2Ki  [NEW] +28.0Ki    agent_data_plane::cli::run::create_topology::_{{closure}}::h75fc88cc95fe3068
  [NEW] +25.1Ki  [NEW] +24.9Ki    _<agent_data_plane::components::host_tags::HostTagsConfiguration as saluki_core::components::transforms::builder::SynchronousTransformBuilder>::build::_{{closure}}::h7dfd0f97fba7a60c
  [NEW] +25.0Ki  [NEW] +24.8Ki    agent_data_plane::internal::remote_agent::run_remote_agent_registration_loop::_{{closure}}::h4de6434850c2e827
  [NEW] +21.4Ki  [NEW] +21.2Ki    agent_data_plane::internal::env::ADPEnvironmentProvider::from_configuration::_{{closure}}::hc6140f422cee1eaa
  [NEW] +21.1Ki  [NEW] +21.0Ki    agent_data_plane::cli::debug::handle_debug_command::_{{closure}}::hb91c7e121632577d
  [NEW] +19.1Ki  [NEW] +19.0Ki    agent_data_plane::internal::env::workload::build_collector::_{{closure}}::h2ff3dd93fec26967
  [NEW] +18.3Ki  [NEW] +18.2Ki    _<backon::retry::Retry<B,T,E,Fut,FutureFn,SF$C&C$NF,AF> as core::future::future::Future>::poll::h329866718dea74d0
  [NEW] +17.5Ki  [NEW]     +76    anon.1ef370b01afc3c06002d6efb66f80e95.853.llvm.4556770598221099425
  [DEL] -17.5Ki  [DEL]     -76    anon.7982b035c2501c8c015ba477222e7e44.7.llvm.16557284064573298568
  [DEL] -19.6Ki  [DEL] -19.3Ki    datadog_agent_commons::ipc::client::RemoteAgentClient::from_client_configuration::_{{closure}}::_{{closure}}::_{{closure}}::h18654b85723a9839
  [DEL] -19.7Ki  [DEL] -19.6Ki    agent_data_plane::internal::env::workload::build_collector::_{{closure}}::h68611de26ec2eb21
  [DEL] -20.6Ki  [DEL] -20.5Ki    agent_data_plane::cli::debug::handle_debug_command::_{{closure}}::he56831c79dc35528
  [DEL] -21.5Ki  [DEL] -21.4Ki    agent_data_plane::internal::env::ADPEnvironmentProvider::from_configuration::_{{closure}}::h898bbdbcf376c435
  [DEL] -23.4Ki  [DEL] -23.2Ki    _<agent_data_plane::components::host_tags::HostTagsConfiguration as saluki_core::components::transforms::builder::SynchronousTransformBuilder>::build::_{{closure}}::hd971eda288ba5bd9
  [DEL] -25.0Ki  [DEL] -24.8Ki    agent_data_plane::internal::remote_agent::run_remote_agent_registration_loop::_{{closure}}::h1d86af97b2fd3319
  [DEL] -28.1Ki  [DEL] -27.9Ki    agent_data_plane::cli::run::create_topology::_{{closure}}::hc7701488cdaf9708
  [DEL] -30.1Ki  [DEL] -29.9Ki    agent_data_plane::cli::dogstatsd::handle_dogstatsd_command::_{{closure}}::hd837c28d99cadabd
  [DEL] -43.9Ki  [DEL] -43.8Ki    agent_data_plane::cli::run::handle_run_command::_{{closure}}::h940827480ed79a43
  +0.4%  +160Ki  +0.5%  +159Ki    TOTAL

[pr-commenter]

Regression Detector (Agent Data Plane)

Run ID: b6e98b35-906d-4cd0-956d-0e5b0cf3062c
Baseline: 5e5efc94 · Comparison: 5ee7dad2 · diff

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment (5)

Experiments configured erratic: true are tagged (ignored) and skipped when determining which experiments regressed or improved. Experiments which are detected as erratic at runtime are tagged (erratic) to flag that the run's sample dispersion was high, but their regression / improvement signal still counts.

experiment	goal	Δ mean %	links
quality_gates_rss_idle	memory	⚪ +0.86	metrics profiles logs
quality_gates_rss_dsd_low	memory	⚪ +0.46	metrics profiles logs
quality_gates_rss_dsd_medium	memory	⚪ +0.45	metrics profiles logs
quality_gates_rss_dsd_heavy	memory	⚪ +0.21	metrics profiles logs
quality_gates_rss_dsd_ultraheavy	memory	⚪ +0.18	metrics profiles logs

Bounds Checks: ✅ Passed (5)

experiment	check	replicates	observed	links
quality_gates_rss_dsd_heavy	memory_usage	10/10	✅ 137 MiB ≤ 140 MiB	metrics profiles logs
quality_gates_rss_dsd_low	memory_usage	10/10	✅ 43.1 MiB ≤ 50 MiB	metrics profiles logs
quality_gates_rss_dsd_medium	memory_usage	10/10	✅ 65.2 MiB ≤ 75 MiB	metrics profiles logs
quality_gates_rss_dsd_ultraheavy	memory_usage	10/10	✅ 191 MiB ≤ 200 MiB	metrics profiles logs
quality_gates_rss_idle	memory_usage	10/10	✅ 29.2 MiB ≤ 40 MiB	metrics profiles logs

Explanation

A change is flagged as a regression when |Δ mean %| > 5.00% in the regressing direction for its optimization goal AND SMP marks the experiment as a regression (is_regression: true). Improvements use the matching criteria for the improving direction. Experiments configured erratic: true (tagged (ignored)) are skipped outright; experiments detected as erratic at runtime (tagged (erratic)) still count, since that flag describes sample dispersion rather than directional certainty. The Δ mean % cell is colored accordingly: 🟢 = improvement, 🔴 = regression, ⚪ = neutral. Reduction in CPU or memory is an improvement; reduction in ingress throughput is a regression.