[AGTMETRICS-439] enhancement(components): add otlp decoder

[rayz]

Summary

This PR creates the OTLP Decoder.
The topology is updated using the new named outputs for the Relay such that metrics and logs will be proxied while traces will go to the OTLP Decoder.
When data_plane.otlp.proxy.traces.enabled is true, traces will be proxied to the trace agent on port 5003

data_plane:
  enabled: true
  otlp:
    enabled: true
    proxy:
      enabled: true
      receiver:
        protocols:
          grpc:
            endpoint: 127.0.0.1:4319
          http:
            endpoint: 127.0.0.1:4320
      traces: 
        enabled: false 
      metrics:
        enabled: true
      logs:
        enabled: true
      

Change Type

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

How did you test this PR?

Run ADP and enable OTLP + proxy:

data_plane:
  enabled: true
  otlp:
    enabled: true
    proxy:
      enabled: true
      receiver:
        protocols:
          grpc:
            endpoint: 127.0.0.1:4319
          http:
            endpoint: 127.0.0.1:4320
      traces: 
        enabled: false 
      metrics:
        enabled: true
      logs:
        enabled: true

Send OTLP traces,metrics,logs and see that they show up in datadog.

References

[pr-commenter]

Binary Size Analysis (Agent Data Plane)

Target: 527d3bc (baseline) vs fced3af (comparison) diff
Baseline Size: 335.80 MiB
Comparison Size: 335.53 MiB
Size Change: -279.12 KiB (-0.08%)
Pass/Fail Threshold: +5%
Result: PASSED ✅

Changes by Module

Module	File Size	Symbols
[debug sections]	-412.44 KiB	7
saluki_components::sources::otlp	-81.32 KiB	104
saluki_components::common::otlp	+80.01 KiB	47
figment	-68.65 KiB	214
saluki_components::forwarders::otlp	+60.86 KiB	33
core	+58.96 KiB	2072
saluki_components::common::datadog	+26.56 KiB	65
saluki_components::forwarders::trace_agent	-25.98 KiB	19
tonic	+21.33 KiB	184
saluki_components::decoders::otlp	+19.78 KiB	29
[sections]	+18.32 KiB	8
tower	-18.13 KiB	144
otlp_protos::otlp_include::opentelemetry	+14.42 KiB	72
tokio_rustls	-11.92 KiB	21
saluki_core::topology::blueprint	+11.68 KiB	45
alloc	+11.37 KiB	413
saluki_core::topology::built	+11.11 KiB	8
serde_core	-10.31 KiB	149
rustls	+10.29 KiB	138
tracing	+9.27 KiB	34

Detailed Symbol Changes

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.5%  +561Ki  [ = ]       0    [section .debug_info]
  +0.8%  +433Ki  [ = ]       0    [section .debug_str]
  +0.6% +91.0Ki  +0.1% +8.76Ki    [11316 Others]
  +0.4% +80.4Ki  [ = ]       0    [section .debug_line]
  [NEW] +62.4Ki  [NEW] +62.3Ki    saluki_core::topology::built::BuiltTopology::spawn::_{{closure}}::h6226374d3a914d2e
  [NEW] +56.0Ki  [NEW] +55.8Ki    saluki_core::topology::blueprint::TopologyBlueprint::build::_{{closure}}::h1e11447a9f0e4c77
  [NEW] +42.3Ki  [NEW] +42.1Ki    _<saluki_components::forwarders::otlp::OtlpForwarder as saluki_core::components::forwarders::Forwarder>::run::_{{closure}}::heda753b23547934e
  [NEW] +23.2Ki  [NEW] +23.1Ki    saluki_components::common::otlp::traces::transform::otel_span_to_dd_span::h8409fb08f6b02279
  [NEW] +22.7Ki  [NEW] +22.3Ki    core::ptr::drop_in_place<saluki_core::topology::blueprint::TopologyBlueprint::build::{{closure}}>::h34f547007d636b49
  [NEW] +22.6Ki  [NEW] +22.4Ki    saluki_components::common::otlp::traces::transform::otel_to_dd_span_minimal::h2171ce35fbb154fb
  [NEW] +19.7Ki  [NEW] +19.5Ki    saluki_core::topology::built::ComponentInterconnects::generate_interconnects::hea89e782bf400097
  [NEW] +16.6Ki  [NEW] +16.4Ki    saluki_components::common::datadog::config::_::_<impl serde_core::de::Deserialize for saluki_components::common::datadog::config::ForwarderConfiguration>::deserialize::h19ce16b63265cfbe
  [DEL] -18.0Ki  [DEL] -17.9Ki    h2::proto::connection::DynConnection<B>::recv_frame::hf2de6f451eaeba62
  [DEL] -18.1Ki  [DEL] -18.0Ki    figment::figment::Figment::extract::hef8645c13a353b1a
  [DEL] -19.0Ki  [DEL] -18.8Ki    saluki_core::topology::built::ComponentInterconnects::generate_interconnects::h1075f63ee5e3f67a
  [DEL] -19.9Ki  [DEL] -19.5Ki    core::ptr::drop_in_place<saluki_core::topology::blueprint::TopologyBlueprint::build::{{closure}}>::h571b4194cbb565f4
  [DEL] -43.9Ki  [DEL] -43.8Ki    saluki_components::sources::otlp::traces::transform::otel_span_to_dd_span::hea28c83999c155e7
  [DEL] -48.7Ki  [DEL] -48.5Ki    saluki_core::topology::blueprint::TopologyBlueprint::build::_{{closure}}::h6a07695e8e502baf
  [DEL] -54.1Ki  [DEL] -53.9Ki    saluki_core::topology::built::BuiltTopology::spawn::_{{closure}}::ha20fdc76361339f8
  -1.7%  -391Ki  [ = ]       0    [section .debug_ranges]
  -1.1% -1.07Mi  [ = ]       0    [section .debug_loc]
  -0.1%  -279Ki  +0.2% +52.4Ki    TOTAL

[pr-commenter]

Regression Detector (Agent Data Plane)

Regression Detector Results

Run ID: 2d707aad-1b55-4187-9ef9-a08360fc99f5

Baseline: 527d3bc
Comparison: fced3af
Diff

❌ Experiments with retried target crashes

This is a critical error. One or more replicates failed with a non-zero exit code. These replicates may have been retried. See Replicate Execution Details for more information.

• otlp_ingest_metrics_adp
• quality_gates_rss_dsd_ultraheavy
• quality_gates_rss_dsd_heavy

Optimization Goals: ✅ No significant changes detected

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	otlp_ingest_logs_adp	memory utilization	+4.75	[+4.21, +5.28]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_idle	memory utilization	+1.01	[+0.97, +1.04]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_low	memory utilization	+0.62	[+0.47, +0.76]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_medium	memory utilization	+0.27	[+0.09, +0.45]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_heavy	memory utilization	+0.17	[+0.03, +0.30]	1	(metrics) (profiles) (logs)
➖	quality_gates_rss_dsd_ultraheavy	ingress throughput	+0.00	[-0.05, +0.06]	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	-0.01	[-0.17, +0.16]	1	(metrics) (profiles) (logs)
➖	dsd_uds_100mb_3k_contexts_throughput	ingress throughput	-0.02	[-0.05, +0.02]	1	(metrics) (profiles) (logs)
➖	otlp_ingest_metrics_adp	memory utilization	-0.67	[-0.89, -0.44]	1
➖	dsd_uds_500mb_3k_contexts_throughput	ingress throughput	-1.94	[-2.08, -1.81]	1	(metrics) (profiles) (logs)

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	links
✅	quality_gates_rss_dsd_heavy	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_low	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_medium	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_dsd_ultraheavy	memory_usage	10/10	(metrics) (profiles) (logs)
✅	quality_gates_rss_idle	memory_usage	10/10	(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".

Replicate Execution Details

We run multiple replicates for each experiment/variant. However, we allow replicates to be automatically retried if there are any failures, up to 8 times, at which point the replicate is marked dead and we are unable to run analysis for the entire experiment. We call each of these attempts at running replicates a replicate execution. This section lists all replicate executions that failed due to the target crashing or being oom killed.

Note: In the below tables we bucket failures by experiment, variant, and failure type. For each of these buckets we list out the replicate indexes that failed with an annotation signifying how many times said replicate failed with the given failure mode. In the below example the baseline variant of the experiment named experiment_with_failures had two replicates that failed by oom kills. Replicate 0, which failed 8 executions, and replicate 1 which failed 6 executions, all with the same failure mode.

Experiment	Variant	Replicates	Failure	Logs	Debug Dashboard
experiment_with_failures	baseline	0 (x8) 1 (x6)	Oom killed		Debug Dashboard

The debug dashboard links will take you to a debugging dashboard specifically designed to investigate replicate execution failures.

❌ Retried Normal Replicate Execution Failures (non-profiling)

Experiment	Variant	Replicates	Failure	Debug Dashboard
otlp_ingest_metrics_adp	baseline	2 (x2)	Failed to shutdown when requested	Debug Dashboard
quality_gates_rss_dsd_heavy	comparison	4	Failed to shutdown when requested	Debug Dashboard
quality_gates_rss_dsd_ultraheavy	comparison	2	Failed to shutdown when requested	Debug Dashboard

❌ Retried Profiling Replicate Execution Failures (target internal profiling)

Note: Profiling replicas may still be executing. See the debug dashboard for up to date status.

Experiment	Variant	Replicates	Failure	Debug Dashboard
quality_gates_rss_dsd_heavy	baseline	10	Failed to shutdown when requested	Debug Dashboard

[tobz]

Just a note/reminder that we'll want to follow this up with a PR to make forwarding conditional: we can already handle all signals natively (with caveats, obviously) so we want the logic to be something like...

let metrics_enabled = dp_config.otlp().metrics().enabled()
let logs_enabled = dp_config.otlp().logs().enabled()
let traces_enabled = dp_config.otlp().traces().enabled()
let any_signals_enabled = metrics_enabled || logs_enabled || traces_enabled

if any_signals_enabled:
    topology.add_relay("otlp_relay_in", otlp_relay_config)
    topology.add_decoder("otlp_decode", otlp_relay_config)

    if metrics_enabled:
        topology.connect("otlp_decode", ["otlp_relay_in.metrics"])
        topology.connect("dd_metrics_encode", ["otlp_decode.metrics"])
    else:
        topology.connect("dd_out", ["otlp_relay_in.metrics"])

    // logs and traces

[tobz]

Looking close overall, just some small feedback to polish things.

[tobz]

One small thing remaining.

[rayz]

Sry, made another change and need anotha review. The gRPC proxying was broken. Deleted my changes in the datadog forwarder and renamed TraceAgent forwarder to just be an OtlpForwarder