Use agent OTel metrics for OpenFeature evaluations

[sameerank]

What changed

This updates the OpenFeature feature flag evaluation metrics implementation to record through GlobalOpenTelemetry instead of constructing its own OpenTelemetry SDK meter provider and OTLP HTTP exporter.

It also removes the OpenTelemetry SDK/exporter dependencies from feature-flagging-api, refreshes the lockfile, and updates the README to document that evaluation metrics use the Datadog Java agent OpenTelemetry metrics pipeline with DD_METRICS_OTEL_ENABLED=true.

Why

The previous implementation required opentelemetry-sdk-metrics and opentelemetry-exporter-otlp on the application classpath and always created an OTLP HTTP exporter. That did not line up with customers already using the Datadog Java agent OTel metrics pipeline for custom metrics, especially when their Agent OTLP receiver is configured for gRPC only.

With this change, feature_flag.evaluations uses the same configured Java agent OTel metrics pipeline as other custom OTel metrics.

Validation

• ./gradlew :products:feature-flagging:feature-flagging-api:dependencies --write-locks
• ./gradlew :products:feature-flagging:feature-flagging-api:test
• git diff --check
• git diff --cached --check

Noted local blockers/noisy checks:

• ./gradlew :products:feature-flagging:feature-flagging-api:spotlessCheck is currently blocked by :spotlessInternalRegisterDependencies failing to provision P2 dependencies.
• ./gradlew :dd-java-agent:instrumentation:opentelemetry:opentelemetry-1.47:test fails before tests in unrelated :dd-java-agent:agent-jmxfetch:compileJava; the local otel-bootstrap shadow artifact is missing datadog.trace.bootstrap.otel.api.common.AttributeKey and Attributes.

[dd-octo-sts]

🟡 Java Benchmark SLOs — Performance SLO warning (near threshold)

Suite	Status
Startup	🟡 warning

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	13.98 s	14.00 s	[-0.9%; +0.6%] (no difference)
startup:insecure-bank:tracing:Agent	12.94 s	13.05 s	[-1.6%; -0.0%] (maybe better)
startup:petclinic:appsec:Agent	17.39 s	17.20 s	[+0.1%; +2.1%] (maybe worse)
startup:petclinic:iast:Agent	17.32 s	17.58 s	[-2.2%; -0.6%] (maybe better)
startup:petclinic:profiling:Agent	17.52 s	17.47 s	[-0.6%; +1.2%] (no difference)
startup:petclinic:sca:Agent	17.45 s	17.29 s	[+0.1%; +1.7%] (maybe worse)
startup:petclinic:tracing:Agent	16.46 s	16.19 s	[-3.0%; +6.2%] (no difference)

Commit: 051539dc · CI Pipeline · Benchmarking Platform UI

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Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.