Add flag evaluation metrics via OTel counter and OpenFeature Hook#11040
Draft
Add flag evaluation metrics via OTel counter and OpenFeature Hook#11040
Conversation
Record a `feature_flag.evaluations` OTel counter on every flag evaluation using an OpenFeature `finallyAfter` hook. The hook captures all evaluation paths including type mismatches that occur above the provider level. Attributes: feature_flag.key, feature_flag.result.variant, feature_flag.result.reason, error.type (on error), feature_flag.result.allocation_key (when present). Counter is a no-op when DD_METRICS_OTEL_ENABLED is false or opentelemetry-api is absent from the classpath.
Replace GlobalOpenTelemetry.getMeterProvider() with a dedicated SdkMeterProvider + OtlpHttpMetricExporter that sends metrics directly to the DD Agent's OTLP endpoint (default :4318/v1/metrics). This avoids the agent's OTel class shading issue where the agent relocates io.opentelemetry.api.* to datadog.trace.bootstrap.otel.api.*, making GlobalOpenTelemetry calls from the dd-openfeature jar hit the unshaded no-op provider instead of the agent's shim. Requires opentelemetry-sdk-metrics and opentelemetry-exporter-otlp on the application classpath. Falls back to no-op if absent. System tests: 11/17 pass. 6 failures are pre-existing DDEvaluator gaps (reason mapping, parse errors, type mismatch strictness).
- Add explicit null guard for details in FlagEvalHook.finallyAfter() - Add OTEL_EXPORTER_OTLP_ENDPOINT generic env var fallback with /v1/metrics path appended (per OTel spec fallback chain) - Add comments clarifying signal-specific vs generic endpoint behavior
typotter
added
type: feature request
tag: ai generated
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What Does This Do
Records a
feature_flag.evaluationsOTel counter metric on every flag evaluation via an OpenFeaturefinallyAfterhook. The hook captures all evaluation paths including type mismatches that occur above the provider level in the OpenFeature SDK pipeline.Creates a dedicated
SdkMeterProviderwith anOtlpHttpMetricExporterthat sends metrics directly to the DD Agent's OTLP endpoint (/v1/metrics). This avoids the agent's OTel class shading (io.opentelemetry.api.*→datadog.trace.bootstrap.otel.api.*) which prevents usingGlobalOpenTelemetryfrom the publisheddd-openfeaturejar.Metric attributes:
feature_flag.keyfeature_flag.result.variantfeature_flag.result.reasonerror.typefeature_flag.result.allocation_keyNew files:
FlagEvalMetrics.java,FlagEvalHook.java,FlagEvalMetricsTest.java,FlagEvalHookTest.javaModified files:
Provider.java(addsgetProviderHooks()),ProviderTest.java,build.gradle.ktsMotivation
Evaluation metrics allow tracking how many times flags are evaluated, with which results, across sessions. This is the Java implementation of the evaluation logging spec (FFL-1942), matching the existing Python (dd-trace-py#17029) and Go (dd-trace-go#4489) implementations.
System tests: 11/17 pass. The 6 remaining failures are pre-existing DDEvaluator gaps (reason mapping, parse error codes) addressed in separate PRs (#11036, #10971).
References:
Additional Notes
opentelemetry-sdk-metrics,opentelemetry-exporter-otlp) arecompileOnly— applications must include them on the classpath for metrics to flow. Falls back to silent no-op when absent.OTEL_EXPORTER_OTLP_METRICS_ENDPOINT→OTEL_EXPORTER_OTLP_ENDPOINT+/v1/metrics→http://localhost:4318/v1/metricsContributor Checklist
type:and (comp:orinst:) labelsclose,fix, or any linking keywords when referencing an issueJira ticket: FFL-1942