# OpenTelemetry Integration

## Module
Telemetry

## Status
IMPLEMENTED

## Description
OpenTelemetry-based telemetry infrastructure with configurable options and custom exporters including TTE percentile exporter.

## Implementation Details
- **StellaOpsTelemetryOptions**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/StellaOpsTelemetryOptions.cs` -- configurable OTEL options with `CollectorOptions` for endpoint, protocol, and component
- **TelemetryServiceCollectionExtensions**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryServiceCollectionExtensions.cs` -- DI registration for OTEL tracing, metrics, and logging
- **TelemetryApplicationBuilderExtensions**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryApplicationBuilderExtensions.cs` -- middleware pipeline integration
- **TelemetryServiceDescriptor**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetryServiceDescriptor.cs` -- service identity for telemetry tagging
- **TelemetrySignal**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TelemetrySignal.cs` -- signal types (traces, metrics, logs)
- **TtePercentileExporter**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/TtePercentileExporter.cs` -- custom OTEL exporter for TTE percentile metrics
- **GoldenSignalMetrics**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/GoldenSignalMetrics.cs` -- golden signal metrics (latency, traffic, errors, saturation)
- **GrpcContextInterceptors**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core/GrpcContextInterceptors.cs` -- gRPC telemetry interceptors
- **Tests**: `src/Telemetry/StellaOps.Telemetry.Core/StellaOps.Telemetry.Core.Tests/GoldenSignalMetricsTests.cs`
- **Source**: Feature matrix scan

## E2E Test Plan
- [ ] Verify OTEL traces are exported with correct service identity and span attributes
- [ ] Test OTEL metrics export includes golden signal metrics (latency, traffic, errors, saturation)
- [ ] Verify TTE percentile exporter publishes p50/p90/p99 buckets
- [ ] Test gRPC interceptors propagate trace context across service boundaries
- [ ] Verify collector endpoint configuration respects sealed mode restrictions