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OpenTelemetry — Traces and Correlation

What and where

  • Code: ms_bff_spike/ms_bff/src/observability/telemetry.py (primary) and ms_bff_spike/ms_bff/src/observability.py (compat path) configure OpenTelemetry exporters and auto‑instrumentation for FastAPI, httpx, and Redis.
  • Collector: defined in CRUDService/docker-compose-authzen4.yml as otel-collector exposing OTLP gRPC 4317 and OTLP HTTP 4318. Vector can forward traces to Jaeger.

How it’s configured

  • Enablement: TELEMETRY_ENABLED=true (default) turns tracing/metrics on in the BFF when OTEL libs are present.
  • Exporter endpoint (BFF picks the first that is set):
    • OTLP_ENDPOINT (preferred in telemetry.py, e.g., http://otel-collector:4317)
    • OTEL_EXPORTER_OTLP_ENDPOINT (alternate, supported by observability.py)
  • Resource attributes: service.name=bff-auth-service, plus service.version from BFF_VERSION and deployment.environment from ENVIRONMENT (see ../reference/settings-reference.md#core-runtime).

Minimal setup (compose)

# CRUDService/docker-compose-authzen4.yml (excerpt)
otel-collector:
  image: otel/opentelemetry-collector-contrib:0.96.0
  ports: ["4317:4317", "4318:4318"]
  volumes:
    - ./otel-collector-config.yaml:/etc/otelcol/config.yaml:ro

# BFF service (env excerpt)
environment:
  - TELEMETRY_ENABLED=true
  - OTLP_ENDPOINT=http://otel-collector:4317
  - BFF_VERSION=1.0.0
  - ENVIRONMENT=development

What gets instrumented

  • FastAPI requests (/auth/*, /api/*), httpx client calls (IdP, PDP, backends), and Redis calls create spans automatically.
  • Manual spans and metrics are available via helpers: start_span, record_forwardauth_metrics, record_session_metrics.

Flow

How to verify

  • Start the stack with the collector; set OTLP_ENDPOINT in the BFF env.
  • Hit /auth/login then any /api/** route; you should see spans in Jaeger.
  • Check logs for connection messages from telemetry setup.

References

  • Reference → Observability (Metrics, Tracing, Health)
  • Reference → Core runtime settings: ../reference/settings-reference.md#core-runtime
  • Code: ms_bff_spike/ms_bff/src/observability/telemetry.py, ms_bff_spike/ms_bff/src/observability.py