Add optional OpenTelemetry traces, metrics and OTLP logs

server/.env.example

@@ -38,6 +38,19 @@ KEYGEN_CONCURRENCY=2
 SESSION_COOKIE_SECURE=false
 #LOGGING_CONFIG=
 
+# --- OpenTelemetry (optional) ----------------------------------------------
+# The Docker image includes the 'otel' extra. Non-image installs need:
+#   uv sync --package kca-app --extra otel
+# Export targets are OTLP/HTTP; the /v1/traces, /v1/metrics and /v1/logs
+# paths are appended automatically.
+OTEL_ENABLED=false
+OTEL_SERVICE_NAME=kca
+#OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
+#OTEL_EXPORTER_OTLP_HEADERS=Authorization=Bearer token,X-Tenant=one
+OTEL_EXCLUDED_PATHS=/api/health
+#OTEL_METRIC_EXPORT_INTERVAL_MILLIS=60000
+#OTEL_METRICS_POLL_INTERVAL_SECONDS=15
+
 # --- CORS (optional) -------------------------------------------------------
 #CORS_ALLOW_ORIGINS=
 #CORS_ALLOW_ORIGIN_REGEX=