server: Address suggestions

server/embed/config.go

@@ -684,6 +684,13 @@ func (cfg *Config) Validate() error {
 		return fmt.Errorf("unknown auto-compaction-mode %q", cfg.AutoCompactionMode)
 	}
 
+	// Validate distributed tracing configuration but only if enabled.
+	if cfg.ExperimentalEnableDistributedTracing {
+		if err := validateTracingConfig(cfg.ExperimentalDistributedTracingSamplingRatePerMillion); err != nil {
+			return fmt.Errorf("distributed tracing configurition is not valid: (%v)", err)
+		}
+	}
+
 	return nil
 }
 

server/embed/config_tracing.go

@@ -30,27 +30,38 @@ import (
 
 const maxSamplingRatePerMillion = 1000000
 
-func (e *Etcd) setupTracingExporter(ctx context.Context) (exporter tracesdk.SpanExporter, options []otelgrpc.Option, err error) {
+func validateTracingConfig(samplingRate int) error {
+	if samplingRate < 0 {
+		return fmt.Errorf("tracing sampling rate must be positive")
+	}
+	if samplingRate > maxSamplingRatePerMillion {
+		return fmt.Errorf("tracing sampling rate must be less than %d", maxSamplingRatePerMillion)
+	}
+
+	return nil
+}
+
+func setupTracingExporter(ctx context.Context, cfg *Config) (exporter tracesdk.SpanExporter, options []otelgrpc.Option, err error) {
 	exporter, err = otlp.NewExporter(ctx,
 		otlpgrpc.NewDriver(
-			otlpgrpc.WithEndpoint(e.cfg.ExperimentalDistributedTracingAddress),
+			otlpgrpc.WithEndpoint(cfg.ExperimentalDistributedTracingAddress),
 			otlpgrpc.WithInsecure(),
 		))
 	if err != nil {
 		return nil, nil, err
 	}
 
 	res := resource.NewWithAttributes(
-		semconv.ServiceNameKey.String(e.cfg.ExperimentalDistributedTracingServiceName),
+		semconv.ServiceNameKey.String(cfg.ExperimentalDistributedTracingServiceName),
 	)
 
-	if resWithIDKey := determineResourceWithIDKey(e.cfg.ExperimentalDistributedTracingServiceInstanceID); resWithIDKey != nil {
+	if resWithIDKey := determineResourceWithIDKey(cfg.ExperimentalDistributedTracingServiceInstanceID); resWithIDKey != nil {
 		// Merge resources into a new
 		// resource in case of duplicates.
 		res = resource.Merge(res, resWithIDKey)
 	}
 
-	sampler, err := determineSampler(e.cfg.ExperimentalDistributedTracingSamplingRatePerMillion)
+	sampler, err := determineSampler(cfg.ExperimentalDistributedTracingSamplingRatePerMillion)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -71,12 +82,12 @@ func (e *Etcd) setupTracingExporter(ctx context.Context) (exporter tracesdk.Span
 		),
 	)
 
-	e.cfg.logger.Debug(
+	cfg.logger.Debug(
 		"distributed tracing enabled",
-		zap.String("address", e.cfg.ExperimentalDistributedTracingAddress),
-		zap.String("service-name", e.cfg.ExperimentalDistributedTracingServiceName),
-		zap.String("service-instance-id", e.cfg.ExperimentalDistributedTracingServiceInstanceID),
-		zap.Int("sampling-rate", e.cfg.ExperimentalDistributedTracingSamplingRatePerMillion),
+		zap.String("address", cfg.ExperimentalDistributedTracingAddress),
+		zap.String("service-name", cfg.ExperimentalDistributedTracingServiceName),
+		zap.String("service-instance-id", cfg.ExperimentalDistributedTracingServiceInstanceID),
+		zap.Int("sampling-rate", cfg.ExperimentalDistributedTracingSamplingRatePerMillion),
 	)
 
 	return exporter, options, err
@@ -87,12 +98,6 @@ func determineSampler(samplingRate int) (tracesdk.Sampler, error) {
 	if samplingRate == 0 {
 		return sampler, nil
 	}
-	if samplingRate < 0 {
-		return sampler, fmt.Errorf("tracing sampling rate must be positive")
-	}
-	if samplingRate > maxSamplingRatePerMillion {
-		return sampler, fmt.Errorf("tracing sampling rate must be less than %d", maxSamplingRatePerMillion)
-	}
 	return tracesdk.TraceIDRatioBased(float64(samplingRate) / float64(maxSamplingRatePerMillion)), nil
 }
 

server/embed/etcd.go

@@ -222,7 +222,7 @@ func StartEtcd(inCfg *Config) (e *Etcd, err error) {
 
 	if srvcfg.ExperimentalEnableDistributedTracing {
 		tctx := context.Background()
-		tracingExporter, opts, err := e.setupTracingExporter(tctx)
+		tracingExporter, opts, err := setupTracingExporter(tctx, cfg)
 		if err != nil {
 			return e, err
 		}