✨ Enhance observability and error handling in NATS integration. Introduce comprehensive OpenTelemetry support with environment-based sampling and semantic attributes for tracing and metrics. Implement an advisory dead-letter queue (DLQ) handler for managing message delivery failures. Update NATS consumer to utilize structured logging and improve error handling strategies. Refactor configuration files for OpenTelemetry collector in both development and production environments, ensuring robust telemetry integration. Enhance documentation to reflect new features and best practices for observability.

internal/infra/nats/error_handler.go

@@ -47,9 +47,7 @@ func (h *ErrorHandler) HandleFetchError(
 	if errors.Is(err, nats.ErrNoResponders) {
 		*fetchErrorStreak++
 		backoff := time.Duration(*fetchErrorStreak) * time.Second
-		if backoff > 30*time.Second {
-			backoff = 30 * time.Second
-		}
+		backoff = min(backoff, 30*time.Second)
 		h.logger.Warn("JetStream not available, will retry with backoff",
 			zap.Error(err),
 			zap.String("stream", streamName),
@@ -91,9 +89,7 @@ func (h *ErrorHandler) HandleFetchError(
 	// Generic error path with modest backoff.
 	*fetchErrorStreak++
 	backoff := time.Duration(*fetchErrorStreak) * time.Second
-	if backoff > 10*time.Second {
-		backoff = 10 * time.Second
-	}
+	backoff = min(backoff, 10*time.Second)
 	h.logger.Error("Failed to fetch messages; backing off",
 		zap.Error(err),
 		zap.Duration("backoff", backoff),
@@ -133,9 +129,7 @@ func (h *ErrorHandler) HandleProcessingError(
 	if consecutiveErrors >= 10 {
 		result.ShouldApplyBackpressure = true
 		result.BackpressureDelay = time.Duration(consecutiveErrors) * 100 * time.Millisecond
-		if result.BackpressureDelay > 5*time.Second {
-			result.BackpressureDelay = 5 * time.Second
-		}
+		result.BackpressureDelay = min(result.BackpressureDelay, 5*time.Second)
 	}
 
 	return result