refactor(backend): local Kafka errors logged on warning level

internal/ingest/kafkaingest/collector.go

@@ -152,7 +152,19 @@ func KafkaProducerGroup(ctx context.Context, producer *kafka.Producer, logger *s
 						// as the underlying client will automatically try to
 						// recover from any errors encountered, the application
 						// does not need to take action on them.
-						logger.Error("kafka error", "error", ev)
+						attrs := []any{
+							slog.Int("code", int(ev.Code())),
+							slog.String("error", ev.Error()),
+						}
+
+						// Log Kafka client "local" errors on warning level as those are mostly informational and the client is
+						// able to handle/recover from them automatically.
+						// See: https://github.com/confluentinc/librdkafka/blob/master/src/rdkafka.h#L415
+						if ev.Code() <= -100 {
+							logger.Warn("kafka local error", attrs...)
+						} else {
+							logger.Error("kafka broker error", attrs...)
+						}
 					}
 				case <-ctx.Done():
 					return ctx.Err()