Estimating the size of list when its possible to reduce memory usage and improve performance

Author: SoulKyu

pkg/k8s/parse_annotations.go

@@ -52,7 +52,8 @@ func NewService(cfg config.Config, pod *corev1.Pod) *ParserService {
 }
 
 func (s *ParserService) GetPodDbConfig() (*podDbConfig, error) {
-	var dbConfigurations []DbConfiguration
+	estimatedSize := len(s.pod.Annotations)
+	dbConfigurations := make([]DbConfiguration, 0, estimatedSize)
 	vaultDbPath, ok := s.pod.Annotations[ANNOTATION_VAULT_DB_PATH]
 	if !ok || vaultDbPath == "" {
 		vaultDbPath = s.cfg.DefaultEngine

pkg/k8s/pod_utils.go

@@ -55,7 +55,9 @@ func (p *podServiceImpl) GetAllPodAndNamespace(ctx context.Context) ([]PodInform
 		return nil, errors.Newf("no pods found in the cluster")
 	}
 
-	var podInfos []PodInformations
+	estimatedSize := len(pods.Items)
+	podInfos := make([]PodInformations, 0, estimatedSize)
+
 	for _, pod := range pods.Items {
 		if uuid, exists := pod.GetAnnotations()[ANNOTATION_VAULT_POD_UUID]; exists {
 			podInfos = append(podInfos, PodInformations{

pkg/k8smutator/k8smutator.go

@@ -83,7 +83,7 @@ func generateUUID(logger log.Logger) string {
 
 func handlePodConfiguration(ctx context.Context, cfg *config.Config, dbConfs *[]k8s.DbConfiguration, logger log.Logger, vaultDbPath, tok string, pod *corev1.Pod) (*corev1.Pod, string, []string, error) {
 	if len(*dbConfs) > 0 {
-		var podUuids []string
+		podUuids := make([]string, 0, len(*dbConfs))
 		for _, dbConf := range *dbConfs {
 			// Configure vault connection using serviceAccount token
 			err := checkConfiguration(dbConf)