app: added helm tgz handle

app/storage/helmmeta.go

@@ -0,0 +1,28 @@
+package storage
+
+import (
+	"encoding/json"
+
+	"helm.sh/helm/v4/pkg/chart/v2/loader"
+	"helm.sh/helm/v4/pkg/provenance"
+)
+
+func (store *Storage) HelmMeta(filename string) (string, string, error) {
+	var err error
+	var meta string
+	var hash string
+	chart, err := loader.Load(filename)
+	if err != nil {
+		return meta, hash, err
+	}
+	hash, err = provenance.DigestFile(filename)
+	if err != nil {
+		return meta, hash, err
+	}
+	metadata, err := json.Marshal(chart.Metadata)
+	if err != nil {
+		return meta, hash, err
+	}
+	meta = string(metadata)
+	return meta, hash, err
+}