added fs encryption overlay

cmd/metadatagen/main.go

@@ -3,6 +3,7 @@
 package main
 
 import (
+	"encoding/hex"
 	"flag"
 	"fmt"
 	"os"
@@ -15,15 +16,26 @@ var (
 	version string
 
 	dst      string
+	dstkey   string
 	metadata string
 )
 
 func main() {
 	flag.StringVar(&dst, "dst", "", "url path to cache files (example: file:///mnt/cache)")
+	flag.StringVar(&dstkey, "dstkey", "", "hex encoded encryption key for dst")
 	flag.StringVar(&metadata, "data", "", "path to metadata file")
 	flag.Parse()
 
-	dstfs, err := parse.FS(dst)
+	var (
+		dstk []byte
+		err  error
+	)
+	if dstkey != "" {
+		dstk, err = hex.DecodeString(dstkey)
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	dstfs, err := parse.FS(dst, dstk)
 	if err != nil {
 		fmt.Println(err)
 		os.Exit(1)