config.FileDef: add Content64 for base64-encoded content

config/config.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"encoding/base64"
 	"fmt"
 	"io"
 	"net"
@@ -136,6 +137,7 @@ type FileDef struct {
 	Path      string
 	Mode      os.FileMode
 	Content   string
+	Content64 string
 	Symlink   string
 	Dir       bool
 }
@@ -158,6 +160,13 @@ type NetworkDef struct {
 func (c *Config) FileContent(filePath string) []byte {
 	for _, f := range c.Files {
 		if f.Path == filePath {
+			if f.Content64 != "" {
+				decoded, err := base64.StdEncoding.DecodeString(f.Content64)
+				if err != nil {
+					panic(fmt.Errorf("invalid base64 content in file %s", f.Path))
+				}
+				return decoded
+			}
 			return []byte(f.Content)
 		}
 	}