move config validation into a separate function

extensions/storage/pkg/config/parser/parse.go

@@ -2,6 +2,7 @@ package parser
 
 import (
 	"errors"
+	"fmt"
 
 	"github.com/owncloud/ocis/extensions/storage-metadata/pkg/config"
 	"github.com/owncloud/ocis/extensions/storage-metadata/pkg/config/defaults"
@@ -29,5 +30,12 @@ func ParseConfig(cfg *config.Config) error {
 
 	defaults.Sanitize(cfg)
 
+	return Validate(cfg)
+}
+
+func Validate(cfg *config.Config) error {
+	if cfg.TransferSecret == "" {
+		return fmt.Errorf("reva transfer secret is not set up properly, bailing out (storage)")
+	}
 	return nil
 }