--- a/pkg/auth/opendb.go	Wed Aug 22 14:34:37 2018 +0200
+++ b/pkg/auth/opendb.go	Wed Aug 22 16:18:14 2018 +0200
@@ -43,7 +43,10 @@
 
 const InvalidRoleCharacters = `\"':;`
 
-var ErrInvalidRoleCharacters = errors.New("rolename contains invalid character")
+var (
+	ErrInvalidRoleCharacters = errors.New("rolename contains invalid character")
+	ErrNoMetamorphUser       = errors.New("No metamorphic user configured")
+)
 
 func AllOtherRoles(user, password string) (Roles, error) {
 	db, err := OpenDB(user, password)
@@ -73,7 +76,11 @@
 	if strings.Contains(role, InvalidRoleCharacters) {
 		return ErrInvalidRoleCharacters
 	}
-	db, err := OpenDB(config.MetamorphDBUser(), config.MetamorhpDBPassword())
+	user := config.MetamorphDBUser()
+	if user == "" {
+		return ErrNoMetamorphUser
+	}
+	db, err := OpenDB(user, config.MetamorhpDBPassword())
 	if err != nil {
 		return nil
 	}