add a dedicated struct to store encrypted credentials

also gcs credentials are now encrypted, both on disk and inside the
provider.

Data provider is automatically migrated and load data will accept
old format too but you should upgrade to the new format to avoid future
issues

dataprovider/mysql.go

@@ -210,28 +210,46 @@ func (p MySQLProvider) migrateDatabase() error {
 	}
 	switch dbVersion.Version {
 	case 1:
-		err = updateMySQLDatabaseFrom1To2(p.dbHandle)
-		if err != nil {
-			return err
-		}
-		err = updateMySQLDatabaseFrom2To3(p.dbHandle)
-		if err != nil {
-			return err
-		}
-		return updateMySQLDatabaseFrom3To4(p.dbHandle)
+		return updateMySQLDatabaseFromV1(p.dbHandle)
 	case 2:
-		err = updateMySQLDatabaseFrom2To3(p.dbHandle)
-		if err != nil {
-			return err
-		}
-		return updateMySQLDatabaseFrom3To4(p.dbHandle)
+		return updateMySQLDatabaseFromV2(p.dbHandle)
 	case 3:
-		return updateMySQLDatabaseFrom3To4(p.dbHandle)
+		return updateMySQLDatabaseFromV3(p.dbHandle)
+	case 4:
+		return updateMySQLDatabaseFromV4(p.dbHandle)
 	default:
 		return fmt.Errorf("Database version not handled: %v", dbVersion.Version)
 	}
 }
 
+func updateMySQLDatabaseFromV1(dbHandle *sql.DB) error {
+	err := updateMySQLDatabaseFrom1To2(dbHandle)
+	if err != nil {
+		return err
+	}
+	return updateMySQLDatabaseFromV2(dbHandle)
+}
+
+func updateMySQLDatabaseFromV2(dbHandle *sql.DB) error {
+	err := updateMySQLDatabaseFrom2To3(dbHandle)
+	if err != nil {
+		return err
+	}
+	return updateMySQLDatabaseFromV3(dbHandle)
+}
+
+func updateMySQLDatabaseFromV3(dbHandle *sql.DB) error {
+	err := updateMySQLDatabaseFrom3To4(dbHandle)
+	if err != nil {
+		return err
+	}
+	return updateMySQLDatabaseFromV4(dbHandle)
+}
+
+func updateMySQLDatabaseFromV4(dbHandle *sql.DB) error {
+	return updateMySQLDatabaseFrom4To5(dbHandle)
+}
+
 func updateMySQLDatabaseFrom1To2(dbHandle *sql.DB) error {
 	logger.InfoToConsole("updating database version: 1 -> 2")
 	providerLog(logger.LevelInfo, "updating database version: 1 -> 2")
@@ -249,3 +267,7 @@ func updateMySQLDatabaseFrom2To3(dbHandle *sql.DB) error {
 func updateMySQLDatabaseFrom3To4(dbHandle *sql.DB) error {
 	return sqlCommonUpdateDatabaseFrom3To4(mysqlV4SQL, dbHandle)
 }
+
+func updateMySQLDatabaseFrom4To5(dbHandle *sql.DB) error {
+	return sqlCommonUpdateDatabaseFrom4To5(dbHandle)
+}