def stop_mysql_service():
    print("################stop mysql service###################")
    print("systemctl stop {}".format(instance_name))

def start_mysql_service():
    print("################stop mysql service###################")
    print("systemctl start {0}".format(instance_name))

#返回备份日志中的最新的一个早于stop_at时间的完整备份，以及其后面的增量备份
def get_restorefile_list():
    list_backup = []
    list_restore_file = []
    if os.path.exists(backupfilelist):
        with open(backupfilelist, 'r') as f:
            lines = f.readlines()
            for line in lines:
                list_backup.append(line.replace("\n",""))
    if (list_backup):
        for i in range(len(list_backup) - 1, -1, -1):
            list_restore_file.append(list_backup[i])
            backup_name = list_backup[i].split("|")[2]
            if "full" in backup_name:
                full_backup_time = list_backup[i].split("|")[1]
                if(stop_at<full_backup_time):
                    break
                else:
                    list_restore_file = None
    #restore file in the list_restore_log
    list_restore_file.reverse()
    return list_restore_file

#解压缩需要还原的备份文件，包括一个完整备份以及N个增量备份（N>=0）
def uncompress_backup_file():
    print("################uncompress backup file###################")
    list_restore_backup = get_restorefile_list()

    #如果没有生成时间早于stop_at的完整备份，无法恢复，退出
    if not list_restore_backup:
        raise("There is no backup that can be restored")
        exit(1)