Python日志记录使用自定义格式加密

Question

我正在尝试创建一个自定义类记录器类来打印日志并将其保存到同时加密的文件中。我用过这个reference。这是我的代码：

import base64
import logging
from pprint import pprint
from Cryptodome.Cipher import AES
from Cryptodome.Hash import SHA256
from Cryptodome.Hash import MD5
from Cryptodome import Random


class logger:
    """
    Encrypt log messages to file as encrypted
    """
    class EncryptedLogFormatter(logging.Formatter):
        def __init__(self, key, fmt=None, datefmt=None):
            self._key = self.hash_gen(key, 16)
            super(logger.EncryptedLogFormatter, self).__init__(fmt=fmt, datefmt=datefmt)

        @staticmethod
        def hash_gen(key, size):
            """
            return a hash object of key base on size
            """
            key = MD5.new(key.encode('utf-8')).digest()  # use SHA-256 for a proper-sized AES key
            return key[:size]

        def format(self, record):
            # pprint(vars(record))
            message = record.msg  # log message to encrypt, if any
            asctime = record.asctime  # asctime to encrypt
            levelname = record.levelname  # levelname to encrypt

            if message:  # no sense to encrypt empty log messages
                iv = Random.new().read(AES.block_size)  # we'll be using CBC so generate an IV
                cipher = AES.new(self._key, AES.MODE_CBC, iv)
                # AES demands all blocks to be of `AES.block_size` so we have to pad the message
                # you can use any padding you prefer, I think PKCS#7 is the best option
                padding = AES.block_size - len(message) % AES.block_size
                # pad the message...
                message += chr(padding) * padding
                message_enc = iv + cipher.encrypt(message.encode())  # add iv and encrypt
                # finally, replace our plain-text message with base64 encoded encrypted one
                record.msg = base64.b64encode(message_enc).decode()

            if asctime:
                iv = Random.new().read(AES.block_size)
                cipher = AES.new(self._key, AES.MODE_CBC, iv)
                padding = AES.block_size - len(asctime) % AES.block_size
                asctime += chr(padding) * padding
                asctime_enc = iv + cipher.encrypt(asctime.encode())
                record.asctime = base64.b64encode(asctime_enc).decode()

            if levelname:
                iv = Random.new().read(AES.block_size)
                cipher = AES.new(self._key, AES.MODE_CBC, iv)
                padding = AES.block_size - len(levelname) % AES.block_size
                levelname += chr(padding) * padding
                levelname_enc = iv + cipher.encrypt(levelname.encode())
                record.levelname = base64.b64encode(levelname_enc).decode()

            return super(logger.EncryptedLogFormatter, self).format(record)

    def __init__(self, key, filename, level=logging.INFO, fmt='%(asctime)s:%(levelname)s: %(message)s', datefmt="%Y-%m-%d %H:%M:%S"):
        root = logging.getLogger()
        root.setLevel(level)
        ch = logging.StreamHandler()
        fh = logging.FileHandler(filename)
        formatter = logging.Formatter(fmt=fmt, datefmt=datefmt)
        ch.setFormatter(formatter)
        fh.setFormatter(logger.EncryptedLogFormatter(key, fmt, datefmt))
        root.addHandler(ch)
        root.addHandler(fh)

    def print(self, message):
        logging.info(message)


if __name__ == "__main__":
    logg = logger("abcdefg", 'Some path')
    logg.print("Hello")

控制台输出：

2018-08-12 13：21：07：INFO：你好

文件输出：

2018-08-12 13：21：07：QcMrG7d7gvxwiagidFozC2v4kQukgnbXv5Hs2rMDAZQ =：Px4ZlIE7usOTTtbURDjrGW4VBXaIKH / F3vhs9pj5G3o =

似乎asctime尚未加密。我想要的只是使用用户格式并加密时间，级别和消息。最好只创建加密的整行，但我不知道如何为用户输入格式创建自定义消息。