如何在 python 日志记录中过滤标准输出

Question

我正在使用库'logging'在我的脚本中记录信息和警告消息，无论如何我可以在打印到标准输出时过滤掉密码（我有多个密码并希望用星号替换它们） ?

Answer 1

过滤掉模式，不打印换行符

对@Dirk 的过滤器类的修改。

此版本不会打印出任何与输入模式匹配的行。跳过过滤的行后，它也不会打印换行符

class Filter(object):
    def __init__(self, stream, re_pattern):
        self.stream = stream
        self.pattern = re.compile(re_pattern) if isinstance(re_pattern, str) else re_pattern
        self.triggered = False

    def __getattr__(self, attr_name):
        return getattr(self.stream, attr_name)

    def write(self, data):
        if data == '\n' and self.triggered:
            self.triggered = False
        else:
            if self.pattern.search(data) is None:
                self.stream.write(data)
                self.stream.flush()
            else:
                # caught bad pattern
                self.triggered = True

    def flush(self):
        self.stream.flush()

# example
sys.stdout = Filter(sys.stdout, r'Read -1')  # filter out any line which contains "Read -1" in it


# No lines (or newline breaks) will be printed to stdout after running the below.
for _ in range(10):
  print('Read -1 expected 4096')

Answer 2

为了从stdout 流（logging.DEBUG 和 logging.INFO 消息所在的位置）和stderr 流（logging.WARNING、logging.ERROR 所在的位置）中过滤掉密码列表中包含的特定单词和logging.CRITICAL messages go），您可以用一个简单的类替换原始流，该类在写出关键字之前替换它们：

class PasswordFilter(object):
    def __init__(self, strings_to_filter, stream):
        self.stream = stream
        self.strings_to_filter = strings_to_filter

    def __getattr__(self, attr_name):
        return getattr(self.stream, attr_name)

    def write(self, data):
        for string in self.strings_to_filter:
            data = re.sub(r'\b{0}\b'.format(string), '*' * len(string), data)
        self.stream.write(data)
        self.stream.flush()

    def flush(self):
        self.stream.flush()

用过滤后的流替换原始流：

top_secret_passwords = ['do not tell me', 'I am secret', 'important', 'foo',
                        'foobar']
sys.stdout = PasswordFilter(top_secret_passwords, sys.stdout)
sys.stderr = PasswordFilter(top_secret_passwords, sys.stderr)

现在，设置日志记录并编写一些日志消息：

# set up your logging after activating the filter, won't work otherwise
logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)

logger.debug('You cannot see me anymore: {0}'.format(top_secret_passwords[0]))
logger.info('You cannot see me anymore: {0}'.format(top_secret_passwords[1]))
logger.warning('You cannot see me anymore: {0}'.format(top_secret_passwords[2]))
logger.error('You cannot see me anymore: {0}'.format(top_secret_passwords[3]))
logger.critical('You cannot see me anymore: {0}'.format(top_secret_passwords[4]))

输出将如下所示：

DEBUG:__main__:You cannot see me anymore: **************
INFO:__main__:You cannot see me anymore: ***********
WARNING:__main__:You cannot see me anymore: *********
ERROR:__main__:You cannot see me anymore: ***
CRITICAL:__main__:You cannot see me anymore: ******