Python3

Question

我当前的格式字符串是：

formatter = logging.Formatter('%(asctime)s : %(message)s')

我想添加一个名为app_name的新字段，该字段在包含此格式化程序的每个脚本中都有不同的值。

import logging
formatter = logging.Formatter('%(asctime)s %(app_name)s : %(message)s')
syslog.setFormatter(formatter)
logger.addHandler(syslog)

但我不确定如何将app_name值传递给记录器以插入格式字符串。我显然可以让它出现在日志消息中，但每次都会传递它，但这很麻烦。

我试过了：

logging.info('Log message', app_name='myapp')
logging.info('Log message', {'app_name', 'myapp'})
logging.info('Log message', 'myapp')

但没有工作。

Answer 1

您可以使用LoggerAdapter，这样您就不必为每次记录调用传递额外的信息：

import logging
extra = {'app_name':'Super App'}

logger = logging.getLogger(__name__)
syslog = logging.StreamHandler()
formatter = logging.Formatter('%(asctime)s %(app_name)s : %(message)s')
syslog.setFormatter(formatter)
logger.setLevel(logging.INFO)
logger.addHandler(syslog)

logger = logging.LoggerAdapter(logger, extra)
logger.info('The sky is so blue')

日志（类似的东西）

2013-07-09 17:39:33,596 Super App : The sky is so blue

Filters也可用于添加上下文信息。

import logging

class AppFilter(logging.Filter):
    def filter(self, record):
        record.app_name = 'Super App'
        return True

logger = logging.getLogger(__name__)
logger.addFilter(AppFilter())
syslog = logging.StreamHandler()
formatter = logging.Formatter('%(asctime)s %(app_name)s : %(message)s')
syslog.setFormatter(formatter)
logger.setLevel(logging.INFO)
logger.addHandler(syslog)

logger.info('The sky is so blue')

生成类似的日志记录。

Answer 2

你需要将dict作为参数传递给extra，以便那样做。

logging.info('Log message', extra={'app_name': 'myapp'})

证明：

>>> import logging
>>> logging.basicConfig(format="%(foo)s - %(message)s")
>>> logging.warning('test', extra={'foo': 'bar'})
bar - test

另外，作为注释，如果您尝试在不传递dict的情况下记录消息，那么它将失败。

>>> logging.warning('test')
Traceback (most recent call last):
  File "/usr/lib/python2.7/logging/__init__.py", line 846, in emit
    msg = self.format(record)
  File "/usr/lib/python2.7/logging/__init__.py", line 723, in format
    return fmt.format(record)
  File "/usr/lib/python2.7/logging/__init__.py", line 467, in format
    s = self._fmt % record.__dict__
KeyError: 'foo'
Logged from file <stdin>, line 1

Answer 3

Python3

从Python3.2开始，您现在可以使用LogRecordFactory

>>> import logging
>>> logging.basicConfig(format="%(custom_attribute)s - %(message)s")
>>> old_factory = logging.getLogRecordFactory()
>>> def record_factory(*args, **kwargs):
        record = old_factory(*args, **kwargs)
        record.custom_attribute = "my-attr"
        return record

>>> logging.setLogRecordFactory(record_factory)
>>> logging.info("hello")
my-attr - hello

当然，record_factory可以自定义为任何可调用对象，并且如果保留对工厂可调用对象的引用，则custom_attribute的值可以更新。

为什么这比使用适配器/过滤器更好？

您无需在应用程序周围传递记录器
它实际上适用于使用自己的记录器的第三方库（只需调用logger = logging.getLogger(..)）现在具有相同的日志格式。（对于“过滤器/适配器”，情况并非如此，您需要使用同一记录器对象）
您可以堆叠/链接多个工厂

Answer 4

另一种方法是创建自定义LoggerAdapter。如果您无法更改格式，或者如果您的格式与不发送唯一密钥的代码共享（在您的情况下为 app_name ），则此功能特别有用：

class LoggerAdapter(logging.LoggerAdapter):
    def __init__(self, logger, prefix):
        super(LoggerAdapter, self).__init__(logger, {})
        self.prefix = prefix

    def process(self, msg, kwargs):
        return '[%s] %s' % (self.prefix, msg), kwargs

在您的代码中，您将像往常一样创建并初始化您的记录器：

    logger = logging.getLogger(__name__)
    # Add any custom handlers, formatters for this logger
    myHandler = logging.StreamHandler()
    myFormatter = logging.Formatter('%(asctime)s %(message)s')
    myHandler.setFormatter(myFormatter)
    logger.addHandler(myHandler)
    logger.setLevel(logging.INFO)

最后，您将创建包装器适配器以根据需要添加前缀：

    logger = LoggerAdapter(logger, 'myapp')
    logger.info('The world bores you when you are cool.')

输出看起来像这样：

2013-07-09 17:39:33,596 [myapp] The world bores you when you are cool.

Answer 5

我自己实施此问题后就发现了它。希望它能帮助某人。在下面的代码中，我在记录器格式中引入了一个称为claim_id的额外密钥。每当环境中存在claim_id密钥时，它将记录claim_id。在我的用例中，我需要记录此信息以使用AWS Lambda函数。

import logging
import os

LOG_FORMAT = '%(asctime)s %(name)s %(levelname)s %(funcName)s %(lineno)s ClaimID: %(claim_id)s: %(message)s'


class AppLogger(logging.Logger):

    # Override all levels similarly - only info overriden here

    def info(self, msg, *args, **kwargs):
        return super(AppLogger, self).info(msg, extra={"claim_id": os.getenv("claim_id", "")})


def get_logger(name):
    """ This function sets log level and log format and then returns the instance of logger"""
    logging.setLoggerClass(AppLogger)
    logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)
    logger = logging.getLogger(name)
    logger.setLevel(logging.INFO)
    return logger


LOGGER = get_logger(__name__)

LOGGER.info("Hey")
os.environ["claim_id"] = "12334"
LOGGER.info("Hey")

要点：https://gist.github.com/ramanujam/306f2e4e1506f302504fb67abef50652

Answer 6

如果您需要一个默认的 extra 映射，并且您想为临时日志消息自定义它，这可以在 Python 2.7+ 中通过创建一个 LoggerAdapter将默认 extra 字典与给定消息中的任何 extra 合并。

import logging
import os
import sys

logging.basicConfig(
    level=logging.DEBUG,
    format='%(asctime)s %(levelname)-8s Py%(python)-4s pid:%(pid)-5s %(message)s',
)
_logger = logging.getLogger("my-logger")
_logger.setLevel(logging.DEBUG)


class DefaultExtrasAdapter(logging.LoggerAdapter):
    def __init__(self, logger, extra):
        super(DefaultExtrasAdapter, self).__init__(logger, extra)

    def process(self, msg, kwargs):
        # Speed gain if no extras are present
        if "extra" in kwargs:
            copy = dict(self.extra).copy()
            copy.update(kwargs["extra"])
            kwargs["extra"] = copy
        else:
            kwargs["extra"] = self.extra
        return msg, kwargs


LOG = DefaultExtrasAdapter(_logger, {"python": sys.version_info[0], "pid": os.getpid()})

if __name__ == "__main__":
    LOG.info("<-- With defaults")
    LOG.info("<-- With my version", extra={"python": 3.10})
    LOG.info("<-- With my pid", extra={"pid": 0})
    LOG.info("<-- With both", extra={"python": 2.7, "pid": -1})

结果：

2021-08-05 18:58:27,308 INFO     Py2    pid:8435  <-- With defaults
2021-08-05 18:58:27,309 INFO     Py3.1  pid:8435  <-- With my version
2021-08-05 18:58:27,309 INFO     Py2    pid:0     <-- With my pid
2021-08-05 18:58:27,309 INFO     Py2.7  pid:-1    <-- With both

Answer 7

使用mr2ert的答案，我想出了一个舒适的解决方案（尽管我不建议这样做）-覆盖内置的日志记录方法以接受自定义参数并在方法内部创建extra字典：

import logging

class CustomLogger(logging.Logger):

   def debug(self, msg, foo, *args, **kwargs):
       extra = {'foo': foo}

       if self.isEnabledFor(logging.DEBUG):
            self._log(logging.DEBUG, msg, args, extra=extra, **kwargs)

   *repeat for info, warning, etc*

logger = CustomLogger('CustomLogger', logging.DEBUG)
formatter = logging.Formatter('%(asctime)s [%(foo)s] %(message)s') 
handler = logging.StreamHandler()
handler.setFormatter(formatter) 
logger.addHandler(handler)

logger.debug('test', 'bar')

输出：

2019-03-02 20:06:51,998 [bar] test

这是供参考的内置函数

def debug(self, msg, *args, **kwargs):
    """
    Log 'msg % args' with severity 'DEBUG'.

    To pass exception information, use the keyword argument exc_info with
    a true value, e.g.

    logger.debug("Houston, we have a %s", "thorny problem", exc_info=1)
    """
    if self.isEnabledFor(DEBUG):
        self._log(DEBUG, msg, args, **kwargs)

Answer 8

导入日志记录；

LogFilter（logging.Filter）类：

def __init__(self, code):
    self.code = code

def filter(self, record):
    record.app_code = self.code
    return True

logging.basicConfig（format ='[％（asctime）s：％（levelname）s] :: [％（module）s->％（name）s]-APP_CODE：％（app_code）s-MSG：％（message）s'）;

类记录器：

def __init__(self, className):
    self.logger = logging.getLogger(className)
    self.logger.setLevel(logging.ERROR)

@staticmethod
def getLogger(className):
    return Logger(className)

def logMessage(self, level, code, msg):
    self.logger.addFilter(LogFilter(code))

    if level == 'WARN':        
        self.logger.warning(msg)
    elif level == 'ERROR':
        self.logger.error(msg)
    else:
        self.logger.info(msg)

类测试： logger = Logger.getLogger（'Test'）

if __name__=='__main__':
    logger.logMessage('ERROR','123','This is an error')

如何将自定义字段添加到Python日志格式字符串？

8 个答案:

Python3

为什么这比使用适配器/过滤器更好？