如何为不同的 Python 日志处理程序设置不同的级别

我已经读了一些关于这方面的文章，但我仍然感到困惑，我有这样的日志设置:

import logging


class MongoHandler(logging.Handler):
def __init__(self):
logging.Handler.__init__(self)
from pymongo import Connection
self.db = Connection('db_server').db_name


def emit(self, record):
try:
self.db.Logging.save(record.__dict__)
except:
print 'Logging Error:  Unable to save log entry to db'


mh = MongoHandler()
sh = logging.StreamHandler()
formatter = logging.Formatter('%(asctime)s - %(threadName)s - %(levelname)s - %(message)s')
sh.setFormatter(formatter)
log = logging.getLogger('DeviceMonitor_%s' % hostname)
log.addHandler(mh)
log.addHandler(sh)
log.setLevel(logging.INFO)

我希望能够为 StreamHandler 和 MongoHandler 设置一个不同的级别。这可能吗? 还是我需要第二个 Logger obj？

57643 次浏览
小开
最佳答案

You can set a different logging level for each logging handler but it seems you will have to set the logger's level to the "lowest". In the example below I set the logger to DEBUG, the stream handler to INFO and the TimedRotatingFileHandler to DEBUG. So the file has DEBUG entries and the stream outputs only INFO. You can't direct only DEBUG to one and only INFO to another handler. For that you'll need another logger.

logger = logging.getLogger("mylog")
formatter = logging.Formatter(
'%(asctime)s | %(name)s |  %(levelname)s: %(message)s')
logger.setLevel(logging.DEBUG)


stream_handler = logging.StreamHandler()
stream_handler.setLevel(logging.INFO)
stream_handler.setFormatter(formatter)


logFilePath = "my.log"
file_handler = logging.handlers.TimedRotatingFileHandler(
filename=logFilePath, when='midnight', backupCount=30)
file_handler.setFormatter(formatter)
file_handler.setLevel(logging.DEBUG)


logger.addHandler(file_handler)
logger.addHandler(stream_handler)


logger.info("Started");
try:
x = 14
y = 0
z = x / y
except Exception as ex:
logger.error("Operation failed.")
logger.debug(
"Encountered {0} when trying to perform calculation.".format(ex))


logger.info("Ended");
小开

In addition to GrantVS's answer:

I had to use

logging.basicConfig(level=logging.DEBUG)

in order for it to work. Otherwise great answer, thanks!

小开

I needed a time to understand the point

  1. Set the general logger below your subloggers (handlers) (your result of logging.getLogger())
  2. Set your subloggers levels on an equal or superior level to your general logger
小开

Had the same problem but the solution didn't work for iPython as the QtConsole automatically creates a handler with no level set:

import logging
root = logging.getLogger()
root.handlers
Out: [<StreamHandler <stderr> (NOTSET)>]

As a result iPython printed both DEBUG and INFO to console in spite of having different levels for my file handler and stream handler.

This thread pointed out this issue for me: Logging module does not print in IPython

I made a helper module (helped greatly by this stack thread!) called custom_logging.py to make logging more convenient in other modules:

import logging
from pathlib import Path
import sys


def _add_stream_handler(logger: logging.Logger):


stream_handler = logging.StreamHandler()
formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')
stream_handler.setFormatter(formatter)
stream_handler.setLevel(logging.INFO)


logger.addHandler(stream_handler)


return logger




def _add_file_handler(logger: logging.Logger, log_path: Path):


file_handler = logging.FileHandler(log_path, mode='w')
formatter = logging.Formatter(
fmt='%(asctime)s %(name)-12s %(levelname)-8s %(message)s', datefmt='%m-%d %H:%M')


file_handler.setFormatter(formatter)
file_handler.setLevel(logging.DEBUG)


logger.addHandler(file_handler)


return logger




def create_logger(root_dir: Path, caller: str) -> logging.Logger:


log_path = root_dir / 'logs' / f'{caller}.log'
logger = logging.getLogger(caller)
root = logging.getLogger()


logger.setLevel(logging.DEBUG)


# If haven't already launched handlers...
if not len(logger.handlers):


_add_file_handler(logger=logger, log_path=log_path)
_add_stream_handler(logger=logger)


logger.info('Logging started.')


# Delete the Qtconsole stderr handler
# ... as it automatically logs both DEBUG & INFO to stderr
if root.handlers:
root.handlers = []


return logger




def log_dataframe(df, logger: logging.Logger, name: str = "DataFrame") -> None:


logger.debug(
f'''{name} head:\n {df.head()}\n----------\n''')




def log_dataframes(*args, logger: logging.Logger) -> None:


for gdf in args:


logger.debug(
f'''DataFrame head:\n {gdf.head()}\n----------\n''')

Can use its functions via:

from custom_logging import create_logger, log_dataframe

Or import custom_logging and custom_logging.create_logger() etc.

Also see sections 'Multiple handlers and formatters' and 'Logging to multiple destinations' in the official logging cookbook at: https://docs.python.org/3/howto/logging-cookbook.html#logging-cookbook


提交答案