BPL BPL - 2 months ago 18
Python Question

how to make logging.logger to behave like print

Let's say I got this logging.logger instance:

import logging
logger = logging.getLogger('root')
FORMAT = "[%(filename)s:%(lineno)s - %(funcName)20s() ] %(message)s"
logging.basicConfig(format=FORMAT)
logger.setLevel(logging.DEBUG)


Problem comes when I try to use it like the builtin print with a dynamic number of arguments:

>>> logger.__class__
<class 'logging.Logger'>
>>> logger.debug("hello")
[<stdin>:1 - <module>() ] hello
>>> logger.debug("hello","world")
Traceback (most recent call last):
File "c:\Python2711\Lib\logging\__init__.py", line 853, in emit
msg = self.format(record)
File "c:\Python2711\Lib\logging\__init__.py", line 726, in format
return fmt.format(record)
File "c:\Python2711\Lib\logging\__init__.py", line 465, in format
record.message = record.getMessage()
File "c:\Python2711\Lib\logging\__init__.py", line 329, in getMessage
msg = msg % self.args
TypeError: not all arguments converted during string formatting
Logged from file <stdin>, line 1


How could i emulate the print behaviour still using logging.Logger?

Jim Jim
Answer

Alternatively, define a function that accepts *args and then join them in your call to logger:

def log(*args, logtype='debug', sep=' '):
    getattr(logger, logtype)(sep.join("{}".format(a) for a in args))

I added a logtype for flexibility here but you could remove it if not required.