Following up on the top-rated answers by Eric S. and Mad Physicist:
Fixed example that checks if the logging level is enabled:
import logging
DEBUG_LEVELV_NUM = 9
logging.addLevelName(DEBUG_LEVELV_NUM, "DEBUGV")
def debugv(self, message, *args, **kws):
if self.isEnabledFor(DEBUG_LEVELV_NUM):
# Yes, logger takes its '*args' as 'args'.
self._log(DEBUG_LEVELV_NUM, message, args, **kws)
logging.Logger.debugv = debugv
This code-snippet
- adds a new log-level "DEBUGV" and assigns a number 9
- defines a
debugv-method, which logs a message with level "DEBUGV" unless the log-level is set to a value higher than 9 (e.g. log-level "DEBUG")
- monkey-patches the
logging.Logger-class, so that you can call logger.debugv
The suggested implementation worked well for me, but
- code completion doesn't recognise the
logger.debugv-method
- pyright, which is part of our CI-pipeline, fails, because it cannot trace the
debugv-member method of the Logger-class (see https://github.com/microsoft/pylance-release/issues/2335 about dynamically adding member-methods)
I ended up using inheritance as was suggested in Noufal Ibrahim's answer in this thread:
I think you'll have to subclass the Logger class and add a method called trace which basically calls Logger.log with a level lower than DEBUG. I haven't tried this but this is what the docs indicate.
Implementing Noufal Ibrahim's suggestion worked and pyright is happy:
import logging
# add log-level DEBUGV
DEBUGV = 9 # slightly lower than DEBUG (10)
logging.addLevelName(DEBUGV, "DEBUGV")
class MyLogger(logging.Logger):
"""Inherit from standard Logger and add level DEBUGV."""
def debugv(self, msg, *args, **kwargs):
"""Log 'msg % args' with severity 'DEBUGV'."""
if self.isEnabledFor(DEBUGV):
self._log(DEBUGV, msg, args, **kwargs)
logging.setLoggerClass(MyLogger)
Next you can initialise an instance of the extended logger using the logger-manager:
logger = logging.getLogger("whatever_logger_name")
Edit: In order to make pyright recognise the debugv-method, you may need to cast the logger returned by logging.getLogger, which would like this:
import logging
from typing import cast
logger = cast(MyLogger, logging.getLogger("whatever_logger_name"))
