Proper way to intercept stdlib logging

The method to intercept stdlib logging in the readme sometimes gives wrong originator of the log message. Currenty in the readme it is recommended to set depth=6:

class InterceptHandler(logging.Handler):
    def emit(self, record):
        # Retrieve context where the logging call occurred, this happens to be in the 6th frame upward
        logger_opt = logger.opt(depth=6, exception=record.exc_info)
        logger_opt.log(record.levelno, record.getMessage())

But this fails for simple program:

import logging

logging.basicConfig(level='INFO')
logging.getLogger(None).addHandler( InterceptHandler())

logging.warning('123')

The originator of the message is wrongly displayed as logging:warning:1979:

2019-04-02 14:24:04.558 | WARNING  | logging:warning:1979 - 123

Similar issue: #69

[matthewlloyd]

If you are using Sentry and seeing sentry_sdk.integrations.logging:sentry_patched_callhandlers:83 as the caller in your logs, just change the while line above to:

import sentry_sdk.integrations.logging

# ...

        while frame.f_code.co_filename in (logging.__file__, sentry_sdk.integrations.logging.__file__):

This is needed even if you haven’t explicitly enabled Sentry’s logging integration, because Sentry enables it by default.

[Delgan]

I updated the InterceptHandler() snippet in the Readme:

class InterceptHandler(logging.Handler):
    def emit(self, record):
        # Get corresponding Loguru level if it exists
        try:
            level = logger.level(record.levelname).name
        except ValueError:
            level = record.levelno

        # Find caller from where originated the logged message
        frame, depth = logging.currentframe(), 2
        while frame.f_code.co_filename == logging.__file__:
            frame = frame.f_back
            depth += 1

        logger.opt(depth=depth, exception=record.exc_info).log(level, record.getMessage())

It should now retrieve the correct frame information and level name. This is not very elegant, but this is the best I could do. See also my comment: https://github.com/Delgan/loguru/issues/154#issuecomment-548761213