[New-bugs-announce] [issue41906] logging.config.dictConfig does not work with callable filters

[raybb]

New submission from raybb <rayz321z at gmail.com>:

According to the docs here (https://docs.python.org/3/library/logging.html):

"You don’t need to create specialized Filter classes, or use other classes with a filter method: you can use a function (or other callable) as a filter. The filtering logic will check to see if the filter object has a filter attribute: if it does, it’s assumed to be a Filter and its filter() method is called. Otherwise, it’s assumed to be a callable and called with the record as the single parameter."


If I use this code:

def noErrorLogs(param):
    return 1 if param.levelno < 40 else 0

logconfig_dict = {
    'filters': {
        'myfilter': {
            '()': noErrorLogs,
        }
    },
    "handlers": {
        "console": {
            "class": "logging.StreamHandler",
            "level": "DEBUG",
            "stream": "ext://sys.stdout",
            "filters": ["myfilter"]
        }
    },
    "root": {"level": "DEBUG", "handlers": ["console"]},
    "version": 1,
}
dictConfig(logconfig_dict)

I get the error "Unable to configure filter 'myfilter'" because "noErrorLogs() missing 1 required positional argument: 'param'"


However, If I use this code:


def noErrorLogs(param):
    return 1 if param.levelno < 40 else 0

logconfig_dict = {
    "handlers": {
        "console": {
            "class": "logging.StreamHandler",
            "level": "DEBUG",
            "stream": "ext://sys.stdout",
        }
    },
    "root": {"level": "DEBUG", "handlers": ["console"]},
    "version": 1,
}

logging.basicConfig()
dictConfig(logconfig_dict)
l = logging.getLogger()
l.handlers[0].addFilter(noErrorLogs)

Then the filter works correctly.




The bug I am reporting is that when using logging.config.dictConfig you cannot pass in a callable that acts a filter. You can only pass in a class with a filter method or a function that returns a callable filter.

If this is the expected behavior perhaps the docs should make it clear that callables cannot be used with dictConfig.

----------
messages: 377791
nosy: raybb
priority: normal
severity: normal
status: open
title: logging.config.dictConfig does not work with callable filters
type: behavior

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue41906>
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