opt_logger

opt_logger option requires a logger. When a logger is passed in then the decorator will log to the logger when validation fails.

Note

When opt_return option is set and/or raise_error is False then logging will not take place as no validation error are raised.

Example logger and function with a decorator that uses logger.

import logging
from pathlib import Path
from kwhelp.decorator import RuleCheckAll
from kwhelp.rules import RuleIntPositive

def _create_logger(level:int, log_path: Path) -> logging.Logger:
    """
    Creates a logging object and returns it
    """
    logger = logging.getLogger("default_logger")
    logger.setLevel(level)
    # create the logging file handler
    fh = logging.FileHandler(str(log_path))

    fmt = '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
    formatter = logging.Formatter(fmt)
    fh.setFormatter(formatter)

    # add handler to logger object
    logger.addHandler(fh)
    return logger

default_logger = _create_logger(level=logging.DEBUG ,log_path=(Path.home() / 'mylog.log'))

@RuleCheckAll(RuleIntPositive, opt_logger=default_logger)
def add_positives(*args) -> int:
    return sum(args)

Call sample function.

>>> try:
>>>     result = add_positives(1, 33, -3)
>>>     print(result)
>>> except Exception as e:
>>>     print(e)
RuleError: 'add_positives' error.
Rule 'RuleIntPositive' Failed validation.
Expected the following rule to match: RuleIntPositive.
RuleCheckAll decorator error.
Inner Error Message: ValueError: Arg error: 'arg' must be a positive int value

Log file contents

2021-11-18 07:58:17,995 - default_logger - ERROR - RuleError: 'add_positives' error.
Rule 'RuleIntPositive' Failed validation.
Expected the following rule to match: RuleIntPositive.
RuleCheckAll decorator error.
Inner Error Message: ValueError: Arg error: 'arg' must be a positive int value
Traceback (most recent call last):
File "/home/paul/Documents/Projects/Python/Publish/kwargs/kwhelp/checks/__init__.py", line 237, in _validate_rules_all
    result = result & rule_instance.validate()
File "/home/paul/Documents/Projects/Python/Publish/kwargs/kwhelp/rules/__init__.py", line 347, in validate
    raise ValueError(
ValueError: Arg error: 'arg' must be a positive int value

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/home/paul/Documents/Projects/Python/Publish/kwargs/kwhelp/decorator/__init__.py", line 1648, in wrapper
    is_valid = self._rulechecker.validate_all(**arg_name_values)
File "/home/paul/Documents/Projects/Python/Publish/kwargs/kwhelp/checks/__init__.py", line 311, in validate_all
    result = result & self._validate_rules_all(key=k, field=k, value=v)
File "/home/paul/Documents/Projects/Python/Publish/kwargs/kwhelp/checks/__init__.py", line 240, in _validate_rules_all
    raise RuleError(
kwhelp.exceptions.RuleError: RuleError:
Rule 'RuleIntPositive' Failed validation.
Expected the following rule to match: RuleIntPositive.
Inner Error Message: ValueError: Arg error: 'arg' must be a positive int value