在Python记录器中覆盖Lineno的最佳方法

正如马丁（Martijn）指出的那样，事情有时会改变。但是，由于您使用的是Python
2（迭代器已将其放弃），因此如果您不介意猴子修补日志记录，则以下代码将起作用：

from functools import wrapsimport loggingclass ArgLogger(object):    """    Singleton class -- will only be instantiated once    because of the monkey-patching of logger.    """    singleton = None    def __new__(cls):        self = cls.singleton        if self is not None: return self        self = cls.singleton = super(ArgLogger, cls).__new__(cls)        self.pre_location = None        # Do the monkey patch exactly one time        def findCaller(log_self): self.pre_location, pre_location = None, self.pre_location if pre_location is not None:     return pre_location return old_findCaller(log_self)        old_findCaller = logging.Logger.findCaller        logging.Logger.findCaller = findCaller        return self    def log_args(self, logger, level=logging.DEBUG):        """Decorator to log arguments passed to func."""        def inner_func(func): co = func.__pre__ pre_loc = (co.co_filename, co.co_firstlineno, co.co_name) @wraps(func) def return_func(*args, **kwargs):     arg_list = list("{!r}".format(arg) for arg in args)     arg_list.extend("{}={!r}".format(key, val)          for key, val in kwargs.iteritems())     msg = "{name}({arg_str})".format(name=func.__name__,       arg_str=", ".join(arg_list))     self.pre_location = pre_loc     logger.log(level, msg)     return func(*args, **kwargs) return return_func        return inner_funclog_args = ArgLogger().log_argsif __name__ == "__main__":    logger = logging.getLogger(__name__)    handler = logging.StreamHandler()    fmt = "%(asctime)s %(levelname)-8.8s [%(name)s:%(lineno)4s] %(message)s"    handler.setFormatter(logging.Formatter(fmt))    logger.addHandler(handler)    logger.setLevel(logging.DEBUG)    @log_args(logger)    def foo(x, y, z):        pass    class Bar(object):        @log_args(logger)        def baz(self, a, b, c): pass    def test_regular_log():        logger.debug("Logging without ArgLog still works fine")    foo(1, 2, z=3)    foo(1, 2, 3)    foo(x=1, y=2, z=3)    bar = Bar()    bar.baz(1, c=3, b=2)    test_regular_log()