[Python-Dev] Proposed change to logging (original) (raw)

Vinay Sajip vinay_sajip at yahoo.co.uk
Tue Aug 24 15:57:18 CEST 2004

An improvement to logging has been proposed by Miki Tebeka, which involves the creation of file-like wrapper objects for loggers. This makes it possible to use the print idiom for logging:

import logging

logging.basicConfig() logger = logging.getLogger("my.app") err = logger.getFileObject(logging.ERROR) dbg = logger.getFileObject(logging.DEBUG) ...

print >> err, "My logging message with %s" % "arguments" print >> dbg, "A message at %s level" % "debug"

Miki has helpfully sent in a patch (#1001864), and I propose to check it in by the 27th of August. I just wanted to get comments from python-dev first. There's one wart in the implementation - to avoid printing out blank lines caused by the "\n" appended by print, we ignore messages which are == "\n". This works only because print does a separate write for the "\n". Can anyone see a problem with this approach?

class LoggerFileObject: """ Simulate a file object for a given logging level. """ def init(self, logger, level): """ Initialize file object with logger and level """ self.logger = logger self.level = level self.closed = 0

def write(self, msg):
    """
    Write message to log.
    """
    if self.closed:
        raise ValueError("I/O operation on closed

file") # Avoid printing blank lines. if msg != "\n": self.logger.log(self.level, msg)

def flush(self):
    """
    Flush the file object. This flushes the

logger's handlers. """ if self.closed: return for handler in self.logger.handlers: handler.flush()

def close(self):
    """
    Close file object.

    Calling "write" after "close" will raise a

ValueError. """ self.closed = 1

Regards,

Vinay

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