[Python-Dev] Proposed change to logging

[Vinay Sajip]

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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