平时logging模块我用得不多，不过在GAE上有时进行测试，我发现它可以输出执行的程序名。其实这一点并不困难，下面就是告诉你如何做。这里我今天在uliweb中修改的一段代码。

    import logging

    log = None
    FORMAT = "%(levelname)-8s %(asctime)-15s %(filename)s,%(lineno)d] %(message)s"

    def get_logger(format=FORMAT, datafmt=None):
        global log
        handler = logging.StreamHandler()
        fmt = logging.Formatter(format, datafmt)
        handler.setFormatter(fmt)
       
        log = logging.getLogger('uliweb')
        log.addHandler(handler)
        log.setLevel(logging.INFO)
        return log
       
    if __name__ == '__main__':
        log = get_logger()
        log.error('This is an error %s', 'aaaa')
        log.warning('This is an warning')
        try:
            1/0
        except Exception, e:
            log.exception(e)

每个Handler可以设置自已的日志格式，上面我预定义了一个FORMAT，其中%(asctime)-15s用来输出日，精确到毫秒，%(filename)s 输出文件主名，%(lineno)d为执行的行号，%(message)是用来输出用户的日志。这些参数都是logging自带的，在logging.py中的Formatter类中的详细的描述：

    %(name)s            Name of the logger (logging channel)
    %(levelno)s         Numeric logging level for the message (DEBUG, INFO,
                        WARNING, ERROR, CRITICAL)
    %(levelname)s       Text logging level for the message ("DEBUG", "INFO",
                        "WARNING", "ERROR", "CRITICAL")
    %(pathname)s        Full pathname of the source file where the logging
                        call was issued (if available)
    %(filename)s        Filename portion of pathname
    %(module)s          Module (name portion of filename)
    %(lineno)d          Source line number where the logging call was issued
                        (if available)
    %(funcName)s        Function name
    %(created)f         Time when the LogRecord was created (time.time()
                        return value)
    %(asctime)s         Textual time when the LogRecord was created
    %(msecs)d           Millisecond portion of the creation time
    %(relativeCreated)d Time in milliseconds when the LogRecord was created,
                        relative to the time the logging module was loaded
                        (typically at application startup time)
    %(thread)d          Thread ID (if available)
    %(threadName)s      Thread name (if available)
    %(process)d         Process ID (if available)
    %(message)s         The result of record.getMessage(), computed just as
                        the record is emitted

比文档好象详细多了。

上面的测试代码输出结果为：

    ERROR    2009-02-10 10:03:10,733 log.py,19] This is an error aaaa
    WARNING 2009-02-10 10:03:10,733 log.py,20] This is an warning
    ERROR    2009-02-10 10:03:10,733 log.py,24] integer division or modulo by zero
    Traceback (most recent call last):
      File "D:\project\svn\uliweb\uliweb\utils\log.py", line 22, in <module>
        1/0
    ZeroDivisionError: integer division or modulo by zero