将日志消息格式化为树

时间:2016-01-27 22:01:07

标签: python logging

我想让python日志记录输出为对应于记录树的树形式。看看例子。

让我们说我们有一个代码:

import logging

logger_a = logging.getLogger("a")
logger_a_b = logging.getLogger("a.b")
logger_a_b_c = logging.getLogger("a.b.c")
# ...


logger_a.debug("One")

logger_a_b.warning("two")
logger_a_b.warning("three")

logger_a_b_c.critical("Four")

logger_a_b.warning("Five")

输出应该是这样的:

<--"a"
   |   DEBUG: One
   |
   o<--"a.b"
   |   | WARNING: Two
   |   | WARNING: Three
   |   |
   |   o<--"a.b.c"
   |       | CRITICAL: Four   
   |       |
   |   | WARNING: Five

我可以手动为每个日志编写格式化程序,但它并没有解决插入类似o&lt; - &#34; a.b&#34;对,我宁愿通过记录结构自动计算偏移量。

有一个名为logging tree的模块。它打印日志记录布局。我想要的是以大致相同的方式打印日志消息。

你知道任何图书馆,方法吗?

1 个答案:

答案 0 :(得分:3)

根据您的示例,我创建了一个自定义Formatter来处理树。

import logging

# custom tree formatter
class TreeFormatter(logging.Formatter):
    formatPrefix = {} # map loggername, formatPrefix

    def format(self, record):
        s = ""
        # first time this name is encountered: create the prefix and print the name
        if not record.name in self.formatPrefix: 
            f = self.getFormatPrefix(record)
            s += "%s \"%s\"\n" % (f, record.name)

        # print the actual message
        s += "%s %s: %s" % (self.formatPrefix[record.name], record.levelname, record.msg) 
        return s


    # create the format prefix for the given package name 
    # (stored in self.formatPrefix[record.name])
    # and return the first line to print
    def getFormatPrefix(self, record):
        depth = record.name.count(".")
        self.formatPrefix[record.name] = "   |" * (depth+1)

        if depth == 0:
            return "<--"

        return "%so<--" % ( ("   |" * depth)[:-1])

然后,您可以使用它来创建第一级记录器(此处为a)。其余的代码没有改变。

以下是一个例子:

# use this to create the first level logger
def createTreeLogger(name, level=logging.DEBUG):
    logger = logging.getLogger(name)
    logger.setLevel(level)
    ch = logging.StreamHandler()
    ch.setLevel(level)
    ch.setFormatter(TreeFormatter())
    logger.addHandler(ch)
    return logger


if __name__ == '__main__':

    logger_a = createTreeLogger("a") # first level: use createLogger
    # then create your loggers as always
    logger_a_b = logging.getLogger("a.b") 
    logger_a_b_c = logging.getLogger("a.b.c")


    logger_a.debug("One")

    logger_a_b.warning("two")
    logger_a_b.warning("three")

    logger_a_b_c.critical("Four")

    logger_a_b.warning("Five")
    logger_a.warning("Six")

值得注意的是,日志包内部将自动为子包使用相同的处理程序(a.b,a.b.c)。因此,通过运行此代码,您将获得:

<-- "a"
   | DEBUG: One
   o<-- "a.b"
   |   | WARNING: two
   |   | WARNING: three
   |   o<-- "a.b.c"
   |   |   | CRITICAL: Four
   |   | WARNING: Five
   | WARNING: Six

一个缺点是,如果您有多个包层次结构,则日志会变得混乱。但TreeFormatter课程很容易根据您的需要进行调整。