logging.handlers:如何在time或maxBytes之后翻转？

Question

我对伐木有点困难.我想在一段时间后以及达到一定尺寸后滚动日志.

经过一段时间后进行翻转TimedRotatingFileHandler,并在达到某个日志大小后进行翻转RotatingFileHandler.

但是TimedRotatingFileHandler没有属性maxBytes并且在RotatingFileHandler一段时间后不能旋转.我还尝试将两个处理程序添加到记录器,但结果是双重记录.

我错过了什么吗？

我也查了一下源代码logging.handlers.我尝试子类化TimedRotatingFileHandler并覆盖该方法shouldRollover()以创建具有以下两种功能的类:

class EnhancedRotatingFileHandler(logging.handlers.TimedRotatingFileHandler):
    def __init__(self, filename, when='h', interval=1, backupCount=0, encoding=None, delay=0, utc=0, maxBytes=0):
        """ This is just a combination of TimedRotatingFileHandler and RotatingFileHandler (adds maxBytes to TimedRotatingFileHandler)  """
        # super(self). #It's old style class, so super doesn't work.
        logging.handlers.TimedRotatingFileHandler.__init__(self, filename, when='h', interval=1, backupCount=0, encoding=None, delay=0, utc=0)
        self.maxBytes=maxBytes

    def shouldRollover(self, record):
        """
        Determine if rollover should occur.

        Basically, see if the supplied record would cause the file to exceed
        the size limit we have.

        we are also comparing times        
        """
        if self.stream is None:                 # delay was set...
            self.stream = self._open()
        if self.maxBytes > 0:                   # are we rolling over?
            msg = "%s\n" % self.format(record)
            self.stream.seek(0, 2)  #due to non-posix-compliant Windows feature
            if self.stream.tell() + len(msg) >= self.maxBytes:
                return 1
        t = int(time.time())
        if t >= self.rolloverAt:
            return 1
        #print "No need to rollover: %d, %d" % (t, self.rolloverAt)
        return 0         

但是像这样,日志会创建一个备份并被覆盖.好像我必须覆盖doRollover()也不那么容易的方法.

还有其他想法如何创建一个记录器,在一定时间后以及达到一定大小后将文件翻转过来？

Answer 1

所以我做了一个小小的黑客,TimedRotatingFileHandler以便能够在时间和大小之后进行翻转.我不得不修改__init__,shouldRollover,doRollover和getFilesToDelete(见下文).这是结果,当我设置='M'时,interval = 2,backupCount = 20,maxBytes = 1048576:

-rw-r--r-- 1 user group  185164 Jun 10 00:54 sumid.log
-rw-r--r-- 1 user group 1048462 Jun 10 00:48 sumid.log.2011-06-10_00-48.001    
-rw-r--r-- 1 user group 1048464 Jun 10 00:48 sumid.log.2011-06-10_00-48.002    
-rw-r--r-- 1 user group 1048533 Jun 10 00:49 sumid.log.2011-06-10_00-48.003    
-rw-r--r-- 1 user group 1048544 Jun 10 00:50 sumid.log.2011-06-10_00-49.001    
-rw-r--r-- 1 user group  574362 Jun 10 00:52 sumid.log.2011-06-10_00-50.001

您可以看到,在达到1MB的大小后,前四个日志被翻转,而最后一个翻转在两分钟后发生.到目前为止,我没有测试删除旧的日志文件,所以它可能无法正常工作.代码肯定不适用于backupCount> = 1000.我只在文件名末尾添加三位数字.

这是修改后的代码:

class EnhancedRotatingFileHandler(logging.handlers.TimedRotatingFileHandler):
    def __init__(self, filename, when='h', interval=1, backupCount=0, encoding=None, delay=0, utc=0, maxBytes=0):
        """ This is just a combination of TimedRotatingFileHandler and RotatingFileHandler (adds maxBytes to TimedRotatingFileHandler)  """
        logging.handlers.TimedRotatingFileHandler.__init__(self, filename, when, interval, backupCount, encoding, delay, utc)
        self.maxBytes=maxBytes

    def shouldRollover(self, record):
        """
        Determine if rollover should occur.

        Basically, see if the supplied record would cause the file to exceed
        the size limit we have.

        we are also comparing times        
        """
        if self.stream is None:                 # delay was set...
            self.stream = self._open()
        if self.maxBytes > 0:                   # are we rolling over?
            msg = "%s\n" % self.format(record)
            self.stream.seek(0, 2)  #due to non-posix-compliant Windows feature
            if self.stream.tell() + len(msg) >= self.maxBytes:
                return 1
        t = int(time.time())
        if t >= self.rolloverAt:
            return 1
        #print "No need to rollover: %d, %d" % (t, self.rolloverAt)
        return 0         

    def doRollover(self):
        """
        do a rollover; in this case, a date/time stamp is appended to the filename
        when the rollover happens.  However, you want the file to be named for the
        start of the interval, not the current time.  If there is a backup count,
        then we have to get a list of matching filenames, sort them and remove
        the one with the oldest suffix.
        """
        if self.stream:
            self.stream.close()
        # get the time that this sequence started at and make it a TimeTuple
        currentTime = int(time.time())
        dstNow = time.localtime(currentTime)[-1]
        t = self.rolloverAt - self.interval
        if self.utc:
            timeTuple = time.gmtime(t)
        else:
            timeTuple = time.localtime(t)
            dstThen = timeTuple[-1]
            if dstNow != dstThen:
                if dstNow:
                    addend = 3600
                else:
                    addend = -3600
                timeTuple = time.localtime(t + addend)
        dfn = self.baseFilename + "." + time.strftime(self.suffix, timeTuple)
        if self.backupCount > 0:
            cnt=1
            dfn2="%s.%03d"%(dfn,cnt)
            while os.path.exists(dfn2):
                dfn2="%s.%03d"%(dfn,cnt)
                cnt+=1                
            os.rename(self.baseFilename, dfn2)
            for s in self.getFilesToDelete():
                os.remove(s)
        else:
            if os.path.exists(dfn):
                os.remove(dfn)
            os.rename(self.baseFilename, dfn)
        #print "%s -> %s" % (self.baseFilename, dfn)
        self.mode = 'w'
        self.stream = self._open()
        newRolloverAt = self.computeRollover(currentTime)
        while newRolloverAt <= currentTime:
            newRolloverAt = newRolloverAt + self.interval
        #If DST changes and midnight or weekly rollover, adjust for this.
        if (self.when == 'MIDNIGHT' or self.when.startswith('W')) and not self.utc:
            dstAtRollover = time.localtime(newRolloverAt)[-1]
            if dstNow != dstAtRollover:
                if not dstNow:  # DST kicks in before next rollover, so we need to deduct an hour
                    addend = -3600
                else:           # DST bows out before next rollover, so we need to add an hour
                    addend = 3600
                newRolloverAt += addend
        self.rolloverAt = newRolloverAt

    def getFilesToDelete(self):
        """
        Determine the files to delete when rolling over.

        More specific than the earlier method, which just used glob.glob().
        """
        dirName, baseName = os.path.split(self.baseFilename)
        fileNames = os.listdir(dirName)
        result = []
        prefix = baseName + "."
        plen = len(prefix)
        for fileName in fileNames:
            if fileName[:plen] == prefix:
                suffix = fileName[plen:-4]
                if self.extMatch.match(suffix):
                    result.append(os.path.join(dirName, fileName))
        result.sort()
        if len(result) < self.backupCount:
            result = []
        else:
            result = result[:len(result) - self.backupCount]
        return result            

Answer 2

如果您确实需要此功能,请根据TimedRotatingFileHandler编写自己的处理程序,主要使用时间进行翻转,但将基于大小的翻转合并到现有逻辑中.你已经尝试过这一点,但你需要(至少)会覆盖shouldRollover()和doRollover()方法.第一种方法确定何时翻转,第二种方法确定关闭当前日志文件,重命名现有文件并删除过时文件,然后打开新文件.

该doRollover()逻辑可能有点棘手,但肯定是可行的.