#!/usr/bin/env python
# encoding: utf-8

"""自定義日志處理類"""


import os
import time
from logging.handlers import TimedRotatingFileHandler


class MyLoggingHandler(TimedRotatingFileHandler):

  def __init__(self, filename, when='h', interval=1, backupCount=0, encoding=None, delay=False, utc=False, atTime=None):
    TimedRotatingFileHandler.__init__(self, filename, when=when, interval=interval, backupCount=backupCount, encoding=encoding, delay=delay, utc=utc, atTime=atTime)

  def computeRollover(self, currentTime):
    # 將時間取整
    t_str = time.strftime(self.suffix, time.localtime(currentTime))
    t = time.mktime(time.strptime(t_str, self.suffix))
    return TimedRotatingFileHandler.computeRollover(self, t)

  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()
      self.stream = None
    # 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.rotation_filename(self.baseFilename + "." +
                   time.strftime(self.suffix, timeTuple))
    # 修改內容--開始
    # 在多進程下，若發(fā)現(xiàn)dfn已經(jīng)存在，則表示已經(jīng)有其他進程將日志文件按時間切割了，只需重新打開新的日志文件，寫入當前日志；
    # 若dfn不存在，則將當前日志文件重命名，并打開新的日志文件
    if not os.path.exists(dfn):
      try:
        self.rotate(self.baseFilename, dfn)
      except FileNotFoundError:
        # 這里會出異常：未找到日志文件，原因是其他進程對該日志文件重命名了，忽略即可，當前日志不會丟失
        pass
    # 修改內容--結束
    # 原內容如下：
    """
    if os.path.exists(dfn):
      os.remove(dfn)
    self.rotate(self.baseFilename, dfn)
    """

    if self.backupCount > 0:
      for s in self.getFilesToDelete():
        os.remove(s)
    if not self.delay:
      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