您不能按照设计将TimedRotatingFileHandler 用于您的用例。处理程序希望“当前”日志文件名保持稳定，并将轮换定义为通过重命名将现有日志文件移动到备份。这些是保留或删除的备份。轮换备份是根据基本文件名加上带有轮换时间戳的后缀创建的。因此实现区分日志文件（存储在baseFilename）和轮换文件（在doRotate() method 中生成。请注意，只有在轮换发生时才会删除备份，因此在处理程序已用于at至少一个完整的间隔。
您希望基本文件名本身携带时间信息，因此改变日志文件名本身。在这种情况下没有“备份”，您只需在轮换时刻打开一个新文件。此外，您似乎正在运行 短暂 Python 代码，因此您希望立即删除旧文件，而不仅仅是在显式旋转时删除，这可能永远无法到达。
这就是TimedRotatingFileHandler 不会删除任何文件的原因，因为*它永远不会创建备份文件。没有备份意味着没有要删除的备份。为了旋转文件，处理程序的当前实现期望负责文件名生成，并且不能期望知道它本身不会生成的文件名。当您使用"M" 每分钟轮换频率对其进行配置时，它被配置为使用{baseFileame}.{now:%Y-%m-%d_%H_%M} 模式将文件轮换到备份文件，因此只会删除与该模式匹配的轮换备份文件。见documentation：
系统将通过在文件名后附加扩展名来保存旧的日志文件。扩展是基于日期和时间的，使用 strftime 格式 %Y-%m-%d_%H-%M-%S 或其前导部分，具体取决于翻转间隔。
相反，您需要的是一个本身带有时间戳的基本文件名，并且在打开具有不同名称的新日志文件时，旧的日志文件（不是备份文件）将被删除。为此，您必须创建一个自定义处理程序。
幸运的是，类层次结构专为轻松定制而设计。你可以在这里继承BaseRotatingHandler，并提供你自己的删除逻辑：
import os
import time
from itertools import islice
from logging.handlers import BaseRotatingHandler, TimedRotatingFileHandler
# rotation intervals in seconds
_intervals = {
"S": 1,
"M": 60,
"H": 60 * 60,
"D": 60 * 60 * 24,
"MIDNIGHT": 60 * 60 * 24,
"W": 60 * 60 * 24 * 7,
}
class TimedPatternFileHandler(BaseRotatingHandler):
"""File handler that uses the current time in the log filename.
The time is quantisized to a configured interval. See
TimedRotatingFileHandler for the meaning of the when, interval, utc and
atTime arguments.
If backupCount is non-zero, then older filenames that match the base
filename are deleted to only leave the backupCount most recent copies,
whenever opening a new log file with a different name.
"""
def __init__(
self,
filenamePattern,
when="h",
interval=1,
backupCount=0,
encoding=None,
delay=False,
utc=False,
atTime=None,
):
self.when = when.upper()
self.backupCount = backupCount
self.utc = utc
self.atTime = atTime
try:
key = "W" if self.when.startswith("W") else self.when
self.interval = _intervals[key]
except KeyError:
raise ValueError(
f"Invalid rollover interval specified: {self.when}"
) from None
if self.when.startswith("W"):
if len(self.when) != 2:
raise ValueError(
"You must specify a day for weekly rollover from 0 to 6 "
f"(0 is Monday): {self.when}"
)
if not "0" <= self.when[1] <= "6":
raise ValueError(
f"Invalid day specified for weekly rollover: {self.when}"
)
self.dayOfWeek = int(self.when[1])
self.interval = self.interval * interval
self.pattern = os.path.abspath(os.fspath(filenamePattern))
# determine best time to base our rollover times on
# prefer the creation time of the most recently created log file.
t = now = time.time()
entry = next(self._matching_files(), None)
if entry is not None:
t = entry.stat().st_ctime
while t + self.interval < now:
t += self.interval
self.rolloverAt = self.computeRollover(t)
# delete older files on startup and not delaying
if not delay and backupCount > 0:
keep = backupCount
if os.path.exists(self.baseFilename):
keep += 1
delete = islice(self._matching_files(), keep, None)
for entry in delete:
os.remove(entry.path)
# Will set self.baseFilename indirectly, and then may use
# self.baseFilename to open. So by this point self.rolloverAt and
# self.interval must be known.
super().__init__(filenamePattern, "a", encoding, delay)
@property
def baseFilename(self):
"""Generate the 'current' filename to open"""
# use the start of *this* interval, not the next
t = self.rolloverAt - self.interval
if self.utc:
time_tuple = time.gmtime(t)
else:
time_tuple = time.localtime(t)
dst = time.localtime(self.rolloverAt)[-1]
if dst != time_tuple[-1] and self.interval > 3600:
# DST switches between t and self.rolloverAt, adjust
addend = 3600 if dst else -3600
time_tuple = time.localtime(t + addend)
return time.strftime(self.pattern, time_tuple)
@baseFilename.setter
def baseFilename(self, _):
# assigned to by FileHandler, just ignore this as we use self.pattern
# instead
pass
def _matching_files(self):
"""Generate DirEntry entries that match the filename pattern.
The files are ordered by their last modification time, most recent
files first.
"""
matches = []
pattern = self.pattern
for entry in os.scandir(os.path.dirname(pattern)):
if not entry.is_file():
continue
try:
time.strptime(entry.path, pattern)
matches.append(entry)
except ValueError:
continue
matches.sort(key=lambda e: e.stat().st_mtime, reverse=True)
return iter(matches)
def doRollover(self):
"""Do a roll-over. This basically needs to open a new generated filename.
"""
if self.stream:
self.stream.close()
self.stream = None
if self.backupCount > 0:
delete = islice(self._matching_files(), self.backupCount, None)
for entry in delete:
os.remove(entry.path)
now = int(time.time())
rollover = self.computeRollover(now)
while rollover <= now:
rollover += self.interval
if not self.utc:
# If DST changes and midnight or weekly rollover, adjust for this.
if self.when == "MIDNIGHT" or self.when.startswith("W"):
dst = time.localtime(now)[-1]
if dst != time.localtime(rollover)[-1]:
rollover += 3600 if dst else -3600
self.rolloverAt = rollover
if not self.delay:
self.stream = self._open()
# borrow *some* TimedRotatingFileHandler methods
computeRollover = TimedRotatingFileHandler.computeRollover
shouldRollover = TimedRotatingFileHandler.shouldRollover
在日志文件名中使用time.strftime() placeholders，这些会为你填写：
handler = TimedPatternFileHandler("logs/%H-%M.log", when="M", backupCount=2)
请注意，这会在您创建实例时清理旧文件。