本文介绍了用于多处理日志记录的QueueHandler的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试调整我的程序，以便将不同进程的日志记录到单个日志文件中。 多天来，我一直在寻找解决方案，但没有成功。我想我仍然不明白队列处理程序是如何工作的。在我看来，这个过程是这样的：- 创建Q
- 将qHandler添加到主记录器
- 所有日志都将被重定向到Q，然后Q将使用附加到记录器的其他处理程序(通过logger.Handle(Record))。 我创建了该程序的简化版本来说明记录器的行为方式
# logger.py
import logging
def listener_configurer():
"""This sets the settings for the root logger. The highest in the hierarchy.
All the handlers added to this root logger are available for all the subloggers.
"""
root = logging.getLogger('main')
file = logging.FileHandler(r'logs emp.log', 'w')
fmt = logging.Formatter('%(asctime)s %(processName)-10s %(name)s %(levelname)-8s %(message)s')
stream = logging.StreamHandler()
stream.setFormatter(fmt)
file.setFormatter(fmt)
root.addHandler(file)
root.addHandler(stream)
root.setLevel(logging.DEBUG)
def listener_process(queue):
listener_configurer()
while True:
try:
record = queue.get()
if record is not None:
print("-------------- using q ------------------ " + record.name + " -> " + record.message)
logger = logging.getLogger(record.name)
logger.handle(record)
else:
break
except Exception:
import sys, traceback
logger.error('Whoops! Problem: %s', "problem", exc_info=1)
traceback.print_exc(file=sys.stderr)
# saver.py (worker)
import logging
import typing
log = logging.getLogger('main.Saver')
class Saver:
def __init__(self) -> None:
log.warning("Instantiating a saver obj")
def doStuff(self, input_line: typing.Tuple,) -> None:
log.info(f"Exporting: {input_line}") # ASSUMING A TUPLE AS INPUT like: email, email_id, email_url
(email, email_id, email_url, *other) = input_line
log.info("Source URL: " + email_url)
log.info(f"EmailName: {email}")
log.warning(f"EmailID: {email_id}")
log.debug("Exporting done!")
# manager.py
import logging
import logging.config
import logging.handlers
import multiprocessing
import logger
from saver import Saver
class Manager:
def __init__(self) -> None:
### LOGGER
# initializing listener -> this queue is going to be used for the multiprocessing logging
self.queue = multiprocessing.Queue(-1)
self.log = self.root_configurer(self.queue) # getting a reference to the root logger -> used to log from this module
self.listener = multiprocessing.Process(target=logger.listener_process, args=(self.queue,))
self.listener.start()
# utils
self.log.info(f"Starting program at 10 am")
# instantiate
self.save = Saver()
def root_configurer(self, queue):
root = logging.getLogger('main')
h = logging.handlers.QueueHandler(queue) # Just the one handler needed
root.setLevel(DEBUG)
root.addHandler(h)
return root # this is the main function -> we need to retrieve the root logger here
def run(self):
tuples = [("email1","id1","url1",""), ("email2","id2","url2",""), ("email3","id3","url3",""), ("email4","id4","url4",""), ("email4","id4","url4","")]
procs = []
for res in tuples:
proc = multiprocessing.Process(target=self.save.doStuff, args=(res,))
procs.append(proc)
proc.start()
# complete the processes
for proc in procs:
proc.join()
self.log.debug("We reached this part!")
# close listener
self.queue.put_nowait(None)
self.listener.join()
if __name__ == "__main__":
m = Manager()
m.run()
我所期望的是一串类似于：
的行-------- using q ------------- main.saver INFO Source URL: ...
-------- using q ------------- main.saver INFO EmailName ...
-------- using q ------------- main.saver WARNING EmailID
-------- using q ------------- main.saver DEBUG ....
加上写入日志的所有这些行。出于某种原因，我收到：
EmailID: id4
EmailID: id3
EmailID: id2
-------------- using q ------------------ main -> Starting program at 10 am
2021-07-01 11:42:16,385 MainProcess main INFO Starting program at 10 am
-------------- using q ------------------ main.Saver -> Instantiating a saver obj
2021-07-01 11:42:16,386 MainProcess main.Saver WARNING Instantiating a saver obj
EmailID: id4
EmailID: id1
-------------- using q ------------------ main -> We reached this part!
2021-07-01 11:42:16,852 MainProcess main DEBUG We reached this part!
和如下文件：
2021-07-01 11:42:16,385 MainProcess main INFO Starting program at 10 am
2021-07-01 11:42:16,386 MainProcess main.Saver WARNING Instantiating a saver obj
2021-07-01 11:42:16,852 MainProcess main DEBUG We reached this part!
有什么想法吗？
编辑 代码取自：
- https://docs.python.org/3/howto/logging-cookbook.html#a-more-elaborate-multiprocessing-example
和
- https://fanchenbao.medium.com/python3-logging-with-multiprocessing-f51f460b8778
推荐答案
您的工作进程不写入队列。
您的代码似乎基于记录Cookbook的Logging to a single file from multiple processes。您可以在那里看到，工作人员将队列作为参数进行配置(通过worker_configurer)。在您的代码中，您只配置您的经理，而不是您的员工。
只需将self.queue添加到进程参数中，并将(略微编辑)root_configurer方法复制到saver.py中，以便在doStuff启动时调用，即可正常工作。
主题吹毛求疵(您没有要求，但它们是免费的！)：
- 根记录器"；未命名，您可以通过执行
logging.getLogger()(不带参数)获得它。因此，记录器"main"不是根目录。请考虑将其命名为main_logger。 - 保留
breakrecord is None时break的评论，我一开始以为这是个错误。 - 如果第一次
get队列中的记录出现错误，您永远不会设置logger变量，因此异常处理程序将在UnboundLocalError写入stderr之前引发它。 - 您没有编写的信用代码：您提交的内容在很大程度上基于日志记录指南示例。
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