tl;dr 我生成了 3 个线程,每个线程都会抛出一个异常,这是引发所有 3 个异常的最 Pythonic 方式吗?
下面是一个与我正在做的类似的代码示例。
from multiprocessing.pool import ThreadPool
def fail_func(host):
raise Exception('{} FAILED!!!'.format(host))
hosts = ['172.1.1.1', '172.1.1.2', '172.1.1.3']
pool = ThreadPool(processes=5)
workers = [pool.apply_async(fail_func(host)) for host in hosts]
# join and close thread pool
pool.join(); pool.close()
# get the exceptions
[worker.get() for worker in workers if not worker.successful()]
它最终所做的只是在第一台主机上失败并出现以下回溯:
Traceback (most recent call last):
File "thread_exception_example.py", line 8, in <module>
workers = [pool.apply_async(fail_func(host)) for host in hosts]
File "thread_exception_example.py", line 4, in fail_func
raise Exception('{} FAILED!!!'.format(host))
Exception: 172.1.1.1 FAILED!!!
但我想要它做的是为每个失败的线程引发多个异常,如下所示:
Traceback (most recent call last):
File "thread_exception_example.py", line 8, in <module>
workers = [pool.apply_async(fail_func(host)) for host in hosts]
File "thread_exception_example.py", line 4, in fail_func
raise Exception('{} FAILED!!!'.format(host))
Exception: 172.1.1.1 FAILED!!!
Traceback (most recent call last):
File "thread_exception_example.py", line 8, in <module>
workers = [pool.apply_async(fail_func(host)) for host in hosts]
File "thread_exception_example.py", line 4, in fail_func
raise Exception('{} FAILED!!!'.format(host))
Exception: 172.1.1.2 FAILED!!!
Traceback (most recent call last):
File "thread_exception_example.py", line 8, in <module>
workers = [pool.apply_async(fail_func(host)) for host in hosts]
File "thread_exception_example.py", line 4, in fail_func
raise Exception('{} FAILED!!!'.format(host))
Exception: 172.1.1.3 FAILED!!!
有没有Pythonic的方法可以做到这一点?或者我是否需要将所有内容包装在 try/except 中,收集所有消息,然后重新引发单个异常?
最佳答案
没有办法“引发多个异常”。在给定的异常上下文中,要么存在异常,要么不存在。
所以,是的,您必须创建一个包含所有异常的包装异常,并引发它。但您几乎已经获得了所需的所有代码:
def get_exception():
try:
worker.get()
except Exception as e:
return e
现在,而不是:
[worker.get() for worker in workers if not worker.successful()]
...你可以这样做:
[get_exception(worker.get) for worker in workers if not worker.successful()]
这是一个异常(exception)列表。
就我个人而言,我一直认为 AsyncResult
应该有一个 exception
方法,类似于 concurrent.futures.Future
中的方法。 。但我会首先在这里使用 futures
(如果我被迫使用 Python 2.x,则安装 backport)。
关于python - 从 Python 中的线程引发多个异常,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18282906/