問題描述

由于它的并發(fā)期貨模塊，我剛剛轉(zhuǎn)向 python3.我想知道是否可以讓它檢測錯誤.我想使用并發(fā)期貨來并行程序，如果有更高效的模塊請告訴我.

I have just moved on to python3 as a result of its concurrent futures module. I was wondering if I could get it to detect errors. I want to use concurrent futures to parallel program, if there are more efficient modules please let me know.

我不喜歡多處理，因為它太復(fù)雜而且沒有多少文檔可用.但是，如果有人可以編寫一個沒有類的 Hello World，只使用多處理并行計算的函數(shù)，這樣它就很容易理解了，那就太好了.

I do not like multiprocessing as it is too complicated and not much documentation is out. It would be great however if someone could write a Hello World without classes only functions using multiprocessing to parallel compute so that it is easy to understand.

這是一個簡單的腳本:

from concurrent.futures import ThreadPoolExecutor

def pri():
    print("Hello World!!!")

def start():
    try:
        while True:
            pri()
    except KeyBoardInterrupt:
        print("YOU PRESSED CTRL+C")


with ThreadPoolExecutor(max_workers=3) as exe:
    exe.submit(start)

以上代碼只是一個演示，說明 CTRL+C 如何無法打印語句.

The above code was just a demo, of how CTRL+C will not work to print the statement.

我想要的是能夠調(diào)用函數(shù)是存在錯誤.這種錯誤檢測必須來自函數(shù)本身.

What I want is to be able to call a function is an error is present. This error detection must be from the function itself.

另一個例子

import socket
from concurrent.futures import ThreadPoolExecutor 
s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
def con():
    try:
        s.connect((x,y))
        main()
    except: socket.gaierror
         err()
def err():
    time.sleep(1)
    con()
def main():
    s.send("[+] Hello")
with ThreadPoolExecutor as exe:
    exe.submit(con)

推薦答案

這里的解決方案.我不確定你是否喜歡它，但我想不出其他的.我已經(jīng)修改了您的代碼以使其正常工作.

Here's a solution. I'm not sure you like it, but I can't think of any other. I've modified your code to make it work.

from concurrent.futures import ThreadPoolExecutor
import time

quit = False

def pri():
    print("Hello World!!!")

def start():
    while quit is not True:
        time.sleep(1)
        pri()

try:
    pool = ThreadPoolExecutor(max_workers=3)
    pool.submit(start)

    while quit is not True:
        print("hei")
        time.sleep(1)
except KeyboardInterrupt:
    quit = True

以下是要點:

1. 當(dāng)您使用 with ThreadPoolExecutor(max_workers=3) as exe 時，它會等待所有任務(wù)完成.看看 Doc

1. When you use with ThreadPoolExecutor(max_workers=3) as exe, it waits until all tasks have been done. Have a look at Doc

如果 wait 為 True，則此方法將不會返回，直到所有未決的期貨都執(zhí)行完畢并且與執(zhí)行程序關(guān)聯(lián)的資源已被釋放.如果 wait 為 False，則此方法將立即返回，并且當(dāng)所有未決的期貨執(zhí)行完畢后，與執(zhí)行程序關(guān)聯(lián)的資源將被釋放.無論 wait 的值如何，整個 Python 程序都不會退出，直到所有未決的期貨都執(zhí)行完畢.

If wait is True then this method will not return until all the pending futures are done executing and the resources associated with the executor have been freed. If wait is False then this method will return immediately and the resources associated with the executor will be freed when all pending futures are done executing. Regardless of the value of wait, the entire Python program will not exit until all pending futures are done executing.

如果您使用 with 語句，您可以避免顯式調(diào)用此方法，該語句將關(guān)閉 Executor(就像 Executor.shutdown() 一樣等待 被調(diào)用，等待設(shè)置為 True)

You can avoid having to call this method explicitly if you use the with statement, which will shutdown the Executor (waiting as if Executor.shutdown() were called with wait set to True)

這就像在線程上調(diào)用 join().
這就是為什么我將其替換為:

It's like calling join() on a thread.
That's why I replaced it with:

pool = ThreadPoolExecutor(max_workers=3)
pool.submit(start)

import socket
import time
from concurrent.futures import ThreadPoolExecutor 
s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

def con():
    try:
        raise socket.gaierror
        main()
    except socket.gaierror:
        print("gaierror occurred")
        err()

def err():
    print("err invoked")
    time.sleep(1)
    con()

def main():
    s.send("[+] Hello")

with ThreadPoolExecutor(3) as exe:
    exe.submit(con)

gaierror occurred
err invoked
gaierror occurred
err invoked
gaierror occurred
err invoked
gaierror occurred
...