Question

似乎有很多方法可以使用python通过命令行调用某些系统进程，然后在进程完成后读取输出。例如，subprocess模块可以通过subprocess.Popen(['ls'])完成此操作。

有没有办法在命令运行时读取的输出？

例如，如果我调用python脚本multiply.py：

import time def multiply(a,b): newA = a newB = b while True: #endless loop newA = newA+1 newB = newB+1 product = newA * newB print 'Product: ',product time.sleep(1) multiply(40,2)

使用subprocess.Popen(['python', 'multiply.py])行的内容，有没有办法

启动流程

在进程运行时静默/主动捕获所有输出

＆＃39;跳进去＆＃39;在任何时候检查整个输出的内容？

上面的python脚本是我对捕获输出感兴趣的一种过程的模型，即有一个无限循环，每秒打印一次输出;正是这个输出我对积极监控/捕获感兴趣。

Answer 1

这是一个在另一个线程上打开进程的实现（因此您不必阻塞主线程）并使用Queue回传线路。使用Event：

按需要杀死该线程

#!/usr/bin/env python

from subprocess import Popen, PIPE
from threading import Thread, Event
from Queue import Queue
from time import sleep

# communicates output lines from process to main thread
lines = Queue()
# kills thread
kill = Event()


def runner():
    p = Popen(["python", "multiply.py"], stdout=PIPE)
    # to get stream behaviour
    while p.poll() is None and not kill.isSet():
        lines.put(p.stdout.readline())

    p.kill()
    # in your use case this is redundant unless the process
    # is terminated externally - because your process is never done
    # after process finished some lines may have been missed
    if not kill.isSet():
        for line in p.stdout.readlines():
            lines.put(line)

# open process on another thread    
t = Thread(target=runner)
t.start()

# do stuff - lines aggregated on the queue    
print "First run"
sleep(1)
while not lines.empty():
    print lines.get()

# move to more important stuff...
sleep(3)

# now check the output we missed
print "Second run"
while not lines.empty():
    print lines.get()

# done doing stuff

# tell thread to kill itself
kill.set()
# wait for thread
t.join()
print "done"

在调用进程仍在运行时使用python读取命令行输出

1 个答案: