Question

这个片段会在Windows中ping一个ip地址并且每2秒获得一次输出行，但是，我发现运行它后ping.exe进程的内存增长很慢，如果我将它部署到ping 1000 ip parallel，很快它会导致服务器挂起，我认为可能是因为stdout缓冲区，我可能知道如何清除标准输出或限制其大小？谢谢！

...
proc = subprocess.Popen(['c:\windows\system32\ping.exe','127.0.0.1', '-l', '10000', '-t'],stdout=subprocess.PIPE, creationflags=subprocess.CREATE_NEW_PROCESS_GROUP) 

while True: 
    time.sleep(2)
    os.kill(proc.pid, signal.CTRL_BREAK_EVENT) 
    line = proc.stdout.readline()

Answer 1

由于读取之间的2秒超时，ping正在生成比您正在读取的更多行。我将os.kill调用移动到另一个线程，并使用主线程从proc.stdout读取每一行：

import sys, os
import subprocess
import threading
import signal
import time

#Use ctrl-c and ctrl-break to terminate the script/ping

def sigbreak(signum, frame):
    import sys
    if proc.poll() is None:
        print('Killing ping...')
        proc.kill()
    sys.exit(0)

signal.signal(signal.SIGBREAK, sigbreak)
signal.signal(signal.SIGINT, sigbreak)

#executes in a separate thread
def run(pid):
    while True:
        time.sleep(2)
        try: 
            os.kill(pid, signal.CTRL_BREAK_EVENT)
        except WindowsError:
            #quit the thread if ping is dead 
            break

cmd = [r'c:\windows\system32\ping.exe', '127.0.0.1', '-l', '10000', '-t']
flags = subprocess.CREATE_NEW_PROCESS_GROUP
proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, creationflags=flags)
threading.Thread(target=run, args=(proc.pid,)).start()

while True:
    line = proc.stdout.readline()
    if b'statistics' in line:
        #I don't know what you're doing with the ping stats.
        #I'll just print them.
        for n in range(4):
            encoding = getattr(sys.stdout, 'encoding', 'ascii') 
            print(line.decode(encoding).rstrip())
            line = proc.stdout.readline()
        print()

Answer 2

尝试使用ping.py，而不是使用ping.exe

如何在Python子进程中清除stdout？

2 个答案: