Jcollado的答案可以使用线程来简化。定时器类:

import shlex
from subprocess import Popen, PIPE
from threading import Timer

def run(cmd, timeout_sec):
    proc = Popen(shlex.split(cmd), stdout=PIPE, stderr=PIPE)
    timer = Timer(timeout_sec, proc.kill)
    try:
        timer.start()
        stdout, stderr = proc.communicate()
    finally:
        timer.cancel()

# Examples: both take 1 second
run("sleep 1", 5)  # process ends normally at 1 second
run("sleep 5", 1)  # timeout happens at 1 second

如果你用的是Unix，

import signal
  ...
class Alarm(Exception):
    pass

def alarm_handler(signum, frame):
    raise Alarm

signal.signal(signal.SIGALRM, alarm_handler)
signal.alarm(5*60)  # 5 minutes
try:
    stdoutdata, stderrdata = proc.communicate()
    signal.alarm(0)  # reset the alarm
except Alarm:
    print "Oops, taking too long!"
    # whatever else

另一种选择是写入临时文件以防止标准输出阻塞，而不需要使用communication()轮询。在其他答案没有的地方，这个方法对我有用;比如在窗户上。

    outFile =  tempfile.SpooledTemporaryFile() 
    errFile =   tempfile.SpooledTemporaryFile() 
    proc = subprocess.Popen(args, stderr=errFile, stdout=outFile, universal_newlines=False)
    wait_remaining_sec = timeout

    while proc.poll() is None and wait_remaining_sec > 0:
        time.sleep(1)
        wait_remaining_sec -= 1

    if wait_remaining_sec <= 0:
        killProc(proc.pid)
        raise ProcessIncompleteError(proc, timeout)

    # read temp streams from start
    outFile.seek(0);
    errFile.seek(0);
    out = outFile.read()
    err = errFile.read()
    outFile.close()
    errFile.close()

有时需要处理(ffmpeg)而不使用communication()，在这种情况下需要异步超时，这是使用ttldict实现的一种实用方法

PIP安装ttldict

from ttldict import  TTLOrderedDict   
sp_timeout = TTLOrderedDict(default_ttl=10)

def kill_on_timeout(done, proc):
    while True:
        now = time.time()
        if sp_timeout.get('exp_time') == None:
                proc.kill()
                break
    
process = subprocess.Popen(cmd, stdout=subprocess.PIPE, text=True, stderr=subprocess.STDOUT)
            
sp_timeout['exp_time'] = time.time()
            
done = Event()
watcher = Thread(target=kill_on_timeout, args=(done, process))
watcher.daemon = True
watcher.start()
done.set()

for line in process.stdout:
.......

一旦你理解了在*unix中运行机器的整个过程，你将很容易找到更简单的解决方案:

考虑这个简单的例子，如何使用select.select()(现在几乎在*nix上随处可见)创建可超时的communication()冰毒。这也可以用epoll/poll/kqueue来编写，但select.select()变体可能是一个很好的例子。select.select()的主要限制(速度和1024 max fds)不适用于您的任务。

它在*nix下工作，不创建线程，不使用信号，可以从任何线程启动(不仅仅是主线程)，并且足够快，可以从我机器上的stdout读取250mb/s的数据(i5 2.3ghz)。

在通信结束时连接stdout/stderr时出现问题。如果你有大量的程序输出，这可能会导致大量的内存使用。但是您可以多次调用communication()，超时时间较小。

class Popen(subprocess.Popen):
    def communicate(self, input=None, timeout=None):
        if timeout is None:
            return subprocess.Popen.communicate(self, input)

        if self.stdin:
            # Flush stdio buffer, this might block if user
            # has been writing to .stdin in an uncontrolled
            # fashion.
            self.stdin.flush()
            if not input:
                self.stdin.close()

        read_set, write_set = [], []
        stdout = stderr = None

        if self.stdin and input:
            write_set.append(self.stdin)
        if self.stdout:
            read_set.append(self.stdout)
            stdout = []
        if self.stderr:
            read_set.append(self.stderr)
            stderr = []

        input_offset = 0
        deadline = time.time() + timeout

        while read_set or write_set:
            try:
                rlist, wlist, xlist = select.select(read_set, write_set, [], max(0, deadline - time.time()))
            except select.error as ex:
                if ex.args[0] == errno.EINTR:
                    continue
                raise

            if not (rlist or wlist):
                # Just break if timeout
                # Since we do not close stdout/stderr/stdin, we can call
                # communicate() several times reading data by smaller pieces.
                break

            if self.stdin in wlist:
                chunk = input[input_offset:input_offset + subprocess._PIPE_BUF]
                try:
                    bytes_written = os.write(self.stdin.fileno(), chunk)
                except OSError as ex:
                    if ex.errno == errno.EPIPE:
                        self.stdin.close()
                        write_set.remove(self.stdin)
                    else:
                        raise
                else:
                    input_offset += bytes_written
                    if input_offset >= len(input):
                        self.stdin.close()
                        write_set.remove(self.stdin)

            # Read stdout / stderr by 1024 bytes
            for fn, tgt in (
                (self.stdout, stdout),
                (self.stderr, stderr),
            ):
                if fn in rlist:
                    data = os.read(fn.fileno(), 1024)
                    if data == '':
                        fn.close()
                        read_set.remove(fn)
                    tgt.append(data)

        if stdout is not None:
            stdout = ''.join(stdout)
        if stderr is not None:
            stderr = ''.join(stderr)

        return (stdout, stderr)

不幸的是，我的雇主在公开源代码方面有非常严格的规定，所以我不能提供实际的代码。但对我来说，最好的解决方案是创建一个子类重写Popen.wait()来轮询，而不是无限期地等待。__init__接受超时参数。一旦你这样做，所有其他Popen方法(调用等待)将按预期工作，包括通信。