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)

虽然我还没有广泛地研究它，但我在ActiveState中发现的这个装饰器似乎对这类事情非常有用。伴随着subprocess.Popen(…， close_fds=True)，至少我已经准备好在Python中编写shell脚本。

我已经实现了我能从其中一些收集到的东西。这适用于Windows，因为这是一个社区维基，我想我也会分享我的代码:

class Command(threading.Thread):
    def __init__(self, cmd, outFile, errFile, timeout):
        threading.Thread.__init__(self)
        self.cmd = cmd
        self.process = None
        self.outFile = outFile
        self.errFile = errFile
        self.timed_out = False
        self.timeout = timeout

    def run(self):
        self.process = subprocess.Popen(self.cmd, stdout = self.outFile, \
            stderr = self.errFile)

        while (self.process.poll() is None and self.timeout > 0):
            time.sleep(1)
            self.timeout -= 1

        if not self.timeout > 0:
            self.process.terminate()
            self.timed_out = True
        else:
            self.timed_out = False

然后从另一个类或文件:

        outFile =  tempfile.SpooledTemporaryFile()
        errFile =   tempfile.SpooledTemporaryFile()

        executor = command.Command(c, outFile, errFile, timeout)
        executor.daemon = True
        executor.start()

        executor.join()
        if executor.timed_out:
            out = 'timed out'
        else:
            outFile.seek(0)
            errFile.seek(0)
            out = outFile.read()
            err = errFile.read()

        outFile.close()
        errFile.close()

我已经修改了sussudio的答案。现在函数返回:(returncode, stdout, stderr, timeout) - stdout和stderr被解码为utf-8字符串

def kill_proc(proc, timeout):
  timeout["value"] = True
  proc.kill()

def run(cmd, timeout_sec):
  proc = subprocess.Popen(shlex.split(cmd), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  timeout = {"value": False}
  timer = Timer(timeout_sec, kill_proc, [proc, timeout])
  timer.start()
  stdout, stderr = proc.communicate()
  timer.cancel()
  return proc.returncode, stdout.decode("utf-8"), stderr.decode("utf-8"), timeout["value"]

有一个想法是子类化Popen类并用一些简单的方法装饰器来扩展它。我们叫它ExpirablePopen吧。

from logging import error
from subprocess import Popen
from threading import Event
from threading import Thread


class ExpirablePopen(Popen):

    def __init__(self, *args, **kwargs):
        self.timeout = kwargs.pop('timeout', 0)
        self.timer = None
        self.done = Event()

        Popen.__init__(self, *args, **kwargs)

    def __tkill(self):
        timeout = self.timeout
        if not self.done.wait(timeout):
            error('Terminating process {} by timeout of {} secs.'.format(self.pid, timeout))
            self.kill()

    def expirable(func):
        def wrapper(self, *args, **kwargs):
            # zero timeout means call of parent method
            if self.timeout == 0:
                return func(self, *args, **kwargs)

            # if timer is None, need to start it
            if self.timer is None:
                self.timer = thr = Thread(target=self.__tkill)
                thr.daemon = True
                thr.start()

            result = func(self, *args, **kwargs)
            self.done.set()

            return result
        return wrapper

    wait = expirable(Popen.wait)
    communicate = expirable(Popen.communicate)


if __name__ == '__main__':
    from subprocess import PIPE

    print ExpirablePopen('ssh -T git@bitbucket.org', stdout=PIPE, timeout=1).communicate()

在Python 3.3+中:

from subprocess import STDOUT, check_output

output = check_output(cmd, stderr=STDOUT, timeout=seconds)

输出是一个字节字符串，包含命令合并的标准输出、标准输出数据。

与proc. communication()方法不同，check_output在问题文本中指定的非零退出状态上引发CalledProcessError。

我删除了shell=True，因为它经常被不必要地使用。如果cmd确实需要它，您总是可以将它添加回来。如果你添加shell=True，也就是说，如果子进程产生了自己的后代;check_output()的返回时间可能比超时时间晚得多，请参见子进程超时失败。

超时特性在Python 2中可用。X通过3.2+ subprocess模块的subprocess32后端端口实现。