下面是运行任意命令返回其标准输出数据的Python代码,或在非零退出码上引发异常:

proc = subprocess.Popen(
    cmd,
    stderr=subprocess.STDOUT,  # Merge stdout and stderr
    stdout=subprocess.PIPE,
    shell=True)

communication用于等待进程退出:

stdoutdata, stderrdata = proc.communicate()

子进程模块不支持超时——杀死运行超过X秒的进程的能力——因此,通信可能需要很长时间才能运行。

在Windows和Linux上运行的Python程序中实现超时的最简单方法是什么?


当前回答

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()

其他回答

对于python 2.6+,使用gevent

 from gevent.subprocess import Popen, PIPE, STDOUT

 def call_sys(cmd, timeout):
      p= Popen(cmd, shell=True, stdout=PIPE)
      output, _ = p.communicate(timeout=timeout)
      assert p.returncode == 0, p. returncode
      return output

 call_sys('./t.sh', 2)

 # t.sh example
 sleep 5
 echo done
 exit 1

下面是Alex Martelli的解决方案,它是一个具有适当进程终止的模块。其他方法不起作用,因为它们没有使用proc. communication()。所以如果你有一个产生大量输出的进程,它会填满它的输出缓冲区,然后阻塞,直到你从中读取一些东西。

from os import kill
from signal import alarm, signal, SIGALRM, SIGKILL
from subprocess import PIPE, Popen

def run(args, cwd = None, shell = False, kill_tree = True, timeout = -1, env = None):
    '''
    Run a command with a timeout after which it will be forcibly
    killed.
    '''
    class Alarm(Exception):
        pass
    def alarm_handler(signum, frame):
        raise Alarm
    p = Popen(args, shell = shell, cwd = cwd, stdout = PIPE, stderr = PIPE, env = env)
    if timeout != -1:
        signal(SIGALRM, alarm_handler)
        alarm(timeout)
    try:
        stdout, stderr = p.communicate()
        if timeout != -1:
            alarm(0)
    except Alarm:
        pids = [p.pid]
        if kill_tree:
            pids.extend(get_process_children(p.pid))
        for pid in pids:
            # process might have died before getting to this line
            # so wrap to avoid OSError: no such process
            try: 
                kill(pid, SIGKILL)
            except OSError:
                pass
        return -9, '', ''
    return p.returncode, stdout, stderr

def get_process_children(pid):
    p = Popen('ps --no-headers -o pid --ppid %d' % pid, shell = True,
              stdout = PIPE, stderr = PIPE)
    stdout, stderr = p.communicate()
    return [int(p) for p in stdout.split()]

if __name__ == '__main__':
    print run('find /', shell = True, timeout = 3)
    print run('find', shell = True)

仅适用于Linux,但如果有人想使用subprocess.getstatusoutput(),其中timeout参数不可用,您可以在命令的开头使用内置的Linux timeout,即:

import subprocess

timeout = 25 # seconds
cmd = f"timeout --preserve-status --foreground {timeout} ping duckgo.com"
exit_c, out = subprocess.getstatusoutput(cmd)

if (exit_c == 0):
    print("success")
else:
    print("Error: ", out)

超时参数:

——preserve-status:保留退出状态 ——前台:在前台运行 25:超时时间,单位为秒

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"]