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
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"]
其他回答
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
我添加了从jcollado线程到我的Python模块easyprocess的解决方案。
安装:
pip install easyprocess
例子:
from easyprocess import Proc
# shell is not supported!
stdout=Proc('ping localhost').call(timeout=1.5).stdout
print stdout
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()
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。
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()
