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
您可以使用select来完成此操作
import subprocess
from datetime import datetime
from select import select
def call_with_timeout(cmd, timeout):
started = datetime.now()
sp = subprocess.Popen(cmd, stdout=subprocess.PIPE)
while True:
p = select([sp.stdout], [], [], timeout)
if p[0]:
p[0][0].read()
ret = sp.poll()
if ret is not None:
return ret
if (datetime.now()-started).total_seconds() > timeout:
sp.kill()
return None
其他回答
在Python 3.7.8中超时测试后捕获的输出示例:
try:
return subprocess.run(command, shell=True, capture_output=True, timeout=20, cwd=cwd, universal_newlines=True)
except subprocess.TimeoutExpired as e:
print(e.output.decode(encoding="utf-8", errors="ignore"))
assert False;
异常子进程。TimeoutExpired有输出和其他成员:
cmd -用于生成子进程的命令。 timeout -超时时间，单位为秒。 output -子进程的输出，如果它是由run()或 check_output()。否则,没有。 stdout -输出的别名，用于与stderr对称。 stderr -子进程的stderr输出，如果它被捕获 run()。否则,没有。
更多信息:https://docs.python.org/3/library/subprocess.html#subprocess.TimeoutExpired
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
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)
只是想写些简单点的东西。
#!/usr/bin/python
from subprocess import Popen, PIPE
import datetime
import time
popen = Popen(["/bin/sleep", "10"]);
pid = popen.pid
sttime = time.time();
waittime = 3
print "Start time %s"%(sttime)
while True:
popen.poll();
time.sleep(1)
rcode = popen.returncode
now = time.time();
if [ rcode is None ] and [ now > (sttime + waittime) ] :
print "Killing it now"
popen.kill()
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()
