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?
我对底层细节了解不多;但是,考虑到这一点
python 2.6的API提供了等待线程和的能力
终止进程,那么在一个单独的进程中运行该进程呢
的线程吗?
import subprocess, threading
class Command(object):
def __init__(self, cmd):
self.cmd = cmd
self.process = None
def run(self, timeout):
def target():
print 'Thread started'
self.process = subprocess.Popen(self.cmd, shell=True)
self.process.communicate()
print 'Thread finished'
thread = threading.Thread(target=target)
thread.start()
thread.join(timeout)
if thread.is_alive():
print 'Terminating process'
self.process.terminate()
thread.join()
print self.process.returncode
command = Command("echo 'Process started'; sleep 2; echo 'Process finished'")
command.run(timeout=3)
command.run(timeout=1)
这段代码在我的机器中的输出是:
Thread started
Process started
Process finished
Thread finished
0
Thread started
Process started
Terminating process
Thread finished
-15
在哪里可以看到,在第一次执行的过程
正确完成(返回代码0),而在第二个
进程被终止(返回代码-15)。
我没有在windows中测试;但是,除了更新示例之外
命令,我想它应该工作,因为我还没有找到
记录任何说明该线程的内容。Join或process.terminate
不支持。
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()
This solution kills the process tree in case of shell=True, passes parameters to the process (or not), has a timeout and gets the stdout, stderr and process output of the call back (it uses psutil for the kill_proc_tree). This was based on several solutions posted in SO including jcollado's. Posting in response to comments by Anson and jradice in jcollado's answer. Tested in Windows Srvr 2012 and Ubuntu 14.04. Please note that for Ubuntu you need to change the parent.children(...) call to parent.get_children(...).
def kill_proc_tree(pid, including_parent=True):
parent = psutil.Process(pid)
children = parent.children(recursive=True)
for child in children:
child.kill()
psutil.wait_procs(children, timeout=5)
if including_parent:
parent.kill()
parent.wait(5)
def run_with_timeout(cmd, current_dir, cmd_parms, timeout):
def target():
process = subprocess.Popen(cmd, cwd=current_dir, shell=True, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
# wait for the process to terminate
if (cmd_parms == ""):
out, err = process.communicate()
else:
out, err = process.communicate(cmd_parms)
errcode = process.returncode
thread = Thread(target=target)
thread.start()
thread.join(timeout)
if thread.is_alive():
me = os.getpid()
kill_proc_tree(me, including_parent=False)
thread.join()
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()