从 Django 内部调用时，Subprocess.Popen 与交互式程序一起挂起

发布于 2024-09-13 07:54:36 字数 1338 浏览 3 评论 0原文

我编写了一个小型 Django 应用程序，它根据用户输入执行交互式程序并将输出作为结果返回。但由于某种原因，子进程挂起。在验证日志时，我发现必须给出“\n”作为对挑战的响应的地方，该响应似乎从未做出过。有趣的是，如果我从 Django 外部运行相同的代码，即从 python 模块或交互式 shell 运行相同的代码，子进程可以顺利运行。我假设 Django 使用的环境中的某些设置是罪魁祸首。以下是我编写的代码片段：

def runtests(test_name, selective=False, tests_file=''):
    if selective:
        run_cmd = ['runtest', '--runfromfile', tests_file, test_name]
    else:
        run_cmd = 'runtest %s' % (test_name)
    print 'Executing command .. '
    print run_cmd
    p = subprocess.Popen(run_cmd, shell=False, stdout=subprocess.PIPE,
                        stderr=subprocess.STDOUT)

    return p.stdout.read()

def result(request):
    test_name = request.GET['test_name']
    if not test_name:
        return render_to_response('webrun/execute.html', {'error_flag':True})

    in_file = os.path.abspath('webrun/log/%s_in.xml' % test_name)
    suites = dict([(field[len('suite_'):],value) 
                            for field,value in request.GET.items() 
                            if field.startswith('suite_')])
    if suites:
        _from_dict_to_xml(suites, in_file, test_name)
    output = runtests(test_name, bool(suites), in_file)

    return render_to_response('webrun/result.html', {'output':output})

我尝试用旧的 os.system 方法替换 subprocess 。但即便如此，它也挂在完全相同的地方。同样，如果我从 Django 执行相同的代码，这也会运行。

原文

I have written a small Django App, that executes an interactive program based on user input and returns the output as the result. But for some reason, the subprocess hangs. On verification of the logs I found that a place where a '\n' has to be given as response to a challenge, the response seems to have never been made. Interestingly, if I run the same code from outside of Django, i.e either from a python module or from the interactive shell, subprocess works without a hitch. I am assuming some settings within the environment used by Django are the culprit here. Here are snippets of the code that I've written:

def runtests(test_name, selective=False, tests_file=''):
    if selective:
        run_cmd = ['runtest', '--runfromfile', tests_file, test_name]
    else:
        run_cmd = 'runtest %s' % (test_name)
    print 'Executing command .. '
    print run_cmd
    p = subprocess.Popen(run_cmd, shell=False, stdout=subprocess.PIPE,
                        stderr=subprocess.STDOUT)

    return p.stdout.read()

def result(request):
    test_name = request.GET['test_name']
    if not test_name:
        return render_to_response('webrun/execute.html', {'error_flag':True})

    in_file = os.path.abspath('webrun/log/%s_in.xml' % test_name)
    suites = dict([(field[len('suite_'):],value) 
                            for field,value in request.GET.items() 
                            if field.startswith('suite_')])
    if suites:
        _from_dict_to_xml(suites, in_file, test_name)
    output = runtests(test_name, bool(suites), in_file)

    return render_to_response('webrun/result.html', {'output':output})

I've tried replacing subprocess with the older os.system method. But even that hangs in the exact same place. Again, this runs too if I were execute same code out of Django.

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忘东忘西忘不掉你 2024-09-20 07:54:36

子流程文档建议您“使用communicate()而不是.stdin.write， .stdout.read 或 .stderr.read 以避免由于任何其他操作系统管道缓冲区填满并阻塞子进程而导致的死锁。”

如果您使用 return p.communicate()[0] 而不是 return p.stdout.read() ，它会起作用吗？

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老子叫无熙 2024-09-20 07:54:36

我在执行此类操作以获得 Mercurial Tip 版本时遇到了同样的问题：

import subprocess

lProcess = subprocess.Popen(["hg","tip"], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
lOutput = lProcess.stdout.readline()
lTipRevision = lOutput[10:].strip()
lTipRevision = lTipRevision[:lTipRevision.find(":")].strip()
print "Repository tip version is %s" % lTipRevision

这在通过 apache (mod_wsgi) 运行时工作正常，但会导致开发服务器中出现空白页。

我已经在与此相关的错误中徘徊，我能找到的错误似乎已作为重复或已关闭的工作形式关闭。

我关于此问题的原始帖子可在 http://groups.google.com/group/django-users/browse_thread/thread/147ffe75899fd6e?pli=1

I've had the same issue doing this sort of thing to get the mercurial tip version:

import subprocess

lProcess = subprocess.Popen(["hg","tip"], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
lOutput = lProcess.stdout.readline()
lTipRevision = lOutput[10:].strip()
lTipRevision = lTipRevision[:lTipRevision.find(":")].strip()
print "Repository tip version is %s" % lTipRevision

This works fine when running through apache (mod_wsgi), but causes blank pages in the development server.

I've had a wander around the bugs related to this and the ones I could find seems to be closed as duplicate, or closed worksforme.

My original post about this is available at http://groups.google.com/group/django-users/browse_thread/thread/147ffe75899fd6e?pli=1

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