Django Web服务器在启动守护进程后挂起 [英] Django web server hangs after it started a daemon

问题描述

我使用Django开发服务器启动一个守护进程，它执行来自views.py的所有命令，但网页挂起。守护进程正常启动，但网页挂起需要修复。我在Red Hat Enterprise Linux 6.3下工作。

为了确保这不是我或我的守护进程错误，我执行了以下测试：

1）我创建了新的Django项目djtesting，其中创建了一个具有以下代码的view.py文件（它启动httpd守护进程）：

  from django.http import HttpResponse 
 import subprocess 
 
 def hello（request）：
 res = subprocess.call（/ usr / sbin / httpd）
返回HttpResponse（测试）
  

2）添加此功能来自djtesting的url.py：

 从django.conf.urls.defaults导入模式，include，url 
。视图import hello 
 
 urlpatterns = patterns（''，
（'^ hello / $'，hello），
）
  / pre> 
 
 
 3）然后我用python manage.py runserver 192.168.1.226:8000启动Web服务器，并打开带有 http：// 1 92.168.1.226:8000/hello/ 。虽然守护进程正常启动，但它显示测试消息，然后挂起（开始加载和挂起）。但是如果使用/etc/init.d/httpd stop来停止守护进程，网页将停止加载。似乎服务器正在等待，直到守护进程完成工作，但我只需要启动它，而不用等到它结束。
 
 
 
我尝试过另一种方法来运行守护进程（当然每一次尝试一行），但结果相同：
  thread.start_new_thread（os.system，（ '/ usr / sbin / httpd'，））
 process = subprocess.Popen（/ usr / sbin / httpd，stdout = subprocess.PIPE，stdin = subprocess.PIPE，shell = True）
 res = subprocess.call（[/ usr / sbin / httpd，&]）
 res = subprocess.Popen（/ usr / sbin / httpd）
 res = os.system （/ usr / sbin / httpd&）
 res = os.spawnl（os.P_NOWAITO，'/ usr / sbin / httpd'，'&'）
  
我发现了类似的问题，但是由于我在RHEL6.3下工作，我不能使用start-stop-daemon：
 为什么挂起网页上启动了一个守护进程底层服务器？ 
解决方案
  subprocess.call 等待一个返回值，所以我很惊讶，你可以得到一个返回值。尝试使用 subprocess.Popen ，因为产生该过程，然后将控制权返回给您，而不是等待结束。
 
I use Django develpment server to start a daemon, it performs all the commands from the views.py, but web page hangs. Daemon is starting normally but web page hanging needs to be fixed. I work under Red Hat Enterprise Linux 6.3.

To make sure that it's not my or my daemon mistake I performed the following test:

1) I created new Django project "djtesting", where created one views.py file with the following code (it starts httpd daemon):
from django.http import HttpResponse
import subprocess

def hello(request):
    res = subprocess.call("/usr/sbin/httpd")
    return HttpResponse("Testing.")
2) Added this function to urls.py:
from django.conf.urls.defaults import patterns, include, url
from djtesting.views import hello

urlpatterns = patterns('',
    ('^hello/$', hello),
    )
3) Then I started web server with "python manage.py runserver 192.168.1.226:8000" and open web page with "http://192.168.1.226:8000/hello/" in browser. It shows "Testing" message and then hangs (starts loading and hangs on this) although daemon started normally. But if to stop the daemon with "/etc/init.d/httpd stop" the web page stops loading. It seems that the server is waiting until the daemon finish working, but I need just to start it without waiting until it ends.

I've tried another ways to run a daemon (one line per one attempt of course) but with the same poor result:
thread.start_new_thread(os.system, ('/usr/sbin/httpd',))
process = subprocess.Popen("/usr/sbin/httpd", stdout=subprocess.PIPE, stdin=subprocess.PIPE, shell=True)
res = subprocess.call(["/usr/sbin/httpd", "&"])
res = subprocess.Popen("/usr/sbin/httpd")
res = os.system("/usr/sbin/httpd &")
res = os.spawnl(os.P_NOWAITO, '/usr/sbin/httpd', '&')
I've found the similar question but I cannot use start-stop-daemon since I work under RHEL6.3:
Why hangs the web page after it started a daemon on the underlying server?
解决方案
subprocess.call waits for a return value, so I'm rather surprised you're able to get a return value at all. Try using subprocess.Popen instead, as that spawns the process and then returns control back to you rather than waiting for the end.

                        
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