development server sometimes takes a long time to restart after source has been changed

[clime]

There are cases when development server takes a long time to restart after sources have been changed. It happens when an exception has been raised. I fix the exception and refresh the page but it keeps throwing the same error. I usually kill the server with ctrl-c to restart it manually. But then comes another problem when I try to start it, that is: "Error: That port is already in use." Django server does not release the port when being killed. Would it be possible to release it so I can start it immediately?

[clime]

One additional note, after ctrl-c, some thread of the server probably keeps running for some time because later I get a message about keyboard interrupt in the console. So that is probably the reason the port is not immediately available in such situations.

[Marc Tamlyn]

I do occasionally see this behaviour. I have no idea what causes it. The thread continuing to run in the background is very annoying and normally I have to resort to kill

[Aymeric Augustin]

Yes, I've seen that too. Last time I hit this problem, I had an infinite loop in a view.

[Claude Paroz]

It would be useful to know on which platform(s) and which exact Django version that behavior arises, as the reload method might be different.

[clime]

Replying to claudep:

It would be useful to know on which platform(s) and which exact Django version that behavior arises, as the reload method might be different.

The first version of Django I have used was 1.4 and I think I have been hitting this issue since beginning. I am totally sure that it is in 1.5 and 1.6.

The platform is linux/fedora. By the way I have just encountered this issue again. This exception was raised:

Environment:


Request Method: GET
Request URL: http://127.0.0.1:8008/messagethreads/

Django Version: 1.6.1
Python Version: 2.7.3
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'south',
 'grappelli',
 'django.contrib.admin',
 'django.contrib.admindocs',
 'endless_pagination',
 'debug_toolbar',
 'djangoratings',
 'imagekit',
 'watson',
 'web')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'middleware.UserMemberMiddleware',
 'middleware.ProfilerMiddleware',
 'middleware.VaryOnAcceptMiddleware',
 'debug_toolbar.middleware.DebugToolbarMiddleware',
 'watson.middleware.SearchContextMiddleware')


Traceback:
File "/srv/www/envs/cb/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  107.                     response = middleware_method(request, callback, callback_args, callback_kwargs)
File "/srv/www/envs/cb/lib/python2.7/site-packages/debug_toolbar/middleware.py" in process_view
  73.             response = panel.process_view(request, view_func, view_args, view_kwargs)
File "/srv/www/envs/cb/lib/python2.7/site-packages/debug_toolbar/panels/profiling.py" in process_view
  133.         return self.profiler.runcall(view_func, *args, **view_kwargs)
File "/usr/lib64/python2.7/cProfile.py" in runcall
  149.             return func(*args, **kw)
File "/srv/www/envs/cb/lib/python2.7/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "/srv/www/cb/web/views.py" in messagethread_list
  1176.         'model_tag': MessageThread.tag,

Exception Type: NameError at /messagethreads/
Exception Value: global name 'model_tag' is not defined

I fixed it and then tried to refresh the page repeatedly. Nevertheless, I was still getting the same exeption. In the end, I lost patience and decided to restart the server (the usual scenario). After killing it by ctrl-c, I tried to restart it:

^C(cb)clime@den /srv/www/cb ./manage.py runserver 127.0.0.1:8008
Validating models...

0 errors found
January 27, 2014 - 18:49:35
Django version 1.6.1, using settings 'cb.settings'
Starting development server at http://127.0.0.1:8008/
Quit the server with CONTROL-C.
Error: That port is already in use.
(cb)clime@den /srv/www/cb $ Exception KeyboardInterrupt in <module 'threading' from '/usr/lib64/python2.7/threading.pyc'> ignored

The KeyboardInterrupt exception appeared around 10 secs later. Then I could finally start the server again.

[mardini]

It's probably not a bug in Django, it might be caused by ThreadingMixIn of Python's SocketServer module, which Django relies on. I didn't investigate it thoroughly though, so I'm not sure.

[mardini]

PR: ​https://github.com/django/django/pull/2690
Thanks.

[Tim Graham <timograham@…>]

In 4f72e5f03ae803fd9faa1445245c1050ca004526:

Fixed #21773 -- made daemon threads default in the development server.

Thanks clime for the report.