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问题:
I've been developing a Django web application deployed on an Apache server with WSGI, and everything has been going smoothly. Today, I made some minor changes to my app's admin.py in an attempt to customize the build-in Django Admin interface, and initially made a syntax error (an unclosed parenthesis). This meant that when I touched wsgi.py and loaded the code (I have WSGI running in daemon mode on my virtual host), my website was replaced with an Internal Server Error because WSGI stopped when it hit the syntax error.
So I fixed the syntax error, checked that I didn't have any more with manage.py check, and touched wsgi.py to redeploy. But my website still displays an Internal Server Error! Checking the Apache logs, this is what I see:
[Sun Nov 23 13:52:46 2014] [info] mod_wsgi (pid=19093): Create interpreter 'quotes.cs.cornell.edu|'. [Sun Nov 23 13:52:46 2014] [info] mod_wsgi (pid=19093): Adding '/extra/www/html/quotes/quotes_django' to path. [Sun Nov 23 13:52:46 2014] [info] mod_wsgi (pid=19093): Adding '/opt/rh/python27/root/usr/lib64/python2.7/site- packages/' to path. [Sun Nov 23 13:52:46 2014] [info] [client 128.84.33.19] mod_wsgi (pid=19093, process='quotes.cs.cornell.edu', application='quotes.cs.cornell.edu|'): Loading WSGI script '/extra/www/html/quotes/quotes_django/quotes_django/ wsgi.py'. [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Target WSGI script '/extra/www/html/ quotes/quotes_django/quotes_django/wsgi.py' cannot be loaded as Python module. [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Exception occurred processing WSGI script '/extra/www/html/quotes/quotes_django/quotes_django/wsgi.py'. [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] Traceback (most recent call last): [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/extra/www/html/quotes/quotes_django/ quotes_django/wsgi.py", line 14, in [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] application = get_wsgi_application() [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/core/wsgi.py", line 14, in get_wsgi_application [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] django.setup() [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/__init__.py", line 21, in setup [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] apps.populate(settings.INSTALLED_APPS) [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/apps/registry.py", line 115, in populate [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] app_config.ready() [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/contrib/admin/apps.py", line 22, in ready [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] self.module.autodiscover() [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/contrib/admin/__init__.py", line 23, in autodiscover [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] autodiscover_modules('admin', register_to=site) [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/utils/module_loading.py", line 74, in autodiscover_modules [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] import_module('%s.%s' % (app_config.name, module_to_search)) [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/usr/lib64/python2.7/importlib/__init__.py", line 37, in import_module [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] __import__(name) [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] File "/extra/www/html/quotes/quotes_django/quotespage/ admin.py", line 25 [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] approve_quotes.short_description = "Approve selected quotes" [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] ^ [Sun Nov 23 13:52:46 2014] [error] [client 128.84.33.19] SyntaxError: invalid syntax [Sun Nov 23 13:53:36 2014] [info] [client 128.84.33.19] mod_wsgi (pid=19093, process='quotes.cs.cornell.edu', application='quotes.cs.cornell.edu|'): Loading WSGI script '/extra/www/html/quotes/quotes_django/quotes_django/ wsgi.py'. [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Target WSGI script '/extra/www/html/ quotes/quotes_django/quotes_django/wsgi.py' cannot be loaded as Python module. [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] mod_wsgi (pid=19093): Exception occurred processing WSGI script '/extra/www/html/quotes/quotes_django/quotes_django/wsgi.py'. [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] Traceback (most recent call last): [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/extra/www/html/quotes/quotes_django/ quotes_django/wsgi.py", line 14, in [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] application = get_wsgi_application() [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/core/wsgi.py", line 14, in get_wsgi_application [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] django.setup() [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/__init__.py", line 21, in setup [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] apps.populate(settings.INSTALLED_APPS) [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] File "/opt/rh/python27/root/usr/lib64/python2.7/site- packages/django/apps/registry.py", line 78, in populate [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] raise RuntimeError("populate() isn't reentrant") [Sun Nov 23 13:53:36 2014] [error] [client 128.84.33.19] RuntimeError: populate() isn't reentrant
The first series of errors shows WSGI failing due to the syntax error in my admin.py. However, the second series of errors seems to show an error internal to Django:
RuntimeError: populate() isn't reentrant
thrown from the populate method of registry.py.
Googling this error message returns surprisingly little information, none of it from Django documentation. Apparently, it can sometimes happen if you name an app twice in your settings.py, but I'm not doing that. More importantly, I haven't changed settings.py since the point where the website was working fine -- the only thing I changed was admin.py.
I tried reverting all the changes I made, so all my Python code is back in the state it was when the website was working -- and I still get the populate() isn't reentrant error when I try to make WSGI reload the code!
I've also tried commenting-out different apps in the INSTALLED_APPS section of settings.py, and even with only 'django.contrib.staticfiles' enabled the error still happens. Weirdly, I still get the error even if I comment out all the apps -- Django throws the error even when it isn't loading any apps!
Does anyone know what's going on here? Or any better way for me to debug this error, since the traceback in the Apache log is pretty unhelpful?
Notes: I'm using Django 1.7, Apache 2.2, and Python 2.7.
回答1:
My server's administrator restarted Apache, and that magically fixed this problem. The exact same Python files loaded without causing populate() isn't reentrant. I even tried loading another file with a syntax error, then fixing it, and the server was able to load the new file and run correctly with no problems.
I still don't know what was going wrong, but I'm marking this as answered since the problem is gone. (Well, I'll mark it as answered as soon as StackOverflow allows me to accept my own answer.)
Update: After continuing to get this error when I accidentally upload Python with syntax errors, I figured out a workaround that's easier than restarting Apache. When WSGI starts throwing the populate() isn't reentrant error, I replace my Django project's wsgi.py with this simple function:
def application(environ, start_response): if environ['mod_wsgi.process_group'] != '': import signal os.kill(os.getpid(), signal.SIGINT) return ["killed"]
Then I reload my website, and the WSGI daemon process restarts (which I can tell by looking at the Apache log, even though the website still displays the same 500 error).
If I then change wsgi.py back to normal and reload again, WSGI successfully picks up my code without throwing populate() isn't reentrant (assuming I have no syntax errors this time). So the entirety of Apache doesn't need to restart, just the WSGI process, and I can do that without root privileges.
回答2:
I know this is an old answer but I will contribute with my solution:
As a way to diagnose the source of the problem run manage.py checkand see if you find anything there
In my case an outdated requirement was the issue and django was failing to import a submodule
Make sure that your requirements are up to date
回答3:
If you're getting this error when using Google App Engine check your logs for other errors which might be causing this. I was getting:
ImproperlyConfigured: Error loading either pysqlite2 or sqlite3 modules (tried in that order): No module named _sqlite3
You can't use SQLite with Google App Engine so commenting out the DATABASES section of settings.py stopped that error and the RuntimeError("populate() isn't reentrant") error as well.
回答4:
It's not a response but a reflexion.
When you upgrade to django 1.7 and you have a 500 error and reload your page, Apache says "pupulate() isn't reentrant". I think it's when you load your page, Apache load all the modules you need for your app and when the error is handle it doesn't unload module. So, when you reload your page, apache load again theses modules but it's already loaded. So, apache says "populate() isn't reentrant".
I've two actions to correct this : Restart apache, or correct the error that handle the first 5OO error.
I hope it will help you.
回答5:
You may be able to fix it without restarting Apache by touching a file (other than wsgi.py) that is early on in the loading process. For example, your settings file:
$ touch settings.py
I haven't properly solved this either, but more info in my question here: Code change monitoring malfunctioning with Django 1.7 on mod-wsgi
回答6:
This looks like a nice collection of valid responses for the same Apache mod-wsgi error, each guy posting the one that works for him/her, so here is mine:
Do not forget to update your project requirements after deploying :)
回答7:
Apache stores the wsgi file in its cache. Disable Apache caching of python files
So first delete the wsgi file and restart your acpache and then add wsgi file again and restart the apache.
回答8:
I just faced the same problem so I started looking around.
Now I've got it working, so I thought I should share it with you guys!
All I did was do chown user:group /to/path -R and chmod 770 /to/path -R all over again and it worked.
回答9:
Setup: Ubuntu 14.04, Django 1.10, Python 3.5 (in virtualenv).
I tried many of these solutions without luck, but then I noticed that the Apache error log contains two different errors in my case. One that happens when someone tries to visit a page, another that happens at start up. I missed the startup one because I usually tried to refresh the page a couple of times and thus only saw the on visit error repeated a few times.
I then searched for solutions to the startup error instead and the solution to this question worked for me. Briefly, it involves updating the mod_wsgi package in a roundabout way.
I had been receiving warnings for months about the mismatch in mod_wsgi versions, but suddenly it resulted in Apache error 500's. Doesn't make any sense to me.
My guess is that this RuntimeError: populate() isn't reentrant error is usually a sign that one should look for a startup error, which indicates the real problem.
on visit
[Sat Oct 15 03:38:08.900966 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] mod_wsgi (pid=28272): Target WSGI script '/django/GP/GP/wsgi.py' cannot be loaded as Python module. [Sat Oct 15 03:38:08.901409 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] mod_wsgi (pid=28272): Exception occurred processing WSGI script '/django/GP/GP/wsgi.py'. [Sat Oct 15 03:38:08.901662 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] Traceback (most recent call last): [Sat Oct 15 03:38:08.902184 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/GP/GP/wsgi.py", line 16, in [Sat Oct 15 03:38:08.902217 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] application = get_wsgi_application() [Sat Oct 15 03:38:08.902501 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/env/lib/python3.5/site-packages/django/core/wsgi.py", line 13, in get_wsgi_application [Sat Oct 15 03:38:08.902529 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] django.setup(set_prefix=False) [Sat Oct 15 03:38:08.902726 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/env/lib/python3.5/site-packages/django/__init__.py", line 27, in setup [Sat Oct 15 03:38:08.902755 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] apps.populate(settings.INSTALLED_APPS) [Sat Oct 15 03:38:08.902924 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/env/lib/python3.5/site-packages/django/apps/registry.py", line 78, in populate [Sat Oct 15 03:38:08.902953 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] raise RuntimeError("populate() isn't reentrant") [Sat Oct 15 03:38:08.903111 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] RuntimeError: populate() isn't reentrant
start up
[Sat Oct 15 03:38:08.900966 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] mod_wsgi (pid=28272): Target WSGI script '/django/GP/GP/wsgi.py' cannot be loaded as Python module. [Sat Oct 15 03:38:08.901409 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] mod_wsgi (pid=28272): Exception occurred processing WSGI script '/django/GP/GP/wsgi.py'. [Sat Oct 15 03:38:08.901662 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] Traceback (most recent call last): [Sat Oct 15 03:38:08.902184 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/GP/GP/wsgi.py", line 16, in [Sat Oct 15 03:38:08.902217 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] application = get_wsgi_application() [Sat Oct 15 03:38:08.902501 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/env/lib/python3.5/site-packages/django/core/wsgi.py", line 13, in get_wsgi_application [Sat Oct 15 03:38:08.902529 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] django.setup(set_prefix=False) [Sat Oct 15 03:38:08.902726 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/env/lib/python3.5/site-packages/django/__init__.py", line 27, in setup [Sat Oct 15 03:38:08.902755 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] apps.populate(settings.INSTALLED_APPS) [Sat Oct 15 03:38:08.902924 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] File "/django/env/lib/python3.5/site-packages/django/apps/registry.py", line 78, in populate [Sat Oct 15 03:38:08.902953 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] raise RuntimeError("populate() isn't reentrant") [Sat Oct 15 03:38:08.903111 2016] [:error] [pid 28272] [remote 95.166.81.114:39651] RuntimeError: populate() isn't reentrant [Sat Oct 15 03:38:43.291502 2016] [:error] [pid 28272] Exception ignored in: [Sat Oct 15 03:38:43.291579 2016] [:error] [pid 28272] Traceback (most recent call last): [Sat Oct 15 03:38:43.291604 2016] [:error] [pid 28272] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Sat Oct 15 03:38:43.292356 2016] [:error] [pid 28272] assert tlock is not None [Sat Oct 15 03:38:43.292377 2016] [:error] [pid 28272] AssertionError: [Fri Oct 14 23:38:43.412942 2016] [:error] [pid 28299] Exception ignored in: [Fri Oct 14 23:38:43.413044 2016] [:error] [pid 28299] Traceback (most recent call last): [Fri Oct 14 23:38:43.413076 2016] [:error] [pid 28299] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Fri Oct 14 23:38:43.425037 2016] [:error] [pid 28275] Exception ignored in: [Fri Oct 14 23:38:43.425125 2016] [:error] [pid 28275] Traceback (most recent call last): [Fri Oct 14 23:38:43.425157 2016] [:error] [pid 28275] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Fri Oct 14 23:38:43.427625 2016] [:error] [pid 28274] Exception ignored in: [Fri Oct 14 23:38:43.427694 2016] [:error] [pid 28274] Traceback (most recent call last): [Fri Oct 14 23:38:43.427722 2016] [:error] [pid 28274] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Fri Oct 14 23:38:43.432020 2016] [:error] [pid 28273] Exception ignored in: [Fri Oct 14 23:38:43.432078 2016] [:error] [pid 28273] Traceback (most recent call last): [Fri Oct 14 23:38:43.432105 2016] [:error] [pid 28273] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Fri Oct 14 23:38:43.438577 2016] [:error] [pid 28299] assert tlock is not None [Fri Oct 14 23:38:43.438654 2016] [:error] [pid 28299] AssertionError: [Fri Oct 14 23:38:43.442174 2016] [:error] [pid 28274] assert tlock is not None [Fri Oct 14 23:38:43.442226 2016] [:error] [pid 28274] AssertionError: [Fri Oct 14 23:38:43.447227 2016] [:error] [pid 28276] Exception ignored in: [Fri Oct 14 23:38:43.447294 2016] [:error] [pid 28276] Traceback (most recent call last): [Fri Oct 14 23:38:43.447326 2016] [:error] [pid 28276] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Fri Oct 14 23:38:43.448813 2016] [:error] [pid 28277] Exception ignored in: [Fri Oct 14 23:38:43.448876 2016] [:error] [pid 28277] Traceback (most recent call last): [Fri Oct 14 23:38:43.448903 2016] [:error] [pid 28277] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Fri Oct 14 23:38:43.450188 2016] [:error] [pid 28273] assert tlock is not None [Fri Oct 14 23:38:43.450231 2016] [:error] [pid 28273] AssertionError: [Fri Oct 14 23:38:43.456680 2016] [:error] [pid 28275] assert tlock is not None [Fri Oct 14 23:38:43.456737 2016] [:error] [pid 28275] AssertionError: [Fri Oct 14 23:38:43.461761 2016] [:error] [pid 28277] assert tlock is not None [Fri Oct 14 23:38:43.461826 2016] [:error] [pid 28277] AssertionError: [Fri Oct 14 23:38:43.466165 2016] [:error] [pid 28276] assert tlock is not None [Fri Oct 14 23:38:43.466219 2016] [:error] [pid 28276] AssertionError: [Fri Oct 14 23:38:43.658971 2016] [mpm_prefork:notice] [pid 28268] AH00169: caught SIGTERM, shutting down [Sat Oct 15 03:38:43.691909 2016] [:error] [pid 28272] Exception ignored in: [Sat Oct 15 03:38:43.691968 2016] [:error] [pid 28272] Traceback (most recent call last): [Sat Oct 15 03:38:43.691996 2016] [:error] [pid 28272] File "/usr/lib/python3.4/threading.py", line 1288, in _shutdown [Sat Oct 15 03:38:43.693126 2016] [:error] [pid 28272] assert tlock is not None [Sat Oct 15 03:38:43.693159 2016] [:error] [pid 28272] AssertionError: [Fri Oct 14 23:38:44.490316 2016] [:warn] [pid 28349] mod_wsgi: Compiled for Python/3.4.0. [Fri Oct 14 23:38:44.490407 2016] [:warn] [pid 28349] mod_wsgi: Runtime using Python/3.4.3. [Fri Oct 14 23:38:44.505672 2016] [mpm_prefork:notice] [pid 28349] AH00163: Apache/2.4.7 (Ubuntu) PHP/5.5.9-1ubuntu4.19 mod_wsgi/3.4 Python/3.4.3 configured -- resuming normal operations [Fri Oct 14 23:38:44.505764 2016] [core:notice] [pid 28349] AH00094: Command line: '/usr/sbin/apache2'
回答10:
I had this problem and couldn't find any answer why until I backtracked my commits. Apparently I had added an accidental import, because of auto-completion, that screwed up the setup.
# found in models.py from msilib.schema import SelfReg
In apache error log: RuntimeError("populate() isn't reentrant")
It worked fine in my windows dev environment but failed on the ubuntu/apache server.
回答11:
I was going into this same error after having change the order of this setting :
MIDDLEWARE_CLASSES = ( 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.auth.middleware.SessionAuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware', 'django.middleware.security.SecurityMiddleware', )
putting it back on the order here before and restarting apache fixed the issue.
回答12:
This can also be caused by having a duplicate entry in INSTALLED_APPS
回答13:
In my case, I had a custom renderer class for Django Rest Framework, for some purpose I had to override the renderer class's method "get_context" (full disclosure : to make django toolbar give correct SQL query count)
I removed that class and redeployed. It Worked.
回答14:
I know it has been a while since this question was asked, but I just ran into this issue due to a problem I haven't seen discussed here. I was getting the RuntimeError: populate() isn't reentrant error due to SELinux on CentOS 7. I had Django served out of a home directory, and I simply had to enable the SELinux boolean that allowed reading home directories, as the populate() error was due to a permissions issue. The solution for me was setsebool -P httpd_read_user_content 1. I hope this helps someone having this issue.
回答15:
In my case the error occured because a required pip-package was missing.
So I did a pip install -r requirements.txt, restarted apache and things worked again.
回答16:
I experienced this same problem, and the source of the error for me was just a syntax error in a file I was working with. After fixing the typo, the populate() is not reentrant error disappeared.
回答17:
In my case, I had a circular import, which cause an error that break the populate method.
回答18:
I solved problem with adding __init__.py to my apps folder.
touch /mainprojectfolder/projectfolderwhichcontainswsgi.py/apps/__init__.py
Then it worked!
回答19:
To throw in my 2 Euro cents:
I recreated a working setup in Docker. The new Docker setup failed with
populate isn't reentrant
which seems to be a generic error. In my case, I overlooked that
pip install Django
installs the latest version (2.0), instead of the required version 1.11. Changing this to
pip install Django==1.11
fixed my problem.
回答20:
Removing the virtualenv directory, recreating the virtualenv, then reinstalling all the requirements fixed it for me.
回答21:
I think this is a generic error when something is wrong with settings.py. Sometimes I can find the problem by trial and error by removing the installed apps one at a time. In some cases, its not related to the installed apps. But from my experience, in all cases its a problem within the settings.py file.
回答22:
This couse of lack of memory on your PC/Host/VPS, free some memory and all will be fine.
