Django 2.1 and Python 3.7: KeyError: 'django' when running Apache2 mod_wsgi and other issues

Question

I'm coming to you after so many hours trying to figure out why my django setup does not work anymore. I swear to whatever God you want I did not sleep last night because of it.

I wanted to switch from Python 3.5 to Python 3.7 because I started to use f-strings , and as this feature was available from Python 3.6, I was like why not using directly Python 3.7. Also, I wanted my 2 domains (mywebsite.fr and mywebsite.com) to point to the same django project. No issue with only mywebsite.fr until now.

I will try to explain as precisely as I can to you what I have done to obtain this hideous code below:

• My install is on Ubuntu 16.04,
• I did some mess with Python versions natively installed on my Ubuntu setup. I finally succeeded in installing properly (I think) Python 3.7,
• I really struggled configuring/making/installing the appropriate mod_wsgi,
• I use venv for my django setup (called m2gvenvprod below),
• I am using mod_wgsi and its daemon mode associated,
• With everything I read, I am sure my conf in apache2 for each of those website/domains are correct (in sites-available),
• And here I am, with the apache2 error.log below, after trying any combination of everything I found on the internet regarding my issue. I am not able to understand that log. I do not understand why django is not a valid key. I know nothing for now... Truly desperate.

One thing maybe interesting I noticed: if I go to mywebsite.com: error 500. But if I go to mywebsite.com/admin, I am redirected to mywebsite.com/admin/login/?next=/admin/: so, there must be something still working, uh?

Traceback (most recent call last):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 66, in __getitem__
    return self._engines[alias]
KeyError: 'django'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 121, in get_package_libraries
    module = import_module(entry[1])
  File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django_libs/templatetags/libs_tags.py", line 6, in <module>
    from django.template.base import TOKEN_BLOCK, TOKEN_VAR
ImportError: cannot import name 'TOKEN_BLOCK' from 'django.template.base' (/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/base.py)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/base.py", line 156, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/base.py", line 154, in _get_response
    response = response.render()
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/response.py", line 106, in render
    self.content = self.rendered_content
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/response.py", line 81, in rendered_content
    template = self.resolve_template(self.template_name)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/response.py", line 63, in resolve_template
    return select_template(template, using=self.using)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/loader.py", line 38, in select_template
    engines = _engine_list(using)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/loader.py", line 66, in _engine_list
    return engines.all() if using is None else [engines[using]]
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 90, in all
    return [self[alias] for alias in self]
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 90, in <listcomp>
    return [self[alias] for alias in self]
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 81, in __getitem__
    engine = engine_cls(params)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 25, in __init__
    options['libraries'] = self.get_templatetag_libraries(libraries)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 43, in get_templatetag_libraries
    libraries = get_installed_libraries()
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 108, in get_installed_libraries
    for name in get_package_libraries(pkg):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 125, in get_package_libraries
    "trying to load '%s': %s" % (entry[1], e)
django.template.library.InvalidTemplateLibrary: Invalid template library specified. ImportError raised when trying to load 'django_libs.templatetags.libs_tags': cannot import name 'TOKEN_BLOCK' from 'django.template.base' (/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/base.py)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 66, in __getitem__
    return self._engines[alias]
KeyError: 'django'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 121, in get_package_libraries
    module = import_module(entry[1])
  File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django_libs/templatetags/libs_tags.py", line 6, in <module>
    from django.template.base import TOKEN_BLOCK, TOKEN_VAR
ImportError: cannot import name 'TOKEN_BLOCK' from 'django.template.base' (/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/base.py)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/utils/deprecation.py", line 91, in __call__
    response = response or self.get_response(request)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/exception.py", line 36, in inner
    response = response_for_exception(request, exc)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/exception.py", line 90, in response_for_exception
    response = handle_uncaught_exception(request, get_resolver(get_urlconf()), sys.exc_info())
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/core/handlers/exception.py", line 129, in handle_uncaught_exception
    return callback(request, **param_dict)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/utils/decorators.py", line 142, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/views/defaults.py", line 69, in server_error
    template = loader.get_template(template_name)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/loader.py", line 12, in get_template
    engines = _engine_list(using)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/loader.py", line 66, in _engine_list
    return engines.all() if using is None else [engines[using]]
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 90, in all
    return [self[alias] for alias in self]
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 90, in <listcomp>
    return [self[alias] for alias in self]
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/utils.py", line 81, in __getitem__
    engine = engine_cls(params)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 25, in __init__
    options['libraries'] = self.get_templatetag_libraries(libraries)
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 43, in get_templatetag_libraries
    libraries = get_installed_libraries()
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 108, in get_installed_libraries
    for name in get_package_libraries(pkg):
  File "/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/backends/django.py", line 125, in get_package_libraries
    "trying to load '%s': %s" % (entry[1], e)
django.template.library.InvalidTemplateLibrary: Invalid template library specified. ImportError raised when trying to load 'django_libs.templatetags.libs_tags': cannot import name 'TOKEN_BLOCK' from 'django.template.base' (/home/krazymax/django/M2Gproject/m2gvenvprod/lib/python3.7/site-packages/django/template/base.py)

Thank you in advance for the advice you could offer me!

---

EDIT 1

Now it is not working at all. I tried to make it work on Python 3.5 like before, but no success.

Answer 1

I also had trouble using apache with python 3.7.0.

Fortunately, django 2.1.4 worked correctly when combined with python 3.6.6.

Answer 2

Well, I would have never thought the official release of Django (2.1) would be the issue, but here we are! When creating my new virtual env under python 3.7 , I did not pay attention immediately to the new version of django. Even afterward, I supposed it was a stable release and that's it. So maybe something's wrong on my Ubuntu install (but really I can not see what), but downgrading from django 2.1 to django 2.0 just solved my issue! Happy even if I spent waaay too much time on that. Notice that it works just fine with Python 3.7 (just like my initial wish).

Thanks for reading!