How to activate virtual envirooment for existing django project using pipenv in python 3.8

Question

I developed a Django webapp project using Django 2.2.1 in python 3.7.2 in a pipenv version 2018.11.26 virtual environment in MacBook Air. After an unintentional update to python 3.8 using brew upgrade, there were problems to work on my webapp and launching it. I installed pipenv pip3 install pipenv, and copied and pasted project folder, and used it with an another name, deleted Pipfiles, and ran pipenv install, but there were error:

✘ Locking Failed!
ERROR:pip.subprocessor:Command errored out with exit status 1:
....
....

After several hours of trial and error, I found the problem is with the version of some packages in my requirements.txt. I have these packages in my project:

backports.csv==1.0.7
certifi==2019.3.9
chardet==3.0.4
defusedxml==0.6.0
diff-match-patch==20181111
Django==2.2.1
django-allauth==0.39.1
django-ckeditor==5.6.1
django-crispy-forms==1.7.2
django-finalware==1.0.0
django-import-export==1.2.0
django-js-asset==1.2.2
django-recaptcha==2.0.5
et-xmlfile==1.0.1
gunicorn==19.9.0
html5lib==1.0.1
idna==2.8
jdcal==1.4
numpy==1.16.3
oauthlib==3.0.1
odfpy==1.4.0
openpyxl==2.6.1
pandas==0.24.1
Pillow==5.4.1
psycopg2==2.7.7
psycopg2-binary==2.7.7
pycparser==2.19
pyparsing==2.3.1
PyPDF2==1.26.0
Pyphen==0.9.5
python-dateutil==2.8.0
python3-openid==3.1.0
pytz==2019.1
PyYAML==3.13
reportlab==3.5.21
requests==2.21.0
requests-oauthlib==1.2.0
six==1.12.0
sqlparse==0.3.0
tablib==0.13.0
urllib3==1.24.3
webencodings==0.5.1
whitenoise==4.1.2
xhtml2pdf==0.2.3
xlrd==1.2.0
xlwt==1.3.0

The first problem was for pandas 0.24.1, and I removed its version number, then pipenv succeeded to lock but it failed to install two other packages

Pipfile.lock not found, creating…
Locking [dev-packages] dependencies…
Locking [packages] dependencies…
Building requirements...
Resolving dependencies...
✔ Success!
Updated Pipfile.lock (1cd6d8)!
Installing dependencies from Pipfile.lock (1cd6d8)…
An error occurred while installing psycopg2==2.7.7 ....
...
...
... Will try again.
An error occurred while installing psycopg2-binary==2.7.7 ....
...
...
... Will try again.
...
ERROR: Couldn't install package: psycopg2
 Package installation failed...
  ☤  ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 1/2 — 00:00:34

Then I removed the version number for psycopg2 and psycopg2-binary, removed the created virtual environment and Pipfiles and ran pipenv install and it was a success.

...
...
✔ Success!
Updated Pipfile.lock (187945)!
Installing dependencies from Pipfile.lock (187945)…
     ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 47/47 — 00:04:21
To activate this project's virtualenv, run pipenv shell.
Alternatively, run a command inside the virtualenv with pipenv run.

Then I ran pipenv shell and python manage.py runserver but the error messages were as below:

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.8/lib/python3.8/threading.py", line 932, in _bootstrap_inner
    self.run()
  File "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.8/lib/python3.8/threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/utils/autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/core/management/commands/runserver.py", line 109, in inner_run
    autoreload.raise_last_exception()
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/utils/autoreload.py", line 77, in raise_last_exception
    raise _exception[0](_exception[1]).with_traceback(_exception[2])
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/utils/autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/apps/registry.py", line 114, in populate
    app_config.import_models()
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/apps/config.py", line 211, in import_models
    self.models_module = import_module(models_module_name)
  File "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.8/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/contrib/auth/models.py", line 2, in <module>
    from django.contrib.auth.base_user import AbstractBaseUser, BaseUserManager
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/contrib/auth/base_user.py", line 47, in <module>
    class AbstractBaseUser(models.Model):
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/models/base.py", line 117, in __new__
    new_class.add_to_class('_meta', Options(meta, app_label))
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/models/base.py", line 321, in add_to_class
    value.contribute_to_class(cls, name)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/models/options.py", line 204, in contribute_to_class
    self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/__init__.py", line 28, in __getattr__
    return getattr(connections[DEFAULT_DB_ALIAS], item)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/utils.py", line 201, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/utils.py", line 110, in load_backend
    return import_module('%s.base' % backend_name)
  File "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.8/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 24, in <module>
    raise ImproperlyConfigured("Error loading psycopg2 module: %s" % e)
django.core.exceptions.ImproperlyConfigured: Error loading psycopg2 module: dlopen(/Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/psycopg2/_psycopg.cpython-38-darwin.so, 2): Symbol not found: _PQencryptPasswordConn
  Referenced from: /Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/psycopg2/_psycopg.cpython-38-darwin.so
  Expected in: /usr/lib/libpq.5.dylib
 in /Users/<My name>/.local/share/virtualenvs/abc-4UXo2PdO/lib/python3.8/site-packages/psycopg2/_psycopg.cpython-38-darwin.so

I searched for this but found a similar problem but nothing as a solution. Would you please look at these messages and show my correct way to launch my django webapp project?

Answer 1

As you said you update unintentional why you don't try to downgrade again to the work version of python?

To change your Python version:

Deactivate your current environment session.

If you have many packages or libraries installed, it would be a good idea to make a requirements.txt file. Remember to edit version as necessary.

Remove the virtualenv with the wrapper command: rmvirtualenv

This will remove the virtualenv, but leave your project files.

Make a new virtualenv with the Python version you want.

Example: mkvirtualenv -p python3 env-name

You can specify the Python version with the -p flag and version. If you have a requirements.txt file, you can specify that with -r requirements.txt

Now bind your new virtualenv to your project directory. You can specify the full paths, but it is easier to have your new virtualenv activated and be in your project directory. Then, run the command:

Example: setvirtualenvproject

Read the docs for more details: http://virtualenvwrapper.readthedocs.io/en/latest/

font: https://mikebarkas.dev/2016/change-python-version-in-virtualenvwrapper/

good luck!

Answer 2

I am new to Django and after I completely set my virtual environment I then close my computer and I tried to open my project the next day. I had no idea what to do to work on my existing project, then I follow the same process of activating a virtual environment on my existing venv.

Here is what I do:

1. Open your cmd, navigate to the folder where you created venv

2. Navigate to the existing venv folder

3. Then Navigate to Scripts folder

4. Once you are in Scripts folder, then write activate then press enter.

It might help someone. Thanks