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python - 如何在 python 3.8 中使用 pipenv 为现有 django 项目激活虚拟环境

问题描述

我在 MacBook Air 的 pipenv 版本 2018.11.26 虚拟环境中使用 python 3.7.2 中的 Django 2.2.1 开发了一个 Django webapp 项目。在无意更新到 python 3.8 之后brew upgrade，在我的 webapp 上工作和启动它时出现了问题。我安装了 pipenv pip3 install pipenv，并复制并粘贴了项目文件夹，并使用了另一个名称，删除了 Pipfiles，然后运行了pipenv install，但是出现了错误：

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

经过几个小时的反复试验，我发现问题出在我的 requirements.txt 中的某些包的版本上。我的项目中有这些包：

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

第一个问题是pandas 0.24.1，我删除了它的版本号，然后pipenv成功锁定但它没有安装另外两个包

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

然后我删除了 psycopg2 和 psycopg2-binary 的版本号，删除了创建的虚拟环境和 Pipfiles 并运行 pipenv install ，它是成功的。

...
...
✔ 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.

然后我运行 pipenv shell 和 python manage.py runserver 但错误消息如下：

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/local/opt/python@3.8/Frameworks/Python.framework/Versions/3.8/lib/python3.8/threading.py", line 932, in _bootstrap_inner
    self.run()
  File "/usr/local/opt/python@3.8/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/python@3.8/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/python@3.8/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

我搜索了这个，但发现了一个类似的问题，但没有任何解决方案。您能否查看这些消息并展示我启动 django webapp 项目的正确方法？

标签： pythondjangopandaspsycopg2pipenv

解决方案

正如您所说，您无意中更新了为什么不尝试再次降级到python的工作版本？

要更改您的 Python 版本：

停用您当前的环境会话。

如果您安装了许多软件包或库，最好创建一个 requirements.txt 文件。记得根据需要编辑版本。

使用 wrapper 命令删除 virtualenv：rmvirtualenv

这将删除 virtualenv，但保留您的项目文件。

使用您想要的 Python 版本创建一个新的 virtualenv。

例子：mkvirtualenv -p python3 env-name

您可以使用 -p 标志和版本指定 Python 版本。如果你有一个 requirements.txt 文件，你可以用 -r requirements.txt 指定它

现在将您的新 virtualenv 绑定到您的项目目录。您可以指定完整路径，但更容易激活新的 virtualenv 并位于项目目录中。然后，运行命令：

例子：setvirtualenvproject

阅读文档了解更多详情：http: //virtualenvwrapper.readthedocs.io/en/latest/

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

祝你好运！

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