Pipenv 安装在加密包上失败：“禁用 PEP 517 处理无效”错误

Question

在没有意识到这一点的情况下，我已经使用密码学包好几个月了，没有出现问题，但突然间它无法构建并且导致我的项目的开发停止。

事实证明，密码学是我的 Pipfile: 中其他包之一的依赖项apns2。正如我所说，它运行良好，但我的环境中肯定发生了一些变化。这是我的 Pipfile，只隔离了那个包：

[[source]]
url = "https://pypi.python.org/simple"
verify_ssl = true
name = "pypi"

[requires]
python_version = "3.7.9"

[packages]

apns2 = "*"

[dev-packages]

这失败了。我使用pipenv（最新版本 2020.11.15），所以当我现在运行它时，这是输出：

# pipenv install
Creating a virtualenv for this project...
Pipfile: /Users/dylan/Dev/RideHare/server/Pipfile
Using /Users/dylan/.pyenv/versions/3.7.9/bin/python3.7m (3.7.9) to create virtualenv...
? Creating virtual environment...created virtual environment CPython3.7.9.final.0-64 in 502ms
  creator CPython3Posix(dest=/Users/dylan/.local/share/virtualenvs/server-2uc2X-TS, clear=False, global=False)
  seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=/Users/dylan/Library/Application Support/virtualenv)
    added seed packages: pip==20.2.2, setuptools==51.0.0, wheel==0.35.1
  activators BashActivator,CShellActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator

? Successfully created virtual environment! 
Virtualenv location: /Users/dylan/.local/share/virtualenvs/server-2uc2X-TS
Installing dependencies from Pipfile.lock (aa4cd9)...
An error occurred while installing cryptography==3.3.1; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4, 3.5' --hash=sha256:84ef7a0c10c24a7773163f917f1cb6b4444597efd505a8aed0a22e8c4780f27e --hash=sha256:788a3c9942df5e4371c199d10383f44a105d67d401fb4304178020142f020244 --hash=sha256:9f6b0492d111b43de5f70052e24c1f0951cb9e6022188ebcb1cc3a3d301469b0 --hash=sha256:a69bd3c68b98298f490e84519b954335154917eaab52cf582fa2c5c7efc6e812 --hash=sha256:b4890d5fb9b7a23e3bf8abf5a8a7da8e228f1e97dc96b30b95685df840b6914a --hash=sha256:0003a52a123602e1acee177dc90dd201f9bb1e73f24a070db7d36c588e8f5c7d --hash=sha256:7e177e4bea2de937a584b13645cab32f25e3d96fc0bc4a4cf99c27dc77682be6 --hash=sha256:dc42f645f8f3a489c3dd416730a514e7a91a59510ddaadc09d04224c098d3302 --hash=sha256:69e836c9e5ff4373ce6d3ab311c1a2eed274793083858d3cd4c7d12ce20d5f9c --hash=sha256:9e21301f7a1e7c03dbea73e8602905a4ebba641547a462b26dd03451e5769e7c --hash=sha256:0e85aaae861d0485eb5a79d33226dd6248d2a9f133b81532c8f5aae37de10ff7 --hash=sha256:c366df0401d1ec4e548bebe8f91d55ebcc0ec3137900d214dd7aac8427ef3030 --hash=sha256:594a1db4511bc4d960571536abe21b4e5c3003e8750ab8365fafce71c5d86901 --hash=sha256:83d9d2dfec70364a74f4e7c70ad04d3ca2e6a08b703606993407bf46b97868c5! Will try again.
     ???????????????????????????????? 10/10 — 00:00:08
Installing initially failed dependencies...
[InstallError]:   File "/usr/local/Cellar/pipenv/2020.11.15/libexec/lib/python3.9/site-packages/pipenv/cli/command.py", line 233, in install
[InstallError]:       retcode = do_install(
[InstallError]:   File "/usr/local/Cellar/pipenv/2020.11.15/libexec/lib/python3.9/site-packages/pipenv/core.py", line 2052, in do_install
[InstallError]:       do_init(
[InstallError]:   File "/usr/local/Cellar/pipenv/2020.11.15/libexec/lib/python3.9/site-packages/pipenv/core.py", line 1304, in do_init
[InstallError]:       do_install_dependencies(
[InstallError]:   File "/usr/local/Cellar/pipenv/2020.11.15/libexec/lib/python3.9/site-packages/pipenv/core.py", line 899, in do_install_dependencies
[InstallError]:       batch_install(
[InstallError]:   File "/usr/local/Cellar/pipenv/2020.11.15/libexec/lib/python3.9/site-packages/pipenv/core.py", line 796, in batch_install
[InstallError]:       _cleanup_procs(procs, failed_deps_queue, retry=retry)
[InstallError]:   File "/usr/local/Cellar/pipenv/2020.11.15/libexec/lib/python3.9/site-packages/pipenv/core.py", line 703, in _cleanup_procs
[InstallError]:       raise exceptions.InstallError(c.dep.name, extra=err_lines)
[pipenv.exceptions.InstallError]: Looking in indexes: https://pypi.python.org/simple
[pipenv.exceptions.InstallError]: Collecting cryptography==3.3.1
[pipenv.exceptions.InstallError]:   Using cached cryptography-3.3.1.tar.gz (539 kB)
[pipenv.exceptions.InstallError]: ERROR: Disabling PEP 517 processing is invalid: project specifies a build backend of setuptools.build_meta in pyproject.toml
ERROR: Couldn't install package: cryptography
 Package installation failed...
  ?  ???????????????????????????????? 0/1 — 00:00:01

如果我显式地代替了 Pipfile 中的 apns2 行（crytography = "*"），它也会以同样的方式失败。

Answer 1

如果您使用的是最新的 macOS 版本，pipenv virtualenv 中的默认 pip 版本会错误地检测您的操作系统版本，这会导致查找兼容的 Wheel 失败（并且它将开始编译加密依赖项）。

为了避免根本问题，您可以将 pip（在 virtualenv 中）升级到能够正确检测 mac 操作系统的版本：

pipenv shell
pip install -U pip

该错误已在 pip 版本 20.3 (2020-11-30) https://github.com/pypa/pip/issues/9138中修复

Answer 2

令人困惑的错误消息是由以下事实引起的：如果/当由于某种原因pipenv无法构建时cryptography，它会再次尝试--no-use-pep517（请参阅下面的评论），然后我们看到那些 PEP 517 禁用错误而不是根本原因！

要追踪您的实际问题，请尝试pip install cryptography(not pipenv) 以便您可以查看根本原因。

很可能，你需要安装rust和/或cargo，或openssl使用你的平台apt-get install，apk add，brew install或什么的，然后再试一次。

以这种方式解决问题后，pipenv安装应该可以正常工作。

另请参阅cryptography包 github 问题 #5773

Answer 3

似乎该cryptography软件包只能用 安装pip，不能用 安装pipenv，所以先执行此操作...

brew install pkg-config libffi openssl
env LDFLAGS="-L$(brew --prefix openssl)/lib" CFLAGS="-I$(brew --prefix openssl)/include" pip install cryptography

（取自这个问题的命令。）

...然后我可以运行pipenv installwhich 构建和安装一切正常。