无法为 Python 3 安装 pyOpenSSL

Can't install pyOpenSSL for Python 3

我是运行一个依赖OpenSSL的Pyhon3脚本,它依赖OpenSSL。但是,我在安装它时遇到问题。

# pip3 install pyOpenSSL
Downloading/unpacking pyOpenSSL
  Downloading pyOpenSSL-17.4.0-py2.py3-none-any.whl (52kB): 52kB downloaded
Requirement already satisfied (use --upgrade to upgrade): six>=1.5.2 in /usr/lib/python3/dist-packages (from pyOpenSSL)
Downloading/unpacking cryptography>=1.9 (from pyOpenSSL)
  Downloading cryptography-2.1.3.tar.gz (441kB): 441kB downloaded
  Running setup.py (path:/tmp/pip-build-ljoosnix/cryptography/setup.py) egg_info for package cryptography
    error in cryptography setup command: Invalid environment marker: python_version < '3'
    Complete output from command python setup.py egg_info:
    error in cryptography setup command: Invalid environment marker: python_version < '3'

----------------------------------------
Cleaning up...
Command python setup.py egg_info failed with error code 1 in /tmp/pip-build-ljoosnix/cryptography
Storing debug log for failure in /root/.pip/pip.log

我不确定 "Invalid environment marker" 是什么意思。这是否意味着我无法为 Python 3 安装它?

这适用于 Debian 8 VM。

尝试运行sudo apt-get install libssl-dev

更新: 尝试 运行 sudo pip3 install --upgrade pip