在ubuntu 14.04上安装scrapy失败，加密设置命令出错，环境标记无效

Question

我尝试在另一台服务器上安装scrapy。 当我运行pip install scrapy时：

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_root/cryptography
Storing debug log for failure in /root/.pip/pip.log

任何想法请帮助

Python 2.7.6

我做了

sudo apt-get install python-dev python-pip libxml2-dev libxslt1-dev zlib1g-dev libffi-dev libssl-dev

和

sudo apt-get install python-dev python-pip libxml2-dev libxslt1-dev zlib1g-dev libffi-dev libssl-dev

我之前也做了sudo apt-get update

Answer 1

在debian 8上也是如此。您可以将cryptography库固定在版本2.0.3上，然后重试。

pip install cryptography==2.0.3

Answer 2

我刚遇到同样的问题并通过以下方式解决了这个问题：

pip install --upgrade setuptools pip

显然是加密包的the default version of setuptools and pip on 14.04 is insufficient。