SSLError(“无法连接到HTTPS，因为SSL模块不可用”)。在pip命令中

Question

在我的Ubuntu 20.04里。我正在使用两个python版本。其中一个是随我的Ubuntu安装而来的Ubuntu，另一个是Python3.7.5。我在系统默认版本的同时使用update-alternatives安装了update-alternatives。但是现在的问题是没有pip命令在Python3.7.5上工作。尽管pip在此(Python3.7.5)安装中可用，并且在打印版本时，它显示了以下内容(使用命令pip3.7 -V)：

pip 19.2.3 from /usr/local/lib/python3.7/site-packages/pip (python 3.7)

但是，每当我试图使用它来安装一个软件包时，总是会显示标题中提到的错误。例如，在安装以下软件包时：

sudo pip3.7 install intel-tensorflow==1.15.2

引发以下错误：

WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Collecting intel-tensorflow==1.15.2
  WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/intel-tensorflow/
  WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/intel-tensorflow/
  WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/intel-tensorflow/
  WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/intel-tensorflow/
  WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/intel-tensorflow/
  Could not fetch URL https://pypi.org/simple/intel-tensorflow/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/intel-tensorflow/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping
  ERROR: Could not find a version that satisfies the requirement intel-tensorflow==1.15.2 (from versions: none)
ERROR: No matching distribution found for intel-tensorflow==1.15.2
WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping

为什么会发生这种情况呢？再次显示了所有pip3.7安装的相同错误，无论我要安装哪个模块。而且，每当我使用系统默认python版本(Python3.8.2)时，也不会出现类似的问题。

Answer 1

您可能缺少了一些系统依赖关系。sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget

请阅读下面的详细信息，了解我们是如何到达那里的。

错误声明SSL python模块不可用；这意味着您要么没有安装适当的ssl库(可能因为您声明了系统python可以很好地执行pip )，要么您从源代码构建的python或以其他方式安装的python不包括ssl模块。

如果您从源代码构建它，则需要确保设置配置选项--with-openssl。

另外，我真的要警告不要安装任何东西的sudo pip。使用类似于维塔列夫的东西，可以将python环境与您安装的系统python或其他python版本分开。

编辑：

仔细研究后，假设出现了dev头，python配置脚本在默认情况下似乎启用了ssl支持。确保sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget中存在所有的dev头，然后重新尝试配置和构建python。