python3.7.2 pip 出现locations that require TLS/SSL异常处理方法

centos7安装python3.7.2后，运行

pip3 install tornado

会报错

[root@localhost ~]# pip3 install tornado
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Collecting tornado
  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/tornado/
  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/tornado/
  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/tornado/
  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/tornado/
  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/tornado/
  Could not fetch URL https://pypi.org/simple/tornado/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/tornado/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping
  Could not find a version that satisfies the requirement tornado (from versions: )
No matching distribution found for tornado
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

解决方法：

在./configure过程中，如果没有加上–with-ssl参数时，默认安装的软件涉及到ssl的功能不可用，
刚好pip3过程需要ssl模块，而由于没有指定，所以该功能不可用。

1. 查看openssl安装包，发现缺少openssl-devel包

   [root@localhost ~]# rpm -aq|grep openssl
   openssl-0.9.8e-.el5
   openssl-0.9.8e-.el5
   [root@localhost ~]#

2. yum安装openssl-devel

   [root@localhost ~]# yum install openssl-devel -y 

   查看安装结果

   [root@localhost ~]# rpm -aq|grep openssl
   openssl-0.9.8e-.el5_9.
   openssl-0.9.8e-.el5_9.
   openssl-devel-0.9.8e-.el5_9.
   openssl-devel-0.9.8e-.el5_9.

3. 重新对python3.7.2进行编译安装，用以下过程来实现编译安装

   cd Python-3.7.2
   ./configure --with-ssl
   make
   sudo make install

参考：

https://blog.csdn.net/zhengcaihua0/article/details/79681991