python3安装过程中出现的ssl问题 ，No module named _ssl

安装Python3.6.4

---

1 安装python3.6可能使用的依赖

yum install openssl-devel bzip2-devel expat-devel gdbm-devel readline-devel sqlite-devel gcc gcc-c++  openssl-devel

2 到python官网找到下载路径, 用wget下载

wget https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tgz

3 解压tgz包

tar -xf Python-3.6.5.tgz

4 进入python目录

cd /Python-3.6.5/

5 编译，安装

5.1 提示找不到SSL模块

python安装完毕后，提示找不到ssl模块：

[root@localhost ~]# python2.7.5
Python 2.7.5 (default, Jun 3 2013, 11:08:43) 
[GCC 4.1.2 20080704 (Red Hat 4.1.2-54)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ssl
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/python27/lib/python2.7/ssl.py", line 60, in <module>
import _ssl # if we can't import it, let the error propagate
ImportError: No module named _ssl
>>>

5.2 重新编译python（去掉最后4行的注释）

#修改Setup文件
vi /root/Python-3.6.5/Modules/Setup.dist
#修改结果如下：
# Socket module helper for socket(2)
_socket socketmodule.c timemodule.c

# Socket module helper for SSL support; you must comment out the other
# socket line above, and possibly edit the SSL variable:
SSL=/usr/local/ssl
_ssl _ssl.c \
-DUSE_SSL -I$(SSL)/include -I$(SSL)/include/openssl \
-L$(SSL)/lib -lssl -lcrypto

5.3 编译安装

./configure --prefix=/usr/local/python
make
make install

5.4 测试，已可正常使用。

[root@localhost ~]# python
Python 3.6.4 (default, Jun 3 2013, 14:56:13) 
[GCC 4.1.2 20080704 (Red Hat 4.1.2-54)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ssl
>>>

注：如需保留旧版本的就不需要执行 6 .7两部

6 重命名旧版本的python依赖

ll /usr/bin | grep python

mv /usr/bin/python /usr/bin/python2.7

7 删除旧的软链接，创建新的软链接到最新的python

rm -rf /usr/bin/python

ln -s /usr/local/bin/python3.6 /usr/bin/python

python -V

使用yum命令报错File "/usr/bin/yum", line 30 except KeyboardInterrupt, e:
问题出现原因：

yum包管理是使用python2.x写的，将python2.x升级到python3.1.3以后，由于python版本语法兼容性导致问题出现
解决办法：
修改yum配置文件，将python版本指向以前的旧版本

# vi /usr/bin/yum
#!/usr/bin/python2.7

修改urlgrabber-ext-down文件，更改python版本

# vi /usr/libexec/urlgrabber-ext-down
#!/usr/bin/python2.7

Could not fetch URL https://pypi.python.org/simple/six/: There was a problem confirming the ssl certificate: Can't connect to HTTPS URL because the SSL module is not available. - skipping

如需安装pip

---

下载相关文件

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

执行

/usr/local/python/bin/python3 get-pip.py

添加环境变量

vim ~/.bash_profile

添加下面这条参数

export PATH=/usr/local/python/bin:$PATH

保存
source ~/.bash_profile

测试

执行

[root@huo ~]# python3
Python 3.6.5 (default, Apr  1 2018, 20:41:34)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

执行脚本如下:

vim install_python.sh

#!/bin/bash
echo "正在安装相关组件"
yum install -y openssl-devel bzip2-devel expat-devel gdbm-devel readline-devel sqlite-devel gcc-c++ gcc openssl-devel

echo "下载安装包"
wget https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tgz

echo "正在解压安装包"
tar -xf Python-3.6.5.tgz -C /root/  && cd /root/Python-3.6.5/

echo "添加ssl支持"
cat >> /root/Python-3.6.5/Modules/Setup.dist <<"EOF"
_socket socketmodule.c

SSL=/usr/local/ssl
_ssl _ssl.c \
-DUSE_SSL -I$(SSL)/include -I$(SSL)/include/openssl \
-L$(SSL)/lib -lssl -lcrypto
EOF

echo "正在编译安装Python"
./configure --prefix=/usr/local/python && make && make install
cd /root

echo "删除安装包"
rm -rf /root/Python-3.6.5.tgz && rm -rf /root/Python-3.6.5

echo "正在添加环境变量"
echo "export PATH=/usr/local/python/bin:$PATH">> ~/.bash_profile
source ~/.bash_profile

echo "安装完成,请执行python3进行测试"