Centos7 deploys python3 virtual environment

1. Deploy Python3 on CentOS
   1、 Install dependencies

yum -y install zlib-devel bzip2-devel openssl-devel sqlite-devel readline-devel curl epel-release gcc

2、 Download the python source code package from the official website

curl -o python3.6.tgz https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tgz

3、 Unzip and install

tar -xf Python-3.6.5.tgz -C /usr/local/src/

4、 Modify the configuration file
First enter the directory decompressed in the previous step

cd /usr/local/src/Python-3.6.5/

Execute the following command to cancel the comment at the corresponding position#

sed -ri 's/^#readline/readline/' Modules/Setup.dist

sed -ri 's/^#(SSL=)/\1/' Modules/Setup.dist

sed -ri 's/^#(_ssl)/\1/' Modules/Setup.dist

sed -ri 's/^#([\t]*-DUSE)/\1/' Modules/Setup.dist

sed -ri 's/^#([\t]*-L$(SSL))/\1/' Modules/Setup.dist

5、 Start compiling and installing

. /configure --enable-shared

- - enable-shared specifies the installation of shared libraries, which will be used when using other software that requires python to be called, such as when using mod_wgsi to connect Apache and python#

make -j 2 && make install

- j cpu core number#

6、 Configure shared library files

1 ) Set the shared library directory for all users

cd /usr/local/src/Python-3.6.5/

cp libpython3.6m.so.1.0 /usr/local/lib64/

cp libpython3.6m.so.1.0 /usr/lib/

cp libpython3.6m.so.1.0 /usr/lib64/

2 ) Refresh environment variables

source /etc/profile

7、 Test python

python3

Python 3.6.5 (default, Mar 29 2019, 17:13:23)
[ GCC 4.8.5 20150623 (Red Hat 4.8.5-36)] on linux
Type "help", "copyright", "credits" or "license" for more information.

exit()

8、 Test pip3

pip3 -V

pip 9.0.3 from /usr/local/lib/python3.6/site-packages (python 3.6)

Second, use the third-party virtual tool Virtualenvwrapper
2.1 Installing virtualenvwrapper provides a series of commands to make working with virtual environments much more enjoyable. It puts all your virtual environments in one place. More importantly, you only need to run a command to enter your virtual environment, you don't need to install it in a directory like the virtual environment before (make sure virtualenv is installed)

pip3 install virtualenvwrapper

2.2 Modify the default environment directory:

cat ~/.bashrc

. bashrc

User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

Source global definitions

if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi

Specify interpreter

export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python3.6

This can customize the virtual environment storage directory

export WORKON_HOME=~/.virtualenv

Project storage directory, you need to create it yourself

export PROJECT_HOME=~/.virtualenv/project_data

Automatically load virtualenvmrapper

source /usr/local/bin/virtualenvwrapper.sh

2.3 Create a directory to store the virtual environment
mkdir ~/.virtualenv

This directory should have the same value as the WORKON_HOME variable above#

2.4 Initialize

source ~/.bashrc

2.5 Basic usage: Create a virtual environment:

mkvirtualenv test

2.6 Exit the virtual environment:
deactivate
[ root@redis ld.so.conf.d]# workon test
( test) [root@redis test]# deactivate

2.7 Enter the virtual environment:
[ root@redis ld.so.conf.d]# workon
python3
test
[ root@redis ld.so.conf.d]# workon test
( test) [root@redis test]#

2.8 Create project:
( test) [root@redis test]# mkproject test1
Using base prefix '/usr/local'
New python executable in /root/.virtualenv/test1/bin/python3.6
Also creating executable in /root/.virtualenv/test1/bin/python
Installing setuptools, pip, wheel...
done.
virtualenvwrapper.user_scripts creating /root/.virtualenv/test1/bin/predeactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/test1/bin/postdeactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/test1/bin/preactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/test1/bin/postactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/test1/bin/get_env_details
Creating /root/.virtualenv/project_data/test1
Setting project for test1 to /root/.virtualenv/project_data/test1
( test1) [root@redis test1]# ls
( test1) [root@redis test1]# ls /root/.virtualenv/project_data/
test test1

2.9 List the available operating environments:

( test1) [root@redis test1]# lsvirtualenv
python3 #

test1

test

2.10 List the packages installed in the current environment:
lssitepackages：
( test1) [root@redis test1]# lssitepackages
easy_install.py pip-19.0.3.dist-info pycache setuptools-40.8.0.dist-info wheel-0.33.1.dist-info
pip pkg_resources setuptools wheel

2.11 Create a temporary operating environment:
mktmpenv
[ root@redis test1]# mktmpenv
Using base prefix '/usr/local'
New python executable in /root/.virtualenv/tmp-4aa130f4957b04a/bin/python3.6
Also creating executable in /root/.virtualenv/tmp-4aa130f4957b04a/bin/python
Installing setuptools, pip, wheel...
done.
virtualenvwrapper.user_scripts creating /root/.virtualenv/tmp-4aa130f4957b04a/bin/predeactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/tmp-4aa130f4957b04a/bin/postdeactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/tmp-4aa130f4957b04a/bin/preactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/tmp-4aa130f4957b04a/bin/postactivate
virtualenvwrapper.user_scripts creating /root/.virtualenv/tmp-4aa130f4957b04a/bin/get_env_details
This is a temporary environment. It will be deleted when you run 'deactivate'.

2.12 Delete when the temporary environment exits:
( tmp-4aa130f4957b04a) [root@redis tmp-4aa130f4957b04a]# deactivate
Removing temporary environment: tmp-4aa130f4957b04a
Removing tmp-4aa130f4957b04a...

2.13 Delete the virtual environment:
rmvirtualenv
[ root@redis .virtualenv]# workon
python3
test1
test
[ root@redis .virtualenv]# rmvirtualenv python3
Removing python3...
[ root@redis .virtualenv]# workon
test1
test

2.14 Install the package in a virtual environment
All virtual environments are under ~/.virtualenv/project_data, which are independent and do not affect each other. To install the package in the virtual environment, you can use pip without root permission
[ root@redis .virtualenv]# workon test
( test) [root@redis test]# pip install selenium
Collecting selenium
Downloading https://files.pythonhosted.org/packages/80/d6/4294f0b4bce4de0abf13e17190289f9d0613b0a44e5dd6a7f5ca98459853/selenium-3.141.0-py2.py3-none-any.whl (904kB)
100 % |████████████████████████████████| 911kB 15kB/s
Collecting urllib3 (from selenium)
Downloading https://files.pythonhosted.org/packages/62/00/ee1d7de624db8ba7090d1226aebefab96a2c71cd5cfa7629d6ad3f61b79e/urllib3-1.24.1-py2.py3-none-any.whl (118kB)
100 % |████████████████████████████████| 122kB 11kB/s
Installing collected packages: urllib3, selenium
Successfully installed selenium-3.141.0 urllib3-1.24.1

( test) [root@redis test]# pip list
Package Version

pip 19.0.3
selenium 3.141.0
setuptools 40.8.0
urllib3 1.24.1
wheel 0.33.1
( test) [root@redis test]# deactivate

Switch to env_python3.6 to view "No selenium package":
[ root@redis test]# workon test1
( test1) [root@redis test1]# pip list
Package Version

pip 19.0.3
setuptools 40.8.0
wheel 0.33.1