Installing Python as local user on Centos 7 – Zentera Systems

This is a cheat-sheet-style article based on information found on other online resources including manuals for Python, Virtual Environments, StackOverflow articles, etc

Objective:

A bare Centos 7 comes with Python 2
Some OS utilities may install Python 3 as dependencies. Don't want to touch them to not break anything else
Hence, installing under local user will side step any dependency conflicts and allow a dedicated Python3 installation that can be used for Zapy SDK
Benefit - removing/reinstalling/upgrading this local Python3 installation becomes simple

Steps

With sudo/root privileges for this step only, install OS level dependency packages

sudo yum install gcc zlib zlib-devel bzip2 bzip2-devel readline-devel sqlite sqlite-devel openssl-devel xz xz-devel libffi libffi-devel lzma

NOTE - If you are missing some of these dependencies, and still try to install python, you might have to reinstall..!
For the rest of these steps, do not use sudo/root
Python3 installation as regular user

version=3.9.12
version_short=3.9

wget https://www.python.org/ftp/python/$version/Python-$version.tgz
tar xzf Python-$version.tgz
cd Python-$version
./configure --enable-optimizations --enable-shared --prefix=$HOME/python$version LDFLAGS=-Wl,-rpath=$HOME/python$version/lib
make altinstall # so it does not trash installed python2 or other system-preinstalled python version
python$version_short -V

echo "export PATH=$HOME/python$version/bin/:$PATH" >> ~/.bashrc
echo "export PYTHONPATH=$HOME/python$version/bin" >> ~/.bashrc

export PATH=$HOME/python$version/bin/:$PATH
export PYTHONPATH=$HOME$version/python/bin

Virtual Environment configuration as regular user

~/python$version/bin/python$version_short -m venv ~/venv_3
source ~/venv_3/bin/activate
pip install --upgrade pip setuptools

# optional:
echo "source ~/venv_3/bin/activate" >> ~/.bashrc

Related articles