Python

General Information

Administration of Python environments.

Checklist

Distro(s): Enterprise Linux 6/7

Python Versions

OS	System Package	EPEL	Software Collections
CentOS 6.x	2.6.6	3.4	2.7, 3.3, 3.4
CentOS 7.x	2.7	3.4, 3.6	2.7, 3.3, 3.4, 3.5

To avoid breaking system packages(ie yum uses python), let system packaged python versions stay maintained by the official repos.
Use EPEL/software collections along with something such as virtualenv to maintain development environments.

Python3 Install: EPEL

To install python 3.4 from the EPEL

3.4
```
yum install python34
```
3.6
```
yum install python36
```

Python3 Install: Software Collections

Software Collections allow for environments such as newer Python versions to be installed via repos and not conflict with the default system version.

See Software Collections Instructions

Pip

Pip is a Python package management tool to install modules.

Install Pip

Install Pip into a Python environment

Python2

wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py

Python3

wget https://bootstrap.pypa.io/get-pip.py
python3.6 get-pip.py

Install devel packages that many pip builds rely upon

Python2
```
yum install gcc python-devel
```
Python3.4
```
yum install gcc python34-devel
```
Python3.6
```
yum install gcc python36-devel
```

Pip Commands

Python 2 vs Python 3 pip commands

Python 2
```
pip <command>
```
Python 3
```
pip3 <command>
```

List installed python modules

pip list

Show details about a Python module

pip show virtualenv

Search for a Python module

pip search "query"

Install a Python module

pip install virtualenv

Upgrade a Python module

pip install --upgrade scipy

Upgrade pip

pip install --upgrade pip

Uninstall

pip uninstall virtualenv

Pip Config

There is a global config file and per user config file locations.

Global pip config file - example to format columns for all users

/etc/pip.conf
[list]
format=columns

User pip config file - for additional config or to over ride the global

Create the pip config directory
```
mkdir ~/.config/pip/
```

Create the pip.conf file and populate it

vim ~/.config/pip/pip.conf
 
#your config here

Python Modules

Some commonly installed Python modules.

Virtualenv

Virtualenv “is a tool to create isolated Python environments.”

Site: https://virtualenv.pypa.io/en/stable/

Python2
```
pip install virtualenv
```
Python3
```
pip3 install virtualenv
```

PipEnv

PipEnv “automatically creates and manages a virtualenv for your projects, as well as adds/removes packages from your Pipfile as you install/uninstall packages. It also generates the ever–important Pipfile.lock, which is used to produce deterministic builds.”

Site: https://github.com/pypa/pipenv

Python2
```
pip install pipenv
```
Python3
```
pip3 install pipenv
```

AWS CLI

AWS CLI “is a unified tool to manage your AWS services. With just one tool to download and configure, you can control multiple AWS services from the command line and automate them through scripts.”

Site: https://aws.amazon.com/cli/

Pre-Reqs

yum install expat-devel

Install

Python2
```
pip install awscli
```
Python3
```
pip3 install awscli
```

Verify

Python2 and Python3
```
aws --version
```

Cert Verify Failed

If you are seeing errors while using the aws cli about “SSL: CERTIFICATE_VERIFY_FAILED”

Point the aws cli to the system ca bundle (per user)

vim ~/.bashrc
 
# AWS CA Bundle
export AWS_CA_BUNDLE="/etc/pki/tls/certs/ca-bundle.crt"

Source the file
```
source ~/.bashrc
```

Table of Contents