====== Python ======

**General Information**

Administration of Python environments. 

**Checklist**
  * Distro(s): Enterprise Linux 6/7

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===== 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.

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====== Python3 Install: EPEL ======

To install python 3.4 from the EPEL
  * 3.4<code bash>yum install python34</code>
  * 3.6<code bash>yum install python36</code>

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====== 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.

[[linux_wiki:repos#software_collections|See Software Collections Instructions]]

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====== Pip ======

Pip is a Python package management tool to install modules.

===== Install Pip =====

Install Pip into a Python environment
  * Python2<code bash>wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py</code>
  * Python3<code bash>wget https://bootstrap.pypa.io/get-pip.py
python3.6 get-pip.py</code>

\\
Install devel packages that many pip builds rely upon
  * Python2<code bash>yum install gcc python-devel</code>
  * Python3.4<code bash>yum install gcc python34-devel</code>
  * Python3.6<code bash>yum install gcc python36-devel</code>
===== Pip Commands =====

**Python 2 vs Python 3 pip commands**
  * **Python 2**<code bash>pip <command></code>
  * **Python 3**<code bash>pip3 <command></code>

\\
List installed python modules
<code bash>
pip list
</code>

\\
Show details about a Python module
<code bash>
pip show virtualenv
</code>

\\
Search for a Python module
<code bash>
pip search "query"
</code>

\\
Install a Python module
<code bash>
pip install virtualenv
</code>

\\
Upgrade a Python module
<code bash>
pip install --upgrade scipy
</code>

\\
Upgrade pip
<code bash>
pip install --upgrade pip
</code>

\\
Uninstall
<code bash>
pip uninstall virtualenv
</code>

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===== 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<code bash>/etc/pip.conf
[list]
format=columns
</code>

\\
**User pip config file** - for additional config or to over ride the global
  * Create the pip config directory<code bash>mkdir ~/.config/pip/</code>
  * Create the pip.conf file and populate it<code bash>vim ~/.config/pip/pip.conf

#your config here</code>

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====== 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<code bash>pip install virtualenv</code>
  * Python3<code bash>pip3 install virtualenv</code>

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===== 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<code bash>pip install pipenv</code>
  * Python3<code bash>pip3 install pipenv</code>

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===== 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<code bash>yum install expat-devel</code>

Install
  * Python2<code bash>pip install awscli</code>
  * Python3<code bash>pip3 install awscli</code>

Verify
  * Python2 and Python3<code bash>aws --version</code>

==== 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**)<code bash>vim ~/.bashrc

# AWS CA Bundle
export AWS_CA_BUNDLE="/etc/pki/tls/certs/ca-bundle.crt"</code>
  * Source the file<code bash>source ~/.bashrc</code>

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