Difference between revisions of "Python deployments"

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== Check Python ==
+
Hynek Schlawack
Check the version of the default Python interpreter:
 
<code>python --version</code>
 
 
 
List the versions of python available:
 
<code>ls /usr/bin/python*</code>
 
 
 
Use <code>update-alternatives</code> to setup system-wide ability to choose Python interpreter.  The one with the '''higher''' priority number will become the default.<br>
 
<code>update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1</code><br>
 
<code>update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2</code>
 
 
 
Now we can list the choices:
 
<code>update-alternatives --list python</code>
 
 
 
And choose one:
 
<code>update-alternatives --config python</code>
 
 
 
We can also remove a choice if it's no longer an option on the system:
 
<code>update-alternatives --remove python /usr/bin/python2.7</code>
 
 
 
== Python Virtual Environments ==
 
See Digital Ocean's quick guide to [https://www.digitalocean.com/community/tutorials/how-to-install-python-3-and-set-up-a-local-programming-environment-on-ubuntu-16-04 setting up a local Python programming environment], including [https://virtualenv.pypa.io/en/stable/ virtual environments], which is what I did for [https://github.com/Miserlou/SoundScrape SoundScrape]  Btw, SoundScrape is a neat tool to download sound files from SoundCloud.
 
<ref>
 
<source lang="bash">
 
cd
 
mkdir environments
 
cd environments/
 
pyvenv my_env
 
source my_env/bin/activate
 
pip install --upgrade pip
 
pip install soundscrape
 
pip install soundscrape --upgrade
 
soundscrape https://soundcloud.com/pianoman_weddings/coldplay
 
</source>
 
</ref>
 
 
 
Hynek Schlawack (from 2013)
 
 
* [https://hynek.me/talks/python-deployments/ Notes]
 
* [https://hynek.me/talks/python-deployments/ Notes]
 
* [https://www.youtube.com/watch?v=RvbDCzroavY Video]
 
* [https://www.youtube.com/watch?v=RvbDCzroavY Video]
  
 
== Python Packaging ==
 
== Python Packaging ==
In the old days (2015) there were still debates about how to package Python and install stuff.  Now, it's settled. Use pip.  Easy_install is dead. See the [https://docs.python.org/3/installing/index.html docs]. Also note that <code>venv</code> is the successor to <code>virtualenv</code>
+
Christoph Haas discusses virtualenv, easy_install, pip, apt/yum
 
+
https://workaround.org/easy-install-debian
== Basic PIP and Virtual Environments ==
 
Do NOT (normally) use sudo with pip. Use a virtual environment. As of Python 3.4, the command is now called <code>pyvenv</code> or simply <code>venv</code>.  As of Python 3.6 <code>pyvenv</code> is '''deprecated''' in favor of using <code>python3 -m venv</code> to help prevent any potential confusion as to which Python interpreter a virtual environment will be based on. '''python3''' is not generic. It represents the '''exact''' version you wish to use in your virtual environment.
 
 
 
As an example, I needed to create a Python Virtual Environment to use the [https://github.com/freephile/meza/issues/63#issuecomment-2020431602 Ansible Playbook Grapher]
 
<source lang="bash">
 
python3.11 -m venv myenv
 
# .. some output ..
 
source myenv/bin/activate
 
# maybe upgrade pip
 
pip install --upgrade pip
 
# then install your local environment packages
 
pip install what-i-want
 
# done using this python?
 
deactivate
 
</source>
 
 
 
You only use sudo or elevated permissions when you want to install stuff for the global, system-wide Python installation.
 
 
 
It is best to use a virtual environment which isolates packages for you. That way you can play around without polluting the global python install.
 
 
 
As a bonus, virtualenv does not need elevated permissions.
 
 
 
* Installing a package is as simple as <code>pip install foo</code>
 
* Upgrades are <code>pip install --upgrade foo</code>
 
* <code>pip uninstall foo</code> if you want to remove foo
 
 
 
{{References}}
 
  
 
[[Category:Python]]
 
[[Category:Python]]

Revision as of 14:12, 16 May 2014

Hynek Schlawack

Python Packaging[edit | edit source]

Christoph Haas discusses virtualenv, easy_install, pip, apt/yum https://workaround.org/easy-install-debian