Add a sample presentation on Python virtual envs

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Michael Mintz 2020-11-17 19:21:45 -05:00
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from seleniumbase import BaseCase
class PythonVirtualEnvPresentation(BaseCase):
def test_py_virtual_envs(self):
self.create_presentation(theme="serif", transition="slide")
self.add_slide(
'<h2>Python Virtual Environments:</h2><br />\n'
'<h2>What, Why, and How</h2><hr /><br />\n'
'\n'
'<h3>Presented by <b>Michael Mintz</b></h3>')
self.add_slide(
'<p><b>About me:</b></p>\n'
'<ul>'
'<li>I created the <b>SeleniumBase</b> framework.</li>'
"<li>I'm currently the DevOps Lead at <b>iboss</b>.</li>"
'</ul>\n',
image="https://seleniumbase.io/other/iboss_booth.png")
self.add_slide(
'<p><b>Topics & tools covered by this presentation:</b></p>'
'<hr /><br />\n'
'<ul>'
'<li>Overview of Virtual Environments</li>'
'<li>Python package management</li>'
'<li>Python 3 "venv"</li>'
'<li>virtualenv / virtualenvwrapper</li>'
'<li>pip / "pip install"</li>'
'<li>requirements.txt files</li>'
'<li>setup.py files</li>'
'</ul>')
self.add_slide(
'<p><b>Topics & tools that are NOT covered here:</b></p><hr />\n'
'<br /><div><ul>'
'<li>"conda"</li>'
'<li>"pipenv"</li>'
'<li>"poetry"</li>'
'<li>"pipx"</li>'
'</ul></div><br />'
'<p>(Other Python package management tools)</p>')
self.add_slide(
'<p><b>What is a Python virtual environment?</b></p><hr /><br />\n'
'<p>A Python virtual environment is a partitioned directory'
' where a Python interpreter, libraries/packages, and scripts'
' can be installed and isolated from those installed in other'
' virtual environments or the global environment.</p>')
self.add_slide(
'<p><b>Why should we use Python virtual environments?</b>'
'</p><hr /><br />\n'
'<p>We should use Python virtual environments because different'
' Python projects can have conflicting Python dependencies that'
' cannot coexist in the same env.</p>')
self.add_slide(
'<p><b>Why? - continued</b></p><hr /><br />\n'
'<p>Example: Project A and Project B both depend on'
' different versions of the same Python library!</p>'
'<p>Therefore, installing the second project requirements'
' would overwrite the first one, causing it to break.</p>',
code=(
'# Project A requirement:\n'
'urllib3==1.25.3\n\n'
'# Project B requirement:\n'
'urllib3==1.26.2'))
self.add_slide(
'<p><b>Why? - continued</b></p><hr /><br />\n'
'<p>It is also possible that Project A and Project B'
' require different versions of Python installed!</p>',
code=(
'# Project A requirement:\n'
'Python-3.8\n\n'
'# Project B requirement:\n'
'Python-2.7'))
self.add_slide(
'<p><b>How do we create and use Python virtual envs?</b>'
'</p><hr /><br />\n'
'<div><b>There are tools/scripts we can use:</b></div><br />'
'<ul>'
'<li>The Python 3 "venv" command</li>'
'<li>virtualenv / virtualenvwrapper</li>'
'</ul>')
self.add_slide(
'<p><b>Python 3 "venv"</b></p><hr /><br />\n'
'"venv" creates virtual environments in the location where run'
' (generally with Python projects).',
code=(
'# Mac / Linux\n'
'python3 -m venv ENV_NAME\n'
'source ENV_NAME/bin/activate\n\n'
'# Windows\n'
'py -m venv ENV_NAME\n'
'call ENV_NAME\\Scripts\\activate\n\n'
'# (Type "deactivate" to leave a virtual environment.)'))
self.add_slide(
'<p><b>"mkvirtualenv" (from virtualenvwrapper)</b></p><hr />\n'
'<br />"mkvirtualenv" creates virtual environments in one place'
' (generally in your home directory).',
code=(
'# Mac / Linux\n'
'python3 -m pip install virtualenvwrapper\n'
'export WORKON_HOME=$HOME/.virtualenvs\n'
'source `which virtualenvwrapper.sh`\n'
'mkvirtualenv ENV_NAME\n\n'
'# Windows\n'
'py -m pip install virtualenvwrapper-win\n'
'mkvirtualenv ENV_NAME\n\n'
'# (Type "deactivate" to leave a virtual environment.)'))
self.add_slide(
'<p><b>List of commands from virtualenvwrapper</b></p>'
'<hr /><br />',
code=(
'# Creating a virtual environment:\n'
'mkvirtualenv ENV_NAME\n\n'
'# Leaving your virtual environment:\n'
'deactivate\n\n'
'# Returning to a virtual environment:\n'
'workon ENV_NAME\n\n'
'# Listing all virtual environments:\n'
'lsvirtualenv # OR "workon"\n\n'
'# Deleting a virtual environment:\n'
'rmvirtualenv ENV_NAME'))
self.add_slide(
'<p><b>Determining if you are in a virtual env</b></p>'
'<hr /><br />'
'<p>When activated, the name of your virtual env'
' will appear in parentheses on the left side of your'
' command prompt.</p>',
code=(
'# Example of how it may look on a Windows machine:\n'
'C:\\Users\\Michael\\github> mkvirtualenv my_env\n'
'(my_env) C:\\Users\\Michael\\github>'))
self.add_slide(
'<p><b>Installing packages with "pip install"</b></p><hr /><br />'
'<p>Once you have created a Python virtual environment and are'
' inside, it is now safe to install packages from PyPI,'
' setup.py files, and/or requirements.txt files.</p>\n',
code=(
'# Install a package from PyPI:\n'
'pip install seleniumbase\n\n'
'# Install packages from a folder with setup.py:\n'
'pip install . # Normal installation\n'
'pip install -e . # Editable install\n\n'
'# Install packages from a requirements.txt file:\n'
'pip install -r requirements.txt\n'))
self.add_slide(
'<p><b>Other useful "pip" commands</b></p><hr /><br />',
code=(
'# See which Python packages are installed:\n'
'pip list\n\n'
'# See which installed Python packages are outdated:\n'
'pip list --outdated\n\n'
'# Create a requirements file from installed packages:\n'
'pip freeze > my_requirements.txt'))
self.add_slide(
'<br /><br /><h2><b>Live Demo Time!</b></h2><hr /><br />',
image="https://seleniumbase.io/other/python_3d_logo.png")
self.add_slide(
'<h2><b>The End. Questions?</b></h2><hr /><br />\n'
'<h3>Where to find me:</h3>'
'<ul>'
'<li><a href="https://github.com/mdmintz">'
'https://github.com/mdmintz</a></li>'
'<li><a href="https://github.com/seleniumbase/SeleniumBase">'
'https://github.com/seleniumbase/SeleniumBase</a></li>'
'<li><a href="https://seleniumbase.io/">'
'https://seleniumbase.io/</a></li>'
'</ul>')
self.begin_presentation(
filename="py_virtual_envs.html", show_notes=False, interval=0)