Configuring Python and NodeJS

This tutorial covers the installation process for Python and Node.js using system package managers, i.e., Chocolatey for Windows, Homebrew for macOS, and the Advanced Package Tool (APT) for Debian flavors of Linux. It also covers how to create and manage virtual environments for Python.

What is Python?

Python is an open-source, high-level, dynamically-typed, general-purpose programming language that is particularly suited for data science and machine learning. However, because of its human-readable syntax, Python has become one of the most popular programming languages in the world, frequently used in back-end web development, networking, automation, and even embedded systems. In September 2023, Mojo was released as a “superset” of Python that uses a “just-in-time” (JIT) compiler to optimize Python source code for parallelization in the CPU and GPU, giving Python more dominance in artificial intelligence.

What is a Python virtual environment?

If not specified, the package installer for Python (pip) will place all external modules inside the site-packages/ directory of the base Python installation. This can become problematic for the following reasons:

1. System pollution: Linux and macOS have preinstalled Python versions that each system uses for internal tasks. Changing the versions of any system-relevant packages may have unintended effects on OS behavior. Updating the OS could also overwrite some of the package installations.

2. Dependency conflicts: Different projects may require different versions of the same package. If all packages are centralized, then certain projects may break unexpectedly.

Virtual environments sidestep these issues by creating sandboxed directories that store all packages for individual projects. These directories also contain aliases (Unix) or shortcuts (Windows) to the relevant Python binaries so that the project can be run with a specific Python version. By activating a virtual environment, you tell the system to point to this directory whenever running the Python executable.

What is Node.js?

Node.js is an open-source JavaScript runtime (server environment) that allows developers to create full stack web, desktop, and mobile apps with one language. (Prior to Node.js, JavaScript could only be run in the browser.) It uses the V8 JavaScript engine—developed by Google for its Chrome browser—to function as a scripting language similar to Python. One of its most popular use cases is as the back-end of the Electron framework, which packages web applications into standalone desktop apps, e.g., Visual Studio Code, Slack, WhatsApp.

The following commands require PowerShell, which has more advanced functionality than the command prompt. Further, to run installation scripts in Windows, you must use a shell with administrator privileges. Search for "PowerShell" in the Windows search box, right-click the application, and select "Run as administrator."

Chocolatey

Set-ExecutionPolicy RemoteSigned
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072

Chocolatey is a community-driven general package manager for Windows that eliminates the need for installation wizards. The developers of Chocolatey created a script to automate the installation process. As stated above, to run a script downloaded from the internet, we need to change the security permissions in PowerShell. (This will also be needed later to install the full developer toolchain. See the PowerShell tutorial for more information on security policies.) In an administrative shell, execute the following commands: Download and run the installation script:

iex ((New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1'))

Refresh the shell environment:

$env:Path = [System.Environment]::GetEnvironmentVariable("Path", "Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path", "User")

Confirm choco installation:

choco --version

Python

Unlike macOS and Linux, Windows does not come prepackaged with Python. Users have the option to manually install a specific Python version or use pyenv-win to manage multiple installations on the same machine.

Pyenv

In an administrative shell, install pyenv with choco:

choco install pyenv-win

Refresh the shell environment:

$env:Path = [System.Environment]::GetEnvironmentVariable("Path", "Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path", "User")

Confirm installation:

pyenv --version

Before proceeding, you must reorder the $Path environment variable to give higher precedence to the binaries stored under pyenv. Otherwise, by default, Windows will search for the Python binaries in its AppData directory. This can be accomplished from the command line, however, I recommend using the environment variable dialog, which can be found via the Windows search box.

After reordering the environment variables, refresh the shell environment:

$env:Path = [System.Environment]::GetEnvironmentVariable("Path", "Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path", "User")

At this point, you are ready to setup Python. To print a list of available Python installations:

pyenv install --list
# restrict output to a specific major Python version
pyenv install --list | Select-String "3.11"

Install a specific version of Python:

# 3.11.3 as an example
pyenv install 3.11.3

Set the global Python version, which will be the Python distribution normally referenced by shell programs:

pyenv global 3.11.3

Confirm that python and pip point to the correct executables:

(Get-Command python).Source ; (Get-Command pip).Source

You should see two paths returned that contain \.pyenv\shims\python and \.pyenv\shims\pip. If not, you may have to recheck your environment variables.

Now, you can run Python:

python --version

Virtual Environments

Unfortunately, pyenv-win does not include the normal pyenv utility for managing virtual environments. Windows users need to follow the traditional approach to create a sandboxed environment:

# env can have any name
python -m venv C:\path\to\env

This will reference the Python version set by pyenv global or local and create a new directory that contains the Python executable and any site packages installed via pip. Note that once created, the virtual environment directory cannot be moved to another location. Many developers choose to store their environments in a dedicated subdirectory of their project folder.

To activate the environment:

C:\path\to\env\Scripts\Activate.ps1

To deactivate:

deactivate

Node.js

Node.js is a popular JavaScript runtime used for server-side programming or desktop app development.

NVM

Similar to Python, Node.js has a version manager (nvm) that was created for macOS and Linux, and later cloned for Windows (nvm-windows). Using nvm allows developers to manage multiple versions of Node.js on one machine, eliminating conflicts between projects with different requirements.

To install nvm, first ensure that there are no pre-existing versions of Node.js installed on the machine, as this may cause conflicts. Then, in an administrative shell, run the automated install script:

choco install nvm

Refresh the shell environment:

$env:Path = [System.Environment]::GetEnvironmentVariable("Path", "Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path", "User")

Confirm nvm installation:

nvm --version

Install the latest version of Node.js:

nvm install latest

Check to see the Node.js available versions:

nvm list

Activate the desired Node.js version:

nvm use 18.4.0

Confirm Node.js activation:

node --version

Homebrew

Similar to Chocolatey, Homebrew is the standard general package manager for macOS.

To install Homebrew (the system may prompt for your user password):

sudo curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh | bash

Update the PATH variable to locate the brew binaries by modifying the special environment file ~/.zshrc:

touch ~/.zshrc
open -e ~/.zshrc

# brew
eval "$(/opt/homebrew/bin/brew shellenv)"

Confirm successful installation:

brew doctor

If the command brew is unrecognized, then there may have been an issue with the installation, probably related to the Xcode command line tools. Unfortunately, this will need to be fixed before proceeding to the next steps.

Python

Although macOS comes prepackaged with Python, it is recommended to reserve that installation for system usage. For this reason, pyenv provides an easy way to manage multiple versions of Python on one machine.

Pyenv

To install pyenv, as well as its convenient virtual environment tool, run the following automated installation scripts:

brew install pyenv
brew install pyenv-virtualenv

After installation, we need to add the .pyenv root directory to the system $PATH and initialize the utility on startup. To do so, open the shell environment file (.zshrc) with the default text editor:

open -e ~/.zshrc

Append the following lines:

# pyenv
export PYENV_ROOT="$HOME/.pyenv"
command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init -)"

Save and close the text file, then refresh the environment:

source ~/.zshrc

Confirm pyenv installation:

pyenv --version

To see a list of available Python installations:

pyenv install --list
# restrict output to a major Python version
pyenv install --list | grep "3.11"

Install a version of Python:

# 3.11.3 as an example
pyenv install 3.11.3

Set the global Python version, which will become the default Python for your shell:

pyenv global 3.11.3

Now you can run Python!

Virtual Environments

Pyenv also provides an easy way to create and manage virtual environments. To create a new environment named “env”:

# assuming you navigated inside the project directory
pyenv local env

To deactivate the environment:

source deactivate

Node.js

As mentioned above, Node.js is a popular JavaScript runtime that can be easily managed with nvm.

NVM

To install nvm:

brew install nvm

Confirm installation:

command -v nvm

If nothing returns, you may need to add the following lines to ~/.zshrc:

# nvm
export NVM_DIR="$HOME/.nvm"
[ -s "/opt/homebrew/opt/nvm/nvm.sh" ] && . "/opt/homebrew/opt/nvm/nvm.sh"
[ -s "/opt/homebrew/opt/nvm/etc/bash_completion.d/nvm" ] && . "/opt/homebrew/opt/nvm/etc/bash_completion.d/nvm"

Refresh the environment:

source ~/.zshrc

Install the latest stable version of Node:

nvm install stable

Confirm Node installation:

node --version

This tutorial only covers Debian flavors of Linux, e.g., Ubuntu, Pop_OS!.

Before installing any software, it is good practice to update, and possibly upgrade, the existing system packages:

sudo apt update && sudo apt upgrade -y

Python

Pyenv

To install pyenv, first install its dependencies:

sudo apt install -y make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev libncursesw5-dev xz-utils tk-dev libffi-dev liblzma-dev python-openssl

Then, execute the pyenv installer:

curl https://pyenv.run | bash

Before running Python, we need to add the .pyenv root directory to the system $PATH and initialize the utility on shell startup. To do so, open the shell environment files with the default text editor:

open -e ~/.zshrc

Append the following lines:

# pyenv
export PYENV_ROOT="$HOME/.pyenv"
command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init -)"

source ~/.zshrc

Confirm pyenv installation:

pyenv --version

To see a list of all Python versions available for installation:

pyenv install --list
# restrict list output to a major Python version
pyenv install --list | grep "3.11"

Install Python:

# 3.11.3 as an example
pyenv install 3.11.3

Set the global Python version:

pyenv global 3.11.3

Confirm that python and pip point to the correct executables:

which python && which pip

Now, you can use Python!

Node.js

NVM

To install nvm, run the automated script:

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.1/install.sh | bash

Refresh the environment and confirm installation:

source ~/.zshrc
nvm --version

Install the latest stable release of Node.js:

nvm install stable

Confirm successful Node installation:

node --version