Managing Virtual environments in Python Poetry

Poetry helps you declare, manage, and install dependencies of Python projects, ensuring you have the right stack everywhere. Poetry is a tool for dependency management and packaging in the PHP programming language that helps in managing project dependencies and creating virtual environments. Unlike other tools like pip and virtualenv, Poetry is a single tool that offers dependency management, packaging, and virtual environment creation. Poetry replaces setup.py, requirements.txt, setup.cfg, MANIFEST.in and Pipfile with a simple pyproject.toml based project format. This guide will guide you on how to create and control virtual environment using Poetry in order to achieve a very clean environment for developers.

Setting Up Virtual Environments

Poetry provides such tools also, which automatically define as well as maintain virtual environments for your respective projects. Here's how you can get started:

Install Poetry

use the following command on the terminal to install poetry:

pip install poetry

Initialize a New Project

Create a new project directory and initialize it with Poetry.

mkdir my_project
cd my_project 

Run poetry init

Use the poetry init command to start the interactive setup for your pyproject.toml file:

poetry init

Follow the Prompts

This shall give you fields that require some input about your project. Below is an example :

Managing Environment Isolation

Another important feature offered by Poetry is controlling of environment isolation concerning dependent packages for different projects. Here's how Poetry handles this:

1. Creating a Virtual Environment

When you use Poetry Install or Poetry Add, Poetry first determines the exact location of the cache directory and then create a virtual environment inside it.

2. Checking the Virtual Environment

You can check the path of the virtual environment using the following command:

poetry env info --path

3. Activating the Virtual Environment

Activate the virtual environment to run commands within it and you will see your virtual env created will get activated.

poetry shell

To deactivate, simply exit the shell session.

4. Customizing Virtual Environment Location

You can configure Poetry to create virtual environments in specific directories by setting the virtualenvs.in-project setting to true.

poetry config virtualenvs.in-project true

This will establish the virtual environment within your project’s root folder so that you can easily find it and control it.

Working with Virtual Environments

Once your virtual environment is set up, you can perform various tasks to manage your dependencies and project environment.

Adding Dependencies

Other related packages can be included in your project and will be installed in the virtual environment created by poetry. Let's say, you want to install Django:

poetry add django

Removing Dependencies

In case the existing dependencies are no longer required, get rid of them in your project, using the following command:

poetry remove <package-name>

Listing Dependencies

Display a list of dependencies and libraries that are installed with the application and their associated version numbers, using the following command:

poetry show

Running Scripts

Run programs and perform operations in the scope of a virtual environment.

poetry run python script.py

Updating Dependencies

Add compatibility to your project dependencies with their newer versions if available.

poetry update

Conclusion

With Poetry, managing dependencies and organizing project-specific virtual environments are streamlined as the tool is designed to handle these aspects within Python. Adherence to the steps drawn here will make your Python projects cleanly separated and easy to organize and manage.