Python Web Development with Flask, Poetry and Pyenv

Torben Dury · March 11, 2023

Development   Python

Switch to the fast lane of web development with Flask, poetry and pyenv. Dive in quickly using these 7 easy steps.

Intro

Python is a versatile language that is widely used for web development, thanks to its simplicity and powerful ecosystem of libraries and frameworks. Flask is one such framework that is particularly popular for building web applications and APIs with Python. In this article, we’ll explore how to set up a professional Python web development environment using Flask, pyenv, and poetry.

Pyenv

Pyenv is a tool that allows you to manage multiple versions of Python on your system. This is particularly useful for web development, where you may need to work with different versions of Python for different projects or to ensure compatibility with specific dependencies. With pyenv, you can easily install and switch between Python versions, and even create virtual environments for each project.

Poetry

Poetry is another tool that simplifies the management of dependencies for Python projects. It allows you to declare your project’s dependencies in a pyproject.toml file and install them with a single command. Poetry also creates a virtual environment for your project, ensuring that your dependencies are isolated from other projects and the global Python environment.

Example

To get started with professional Python web development using Flask, pyenv, and poetry, follow these steps:

  1. Install pyenv and poetry on your system. This can usually be done using your system’s package manager or by downloading and installing the tools directly from their respective websites.

  2. Use pyenv to install the version of Python required for your project. For example, if your project requires Python 3.8, you can install it using the following command:

pyenv install 3.8.0
  1. Create a virtual environment for your project using pyenv. This ensures that your project’s dependencies are isolated from other projects and the global Python environment. For example, to create a virtual environment named myproject using Python 3.8, use the following command:
pyenv virtualenv 3.8.0 myproject
  1. Activate the virtual environment using pyenv. This sets the PATH environment variable to include the virtual environment’s Python executable and ensures that any packages you install are installed in the virtual environment. For example:
pyenv activate myproject
  1. Use poetry to create a new Flask project and install its dependencies. Poetry will create a pyproject.toml file that lists the project’s dependencies, and install them in the virtual environment. For example, to create a new Flask project named myflaskproject and install Flask, use the following commands:
poetry new myflaskproject
cd myflaskproject
poetry add flask
  1. Write your Flask application code in myflaskproject/app.py, and run it using the Flask development server. For example:
from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, World!'

if __name__ == '__main__':
    app.run()
  1. Run the Flask development server using the flask command provided by Flask. For example:
export FLASK_APP=myflaskproject/app.py
flask run

This will start the development server at http://127.0.0.1:5000/.

By following these steps, you can set up a professional Python web development environment using Flask, pyenv, and poetry. This allows you to easily manage Python versions, project dependencies, and virtual environments, ensuring that your projects are isolated, reproducible, and maintainable.

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