Book Image

Flask Framework Cookbook - Second Edition

By : Shalabh Aggarwal
Book Image

Flask Framework Cookbook - Second Edition

By: Shalabh Aggarwal

Overview of this book

Flask, the lightweight Python web framework, is popular thanks to its powerful modular design that lets you build scalable web apps. With this recipe-based guide, you’ll explore modern solutions and best practices for Flask web development. Updated to the latest version of Flask and Python 3, this second edition of Flask Framework Cookbook moves away from some of the old and obsolete libraries and introduces new recipes on cutting-edge technologies. You’ll discover different ways of using Flask to create, deploy, and manage microservices. This Flask Python book starts by covering the different configurations that a Flask application can make use of, and then helps you work with templates and learn about the ORM and view layers. You’ll also be able to write an admin interface and get to grips with debugging and logging errors. Finally, you’ll learn a variety of deployment and post-deployment techniques for platforms such as Apache, Tornado, and Heroku. By the end of this book, you’ll have gained all the knowledge you need to confidently write Flask applications and scale them using standard industry practices.
Table of Contents (15 chapters)

Migrating databases using Alembic and Flask-Migrate

Now, let's say we want to update our models to have a new field called company in the Product model. One way is to drop the database and then create a new one using db.drop_all() and db.create_all(). However, this approach cannot be followed for applications in production or even in staging. We would want to migrate our database to match the newly updated model with all the data intact.

For this, we have Alembic, which is a Python-based tool to manage database migrations and uses SQLAlchemy as the underlying engine. Alembic provides automatic migrations to a great extent with some limitations (of course, we cannot expect any tool to be seamless). To act as the icing on the cake, we have a Flask extension called Flask-Migrate, which eases the process of migrations even more. In this recipe, we will cover the basics of database...