How do I run a Flask app in Docker?

Write a Dockerfile (Python base image, copy your code, pip install -r requirements.txt , expose the port, CMD ["python", "app.py"] ), build it with docker build -t my-flask-app . , then run docker run -p 5000:5000 my-flask-app and open the mapped port in your browser.

What is Docker and why use it for a Flask app?

Docker packages an application with its dependencies into a portable container that runs the same on any machine. For Flask it gives a reproducible environment, so the app behaves identically in development and production without dependency conflicts.

What goes in a Dockerfile for a Flask app?

Start from a Python base image, set a working directory, copy your code and requirements.txt , install dependencies with pip install -r requirements.txt , expose the port, and set the command to run the app (for example CMD ["python", "app.py"]) .

How do I build and run a Docker image for Flask?

Build with docker build -t my-flask-app . and run with docker run -p 5000:5000 my-flask-app . The -p flag maps the container port to your host so you can open the app in a browser.

What is the difference between a Docker image and a container?

An image is the immutable template built from your Dockerfile; a container is a running instance of that image. You build an image once and can run many containers from it.

Introduction: Dockerising a Python Flask App

Docker lets you quickly deploy microservices, cloud-native architectures, or web apps. In this post, we will use Docker to create a reliable environment for Flask applications that efficiently manages dependencies and deployment intricacies.

What is Docker?

Docker is a platform for developers and sysadmins to build, deploy, and run applications inside containers. Containers are a form of lightweight virtualisation that allows you to package an application, along with its dependencies and libraries, in a single unit that can run on any infrastructure.

This makes creating, managing, and deploying applications easier, especially in a microservices architecture, where an application comprises many small, self-contained services.

In addition to providing an isolated environment for your applications, Docker offers several other benefits, such as increased consistency and reproducibility, better resource utilisation, and easier scaling and deployment.

Docker was developed by Docker, Inc., a company founded in 2010. Docker became popular quickly and was widely adopted by organisations and developers for containerisation. In 2011, Docker, Inc. was acquired by Mirantis, a company specialising in cloud infrastructure software, see Adrian Ionel’s post What We Announced Today and Why it Matters.

Installing Docker (macOS, Windows, Linux)

🔒 Subscribe to keep reading.

Using Docker

🔒 Subscribe to keep reading.

Dockerising a Flask application

🔒 Subscribe to keep reading.

Conclusion: Running Flask in Docker

🔒 Subscribe to keep reading.

References

🔒 Subscribe to keep reading.

You've hit a Deep Dive tutorial.

I spend dozens of hours researching, coding, and breaking things to write these guides. This content is free, but reserved for my subscriber community. Drop your email below to unlock this guide (and all past/future deep dives):

Already a subscriber? Use the magic link from your last newsletter, or reset your password.

New subscribers get an inbox mail: Set a password to unlock articles. The form does not log you in — use the same email afterwards.

What is Docker?

📚 This post is part of the "Python Projects & Utilities" series

Introduction: Dockerising a Python Flask App

What is Docker?

Installing Docker (macOS, Windows, Linux)

Using Docker

Dockerising a Flask application

Conclusion: Running Flask in Docker

References

References

Citation

What is Docker?

📚 This post is part of the "Python Projects & Utilities" series

Introduction: Dockerising a Python Flask App

What is Docker?

Installing Docker (macOS, Windows, Linux)

Using Docker

Dockerising a Flask application

Conclusion: Running Flask in Docker

References

You're in

References

Citation