Deploy Flask App on AWS EC2 Instance

Table of Contents

1. 🤖 Introduction
2. 🔋 Features
3. ⚙️ Tech Stack
4. 📂 Folder Structure
5. 🧰 Prerequisites
6. ⭐ Give A Star
7. 🚀 Follow Me
8. 📚 Learn More

🤖 Introduction

In this tutorial, we'll guide you through the process of deploying a Flask web application on an AWS EC2 instance. Flask is a lightweight web application framework written in Python, and AWS EC2 (Elastic Compute Cloud) provides scalable computing capacity in the cloud.

🔋 Features

• Deploy a Flask web application on AWS EC2.
• Use Gunicorn as the WSGI server.
• Configure Nginx as a reverse proxy.

⚙️ Tech Stacks

• Python
• Flask
• AWS EC2
• Gunicorn
• Nginx

📂 Folder Structure

• helloworld/
  • venv/
  • app.py

🧰 Prerequisites

• An AWS account
• Basic knowledge of Python and Flask
• Familiarity with the Linux command line

Steps

1. Install Python Virtual Environment

First, SSH into your EC2 instance and update the package list:

sudo apt-get update && sudo apt-get upgrade

Then, install the Python virtual environment package:

sudo apt-get install python3-venv

2. Set up the Virtual Environment

Create a new directory for your Flask app and navigate into it:

mkdir helloworld
cd helloworld

Create a virtual environment named 'venv':

python3 -m venv venv

Activate the virtual environment:

source venv/bin/activate

3. Install Flask

Within the virtual environment, install Flask using pip:

pip install Flask

4. Create a Simple Flask API

Create a file named app.py

sudo vi app.py

And add the following code:

from flask import Flask

app = Flask(__name__)

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

if __name__ == "__main__":
    app.run()

5. Verify Flask App

Run the Flask app to verify it works:

python app.py

6. Run Gunicorn WSGI Server

Run Gunicorn WSGI server to serve the Flask Application When you “run” flask, you are actually running Werkzeug’s development WSGI server, which forward requests from a web server. Since Werkzeug is only for development, we have to use Gunicorn, which is a production-ready WSGI server, to serve our application.

Install Gunicorn using pip:

pip install gunicorn

Run Gunicorn to serve the Flask application:

gunicorn -b 0.0.0.0:8000 app:app

Gunicorn is running (Ctrl + C to exit gunicorn)!

Use systemd to manage Gunicorn Systemd is a boot manager for Linux. We are using it to restart gunicorn if the EC2 restarts or reboots for some reason. We create a .service file in the /etc/systemd/system folder, and specify what would happen to gunicorn when the system reboots. We will be adding 3 parts to systemd Unit file — Unit, Service, Install

Unit — This section is for description about the project and some dependencies Service — To specify user/group we want to run this service after. Also some information about the executables and the commands. Install — tells systemd at which moment during boot process this service should start. With that said, create an unit file in the /etc/systemd/system directory

7. Manage Gunicorn with systemd

Create a systemd unit file:

sudo nano /etc/systemd/system/helloworld.service

Add the following configuration:

[Unit]
Description=Gunicorn instance for a simple hello world app
After=network.target

[Service]
User=ubuntu
Group=www-data
WorkingDirectory=/home/ubuntu/helloworld
ExecStart=/home/ubuntu/helloworld/venv/bin/gunicorn -b localhost:8000 app:app
Restart=always

[Install]
WantedBy=multi-user.target

Enable and start the service:

sudo systemctl daemon-reload
sudo systemctl start helloworld
sudo systemctl enable helloworld

Check if the app is running with

curl localhost:8000

Run Nginx Webserver to accept and route request to Gunicorn Finally, we set up Nginx as a reverse-proxy to accept the requests from the user and route it to gunicorn.

8. Set up Nginx as a Reverse Proxy

Install Nginx:

sudo apt-get install nginx

Start and enable the Nginx service:

sudo systemctl start nginx
sudo systemctl enable nginx

Edit the Nginx default configuration file:

sudo nano /etc/nginx/sites-available/default

Add the following code at the top of the file (below the default comments)

upstream flaskhelloworld {
    server 127.0.0.1:8000;
}

Add a proxy_pass to flaskhelloworld atlocation /

location / {
    proxy_pass http://flaskhelloworld;
}

Restart Nginx for changes to take effect:

sudo systemctl restart nginx

Now, your Flask application should be accessible via your EC2 instance's public IP address.

Congratulations! You have successfully deployed a Flask web application on an AWS EC2 instance using Gunicorn and Nginx as a reverse proxy.

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🚀 Follow Me

📚 Learn More

Of course! Here are the resources with descriptions and direct links:

Python:

1. Official Python Documentation: The Python Software Foundation maintains comprehensive documentation covering all aspects of Python, from beginner to advanced topics.

   • Documentation Link

2. Python Crash Course by Eric Matthes: This book is great for beginners who want to get started with Python programming. It covers the basics of Python syntax and also delves into more advanced topics.

   • Book Link

3. Automate the Boring Stuff with Python by Al Sweigart: Perfect for those interested in automating tasks using Python, this book covers practical Python programming for total beginners.

   • Book Link

Flask:

1. Flask Documentation: The official Flask documentation is an excellent resource for learning Flask. It covers everything from installation to advanced topics like Blueprints and Extensions.

   • Documentation Link

2. Flask Web Development by Miguel Grinberg: This book provides a comprehensive guide to building web applications with Flask. It covers everything from basic concepts to more advanced topics like deployment and testing.

   • Book Link

3. Flask Mega-Tutorial by Miguel Grinberg: This online tutorial series covers building a full-featured web application with Flask, step by step. It's a great resource for hands-on learning.

   • Tutorial Link

AWS EC2:

1. AWS Documentation - EC2: The official AWS documentation provides comprehensive guides and tutorials for using EC2 instances, covering everything from launching instances to managing security and scalability.

   • Documentation Link

2. AWS Certified Solutions Architect - Associate Certification Guide: This guide covers all the topics you need to know to become certified in AWS, including EC2 instances.

   • Book Link

3. AWS in Action by Andreas Wittig and Michael Wittig: This book provides practical examples and insights into using various AWS services, including EC2.

   • Book Link

Gunicorn:

1. Gunicorn Documentation: The official Gunicorn documentation provides information on installing, configuring, and using Gunicorn as a WSGI server for Python web applications.

   • Documentation Link

2. Deploying Django by Kenneth Love: While focusing on Django, this book includes a chapter on deploying Django applications with Gunicorn, useful for understanding its usage in real-world scenarios.

   • Book Link

3. Real Python Tutorials: Real Python offers tutorials on various Python-related topics, including deploying web applications with Gunicorn.

   • Tutorial Link

Nginx:

1. Nginx Documentation: The official Nginx documentation provides detailed information on installing, configuring, and using Nginx as a web server and reverse proxy.

   • Documentation Link

2. Nginx Essentials by Valery Kholodkov: This book covers the essentials of Nginx configuration and usage, making it a good resource for beginners.

   • Book Link

3. DigitalOcean Tutorials: DigitalOcean offers numerous tutorials on web development and server administration topics, including configuring Nginx.

   • Tutorial Link