How to Deploy Flask to AWS: Step-by-Step Guide

To deploy a Flask app to AWS, package your app and use AWS Elastic Beanstalk to create an environment that runs your Flask app automatically. You upload your code, configure the environment, and AWS handles the server setup and deployment.

Syntax

Deploying Flask to AWS Elastic Beanstalk involves these main steps:

• Prepare your Flask app: Ensure your app has a application.py or application callable.
• Create a requirements file: List dependencies in requirements.txt.
• Initialize Elastic Beanstalk: Use eb init to set up your AWS project.
• Create an environment: Use eb create to launch your app environment.
• Deploy your app: Use eb deploy to upload and run your app on AWS.

bash

flask-app/
├── application.py
├── requirements.txt
└── .elasticbeanstalk/

# Commands to deploy
$ eb init -p python-3.8 flask-app
$ eb create flask-env
$ eb deploy

Example

This example shows a simple Flask app and how to deploy it using AWS Elastic Beanstalk CLI.

python

from flask import Flask

application = Flask(__name__)

@application.route('/')
def home():
    return 'Hello, AWS Elastic Beanstalk!'

if __name__ == '__main__':
    application.run(debug=True)

# requirements.txt content:
# Flask==2.3.2

# Deployment commands:
# $ eb init -p python-3.8 flask-app
# $ eb create flask-env
# $ eb deploy

Output

When deployed, visiting the AWS Elastic Beanstalk URL shows: Hello, AWS Elastic Beanstalk!

Common Pitfalls

• Missing application callable: AWS Elastic Beanstalk expects your Flask app to be named application, not app.
• Incorrect Python version: Specify the correct Python platform version during eb init.
• Not including requirements.txt: AWS needs this file to install dependencies.
• Not committing changes before deploy: Elastic Beanstalk deploys the current directory state.
• Ignoring environment variables: Use Elastic Beanstalk configuration to set secrets, not hardcode them.

python

Wrong:
from flask import Flask
app = Flask(__name__)

Right:
from flask import Flask
application = Flask(__name__)

Quick Reference

Summary tips for deploying Flask to AWS Elastic Beanstalk:

• Use application as the Flask app variable name.
• Create requirements.txt with all dependencies.
• Use eb init and eb create commands to set up AWS environment.
• Deploy with eb deploy and monitor logs with eb logs.
• Configure environment variables via Elastic Beanstalk console or config files.

Key Takeaways

Use AWS Elastic Beanstalk CLI commands to deploy Flask apps easily.

Name your Flask app variable 'application' for AWS compatibility.

Always include a requirements.txt file listing your Python dependencies.

Configure environment variables securely through AWS Elastic Beanstalk settings.

Monitor your app with Elastic Beanstalk logs and health dashboard.