Python Flask App with Docker on EC2 & AWS Lambda

This is a simple Python Flask application that prints the hostname and IP address of the container it's running in.

🐳 Part 1: EC2

📦 Prerequisites

• AWS EC2 instance (Amazon Linux 2 or similar)

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🚀 Setup Python Flask App with EC2

1. Install Git

sudo yum install git -y

2. Clone the Repository

git clone https://github.com/arumullayaswanth/python-flask-docker.git
cd python-flask-docker

3. Install Python3 and pip

sudo yum install python3 -y
sudo yum install python3-pip -y

4. Install Flask Requirements

pip3 install -r requirements.txt

5. Navigate to App Directory

cd src/
ls

6. Run the App

python3 app.py

🔍 To check running processes:

ps aux | grep python

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🌀 Run App in Background with nohup

nohup allows your app to continue running even after terminal disconnect:

nohup python3 app.py > flask.log 2>&1 &

💪 Check logs:

tail -f flask.log

❗ If port 5000 is in use:

lsof -i :5000
kill -9 <PID>

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🚀 Python Flask App in Docker on AWS EC2

This guide walks you through setting up a Python Flask app inside a Docker container on an AWS EC2 instance.

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📦 Prerequisites

• AWS EC2 instance (Amazon Linux 2 or similar)
• Security group allowing inbound traffic on port 5000
• SSH access to EC2 instance

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🧰 Step-by-Step Setup

1. ✅ Install System Dependencies

sudo yum update -y
sudo yum install git -y
sudo yum install python3-pip -y

2. 🔄 Clone the GitHub Repository

git clone https://github.com/arumullayaswanth/python-flask-docker.git
cd python-flask-docker

3. 📦 Install Python Dependencies

pip3 install -r requirements.txt

4. 🐳 Install and Enable Docker

sudo yum install docker -y
sudo systemctl start docker
sudo systemctl enable docker
sudo systemctl status docker

If

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🐋 Dockerize the Application

5. 📄 Dockerfile (should already exist)

Ensure the file has the following content:

FROM python:3.13-alpine
LABEL maintainer="yaswanth@gmail.com"
COPY . /app
WORKDIR /app
RUN pip install -r requirements.txt
EXPOSE 5000
ENTRYPOINT ["python"]
CMD ["src/app.py"]

6. 🏗️ Build Docker Image

docker build -t flask-docker-app .
docker images

7. 🚀 Run the Docker Container

docker run -d -p 5000:5000 flask-docker-app
docker ps

8. ✅ Verify

Open your browser and visit:

http://<your-ec2-public-ip>:5000

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🧼 Useful Docker Commands

# List running containers
docker ps

# List all containers
docker ps -a

# Stop a container
docker stop <container-id>

# Kill a container
docker kill <container-id>

# Remove stopped containers
docker container prune

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☁️ AWS Lambda (Optional Version)

You can’t run Flask directly on Lambda, but here’s what you can do:

✅ If you need API-like behavior in Lambda:

• Use AWS Lambda + API Gateway instead of Flask.
• Convert Flask logic into a Lambda-compatible handler:

import json
import socket

def lambda_handler(event, context):
    return {
        'statusCode': 200,
        'body': json.dumps({
            'hostname': socket.gethostname(),
            'ip': socket.gethostbyname(socket.gethostname())
        })
    }

🛠️ Package and Deploy

1. Create a zip package of your code.
2. Deploy it to Lambda.
3. Use API Gateway to trigger it.

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�� Clean Up

ps aux | grep python
kill -9 <PID>  # If needed
docker ps
docker stop <container_id>

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🙌 Done!

Your Flask app is now running in Docker on EC2, and optionally portable to Lambda.