Flask API with AWS EC2 and RDS Deployment

This is a Flask API that connects to a PostgreSQL database hosted on AWS RDS and can be deployed on an EC2 instance.

Prerequisites

• AWS account
• AWS CLI installed and configured on your local machine
• Python 3.7+ installed

Setup

1. Clone the repository and navigate into the project directory.

git clone https://github.com/your-repo/flask-api
cd flask-api

2. Install dependencies:

pip install -r requirements.txt

3. Configure environment variables for database connection. Create a .env file with the following format:

DB_HOST=<your-rds-endpoint>
DB_PORT=5432
DB_NAME=<your-database-name>
DB_USER=<your-username>
DB_PASSWORD=<your-password>

4. Create the items table in your PostgreSQL database:

CREATE TABLE items (
    id SERIAL PRIMARY KEY,
    name VARCHAR(255) NOT NULL
);

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Deploying to AWS

Step 1: Set Up RDS

1. Go to the RDS section in the AWS Console and create a PostgreSQL instance.
2. In Connectivity & Security:
   • Enable Public Access.
   • Configure the VPC security group to allow inbound traffic on the PostgreSQL port (default is 5432) from your EC2 instance.
3. After the instance is created, note down the endpoint and port.

Step 2: Set Up EC2

1. Go to the EC2 section in the AWS Console and launch a new instance:

   • Select an Amazon Linux or Ubuntu instance.
   • Choose an instance type (t2.micro is recommended for testing).
   • Configure the security group to allow inbound traffic on ports 22 (SSH) and 5000 (Flask app).

2. SSH into your EC2 instance using the key pair you specified when creating the instance:

ssh -i /path/to/key.pem ec2-user@your-ec2-public-ip

3. Update packages and install necessary software on EC2:

# Update the package lists
sudo apt update

# Install Python 3 and pip
sudo apt install python3 python3-pip -y

# Install virtualenv (recommended)
pip3 install virtualenv

4. Clone your repository on EC2:

# Clone the repository
git clone https://github.com/your-repo/flask-api.git
cd flask-api

# Create a virtual environment and activate it
python3 -m venv venv
source venv/bin/activate

5. Install the dependencies:

pip install -r requirements.txt

6. Configure your .env file on EC2 with the database credentials for RDS:

echo "DB_HOST=<your-rds-endpoint>" >> .env
echo "DB_PORT=5432" >> .env
echo "DB_NAME=<your-database-name>" >> .env
echo "DB_USER=<your-username>" >> .env
echo "DB_PASSWORD=<your-password>" >> .env

Step 3: Run the Flask App

1. Start the Flask app:

# Set Flask to listen on all interfaces and port 5000
flask run --host=0.0.0.0 --port=5000

2. Test the app by going to your EC2 public IP and port 5000 in the browser or using curl:

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

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Configuring Flask as a Service (Optional)

To run Flask as a background service on EC2:

1. Create a systemd service file for the Flask app:

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

2. Add the following content to the file:

[Unit]
Description=Flask Application
After=network.target

[Service]
User=ec2-user
WorkingDirectory=/home/ec2-user/flask-api
Environment="DB_HOST=<your-rds-endpoint>"
Environment="DB_PORT=5432"
Environment="DB_NAME=<your-database-name>"
Environment="DB_USER=<your-username>"
Environment="DB_PASSWORD=<your-password>"
ExecStart=/home/ec2-user/flask-api/venv/bin/python /home/ec2-user/flask-api/app.py

[Install]
WantedBy=multi-user.target

3. Reload the systemd daemon, start the service, and enable it to start on boot:

sudo systemctl daemon-reload
sudo systemctl start flaskapp
sudo systemctl enable flaskapp

4. Verify the service is running:

sudo systemctl status flaskapp

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Testing the API

Available Endpoints

• GET /health: Check the health of the API and database connection.
• POST /items: Create a new item.
• GET /items/<item_id>: Retrieve an item by ID.
• PUT /items/<item_id>: Update an item by ID.
• DELETE /items/<item_id>: Delete an item by ID.

# Example curl request
curl http://<your-ec2-public-ip>:5000/health

Your API is now deployed and connected to an RDS PostgreSQL database on AWS.