AWS Serverless Application

Overview

This project demonstrates a serverless application using AWS services. The application consists of an API Gateway, AWS Lambda functions, and DynamoDB for data storage.

Created By

Venkatesh Pattem - DevOps Engineer with a passion for serverless architecture and cloud computing.

Prerequisites

• AWS CLI installed and configured
• AWS SAM CLI installed
• Python 3.8 or later
• Docker (for local testing)

Project Structure

• app/: Contains the Lambda function code.
• tests/: Contains the unit tests for the application.
• infra/: Infrastructure as code (IaC) templates and deployment scripts.

Getting Started

1. Clone the Repository

git clone https://github.com/venpattem/aws-serverless-app.git
cd aws-serverless-app

2. Set Up the Environment

Copy the example environment file and update it with your configuration.

cp .env.example .env

Open the .env file and update it with your AWS credentials and other necessary information:

AWS_ACCESS_KEY_ID=your_access_key_id
AWS_SECRET_ACCESS_KEY=your_secret_access_key
TABLE_NAME=SampleDynamoDBTable
AWS_REGION=us-east-1

3. Install Dependencies

Install the dependencies for both the application and the infrastructure.

# Application dependencies
pip install -r app/requirements.txt

# Infrastructure dependencies
pip install -r infra/requirements.txt

4. Deploy the Application

Navigate to the infra/ directory and deploy the application using the AWS SAM CLI.

cd infra
./deploy.sh

5. Test the Application

Run unit tests to ensure the application works correctly.

pytest tests/

Deployment

AWS SAM Template (template.yaml)

The template.yaml file in the infra/ directory defines the AWS resources for the serverless application.

Deploy Script (deploy.sh)

The deploy.sh script automates the deployment process.

#!/bin/bash

# Build the application
sam build

# Deploy the application
sam deploy --guided

Lambda Function (app/app.py)

This is the main Lambda function code. It handles API requests and interacts with DynamoDB.

import json
import boto3
import os

def lambda_handler(event, context):
    dynamodb = boto3.resource('dynamodb', region_name=os.environ['AWS_REGION'])
    table = dynamodb.Table(os.environ['TABLE_NAME'])
    
    # Example operation: Put item into DynamoDB
    response = table.put_item(
       Item={
            'id': '123',
            'data': 'Hello from Lambda!'
        }
    )

    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }

Testing (tests/test_app.py)

Unit tests for the Lambda function.

import pytest
from app import app

def test_lambda_handler():
    event = {}
    context = {}
    response = app.lambda_handler(event, context)
    assert response['statusCode'] == 200
    assert response['body'] == '"Hello from Lambda!"'

Cleanup

To delete the resources created by the stack, run:

aws cloudformation delete-stack --stack-name your-stack-name

Conclusion

This project provides a basic structure for an AWS serverless application with clear instructions on setup, deployment, and testing. Feel free to modify and expand it according to your needs.