🚀 Features

• AWS Lambda functions in Python
• API Gateway integration
• CloudWatch logging
• Event-driven triggers (S3, EventBridge)
• Infrastructure as code with AWS SAM
• CI/CD pipeline using GitHub Actions
• Easy local testing and deployment

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🛠 Prerequisites

Before you start, ensure you have:

1. AWS Account

   • Create an account: https://aws.amazon.com

2. AWS IAM User

   • Create an IAM user with programmatic access

   • Attach the following policies:

     

   • Save Access Key ID and Secret Access Key

3. AWS CLI Installed

   • Install: https://aws.amazon.com/cli/

4. AWS SAM CLI Installed

   • Install SAM CLI: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-install.html

5. Python 3.10+ installed

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⚙️ AWS Configuration

Configure AWS CLI with your IAM user credentials:

aws configure

You will be prompted for:

• AWS Access Key ID
• AWS Secret Access Key
• Default region (e.g., ap-south-1)
• Default output format (json)

Test configuration:

aws sts get-caller-identity

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🏗 SAM Project Setup

1. Clone Repository

git clone https://github.com/vktrenga/lambda-python-sam.git
cd lambda-python-sam

2. Create Virtual Environment

python3 -m venv venv
source venv/bin/activate    # Windows: venv\Scripts\activate
pip install -r user/requirements.txt

3. Build SAM Application

sam build

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📝 Create a Simple Lambda App

1. Open user/app.py and add your function:

import json

def lambda_handler(event, context):
    return {
        "statusCode": 200,
        "body": json.dumps({"message": "Hello from Lambda!"})
    }

2. Add function to template.yaml:

Resources:
  UserApiFunction:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: python3.10
      Handler: app.lambda_handler
      CodeUri: user/
      Timeout: 10
      Events:
        GetUsers:
          Type: Api
          Properties:
            Path: /users
            Method: get

3. Test locally:

sam local invoke UserApiFunction --event events/event.json
sam local start-api

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🚀 Deploy to AWS

sam deploy --guided

• Provide stack name, region, and confirm IAM role creation
• After deployment, you’ll get the API Gateway URL:

https://<api-id>.execute-api.<region>.amazonaws.com/Prod/users

Test in browser or Postman.

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📈 CI/CD Pipeline (GitHub Actions)

The project includes a workflow .github/workflows/sam-ci-cd.yml:

Pipeline steps:

1. Linting & Code Checks: Ensure Python code quality
2. Build: sam build
3. Deploy: sam deploy automatically on main branch
4. Notifications: Optional Slack/Email alerts

Example workflow snippet:

name: SAM CI/CD

on:
  push:
    branches: ["main"]

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Set up Python
        uses: actions/setup-python@v4
        with:
          python-version: 3.10
      - name: Install SAM CLI
        run: |
          pip install aws-sam-cli
      - name: Build SAM app
        run: sam build
      - name: Deploy SAM app
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: ap-south-1
        run: sam deploy --no-confirm-changeset --stack-name lambda-python-sam --capabilities CAPABILITY_IAM

Tip: Add AWS credentials as GitHub secrets for secure CI/CD.

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🔧 Logging & Monitoring

• Lambda logs are automatically sent to CloudWatch
• Optional: Add custom log statements in app.py
• Supports triggers: S3 events, EventBridge scheduled tasks

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📜 License

This project is licensed under MIT License. See LICENSE for details.

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