Lambda Functions

This directory contains Lambda function examples demonstrating various serverless patterns.

Functions

hello-world

A simple "Hello World" function demonstrating basic Lambda concepts.

Key Features:

• Basic event handling
• Logging
• Error handling
• Environment variables

Use Case: Learning Lambda basics

api-handler

An API handler that processes HTTP requests from API Gateway.

Key Features:

• API Gateway integration
• HTTP method routing (GET, POST, PUT, DELETE)
• Request parsing
• CORS support

Use Case: RESTful API backends

event-processor

Processes events from various sources (S3, EventBridge, CloudWatch).

Key Features:

• Multi-source event handling
• S3 event processing
• EventBridge integration
• DynamoDB storage

Use Case: Event-driven processing

Deployment

All functions are deployed via Terraform. See main.tf for configuration.

Testing

Local Testing

# Test hello-world
cd lambda/hello-world
python -c "from lambda_function import lambda_handler; print(lambda_handler({}, None))"

AWS Testing

# Invoke function
aws lambda invoke \
  --function-name function-name \
  --payload '{"key": "value"}' \
  response.json

# View response
cat response.json

Best Practices

1. Error Handling: Always wrap code in try/except
2. Logging: Use structured logging
3. Environment Variables: Use for configuration
4. Idempotency: Make functions safely retryable
5. Timeouts: Set appropriate timeout values
6. Memory: Right-size memory allocation

Monitoring

View logs in CloudWatch:

aws logs tail /aws/lambda/function-name --follow