AWS Lambda Functions
Table of Contents
Overview
AWS Lambda enables you to run code without provisioning or managing servers. Build serverless applications using event-driven triggers, pay only for compute time consumed, and scale automatically with workload.
When to Use
- API endpoints and webhooks
- Scheduled batch jobs and data processing
- Real-time file processing (S3 uploads)
- Event-driven workflows (SNS, SQS)
- Microservices and backend APIs
- Data transformations and ETL jobs
- IoT and sensor data processing
- WebSocket connections
Quick Start
Minimal working example:
# Create Lambda execution role
aws iam create-role \
--role-name lambda-execution-role \
--assume-role-policy-document '{
"Version": "2012-10-17",
"Statement": [{
"Effect": "Allow",
"Principal": {"Service": "lambda.amazonaws.com"},
"Action": "sts:AssumeRole"
}]
}'
# Attach basic execution policy
aws iam attach-role-policy \
--role-name lambda-execution-role \
--policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
# Create function from ZIP
zip function.zip index.js
aws lambda create-function \
--function-name my-function \
--runtime nodejs18.x \
--role arn:aws:iam::ACCOUNT:role/lambda-execution-role \
--handler index.handler \
--zip-file fileb://function.zip \
// ... (see reference guides for full implementation)Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| Basic Lambda Function with AWS CLI | Basic Lambda Function with AWS CLI |
| Lambda Function with Node.js | Lambda Function with Node.js |
| Terraform Lambda Deployment | Terraform Lambda Deployment |
| Lambda with SAM (Serverless Application Model) | Lambda with SAM (Serverless Application Model) |
| Lambda Layers for Code Sharing | Lambda Layers for Code Sharing |
Best Practices
✅ DO
- Use environment variables for configuration
- Implement proper error handling and logging
- Optimize package size and dependencies
- Set appropriate timeout and memory
- Use Lambda Layers for shared code
- Implement concurrency limits
- Enable X-Ray tracing for debugging
- Use reserved concurrency for critical functions
❌ DON'T
- Store sensitive data in code
- Create long-running operations (>15 min)
- Ignore cold start optimization
- Forget to handle concurrent executions
- Ignore CloudWatch metrics
- Use too much memory unnecessarily