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AWS Lambda

• Serverless compute requires a novel approach and mindset
• But... the basics of Lambda will still allow to gain benefits (cost, scale etc)
• Reach for the advanced features as complexity grows

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Lifecycle

https://aws.amazon.com/blogs/compute/understanding-aws-lambda-scaling-and-throughput/

• Compute model → programming model
• Init phase runs "code outside handler"
• Invocation phase runs "code inside handler"

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Concurrency Model

Lambda's unit of scale is concurrency

https://aws.amazon.com/blogs/compute/understanding-aws-lambda-scaling-and-throughput/

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Work With Constraints

• Maximum concurrent executions = 1,000

• Maximum function duration = 15 minutes

• Maximum memory allocation = 10,240 MB

Optimise with Lambda Insights

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Runtime & Language

• Choose runtime/language to suit use case and team
• Use latest Node.js version when possible
• Use arm64 architecture (AWS Graviton2)

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Files and Folders

• Prefer a single file per function over early abstractions
• If the file/function grows substantially consider architecture
• Use a directory structure that works for you and change if needed

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Code Standards

• Use Prettier's default rules
• Keep ESLint rules to a minimum. Use someone else’s rules with caution
• Keep config in root, not tied to specific functions or services

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TypeScript

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AWS SDK

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Testing

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Security

• Keep dependencies updated, especially vulnerability patches
• Apply the Principle of Least Privilege to IAM policies - i.e. do not use * (wildcards)!
• Use the OWASP Serverless Top 10 to mitigate common serverless application security vulnerabilities

https://owasp.org/www-project-serverless-top-10

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Observability

• Monitor metrics for Concurrent Executions, Throttles and Errors
• Route alarms to team chat
• Use dashboards to view critical health

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Powertools

• Lambda Powertools for TypeScript
• Logs, metrics and tracing

https://awslabs.github.io/aws-lambda-powertools-typescript/

Resources

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- Next: CDK Workshop cdkworkshop.com

- More from me twitter.com/level_out

- These slides 🤳👇