Serverless Rust on AWS Lambda
"for fun and profit"

Luciano Mammino (@loige)

loige.link/cm2024-rust

2024-03-19

👋 I'm Luciano (🇮🇹🍕🍝🤌)

👨‍💻 Senior Architect @ fourTheorem

nodejsdp.link

📔 Co-Author of Node.js Design Patterns  👉

Let's connect!

linktr.ee/loige

$ ~ whoami

loige.link/cm2024-rust

Grab the slides

Always re-imagining

We are a pioneering technology consultancy focused on AWS and serverless

✉️ Reach out to us at  hello@fourTheorem.com

😇 We are always looking for talent: fth.link/careers

We can help with:

Cloud Migrations

Training & Cloud enablement

Building high-performance serverless applications

Cutting cloud costs

𝕏 loige

awsbites.com

𝕏 loige

What is Rust? 🦀

  • A (relatively) new programming language

  • Most loved... for 7 years in a row!

  • Low-level, yet general-purpose

  • Performant & memory-safe

𝕏 loige

Why do I like it ❤️

  • A lovely mascot

  • Strongly typed with a really good type-system

  • Takes inspiration from Haskell, C++, OCaml, JavaScript, Ruby

  • Great (built-in) package manager (Cargo)

  • Good ecosystem of libraries

  • Pattern matching

  • No null, Option & Result types

𝕏 loige

use std::env;

fn main() {
    let region = env::var("AWS_REGION");
}






Result<String, VarError>

𝕏 loige

😀 Happy path

🥺 Sad path

use std::env;

fn main() {
    let region = env::var("AWS_REGION");
    
    match region {
        Ok(region) => println!("Selected region: {}", region),
        Err(_) => println!("Error: AWS_REGION not set"),
    }
}

𝕏 loige

😀 Happy path

🥺 Sad path

use std::env;

fn main() {
    let region = env::var("AWS_REGION")
        .expect("AWS_REGION environment variable not set");
}





String

𝕏 loige

If you cannot get the value, panic!

use std::env;

fn main() {
    let region = env::var("AWS_REGION")
        .unwrap_or_else(|_| "eu-west-1".to_string());
}

Rust makes it very hard for you to ignore possible errors or the absence of values.

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if you cannot get the value, use a default value!

Serverless, in a nutshell 🥜

  • A way of running applications in the cloud

  • Of course, there are servers... we just don't have to manage them

  • We pay (only) for what we use

  • Small units of compute (functions), triggered by events

𝕏 loige

Serverless... with benefits 🎁

  • More focus on the business logic (generally)

  • Increased team agility (mostly)

  • Automatic scalability (sorta)

  • Not a universal solution, but it can work well in many situations!

𝕏 loige

AWS Lambda

Serverless FaaS offering in AWS

Can be triggered by different kinds of events

  • HTTP Requests
  • New files in S3
  • Jobs in a Queue
  • Orchestrated by Step Functions
  • On a schedule
  • Manually invoked

𝕏 loige

(some) Limitations 😖

  • Maximum execution time is 15 minutes...
  • Payload size (request/response) is limited
  • Doesn't have a GPU option (yet)

... so again, it's not a silver bullet for all your compute problems! 🔫

𝕏 loige

AWS Lambda Pricing 💸

Cost = Allocated Memory 𝒙 time

aws.amazon.com/lambda/pricing/

𝕏 loige

         💰                    🏋️‍♂️                   ⏱️

AWS Lambda Pricing 💸

Cost = Allocated Memory 𝒙 time

aws.amazon.com/lambda/pricing/

𝕏 loige

         💰                    🏋️‍♂️                   ⏱️

AWS Lambda... what about CPU? 🙄

You don't explicitly configure it:

CPU scales based on memory

loige.link/lambda-cpu

𝕏 loige

AWS Lambda... what about CPU? 🙄

You don't explicitly configure it:

CPU scales based on memory

Memory vCPUs
128 - 3008 MB 2
3009 - 5307 MB 3
5308 - 7076 MB 4
7077 - 8845 MB 5
8846+ MB 6

loige.link/lambda-cpu

𝕏 loige

🏃‍♂️ Lambda execution model

  • It's serverless: it should run only when needed
  • Lambda code is stored in S3
  • event-based: an event can trigger a lambda execution
  • if no instance is available, one is created on the fly (cold-start)
  • if an instance is available and ready, use that one
  • if an instance is inactive for a while, it gets destroyed

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🏃‍♂️ Lambda execution model

in detail

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🏃‍♂️ Lambda execution model

Runtime

Handler (logic)

in detail

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🏃‍♂️ Lambda execution model

Runtime

Handler (logic)

Poll for events

in detail

𝕏 loige

🏃‍♂️ Lambda execution model

Runtime

Handler (logic)

Poll for events

event (JSON)

in detail

𝕏 loige

🏃‍♂️ Lambda execution model

Runtime

Handler (logic)

Poll for events

event (JSON)

execute

in detail

𝕏 loige

🏃‍♂️ Lambda execution model

Runtime

Handler (logic)

Poll for events

event (JSON)

execute

response or
error

in detail

𝕏 loige

🏃‍♂️ Lambda execution model

Runtime

Handler (logic)

Poll for events

event (JSON)

execute

response or
error

response (JSON)
or error

in detail

𝕏 loige

Why Rust + Lambda = ❤️

  • Performance + Efficient memory-wise = COST SAVING 🤑
  • Very fast cold starts! (proof) ⚡️
  • Multi-thread safety 💪
  • No null types + Great error primitives = fewer bugs 🐞

𝕏 loige

Supported Lambda runtimes

  • Node.js

  • Python

  • Java

  • .NET

  • Go

  • Ruby

  • Custom

𝕏 loige

Supported Lambda runtimes

  • Node.js

  • Python

  • Java

  • .NET

  • Go

  • Ruby

  • Custom

RUST?!

[deprecated]

𝕏 loige

Rust Runtime for Lambda

github.com/awslabs/aws-lambda-rust-runtime

𝕏 loige

OK, Let's do this!

𝕏 loige

𝕏 loige

github.com/lmammino/rust-lambda-workshop

Closing notes

  • Lambda is great (most of the time)
  • Writing Lambdas in Rust is fun and it can be very cost-efficient
  • Still not very common to write Lambdas in Rust, but the tooling is already quite good (Cargo Lambda + SAM)
  • Go, have fun, share your learnings!

𝕏 loige

BONUS: SAM + Cargo Lambda
a complete example

github.com/lmammino/earthquake-notifier

𝕏 loige

BONUS 2: another complete example

github.com/lmammino/oidc-authorizer

𝕏 loige

Thanks to @gbinside, @conzy_m, @eoins, and @micktwomey for kindly reviewing this material!

THANKS!

nodejsdp.link

loige.link/cm2024-rust

Grab these slides!

𝕏 loige