Your Lambdas, in Rust!

Luciano Mammino (@loige)

loige.link/rusty-lambdas

Cloud Native 2023
2023-03-30

👋 I'm Luciano (🇮🇹🍕🍝🤌)

👨‍💻 Senior Architect @ fourTheorem

nodejsdp.link

📔 Co-Author of Node.js Design Patterns 👉

Let's connect!

loige.co (blog)

@loige (twitter)

loige (twitch)

lmammino (github)

loige.link/rusty-lambdas

Grab the slides

$ ~ whoami

Always re-imagining

We are a pioneering technology consultancy focused on AWS and serverless

loige

✉️ 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

We host a weekly podcast about AWS

awsbites.com

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Agenda

Serverless and its benefits
AWS Lambda and its pricing model
Why Rust
Cargo Lambda example
Using it with SAM
Lambda tuning
Closing notes

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⚡️Serverless

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Serverless, in a nutshell 🥜

A way of running applications in the cloud
Of course, there are servers... we just don't manage them
You pay for what you use
Small units of compute (functions), triggered by events

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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!

loige

AWS Lambda

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

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AWS Lambda Pricing 💸

Cost = Allocated Memory 𝒙 time

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aws.amazon.com/lambda/pricing/

AWS Lambda Pricing 💸

Cost = Allocated Memory 𝒙 time

loige

aws.amazon.com/lambda/pricing/

512 MB = $0.0000000083/ms

Executing a lambda for 15 mins...

0.0000000083 * 900000 = 0.007 $

AWS Lambda... what about CPU? 🙄

You don't explicitly configure it:

CPU scales based on memory

loige

loige.link/lambda-cpu

AWS Lambda... what about CPU? 🙄

You don't explicitly configure it:

CPU scales based on memory

loige

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

Writing Lambdas

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in Node.js

export const handler = async(event, context) => {
  // ... get data from event
  // ... run business logic
  // ... return a result
}

loige

export const handler = async(event, context) => {
  // ... get data from event
  const { url } = event

  // ... run business logic
  const res = await fetch(url)
  console.info(`Status of ${url} : ${res.status}`)

  // ... return a result  
  return res.status
}

loige

Supported runtimes

Node.js
Python
Java
.NET
Go
Ruby
Custom

loige

Supported runtimes

Node.js
Python
Java
.NET
Go
Ruby
Custom

loige

RUST?!

Rust Runtime for Lambda

loige

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

use lambda_runtime::{service_fn, LambdaEvent, Error};
use serde_json::{json, Value};

#[tokio::main]
async fn main() -> Result<(), Error> {
    let func = service_fn(func);
    lambda_runtime::run(func).await?;
    Ok(())
}

async fn func(event: LambdaEvent<Value>) -> Result<Value, Error> {
    let (event, _context) = event.into_parts();
    let first_name = event["firstName"].as_str().unwrap_or("world");

    Ok(json!({ "message": format!("Hello, {}!", first_name) }))
}

Your Rust Lambda handler

Runs the handler

Extra boilerplate 🤷‍♀️

loige

Y Rust tho?

loige

Rust

Relatively new language (2015)
It's a compiled language
Focused on performance and memory safety
But also providing great high-level constructs
Great as a general-purpose language
Very modern toolchain
Great ecosystem
Awesome mascot

loige

Cargo

Rust built-in package manager
(like npm but for Rust)
Also used for scaffolding, testing & more
It can be extended with third-party commands

loige

Why Rust + Lambda = ❤️

Performance + Efficient memory-wise = COST SAVING 🤑
Multi-thread safety 💪
No null types + Great error primitives = fewer bugs 🐞

loige

Cargo Lambda

A third-party command for Cargo that makes it easier to author, test and deploy Lambdas in Rust
It can cross-compile for Linux ARM (on Win/Mac/Linux)

loige

cargo-lambda.info

Commands

cargo lambda new - scaffolds a new project

cargo lambda watch - starts a dev environment (lambda emulator)

cargo lambda invoke (sends an event to the dev environment)

```
cargo lambda build (builds the lambda)
```

cargo lambda deploy (deploys the lambda to AWS)

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Cargo Lambda

DEMO 🤞

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Cargo Lambda

SAM

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Serverless Application Model

AWS SAM

YAML-based Infrastructure as code (IaC) tool focused on serverless apps
Great when you have to go beyond just one lambda

loige

aws.amazon.com/serverless/sam

Some example use cases:

You need to provision multiple lambdas
You need to provision multiple pieces of infrastructure (e.g. S3 buckets, permissions, DynamoDB tables, etc)
It supports everything that is natively supported with CloudFormation, but with a slightly simpler syntax
Deploys through CloudFormation!

loige

AWS SAM

# template.yaml

AWSTemplateFormatVersion : '2010-09-09'
Transform:
  - AWS::Serverless-2016-10-31

Description: |
  A sample Serverless project triggered from S3 CreateObject events
Resources:
  ExampleFunction:
    Type: AWS::Serverless::Function
    Properties:
      Runtime: nodejs18.x
      Handler: index.handler
      Events:
        S3CreateObject:
          Type: S3
          Properties:
            Bucket: !Ref MyPhotoBucket
            Events: s3:ObjectCreated:*

  MyPhotoBucket:
    Type: AWS::S3::Bucket

loige

AWS SAM + Cargo Lambda

SAM Works with Cargo Lambda (still experimental):

Define IaC with the full power of SAM
Build and run your Rust lambdas with Cargo Lambda

loige

Note: Cargo Lambda also works with CDK
(github.com/cargo-lambda/cargo-lambda-cdk)

SAM + Cargo Lambda, a complete example

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github.com/lmammino/earthquake-notifier

🔧Fine Tuning

loige

Your lambdas

Fine tuning your Lambdas

If you give your lambdas more memory you get more CPU
Sometimes having more memory (hence more CPU) can make your executions faster and you can save money
So how do we find the sweet spot?!

loige