Aws Lambda in Swift - NSLondon - 3rd December 2020

AWS Lambda in Swift
Andrea Scuderi - Lead iOS @ Shpock

@andreascuderi13
NSLondon - 3rd of December 2020

AWS Lambda in Swift
Agenda
• What is a Lambda?

• How can I code a Lambda with Swift?

• Development Tools

• Building Tools

• Deployment Tools

• Introduction to a Serverless REST API in Swift

HW, VM, Container vs Serverless
What are the advantages of it?
λServers Virtual Machines Containers
Function as a Service

FaaS
Abstraction LevelHW SW


FaaS
Deployment SpeedDays μs (micro-seconds)


FaaS
ScalabilitySPoF

(Single Point of Failure)
Auto-Scaling


FaaS
Business ModelPay Upfront Pay Per Use

Monolithic vs Microservices
Architecture
User
Interface
Business
Logic
Data
Access
Layer
DB
User
Interface
Micro

service Micro

service
Micro

service
Micro

service
Micro

service
DB DB DB
Monolithic

• Simpler

• Lower Latency

• Higher Throughput
Microservice

• Loose coupling

• More reliable

• Less resource

• Easier scaling

• More Agile

• High complexity

• Less communication

AWS Serverless Landscape
• COMPUTE: Lambda

• STORAGE: S3, EFS

• DATA STORE: DynamoDB, Aurora

• API PROXY: API Gateway

• MESSAGING: SNS, SQS, Kinesis

• ORCHESTRATION: Step Functions

• MONITORING: CloudTrail

• SECURITY: IAM, Cognito

AWS Lambda
Function as a Service (FaaS)
• Serverless

• Managed Micro-Service

• Event driven

• Stateless

• Auto-Scaling

• Pay per use (Sub-second metering)

• Logging and monitoring is included

• Code container

• Multi-Language support

• Can run Linux compatible language runtime via Runtime API
© 2019, Amazon Web Services, Inc. or its affiliates. All rights reserved.S U M M I T
Serverless applications
Services (anything)
Changes in
data state
Requests to
endpoints
Changes in
resource state
Event source Function
Node.js
Python
Java
C# / F# / PowerShell
Go
Ruby
Runtime API

How can I code a Lambda with Swift?

Hello World
Project setup
> mkdir HelloWorldLambd
a

> cd HelloWorldLambd
a

> swift package init --type=executabl
e

> xed Package.swif
t

Hello World
Update Package.swift
import PackageDescription

let package = Package(

name: "HelloWorldLambda",

products: [

.executable(name: "HelloWorldLambda", targets: ["HelloWorldLambda"]),

],

dependencies: [

.package(url: "https://github.com/swift-server/swift-aws-lambda-runtime.git", from: "0.1.0"),

],

targets: [

.target(

name: "HelloWorldLambda",

dependencies: [

.product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime"),

]),

.testTarget(

name: "HelloWorldLambdaTests",

dependencies: ["HelloWorldLambda"]),

]

)

Hello World
Add your code to main.swift
import AWSLambdaRuntime

struct Request: Codable {

let name: String

}

struct Response: Codable {

let message: String

}

Lambda.run { (context, request: Request, callback: @escaping (Result<Response, Error>) -> Void) in

let response = Response(message: "Hello!: (request.name)")

callback(.success(response))

}

Hello World
Run your Lambda locally
> export LOCAL_LAMBDA_SERVER_ENABLED=tru
e

> swift run HelloWorldLambd
a

> curl --location --request POST 'http://localhost:7000/invoke'

--header 'Content-Type: text/plain'

--data-raw '
{

"name": "Andrea
"

}
'

{"message":"Hello!: Andrea"
}

Apple - Swift NIO
https://github.com/apple/swift-nio
• SwiftNIO - NIO == non-blocking I/O

• cross-platform

• asynchronous event-driven network application framework

• for rapid development of maintainable high performance protocol servers &
clients.

• Low level framework

• use-cases: where"thread-per-connection" model of concurrency is inef
f
icient or
untenable.

• Is the fundamental part of most of the Server Side Swift frameworks

Apple - Swift NIO
https://github.com/apple/swift-nio
• EventLoop:

• The event loop is an object that waits for events (usually I/O) to happen and then
f
ires
some kind of callback when they do.

• EventLoopFuture<T>:

• manage operations that complete asynchronously.

• a container for the return value of a function that will be populated at some time in the
future

• EventLoopPromise<T>:

• Each EventLoopFuture<T> has a corresponding EventLoopPromise<T>, which is the object
that the result will be put into. When the promise is succeeded, the future will be ful
f
illed.

HTTPSLambda
Swift NIO + AsyncHTTPClient
import AWSLambdaRuntime

import AsyncHTTPClient

import NIO

struct Event: Codable {

let url: String

}

struct Response: Codable {

let content: String

}

struct HTTPSLambda: EventLoopLambdaHandler {

// MARK: - In & Out

typealias In = Event

typealias Out = Response

// MARK: - Lambda Handler

func handle(context: Lambda.Context, event: Event) -> EventLoopFuture<Response> {

guard let request = try? HTTPClient.Request(url: event.url) else {

return context.eventLoop.makeFailedFuture(LambdaError.invalidRequest)

}

return httpClient.execute(request: request, deadline: nil)

.flatMapThrowing { (response) throws -> String in

guard let body: ByteBuffer = response.body,

let value: String = body.getString(at: 0, length: body.readableBytes) else {

throw LambdaError.invalidContent

}

return value

}.map { content -> Response in

return Response(content: content)

}

}
> git clone https://github.com/Andrea-Scuderi/HelloWorldLambda

HTTPSLambda
Swift NIO + AsyncHTTPClient
// MARK: - HTTPClient Configuration

let httpClient: HTTPClient

static let lambdaRuntimeTimeout: TimeAmount = .seconds(30)

static let timeout = HTTPClient.Configuration.Timeout(

connect: lambdaRuntimeTimeout,

read: lambdaRuntimeTimeout

)

static let configuration = HTTPClient.Configuration(timeout: timeout)

// MARK: - LambdaError

enum LambdaError: Error {

case invalidRequest

case invalidContent

}

// MARK: - Init

init(context: Lambda.InitializationContext) {

// Use HTTPClient on the same EventLoop used by AWSLambda

self.httpClient = HTTPClient(

eventLoopGroupProvider: .shared(context.eventLoop),

configuration: HTTPSLambda.configuration

)

}

}

Lambda.run(HTTPSLambda.init)

AWS Lambda Swift Runtime
Lambda Architecture & Building pipeline
User Lambda Swift Code
AWS Lambda Swift Runtime
bootstrap
Swift Libraries for Runtime
swift:5.3-amazonlinux2
❌
To run the Lambda on AWS we need:

- build the binary for Amazon Linux 2

- copy all the Swift runtime libraries required
in the zip bundle

AWS Lambda in Swift
Development Tools
Code
Build+
Deploy
Swift Amazon Linux 2
Swift 5.x

Build AWS Lambda in Swift
• Requirements: Docker Desktop, Bash

> git clone https://github.com/Andrea-Scuderi/HelloWorldLambd
a

> cd HelloWorldLambd
a

> ./scripts/build-and-package.sh HelloWorldLambd
a

> ls .build/lambda/HelloWorldLambda/lambda.zi
p
swift:5.3-amazonlinux2

AWS Lambda Deployment tools
Pick your favourite…, mine is Serverless framework
• AWS Management Console (manual upload)

• AWS CLI - Command line interface (Scripting)

• AWS CloudFormation: Infrastructure as code

• AWS SAM Serverless Application Model: deployment tool

• Serverless: Cloud Agnostic Multiplatform deployment tool

• ….

Deploy AWS Lambda in Swift
After you have created your account on AWS, you need to install:

• AWS CLI: https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2-
mac.html

• Serverless framework:

> curl -o- -L https://slss.io/install | bas
h

> ./scripts/serverless-deploy.s
h

CloudFormation
• Cleanup

> ./scripts/serverless-remove.sh HelloWorldLambd
a

Introduction to a Serverless REST API in Swift

REST API
AWS Serverless Architecture
• API Gateway

• Lambda

• Create

• Read

• Update

• Delete

• List

• DynamoDB

AWS Serverless Swift API Template
Full working Demo

• https://github.com/swift-sprinter/aws-serverless-swift-api-template

• `Product` demo API in Swift

• Use SOTO Library (AWS SDK for Swift)

• YAML template for Serverless

• Deployments Scripts

Question Time
Tanks for listening
• Follow me!

• Twitter: @andreascuderi13

• Linkedin: https://www.linkedin.com/in/andreascuderi/

• Medium: https://medium.com/@andreascuderi73

Aws Lambda in Swift - NSLondon - 3rd December 2020

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