AWS Lambda can now be developed in Swift. A presentation on what is Lambda and Serverless, how to code, build and deploy a Lambda in Swift.

1. AWS Lambda in Swift
Andrea Scuderi - Lead iOS @ Shpock
@andreascuderi13
NSLondon - 3rd of December 2020

2. 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

3. What is a Lambda?

4. HW, VM, Container vs Serverless
What are the advantages of it?
λServers Virtual Machines Containers
Function as a Service
FaaS
Abstraction LevelHW SW

5. HW, VM, Container vs Serverless
What are the advantages of it?
λServers Virtual Machines Containers
Function as a Service
FaaS
Deployment SpeedDays μs (micro-seconds)

6. HW, VM, Container vs Serverless
What are the advantages of it?
λServers Virtual Machines Containers
Function as a Service
FaaS
ScalabilitySPoF
(Single Point of Failure)
Auto-Scaling

7. HW, VM, Container vs Serverless
What are the advantages of it?
λServers Virtual Machines Containers
Function as a Service
FaaS
Business ModelPay Upfront Pay Per Use

8. 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

9. 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

10. 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

11. How can I code a Lambda with Swift?

12. Hello World
Project setup
> mkdir HelloWorldLambd
a
> cd HelloWorldLambd
a
> swift package init --type=executabl
e
> xed Package.swif
t

13. 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"]),
]
)

14. 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))
}

15. 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"
}

16. 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

17. 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.

18. 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

19. 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)

20. 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

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

22. 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

23. 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
• ….

24. 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

25. Test the Deployment

26. CloudFormation
• Cleanup
> ./scripts/serverless-remove.sh HelloWorldLambd
a

27. Introduction to a Serverless REST API in Swift

28. REST API
AWS Serverless Architecture
• API Gateway
• Lambda
• Create
• Read
• Update
• Delete
• List
• DynamoDB

29. 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

30. Question Time
Tanks for listening
• Follow me!
• Twitter: @andreascuderi13
• Linkedin: https://www.linkedin.com/in/andreascuderi/
• Medium: https://medium.com/@andreascuderi73