Building a Reactive RESTful API with Akka Http & Slick

Codemotion 2015,Berlin, Germany

Building a

Reactive RESTful APIwith Akka Http & Slick

Dan Persa - @danpersa

Dan Persa● Senior Software Engineer

● Twitter: @danpersa

● dan.persa@zalando.de

EUROPE’S LEADING ONLINE FASHION PLATFORM

15 countries3 fulfillment centers16+ million active customers2.2+ billion € revenue 2014130+ million visits per month9.000+ employees

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ZALANDOTECHNOLOGY

500+Apps

800+ Tech employees

August

Conway’s Law

“organizations which design systems ...are constrained to produce designs which are copies of the communication structures of these organizations”

ARCHITECTURE

AN ARCHITECTURE FOR INNOVATION

API FIRSTRESTSAAS

MICRO SERVICESCLOUD

OPEN SOURCE

THE SHOP MONOLITH

http://blog.codinghorror.com/new-programming-jargon/

We call it “Jimmy”

Thousands of Java classes, undocumented featuresBusiness logic on all layers (including the database)

MICROSERVICES

Internet

LB

SKIPPERSKIPPER

SKIPPERSKIPPER

JIMMYMOSAIC

INNKEEPERINNKEEPER

INNKEEPERLB

REST APIs

HIGHLY AVAILABLE0 DOWNTIMERELIABLEFAST

INNKEEPER github.com/zalando/innkeeper

API FIRSTREST

FORMAL SPECIFICATION FOR RESTful APIs

The World's Most Popular Framework for APIs.

REST RESOURCES

GET /routesGET /routes/{id}POST /routesDELETE /routes/{id}

GET /updated-routes/{id}

GOING REACTIVE

MODEL DBCONTROLLER

BUFFERBUFFERDB RecordsDTOsJSON

CLIENT

TRADITIONAL APPLICATION

HTTP Request Method Call SQL

Blocking IO

MODEL DBCONTROLLER

DB StreamDTOsJSON

CLIENT

REACTIVE APPLICATION

HTTP Request Method Call SQL

Non-Blocking IO

StreamStreamStream

ScalaTypesafeComposable

Meet

Separation of I/0ResilienceReactive Streams

Meet

def routesModifiedSince(localDateTime: LocalDateTime): DatabasePublisher[RouteRow] = {

}

val routesTable = TableQuery[RoutesTable]

val q = for { routeRow <- routesTable if (routeRow.createdAt > localDateTime | routeRow.deletedAt > localDateTime)} yield routeRow

db.stream { q.result }

ComposableMaterializableReactive Streams

Meet

Streams

import akka.stream.scaladsl.Source

def findRoutesModifiedSince(localDateTime: LocalDateTime): Source[Route, Unit] = {

}

Source(

).mapConcat(_.toList)

routesRepo.selectModifiedSince(localDateTime).mapResult { row =>

}

row.id.map { id => Route( id = id, route = row.routeJson.parseJson.convertTo[NewRoute], row.createdAt, row.deletedAt )}

val route = path("hello") { get { complete { <h1>Hello World</h1> } } }

Meet

Http

object Main extends App {

}

implicit val system = ActorSystem("my-system")implicit val materializer = ActorMaterializer()val route = ...val bindingFuture = Http().bindAndHandle(route, "localhost", 8080)...

Innkeeper’s AKKA HTTP Routesval route = path("updated-routes" / Rest) { lastModifiedString => get { complete(…) } } ~ path("routes") { get { complete(…) } ~ post { complete(…) } } ~ path("routes" / LongNumber) { id => get { … } ~ delete { … } }

path("routes") { get {

complete { HttpResponse(

) } }}

entity = HttpEntity.Chunked( MediaTypes.`application/json`, chunkedStreamSource )

val chunkedStreamSource = jsonService.sourceToJsonSource(routesService.allRoutes)

def sourceToJsonSource[T](source: Source[T, Unit]) (implicit writer: JsonWriter[T]):

Source[ChunkStreamPart, ((Unit, Unit), Unit)] = {

val commaSeparatedRoutes: Source[ChunkStreamPart, Unit] = source .map(t => Some(t.toJson.compactPrint)) .scan[Option[ChunkStreamPart]](None)({ case (None, Some(sourceElement)) => Some(ChunkStreamPart(sourceElement)) case (_, Some(sourceElement)) => Some(ChunkStreamPart(s", $sourceElement")) }) .mapConcat(_.toList)

Source.single(ChunkStreamPart("[")) ++ commaSeparatedRoutes ++ Source.single(ChunkStreamPart("]")) }

SAAS

OAUTH

val route: RequestContext => Future[RouteResult] = authenticationToken { token => authenticate(token, authService) { authenticatedUser => path("updated-routes" / Rest) { lastModifiedString => get { hasOneOfTheScopes(authenticatedUser)(scopes.READ) { ...

import akka.http.scaladsl._import akka.http.scaladsl.server.directives.HeaderDirectives._

trait OAuthDirectives { def authenticationToken: Directive1[String] = headerValue(optionalValue("authorization")) | reject {

AuthenticationFailedRejection( CredentialsMissing, HttpChallenge("", "")

) }...

CLOUD

STUPS.IO

FROM zalando/openjdk:8u45-b14-5MAINTAINER Team Spearheads <team-spearheads@zalando.de>

EXPOSE 8080

RUN mkdir -p /opt/innkeeper

ADD target/scala-2.11/innkeeper-assembly-0.0.1.jar /opt/innkeeper/

WORKDIR /opt/innkeeper

ENTRYPOINT java $(java-dynamic-memory-opts) -Dinnkeeper.env=prod -server -jar innkeeper-assembly-0.0.1.jar

docker:sbt assemblydocker build -t innkeper:latest-SNAPSHOT .

docker-push:docker push innkeper:latest-SNAPSHOT

docker-run:docker run -p 8080:8080 -t innkeper:latest-SNAPSHOT

test-db:docker run -e POSTGRES_PASSWORD=innkeeper-test -e

POSTGRES_USER=innkeeper-test -p 5433:5432 postgres:9.4

tick:senza create senza.yaml tick latest-SNAPSHOT

tock:senza create senza.yaml tock latest-SNAPSHOT

OPENSOURCE

github.com/zalando/innkeeper

DOOSF

RADICAL AGILITY

TRUSTINSTEAD OF CONTROL

# use Docker-based container (instead of OpenVZ)sudo: false

cache: directories: - $HOME/.sbt - $HOME/.ivy2

language: scala

script: - sbt ++$TRAVIS_SCALA_VERSION test - sbt ++$TRAVIS_SCALA_VERSION it:test

# Trick to avoid unnecessary cache updates - find $HOME/.sbt -name "*.lock" | xargs rm

scala: - 2.11.7jdk: - oraclejdk8

addons: postgresql: "9.4"

before_script: - psql -c 'CREATE ROLE innkeepertest superuser login createdb;' -U postgres - psql -c 'CREATE DATABASE innkeepertest;' -U postgres

NEXTSTEPS

APPLICATION LOGS: SCALYR

TODO: Screenshot

ZMON

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THANK YOU!QUESTIONS?