hypermedia-driven orchestration in microservices

Hypermedia-DrivenOrchestrationinMicroservices

IrakliNadareishvili

DevOps:APIManagementandApplicationDevelopment

CATechnologiesDirectorofStrategy,APIAcademySessionDO3T25T

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Abstract

Hypermedia-DrivenOrchestrationinMicroservicesThenotionof"affordances"hasplayedseminalroleintransformingourunderstandingofusableservicedesign.Itiskeyinhypermediaarchitecturalstyleandenablesustobuildresilientsystems“atthescaleofdecades”.Withthemicroservice architecturalstyle,wecanbuildsystemsthathavehigherdegreesoffreedomthanthosehavingmonolitharchitectures.Insuchsystems,effectiveorchestrationandchoreographyarecrucial.Duringthispresentation, IrakliNadareishvili,DirectorofAPIStrategy,APIAcademy,exploreshypermedia-enabledapproachthatleadsto loosely-coupled,evolvableservicedesign.

IrakliNadareishviliCATechnologiesDirectorofStrategy,APIAcademy


ArchitecturalStylesandtheDesignofNetwork-based Software,2001- RoyT.Fielding

“Hypermediaisdefinedbythepresenceofapplicationcontrolinformationembeddedwithin,orasalayer

above,thepresentationofinformation”

HypermediaperFielding


LetAPIserverdynamicallyguideaclientbyrespondingtoclientwithnotjuststatic databutalsocontrolsdescribingAPIaffordances.

Or:Response=Data+Controls


Mostcommonhypermediacontrolsfacilitate:“single,nextstep.”

HypermediaShortcoming?

Howdoweorchestrateloosely-coupledmicroservices

forcomplexworkflows?


Examples:

E-COMMERCE

BOOKINGTRAVEL1

2


BookingTravel


Saga:Long-LivedCompensatingTransactions

SagawasintroducedbyHectorGarcia-MolinaandKennethSalemin1987.

ExamplescenariobyClemensVasters:http://vasters.com/clemensv/2012/09/01/Sagas.aspx

Car Hotel Flight

RoutingSlip


@see:http://rels.messages.io

LinkRelationsforSaga:

§ rel =“routing-slip”(microformats)

§ rel =“compensatingtx”(microformats)


E-Commerce


3TypesofComplexWorkflows

BROWSING/DISCOVERY—“HYPERMEDIAMAZE”(AMUNDSEN)

CHECKOUT—SERVICE ORCHESTRATION

POST-PURCHASE—SERVICECHOREOGRAPHY

1

2

3


Source:Richardson, Amundsen,Ruby, “RESTfulWebAPIs,”O’Reilly, 2013.

MazeProblems

– MikeAmundsen

“Problemistoocomplextobeunderstoodallatonce,soit’ssplitupintosteps.”


Maze+XML

Source:Richardson, Amundsen,Ruby, “RESTfulWebAPIs,”O’Reilly, 2013.


Checkout

1.CollectShipping Info 2.BillingInfo 3.AuthorizePayment

4.Post-PurchaseProcessing

Checkout:Orchestration


OrchestrationforWizard-StyleWFs:

StandardIANAlinkrelations:

§ rel =“next”

§ rel =“prev”


Post-Purchaseservice

Shipping Service

E-mailNotificationService

SMS NotificationService

PurchaseCompleted

event

PushNotificationService

Inspiredbyachoreographyexamplein:SamNewman,BuildingMicroservices,O’Reilly,2015.

«subscribes to»

PostPurchase:Choreography


@see:http://rels.messages.io

ServiceChoreography

§ rel =“hub”(IANAstandard)§ rel =“sub”(new:microformats)§ rel =“unsub”(new:microformats)§ rel =“events”(new:microformats)

Async andevent-driven.Standard:Pubsubhubbub


TypesofComplexWorkflows

BROWSING/DISCOVERY—“HYPERMEDIAMAZE”(MIKEAMUNDSEN)

CHECKOUT—SERVICEORCHESTRATION

POST-PURCHASE—SERVICECHOREOGRAPHY

1

2

3

DISTRIBUTEDTRANSACTIONS—SAGA4

Aretheremoreworkflowtypes?Probably,but:nexttime!


Q&A

hypermedia-driven orchestration in microservices

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