growing a microservices landscape (with smart use cases)

@aahoogendoorn

GROWING A MICROSERVICES LANDSCAPE (WITH SMART USE CASES)Sander HoogendoornIndependent dad, mentor, trainer, software architect, developerPrincipal technology officer, global agile thoughtleader Capgemini

@aahoogendoorn

2Sander HoogendoornMe independent..

Mentor, trainer, software architect, programmer

Books, articles, conferences

Principal technology officer Capgemini

Global design authority agile Capgemini

Chief technology officer insurance company

www.sanderhoogendoorn.com

www.smartusecase.com

www.speedbird9.com

@aahoogendoorn

sander@ditisagile.nl

4On being a developer...

5Agenda Monoliths

Microservices? Past the hype?

Promises

But…

From monoliths to a micro-landscape

Micro-applications

Components and microservices

Requirements in a micro-landscape

Smart use cases

Recommendations & considerations

@aahoogendoorn

MONOLITHS Hard to deliver, even harder to test and impossible to maintain

@aahoogendoorn

THE DEPENDENCIES WILL KILL YOU

@aahoogendoorn

MICROSERVICESBeyond the hype?

10Microservices. Beyond the hype?

11Microservices. Beyond the hype?

12Gartner hype cycle

@aahoogendoorn

MICROSERVICESThe clear benefits

In short, the microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and

communicating with lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities and independently deployable by fully

automated deployment machinery. There is a bare minimum of centralized management of these services, which may be written in different programming

languages and use different data storage technologies.

Martin Fowler

15Microservices. Scalability

16Microservices. Polyglot persistence

17Microservices. Promises Products not projects

Scalable

Decentralized governance

Replaceable parts

High performance

Technology independent

Polyglot persistence

Easy to build

Easy to test

Easier deployment than monoliths

18Microservices. But… What is a microservice exactly?

Or are we building nanoservices? Miniservices?

Micro-requirements

Components or services

How big is a microservice

Who owns the microservices

What technology

How to define messages

How to test microservices

How to coordinate when services run across components

How to build a deployment pipeline

19Microservices. Building a deployment pipeline

CodeDeveloper

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20Microservices. Pipeline hell?

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21Microservices. Pipeline hell?

Codev.2

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@aahoogendoorn

ARE MICROSERVICESA STAIRWAY TO HEAVEN?

@aahoogendoorn

OR A HIGHWAY TO HELL?

FOR THE THINGS WE HAVE TO LEARN

BEFORE WE CAN DO THEM,

WE LEARN BY DOING THEMAristotle

@aahoogendoorn

A MICRO-LANDSCAPE SOFTWARE ARCHITECTURE

26A major Dutch insurance companyWe have

Most functionality on an expensive mainframe

A wide variety of large systems written in Java that are hard to maintain and to test, and that are very hard to replace

Individual systems that cover large areas of functionality, usually coupled to departments

Aging technology

No mobile strategy, allowing for new business or new services to clients, and intermediaries

We need to

Shorten time-to-market

Lower TCO

Uphold a fully secure systems landscape

@aahoogendoorn

THE MICRO-LANDSCAPEA software architecture for the near future

28A micro-landscape architecture

Communication architecture. The glueHow do we define interfaces between apps and component?

How do we arrange messaging?How do we glue together rapidly changing apps and component?

Application architectureEnd user facing

Different users, different fast evolving needs Which technology is the best for which purpose?

Component architectureComponents and services are evolving rapidly

How do we decide which components we need? How do we deal with versioning?

How do we deal with distributed processes and transactions?

29The new micro-landscape Client thinks in business processes, so we implement

business processes

Moving to a new systems landscape, consisting of micro-applications and micro-components

Requirements and documentation are modeled rather than written

Each micro-application implements a single business process

Components serve a single purpose and offers services

Each application and component has its own domain model

Applications and components will have an similar internal software architecture to facilitate ease of maintenance and allow for harvesting re-use

Communication using simple open protocols - REST

@aahoogendoorn

APPLICATIONS

32Micro-applications Each micro-application serves a single purpose and

mostly target a single audience, either client, intermediaries, in-house or third parties

Each application implements a single business process

Micro-applications are always human facing, they have a graphical user interface

These user interfaces can be responsive web, native device or even desktop (not preferred) depending on the target audience

Current user interfaces are implemented using HTML5, JavaScript (client-side), Bootstrap (responsive UI), and JSF (server-side)

Presentation

Process

Domain

Services

Outside world

PagesGrids / Panels

Controls

Use casesFlow

Domain objectsFactories / Repositories

Enums / Value objects / Tupels / Reference objects

Service gatewaysService clients

Info objects / Search objects

ComponentsRelations Dossiers Intermediaries Accounts Rates

35Architecture in code

@aahoogendoorn

COMPONENTS

37Components Components are the workers of our software

architecture

Components are fine-grained and targeted at servicing a single business purpose, such as Accounts, Relations or Rates

Components follow the Single Responsibility Principle (SRP).

Over time, components will more and more implement a micro-services architecture

Components will evolve over time

Each component exposes a set of services to the landscape

Service interface

Process

Domain

Services

Outside world

Service interfaces

Use casesFlow

Enums / Value objects / Reference objects

Service gateways / Table gatewaysService clients / Connectors

ComponentsDatabasesRelations Dossiers Rates DB2 MongoDB

@aahoogendoorn

COMMUNICATION

41Communication Communication between applications and

components or between components and components needs to be easy to develop, secure and fast

Communication will leverage simple, scalable and safe web protocols, such as REST

Structures from the component’s domain model can be passed between parts in the landscape, either through info objects (DTO’s) or JSON

Structures offered from producers do not necessarily have the same structure required by the consumer

Mapping or wrapping is inevitable

Be aware that neither REST nor JSON is really fully standardized

42Standardizing communication

43Testing communication

@aahoogendoorn

MODEL FIRST DEVELOPMENTRequirements in the micro-landscape

DOING BIG UP-FRONT DESIGN IS DUMB

DOING NO DESIGN IS EVEN DUMBERDave Thomas

46Model first

47Requirements

48Processes, processes and processes

Step 1 Step 2 Step 3 Step 4 Step 5 Step 6

Step 3.1 Step 3.2 Step 3.3 Step 3.4

Step 3.3.1 Step 3.3.2 Step 3.3.3 Step 3.3.4 Step 3.3.5

49Agile requirements. Approach

SmartUse Cases

Project

Use Cases

Hierarchical

Processes

Hierarchical

Processes

Chronological

Processes

Cloud Level Kite Level Sea Level Fish Level

50Identifying scope at cloud level

51Cloud level

52Kite level

53Modeling smart use cases. Sea and fish level

54Different levels of use casesTraditional

use cases

Format Textual Visual

Granularity Different Unified

Estimate Hard Easy

Unit of work Lousy Good

Reuse Incidental Normal

Traceability Possible Normal

Testability Poor Good

@aahoogendoorn

MODELING APPS

56App smart use case model

57Smart use cases in code

58App domain modelclass Domeinmodel Aanv raag

«domain object»Domein Objecten::Aanvraag

+ AanvraagId :AanvraagId+ Aanvraagstatus :Aanvraagstatus = Nieuw+ Opslagdatum :LocalDate+ Dossiernummer :Dossiernummer+ Communicatie :Communicatie = Standaardregeling+ Betaalwijze :Betaalwijze = Overschrijving+ Betalingstermijn :Betalingstermijn = Maand+ IBAN :IBAN+ Naam rekeninghouder :String+ Betaalregeling :Betaalregeling = Standaardregeling+ Verzekeringnemers betalen premie :boolean+ Splitsen premie :boolean+ Distributiekanaal :Distributiekanaal

+ getRelatiesBijAanvraag() :DomainList<Relatie>+ getORV() :void+ isRechtstreeksBetalen() :void

«business rule»+ KvK of BSN verzekeringnemer verplicht() :void

«domain object»Domein Objecten::Product

+ Naam :String+ Identificatie :Productidentificatie+ Ingangsdatum :LocalDate+ Type :Producttype = ORV premie A

«domain object»Domein Objecten::Verzekeringnemer

+ Premievrijstelling :boolean+ Beroep :String [0..1]+ Type :TypeVerzekeringnemer

«business rule»+ Woonadres of postbusadres verplicht() :void

«domain object»Domein Objecten::Toetsing

- Geslaagd :boolean- Meldingen :List<String>

«domain object»Domein Objecten::Premiebetaler

«domain object»Domein Objecten::Pandnemer

+ Volgnummer :int+ Verpandingsacte :boolean+ Verpandingsactedatum :LocalDate

«domain object»Domein Objecten::Relatie

+ Achternaam :String [0..1]+ Bedrijfsnaam :String [0..1]+ Burgerservicenummer :Burgerservicenummer [0..1]+ Email :Email [0..1]+ Geboortedatum :LocalDate [0..1]+ Geldig tot :LocalDate [0..1]+ Geldig vanaf :LocalDate+ Geslacht :Geslacht [0..1]+ Klantnummer :Relatienummer+ KvK nummer :KvKNummer [0..1]+ Loonheffingskorting :Boolean [0..1]+ Mobiel :Telefoonnummer [0..1]+ Overlijdensdatum :LocalDate [0..1]+ RDW nummer :RDW Nummer [0..1]+ Rechtsvorm :Rechtsvorm [0..1]+ Toestand :Relatietoestand+ Type :Relatietype+ Vast :Telefoonnummer+ Voorletters :String [0..1]+ Voorvoegsel :String [0..1]

«domain object»Domein Objecten::Adres

+ Adrestype :Adrestype+ Huisnummer :Huisnummer [0..1]+ Huisnummertoevoeging :String+ Land :Land [0..1]+ Woonplaats :String [0..1]+ Postcode :Postcode [0..1]+ Straat :String [0..1]

«domain object»Domein Objecten::ORV

+ Distributiekosten :Bedrag+ Totale kosten :Bedrag+ Verpandingsvoornemen :boolean+ Standaardbegunstiging :boolean = true

+ getRelatiesBijProduct() :DomainList<Relatie>+ getTotaleKosten() :void

«business rule»+ pandnemer verplicht bij verpandingsvoornemen() :void

«domain object»Domein Objecten::Begunstiging

+ Hoedanigheid :Hoedanigheid+ Volgnummer :int+ Begunstigde :String

«domain object»Domein Objecten::Assurantieadviseur

+ AANummer :AANummer+ Naam :String+ Voorvoegsel :String [0..1]+ Achtervoegsel :String [0..1]+ Telefoonnummer :Telefoonnummer [0..1]+ EmailAdres :Email+ Status :AA Status+ Rayonnummer :Rayonnummer+ Verplichtmaatchappijincasso :boolean+ Schadeuitkering :Schadeuitkering+ HeeftVergunningSchadeZakelijk :boolean+ HeeftVergunningSchadeParticulier :boolean+ HeeftVergunningSchadeInkomen :boolean+ HeeftVergunningSchadeVermogen :boolean+ Vergunningplicht :boolean+ VergunningVermogen :boolean

+ getVestiging() :void+ vindAdres(Adrestype) :void+ getVolledigeNaam() :void+ getPostbus() :void

«domain object»Domein Objecten::Dossier

+ Dossiernummer :Dossiernummer

«domain object»Domein Objecten::Portefeuille

+ Portefeuillenummer :Portefeuillenummer+ Rekeningnummer :IBAN+ NRC rekeningnummer :NRC Rekeningnummer+ Incassomethode bij mutatie :InExcassotraject+ Incassomethode bij prolongatie :InExcassotraject

«domain object»Domein Objecten::Notitie

+ Titel :String+ Tekst :String

«domain object»Domein Objecten::Vraag

+ Identificatie :Vraagidentificatie+ Vraagtype :Vraagtype+ Vraagtekst :String+ Antwoordtype :Antwoordtype+ Volgorde :Rangnummer

+ isToelichtingVerplicht() :boolean

«domain object»Domein Objecten::Clausule

+ Identificatie :ClausuleIdentificatie+ Naamgeving :Naamgeving+ Tekst :String+ Optionaliteit :Optionaliteit+ Ingangsdatum :LocalDate+ Einddatum :LocalDate

Volgnummer hier betekent

rangnummer in de component

Overeenkomst.

«domain object»Domein Objecten::Antwoord

+ Code :String+ Antwoordvolgorde :Rangnummer+ Antwoordtekst :String+ Waarde :String+ ToelichtingVerplicht :boolean+ GegevenAntwoord :String+ GegevenToelichting :String

«domain object»Domein Objecten::Voorwaarden

+ Code :String+ NaamIntern :String+ NaamExternKort :String+ NaamExternLang :String+ Optionaliteit :Optionaliteit+ Url :URL

1 1..2

+verpanding0..*

+postbusadres 1

+woonadres 1

1 1..*

+productClausules

Presentation

Process

Domain

Services

Outside world

PagesGrids / Panels

Controls

Use casesFlow

Enums / Value objects / Tupels / Reference objects

Service gatewaysService clients

ComponentsRelations Dossiers Intermediaries Accounts Rates

@aahoogendoorn

MODELING COMPONENTS

61Component smart use case model

62Component smart use case modelclass Aanv raag

«service interface»OphalenAanvraagService

«get»+ Ophalen(AanvraagId) :void

«service interface»AanvraagService

«post»+ Opslaan(String)

«read»

Ophalen Aanvraag

Aanvragen

«write»

Opslaan Aanvraag

«write»

Deleten Aanvraag

«service interface»DeleteService

+ Delete(AanvraagId) :void

class Begunstiging

«service interface»BegunstigingService

«get»+ BepalenBegunstiging(Productidentificatie) :BegunstigingInfo[] A

(from Processen)

«read»

Bepalen Begunstiging

Aanvragen

63Component domain model

64Business rules on the domain model

Service interface

Process

Domain

Services

Outside world

Service interfaces

Use casesFlow

Enums / Value objects / Reference objects

Service gateways / Table gatewaysService clients / Connectors

ComponentsDatabasesRelations Dossiers Rates DB2 MongoDB

@aahoogendoorn

MODEL FIRST DEVELOPMENTBringing it all together

69Smart use cases

70Identifying reuse

72The smart use case life cycle

Define work

on use case

test cases

Generate

and build

use case

test cases

Adjust

use case

Describe

use case

Accept

use case

73Smart use case life cycle in real life

74Lifecycle on a board

75Definition of Done

76Writing smart use cases. Using Enterprise Architect

77Analysis & Design. Wire frame with use case

Alternative flows

Exception flows

Basic flow

79Test Design. Testing smart use cases

80Test scenarios for a smart use case

81Testing a smart use case. Using Enterprise Architect

Fields on form

with smart use cases

Smart use case

specific business rules

and validations

83Building code. Twitter Bootstrap & JSF

85Shared libraries?

@aahoogendoorn

(SOME) RECOMMANDATIONSAND CONSIDERATIONS

87Minimal viable product

@aahoogendoorn

FIRST DO ITTHEN DO IT RIGHTTHEN DO IT BETTER

@aahoogendoorn

COMMUNICATIONVIA REST IS NOT

AS EASY AS IT PROMISES

@aahoogendoorn

GO WITH THE FLOW…

@aahoogendoorn

ALLOW THE TEAM TO LEARN…

@aahoogendoorn

AND HAVE FUN

@aahoogendoorn

www.sanderhoogendoorn.comwww.smartusecase.comwww.speedbird9.com

sander@ditisagile.nl

@aahoogendoorn

REFERENCES AND QUESTIONS

growing a microservices landscape (with smart use cases)

smart use cases2014

microservices landscape

microservices requirements

software architect

dad mentor

suite of small services

easier deployment

automated deployment

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