A P I R E S T W I T H J AVAA N O P I N I O N A T E D A P P R O A C H

Lima, Perú. Diciembre 2015

– B E C A U S E A N A

'Como construir APIs REST para sistemas distribuidos con alta escalabilidad y resilencia '

D I S C L A I M E R

• This talk and its contents are based in my own experience.

• I’m not trying to say all the following IS the way to do the right thing. Just my opinion. :)

• All I want is to share my experience with the community.

• This talk is huge. Hope I can finish on time.

M O T I VAT I O N

• Functional requirements is THE challenge.

• API Documentation is always a PITA, keep in sync with the maintenance, new features, fixes, etc.

• Build any API (REST, SOAP, RPC) is hard.

• Development tools choice (programming language, libraries, frameworks, runtime, etc).

• Non functional requirements, quality attributes.

A P I C O N T R A C T

A P I C O N T R A C T

• Always is over there. Implicit/Explicit

• You should have one.

• You should know it.

• No matter if you build it or you consume the API.

• You should give it so much love.

• Learn to love it.

A P I C O N T R A C T A P P R O A C H E S

• Contract last

• Code driven contract

• Contract first

• Upfront design

C O N T R A C T L A S T

• Sadly is the commonest.

• Server-side developers dictate the contract.

• Most of the time with only one perspective.

• Implementator perspective VS consumer perpective

• Flaky. If missing test cases. Fragile.

• The documentation is done at the end.

• Bottleneck.

C O N T R A C T F I R S T

• Upfront design API

• Consumer perspective design

• Reusability

• Versioning

• Performance

The contract as corner stone for REST APIs

H O W T O B U I L D T H E C O N T R A C T ?

T O O L S

S O M A N Y O T H E R S : )

R A M L , M Y FAV O R I T E

• YAML dialect + JSON schema #ftw (types)

• Readable for humans.

• Can be procesable by machines.

• Design clear, correct, precise & consistent APIs.

• No vendor lock-in.

J S O N - S C H E M A S A M P L E

D E S I G N & B U I L D

R A M L + R A M L - M O C K U P

We can deliver an API in days or hours

R A M L & C O D E G E N E R AT I O N

• Server side

• JAX-RS

• Client

• Square Retrofit

• Documentation

• HTML

R A M L 2 C O D E

• OpenSource project from Grupo Expansión

• Generates Plain Old Java/Groovy Objects

• Generates JAX-RS interfases

• Generates an API client with Retrofit

• Can run in Android also in any JVM application.

N I C E , N O W I K N O W H O W T O C R E AT E A C O N T R A C T. W H AT ’ S N E X T ?

P R O G R A M M I N G M O D E LArchitecture

S O A + E D A

S E R V I C E S

• Build, deploy, and monitor any kind of services in agile, efficient way with open standards.

• Deployment on-premise, in the cloud, mix of both.

• Deploy services independently from each other.

• Decoupled & scale linearly across commodity hardware.

W A I T, A B U Z Z W O R D I S C O M I N G …

M I C R O S E R V I C E S A R C H I T E C T U R E

• Service Contracts

• RAML

• Exposing new & existing services

• Enterprise Integration Patterns (integration, routing, transformation)

• Discovery of services

• Service Registry

M I C R O S E R V I C E S A R C H I T E C T U R E

• Coordination across services

• Event Bus, (smart service, dump pipe)

• Managing complex deployments and their scalability

• Build Tool, CI, DevOps (Chef, Puppet), Linux Containers, Cloud, monitoring

• Visibility and correlation across services

• Event correlation, ElasticSearch, Logstash, Kibana.

S O U N D S N I C E , B U T…

I M P L E M E N TAT I O N D E TA I L S

S P R I N G B O O T I S A W E S O M E

– S P R I N G B O O T R E F E R E N C E D O C U M E N TAT I O N

“Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that

you can “just run”. We take an opinionated view of the Spring platform and third-party libraries so you

can get started with minimum fuss. Most Spring Boot applications need very little Spring

configuration.”

S P R I N G B O O T

• Embedded Servlet container

• Tomcat

• Jetty

• Undertow

• Executable jar file. Key feature for microservices!

• Monitoring capabilities thanks to actuator

• HealthChecks

• Metrics (Dropwizard aka Coda Hale Metrics)

• Jolokia

S P R I N G B O O T & J A X - R S

• Jersey 2.x support out of the box

• Just use the Jersey Starter

• spring-boot-starter-jersey

• raml2code generates JAX-RS artifacts, remember?

S P R I N G C L O U D

• Distributed/versioned configuration

• Service registration and discovery

• Routing

• Service-to-service calls

• Load balancing

• Circuit Breakers

• Global locks

• Leadership election and cluster state

• Distributed messaging

N E T F L I X O S S

• Netflix is released tons of good stuff.

• Reactive Extensions for Java

• Hystrix (Circuit breaker)

• Eureka (Service registry)

• Archaius (Configuration management)

• Zuul (Dynamic routing, monitoring, resilience, security)

• And many more…

S P R I N G B O O T L O V E S N E T F L I X O S S

S P R I N G B O O T & S P R I N G C L O U D F O R I M PAT I E N T D E V E L O P E R S

A C K N O W L E D G M E N T S

• To all the platform team at Grupo Expansión

• Alvaro Cabrera (@pateketrueke)

• Anallely Olivares (@tsunllly)

• Angel Pimentel (@blzb)

• Eduardo Diaz (@iamedu)

• Tomás Salazar (@atomsfat)

• Domingo Suarez Torres (@domix)

C O N TA C T O

• http://twitter.com/domix

• domingo.suarez@gmail.com

• http://domingosuarez.com

• http://github.com/domix