2018-Devoxx.md

footer: © Object Computing Inc., 2018 slidenumbers: false

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[FIT] Introduction to Micronaut

Ultra-Lightweight Microservices for the JVM -- by Graeme Rocher

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About Me - Graeme Rocher

• Creator of Grails (http://grails.org)
• Creator of Micronaut (http://micronaut.io)
• Author "The Definitive Guide to Grails"
• Former SpringSource -> VMware -> Pivotal
• Software Engineer at Object Computing (http://objectcomputing.com)
• 2018 Oracle Groundbreaker Award Winner

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Agenda

• How we got here
• Microservice Challenges
• Microservice Framework Lanscape
• Micronaut Demos

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Then and Now

• Since 2008, a lot has changed
• 10 Years is a long time in technology
• Everybody was building Monoliths
• No Angular, No React, No Docker, No Microservices

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So We Try to Adapt

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• Let's try adapt existing legacy technologies for Microservices
• Technologies like Spring, Jakarta EE etc were never optimized for low memory footprint Microservices

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What to do, What to do?

Shall we:

1. Try and convince people that something never designed for Microservices is still ok?
2. Go back to the drawing board

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The Goal

• Create a New Framework designed from the ground-up for Microservices and Serverless Computing
• Blazing fast startup time
• Low Memory Footprint
• As Small As Possible JAR Sizes
• Zero Dependency
• 12 Factor - https://12factor.net

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The Analysis

To meet this goal we performed an analysis of Spring and Grails and the challenges to using them to develop Microservice applications

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What Spring and Jakarta EE Do

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Spring is an amazing technical achievement and does so many things, but does them at Runtime.

• Reads the byte code of every bean it finds
• Synthesizes new annotations for each annotation on each bean method, constructor, field etc. to support Annotation metadata
• Builds Reflective Metadata for each bean for every method, constructor, field etc.

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The Micro Reality

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• Frameworks based on reflection and annotations become fat
• But we love the programming model and productivity so we live with it
• So ... why should we be more efficient?

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Imagine if Kubernetes or Docker had been written in Spring or Jakarta EE instead of Go?

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Already Solved by Ahead of Time (AOT) Compilation

• The Android Community already solved the problem
• Ahead of Time Compilation used extensively
• Google Dagger 2.x
  • Compile Time Dependency Injector
  • Reflection Free
  • Limited in Scope to just DI

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Introducing Micronaut

• Designed from the ground up with Microservices in mind
• Ultra-light weight and Reactive - Based on Netty
• Uses Ahead of Time Compilation
• HTTP Client & Server
• Support for Java, Kotlin and Groovy

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[fit] DEMO

• Micronaut AOT

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Hello Micronaut

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@Controller
class HelloController {
    @Get("/hello/{name}")
    String hello(String name) { return "Hello " + name; }
}
@Client("/") // Client Generated at Compile Time
interface HelloClient {
  @Get("/hello/{name}")
  String hello(String name);
}

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How Small?

• Smallest Micronaut Hello World JAR is 12MB when written Java or 14MB in Groovy
• Can be run with as little as 12mb Max Heap with Kotlin or Java (22mb for Groovy)
• Startup time around a second for Kotlin or Java (a little more for Groovy)
• All Dependency Injection, AOP and Proxy generation happens at compile time

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What Micronaut Computes at Compile Time

• All Dependency & Configuration Injection
• Annotation Metadata (Meta annotations)
• AOP Proxies
• Essentially all framework infrastructure
• ie. What Spring/CDI do at runtime
• Essentially, Micronaut is a AOT framework

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Not Another Framework!?

• New Little HTTP Frameworks appearing all the time
• If all we had achieved was another HTTP server Micronaut wouldn't be very interesting
• What else does it do?

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Natively Cloud Native

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• Service Discovery - Consul, Eureka, Route 53 and Kubernetes
• Configuration Sharing - Consul Supported and Amazon ParameterStore
• Client Side Load Balancing - Integrated or Netflix Ribbon Supported
• Support for Serverless Computing; AWS Lambda, OpenFaas, Fn Supported; Azure coming

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[fit] DEMO

• Micronaut Pet Store

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Serverless Computing

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• Write Functions and Run them locally or as regular server applications
• Deploy Functions to AWS Lambda - after warm-up functions execute in milliseconds

@Field @Inject Twitter twitter

@CompileStatic
URL updateStatus(Message status) {
    Status s = twitter.updateStatus(status.text)
    String url = "https://twitter.com/$s.user.screenName/status/${s.id}"
    return new URL(url)
}

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GraalVM

• New Polyglot VM from Oracle
• Runs JS, Java, Ruby, R etc.
• Ability to turn Java code native
• https://www.graalvm.org

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GraalVM Native

• Works well when:
  • Little or no runtime reflection is used
  • Limited or no dynamic classloading
  • You plan ahead
  • You use third party libraries selectively

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Micronaut + GraalVM

• Like Graal itself at the Experimental Phase
• Mirconaut AOT compilation and refection free model makes it easier
• A lot of Micronaut already working:
  • HTTP Server, Client & Serverless
  • Service Discovery
  • DI and AOP

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Micronaut for Spring

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• Compile a Spring Boot into a Micronaut application
• Uses AOT - no runtime overhead
• IDE support improves
• Build applications that support Spring, Micronaut and Grails
• https://github.com/micronaut-projects/micronaut-spring

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[fit] DEMO

• Micronaut for Spring + GraalVM

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Micronaut for Spring

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• Take the Spring programming model to new places!
• GraalVM
• Android
• AOT
• Serverless

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Micronaut 1.0 Out Now

• Compile Time DI & AOP
• HTTP Client & Server
• Service Discovery
• Distributed Tracing
• Serverless Functions
• Data Access: SQL, MongoDB, Redis, Cassandra etc.

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Micronaut 1.0 on SDKman!

• The Micronaut CLI now available via SDKman!

$ curl -s "https://get.sdkman.io" | bash
$ source "$HOME/.sdkman/bin/sdkman-init.sh"
$ sdk install micronaut
$ mn create-app hello-world

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Micronaut project is healthy

• ~2 years of development by several OCI engineers.
• 70 contributors (19 from OCI).
• ~1300 stars on GitHub.

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Micronaut ROADMAP

• Micronaut for Spring 1.0 GA
• AOT Improvements
• OpenID Connect Support
• RabbitMQ Support
• Improved Google Cloud Support
• GRPC Support
• https://github.com/micronaut-projects/micronaut-core/projects/5

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Micronaut Resources

• Gitter Community: https://gitter.im/micronautfw
• User Guide: http://micronaut.io/documentation.html
• Micronaut Guides: http://guides.micronaut.io
• FAQ: http://micronaut.io/faq.html
• Github: https://github.com/micronaut-projects/micronaut-core
• Examples: https://github.com/micronaut-projects/micronaut-examples

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Micronaut Events

• Loads of upcoming Events
• Checkout - http://micronaut.io/events.html
• Webinar
  • https://objectcomputing.com/resources/events/webinars/introduction-to-micronaut

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Summary

• Micronaut aims to provide the same wow factor for Microservices that Grails did for Monoliths
• Built by the people that made Grails, leveraging over 10 years experience in framework development
• Uses Ahead of Time Compilation to support low-memory footprint
• Micronaut 1.0 is available now

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[FIT] Q & A