Building microservices web application using

Scala & Akka

Grokking Engineering, March 2015Binh Nguyen - Anduin Transactions, Inc.

March 21st, 2015 HCMC

Introduction: Who?

Engineer at-large with strong interest in engineering

processeses.

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Who?

August 2014 - now

Anduin Transactions

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Who?

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PalantirTechnologies2011-2014

Who?

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What?

● What is µ-services architecture? pros and cons

● Why Anduin µ-services?● How can Akka & Scala help?

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The world before microservices

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Monolithic vs microservices

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Monolithic problems

● Complexity

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Monolithic problems

● Complexity● Conway’s law => silos

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Monolithic problems

● Complexity● Conway’s law => silos● Modules development speed

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Monolithic problems

● Complexity● Conway’s law => silos● Modules development speed● Dependencies collision

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Monolithic problems

● Complexity● Conway’s law => silos● Modules development speed● Dependencies collision● Deployment

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Monolithic problems

● Complexity● Conway’s law => silos● Modules development speed● Dependencies collision● Deployment

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Can it be fixed?

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So what’s microservices?

Microservices

The term "Microservice Architecture" has sprung up over the last few years to describe a particular way of designing

software applications as suites of independently deployable services. While there is no precise

definition of this architectural style, there are certain common

characteristics around organization around business capability, automated deployment, intelligence in the

endpoints, and decentralized control of languages and data.

Martin Fowler http://martinfowler.com/articles/microservices.html

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So what’s microservices?

“complex applications are composed of small, independent processes communicating with each other using language-agnostic APIs”

Wikipedia

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Some key takeaways

● should be something one developer can fit in their head

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Some key takeaways

● Can fit in one developer head

● One developer should be able to independently produce

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Some key takeaways

● Can fit in one developer head

● One developer should be able to independently produce

● One "verb" (single concern/function, not

GET/PUT/DELETE) per microservice

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Some key takeaways

● Can fit in one developer head

● One developer should be able to independently produce

● One "verb" (single concern/function, not

GET/PUT/DELETE) per microservice

● Should be possible to deploy in a container

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Some key takeaways

● Can fit in one developer head

● One developer should be able to independently produce

● One "verb" (single concern/function, not

GET/PUT/DELETE) per microservice

● Should be possible to deploy in a container

● Can be upgraded independently

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So...what is microservices?

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Microservices challenges

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So why chasing that unicorn?

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So why chasing that unicorn?

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Iteration speed

So why chasing that unicorn?

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Engineers autonomy

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So why chasing that unicorn?

29More tools available = it’s not too bad

Summary - microservices

● Microservices is challenging● ...But worths it (in my view)● Modern tools like Amazon AWS, Docker,

Deis, CoreOS, Kubenettes, Ansible, Akka, … help a lot!

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So...programming language?

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Obligatory joke on language war

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Node.js/Vert.x/Meteor

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Go

● Readability over everything else● Battery included● Google● Easy to pick up● A bit of niche feel (more system oriented)● No Type safety● Some problems with cross OSs compiling

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OK, more serious choice: Java

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OK, more serious choice: Java

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Java: Multithreaded programming

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In Theory

Java: Multithreaded programming

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In Practice

Java: Lack of functional and Immutability

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ClojureMy personal favorite language

● Simple but no simpler● Lisp● Rich Hickey & the likes● ClojureScript● Weak libraries● Dynamic typing

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Scala: Very complicated

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Scala: Long time to master

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Akka = Actor model

● One of the biggest reason for choosing Scala!

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Concurrent and distributed programming done right

Akka’s “cool kids” club!

● Apache Spark● Apache Kafka● Apache Samza● Spray● ….

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Akka Remote Actor and Clustering

● Location transparency● Distributed by default (beware: Fallacies of

distributed computing)

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Akka Persistence

● Actor state snapshot for easier recovery● Event sourcing

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Akka reactive streaming

Data flow at the same speed as the slowest link to prevent buffer blows up.

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Akka: built for modern web

● Akka http 2.0● Akka websocket● Akka webRTC

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Conclusion: Scala & Akka

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