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Building microservices
web application using
Scala & Akka
Grokking Engineering, March 2015
Binh Nguyen - Anduin Transactions, Inc.
March 21st, 2015 HCMC

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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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Palantir
Technologies
2011-2014

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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

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So why chasing that unicorn?
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Engineers autonomy

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So why chasing that unicorn?
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More tools available = it’s not too bad

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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

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Java: Multithreaded programming
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In
Practice

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Java: Lack of functional and Immutability
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Clojure
My 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

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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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