Distributed Transactions: The Icebergs of Microservices

An antarctic iceberg which, much like distributed transactions in microservices, can be hard to see and can wreck your ship.Why are distributed transactions icebergs? It’s not because they’re cool and beautiful and you have to look under the surface to comprehend them.

Distributed transactions are icebergs because (1) it’s easy to not see them, even when they’re right in front of you, and (2) if you run into one, it’s got a great potential to sink your ship. Continue reading

(My notes from) Ken Scambler on ‘Two Years of Real-World FP at REA’

This evening I went to a YOW Night where Ken Scambler (@KenScambler) spoke about the introduction and evolution of using Scala at REA Group. Here’s my notes…

Functional Scala Benefits

The sprial logo of the functional programming language language ScalaThe benefits of going functional are to get to code that is: Modular, Abstract, Composable.

Modularity is about being able to fit entire sections of code in your head without having to consider things going on outside that code, and also about being able to replace small parts without affecting the whole.

To write a total function (a function that returns a result for all possible input values), you need to elevate all possibilities into the type system. For example, you can’t throw an exception, you have to encode that possibility of an error into the return value somehow.

Abstraction should reduce changes to code, because unnecessary detail is not all across the code.

Whole systems can be composed from functional components.

Functional programming is not about picking up a hipster language. It’s about producing better software.
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Microservices at Tyro: An Evolutionary Tale (Presentation)

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In February, I presented a talk at the Sydney Microservices Meetup titled “Microservices at Tyro: An Evolutionary Tale”.

Microservices at Tyro

I wanted to talk mostly about things we’ve been doing with microservices at Tyro Payments over the last year, but also about the almost 10 years of practice with distributed computing that has led us towards what we’re doing today.

I’ve merged my slides and the audio from the talk into a video, which you can watch below. If you’re more the reading type, there’s a transcript from the talk beneath the video. My talk goes for 40 minutes and then there’s 20 minutes of Q&A.

The talk covers:

  • Who is Tyro Payments?
  • Why are we doing Microservices?
  • Tyro’s Architecture History
  • Current development in Microservices
  • Tyro Microservices Practices
  • Asynchronous Communication Strategies
  • Helping Out Ops
  • Microservices Technologies and Patterns
  • Challenges we’ve been having at Tyro
  • Microservices pre-requisites

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9 Design Patterns Translated Into Java 8’s Lambdas

LAMBDAS!

There’s been a lot of hype around lambdas getting introduced in Java 8, and I have a good theory on why: hype is often born out of anticipation, and we’ve been anticipating lambdas in Java for a LONG time.

Lambdas?

A lambda spray paint pattern, the same design as in Half-LifeThe funny thing is that lambdas don’t, by themselves, do anything new. They’re just a succinct form for turning a block of code into an object that can be passed around – syntactic sugar. Some of us have been doing this for a while without the succinctness and we call it… object-oriented programming! Yes, passing blocks of code (aka functions) around as objects (aka values) is also core to functional programming, but certainly not unique to it.

Patterns!

Somewhere that this idea of “passing code around” is heavily utilised is in Continue reading

Notes from YOW! 2013: Hadi Hariri on ‘Refactoring Legacy Codebases’

I attended Day 1 of YOW! Sydney 2013 and thought some people might get something useful out of my notes. These aren’t my complete reinterpretations of every slide, but just things I jotted down that I thought were interesting enough to remember or look into further.

A stack of stickers showing the word 'refactor' in a stylised, death-metal-like font.Hadi Hariri is a Developer and Technical Evangelist at JetBrains. He spoke at YOW! about refactoring legacy codebases.

Hadi started by offering reasons for refactoring:

  • increase the understandability of the code
  • decrease the impact of change
  • reduce the cost of change

He described how refactoring relies on culture: Continue reading

Murphy’s Law Should Appear In Every Line Of Your Code

A graphic from a 1930s German pamphlet showing a woman being electrocuted because she touched an overhead lamp and a gas pipe at the same time. Murphy's Law aims to stop these kinds of catastrophes.You know Murphy’s Law, right? Or at least you know the way most people remember it: “Anything that can go wrong will go wrong.” It’s a fairly depressing way of summarising life, but we all recognise a large portion of truth within it. Things go wrong. All the time.

There’s actually contention over whether this is the original form of the law, which is named after aerospace engineer Capt. Edward A. Murphy, and there are several differing accounts of how the saying came about. My preferred account is that relayed by Australia’s Dr Karl Kruszelnicki, whose record of Captain Murphy’s original exclamation is:

If there are two or more ways to do something, and one of those results in a catastrophe, then someone will do it that way.

I like this version because it’s easier to see the qualified optimism that Murphy juxtaposed with his frustration. As Dr Karl explains, there is a hope embedded in this form of the law because it starts with a proposition: “IF there are two or more ways to do something…” Continue reading

ScalaSyd Wrap-Up: November 2012

ScalaSyd: Episode 9

We had a great meeting at ScalaSyd last Wednesday night, probably one of the best I’ve been to. These are my notes from the evening, which are in no way comprehensive – they are just the points I found most interesting.

Jed (@jedws) warned us at the start that there were two “pointy” talks with some soft stuff in the middle, but I found the two pointy talkers did an excellent job of conveying their pointy subjects to neophytes. Not an easy task, so well done, guys.

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