Modeling the real world with Elixir and OTP Aish Raj Dahal - - PowerPoint PPT Presentation

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Modeling the real world with Elixir and OTP Aish Raj Dahal - - PowerPoint PPT Presentation

Aug 11, 2023 221 likes •1.13k views

Modeling the real world with Elixir and OTP Aish Raj Dahal Concurrency, Events and Why are we the Real World here? Case study of an Elixir use Tour of the BEAM and OTP Demo time! Epilogue How did we get here ? Can

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Modeling the real world with Elixir and OTP

Aish Raj Dahal

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Why are we here?

  • Concurrency, Events and

the Real World

  • Case study of an Elixir

use

  • Tour of the BEAM and OTP
  • Demo time!
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How did we get here ?

Epilogue

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“Can programming be liberated from the von Neumann style” ?

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Elixir is a programming language that leverages the power of Erlang VM (BEAM)

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With a simple syntax and a supportive community the language has seen tremendous growth

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A lot* of PagerDuty is powered by Elixir

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It has always not been this way.

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At PagerDuty it started as a language of choice for Rails- native way to talk to Kafka

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Why ?

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It was high value

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It was easy to redo it in a different language

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How was it ?

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It was not all rainbows and unicorns

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The application needed some tuning

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But language never got in the way

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Since then...

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A cambrian explosion in Elixir based services

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A good number of critical backend applications are written in Elixir

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All with the niceness of being built for the Real- World ™

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The Real World

Chapter I

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What is the Real World™?

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Are we talking about the universe ?

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In the beginning the universe was created. This has made a lot of people very angry and been widely regarded as a bad move.

Douglas Adams, The Hitchhiker’s guide to the Galaxy

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The Real World ™ is the world we live in

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You must care about it because….

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When was the last time you programmed a non- multi-core computer ?

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Computer science is no more about computers than astronomy is about telescopes.

Edsger Dijkstra

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Software you write probably models a real world situation

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Software you write probably deals with events

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Mental model of the real world:

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It is inherently concurrent

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It is event-based

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Failures are unpredictable

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It tends to be “real time”

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Software you write for the Real World ™ should deal with these situations.

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Which means...

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Your software should be concurrent.

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Your software should deal with events

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Your software should be fault- tolerant.

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Your software should respond to the user-input within a reasonable* time.

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Erlang solved these problems around three decades ago

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But this talk is not really about the Erlang programming language

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A Whirlwind tour of Elixir, BEAM and OTP

Chapter II

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Key ideas in Elixir

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Isolated Processes

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Pure Message Passing between processes

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The ability to detect errors in remote processes

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A method for determining what error caused a process to crash

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This means that Elixir is

  • Concurrent
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This means that Elixir is

  • Concurrent
  • Fault tolerant
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This means that Elixir is

  • Concurrent
  • Fault tolerant
  • Soft real time
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And built in support for things like hot code swap

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Detour: Open Telecom Platform (OTP)

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OTP is a set of libraries and tools that provides fundamental abstractions for BEAM languages

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Here are some nice building blocks that OTP provides

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GenServer: A generic server

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Process Supervisors

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Agents: State Wrappers

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Sounds like what you will want for the Real World ™

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Demo time

Chapter III

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Boids

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The rules of flight

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Separation: Steer to avoid crowding local flockmates

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Rule I: Separation

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Alignment: Steer towards the average heading of local flockmates

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Rule II: Alignment

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Cohesion: Steer to move toward the average position (center of mass) of local flockmates

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Rule III: Cohesion

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Modeling this with Elixir/OTP

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Modeling the events

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Move

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Render

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Dealing with failures

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Restart the boid

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Concurrency

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Keep your processes light and have many of them.

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Epilogue

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Make it work, then make it beautiful, then if you really, really have to, make it fast.

Joe Armstrong

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  • @aishrajdahal