The Plan

Splashing

First Looks

Pool Rules

Foundations

The Kiddy Pool

Meet Whoppex

Splashing

First Looks

Hello Elixir

2 + 2                               # 4

IO.puts "Oh, Hey!"                  # :ok, prints "Oh, Hey!"

events = [404, 500, :create, "dog"] # lists, dynamic typing
hd(events)                          # 404
tail(events)                        # [500, :create, "dog"

person = {:name, "Ben"}             # 2-tuple

def fib(0) do: 0                    # recursive fibonocci
def fib(1) do: 1                    # pattern matching
def fib(n) do                       # multiple fun definitions
  fib(n - 2) + fib(n - 1)
end

addTwo = fn a -> a + 2 end          # anon function, 1st class
addTwo(2)                          # 4
Enum.map([1, 2, 3], addTwo)         # [3, 4, 5]
            

Pids for all

iex(1)> pid = spawn fn -> IO.puts "I ... AM ... ALIVE!" end
I ... AM ... ALIVE!             # printed from other process
#PID<0.85.0>                    # process identifier
iex(2)> Process.alive?(pid)
false                           # sadly, our process is dead :(

iex(3)> echoer = fn ->           # define fun to receive msg
...(3)>   receive do             # blocking receive
...(3)>     name -> IO.puts "Hi #{name}!"
...(3)>   end
...(3)> end

iex(4)> pid2 = spawn echoer      # create process, return pid
#PID<0.94.0>
iex(5)> Process.alive?(pid2)     # alive, waiting for our msg
true

iex(6)> send(pid2,"Bob")         # send async msg to other process
Hi Bob!                          # printed from other process
"Bob"                            # returned from send function
            

Room to Improve

foo(0, 0) ->
  boring;               % Line terminator #1
foo(X, Y) ->
  Y = math:add(X, Y),   % Now we have 2
  Z = Y rem 2,
  case Z of
    0 -> true;          % Three for the win!
    1 -> undefined      % FOUR? nothing is really something
  end.
            

this is Erlang

Who is Using It?

• Phoenix - 2 million websockets
• Discord - 1 million/min bursts msgs
• Bleacher Report - from 150 server to 5!
• Nerves - IoT - Run Elixir on a RaspberryPi
• Pinterest? Facebook?
• Erlang projects - RabbitMQ, ejabberd, CouchDB

Where Things Stand

• Elixir 1.5 released 1 week ago
• Active Community Almost 5k Hex Packages
• ~5 years old get in on the ground floor!
• Lots of learning resources
• Dave Thomas thinks you should learn Elixir

Pool Rules

Foundations and Basics

Erlang

What is the big deal?!

Erlang

OK, that is a big deal...

But how does it do it?

Elixir

but, why?

The Basics again

200 + 200                   # numbers
:dog                        # atoms (like symbols in Ruby)
name = "Ben"                # binary strings
'Spruce'                    # list of ascii numbers ;)
person = {:name, name}      # variable asigned a 2-tuple value

data = [1, 2, "dog"]        # singly linked list
[100 | data]                # [100, 1, 2, "dog"]         # cheap
data ++ data                # [1, 2, "dog", 1, 2, "dog"] # expensive

[id: 100, name: "Jane"]     # keywordlist = [{:id, 100}, {:name, "Jane"}]

map = %{:a => 1, 2 => :b}   # a map structure
map[:a]                     # returns 1

def print([]) do: :ok       # pattern matching on function
def print([head | tail) do  # pattern matching on value decomposition
  IO.puts head
  print(tail)
end                         # tail call optimized recursion
            

gen_server

defmodule GreeterServer do
  require Logger
  use GenServer

  def start_link(name) do  # API METHOD, CALLED BY SUPERVISION TREE
    GenServer.start_link(__MODULE__, name, [])
  end

  def init(my_name) do  # initialize and return initial state
    log("starting")
    {:ok, my_name}
  end

  # async, use handle_call for simulated synchronous messages
  def handle_cast(your_name, my_name) do
    log("Hi #{your_name}, my name is #{my_name}")
    {:noreply, my_name}
  end
end
            

Kiddy Pool

Meet Whoppex

The Problem

Scaling is hard

A Sample App

See It In Action

Whoppex Overview

Time For a Quick Detour

I need your help

Stop checking Facebook and go to this URL

http://tinyurl.com/picktheicon

http://tinyurl.com/picktheicon

Please play around on the site for 60 seconds...

How could we load test this?

STOP PLAYING WITH THE GAME!

Lets put Whoppex to work!