Bootstrap EASY FUN FOR BUSY DEVELOPERS

|> Elixir

YET ANOTHER PROGRAMMING LANGUANGE?

Y A P L

DON’T RUN AWAY

Elixir is special!

Elixir in a Nutshell

= +Elixir in a Nutshell

+

PROGRAMMERS OFTEN FEEL JOY WHEN THEY CAN CONCENTRATE ON THE CREATIVE SIDE OF PROGRAMMING, SO RUBY IS DESIGNED TO MAKE PROGRAMMERS HAPPY. I CONSIDER A PROGRAMMING LANGUAGE AS A USER INTERFACE, SO IT SHOULD FOLLOW THE PRINCIPLES OF USER INTERFACE.

Yukihiro Matsumoto, Ruby Inventor

Why Ruby is awesome

Principle of Conciseness Principle of Consistency Principle of Flexibility

Why Ruby is awesome

THE AXD301 HAS ACHIEVED A NINE NINES RELIABILITY (YES, YOU READ THAT RIGHT, 99.9999999%). LET’S PUT THIS IN CONTEXT: 5 NINES IS RECKONED TO BE GOOD (5.2 MINUTES OF DOWNTIME/YEAR). 7 NINES ALMOST UNACHIEVABLE ... BUT WE DID 9.

Joe Armstrong, Erlang Designer

Why Erlang is awesome

Battle-proven BEAM and OTP

Ever seen WhatsApp crash?

Reactive before Reactive-is-HipTm

Actors before Actors-are—HipTm

Why Erlang is awesome

Why Clojure is awesome

Because Rich Hickey is always right

SO…WHY NOT DO RUBY, ERLANG OR CLOJURE?

WHY NOT USE RUBY? SPEED, CONCURRENCY, SCALABILITY

WHY NOT USE ERLANG? SYNTAX, BAROQUE TOOLING

WHY NOT USE CLOJURE? …NO REASON, REALLY. GO AHEAD USE IT!

Scalability, lightweight Threads

Fault-tolerance, Supervisor

Functional, immutable DSLs using Meta-Programming

Mix, Hex, ExUnit,…

REPL for easy learning

Why Elixir is awesome

Scalability, lightweight Threads

Fault-tolerance, Supervisor

Functional, immutable DSLs using Meta-Programming

Mix, Hex, ExUnit,…

REPL for easy learning

Why Elixir is awesome

100000 Processes

1..100_000 |> Enum.map(&(Task.async( fn -> &1 * &1 end ))) |> Enum.map(&Task.await/1)

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, 729, 784, 841, 900, 961, 1024, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025, 2116, 2209, 2304, 2401, 2500, ...]

100000 Processes

1..100_000 |> Enum.map(&(Task.async( fn -> &1 * &1 end ))) |> Enum.map(&Task.await/1)?what?

100000 Processes

Quick syntax

bootcamp

Creating a project

$ mix new demo $ cd demo $ mix test

Read Eval Print Loop

$ iex -S mix Erlang/OTP 18 …

Interactive Elixir (1.2.4) - press Ctrl+C to exit (type h() ENTER for help) iex(1)> IO.puts “Hello Elixir” Hello Elixir :ok

Transform - don’t mutate

10 |> fib |> IO.puts

IO.puts(fib(10))

transformation pipeline

Declaring functions

def fib(0), do: 0

def fib(0) do 0 end (n-1) + fib(n-2) end

same thing

Pattern matching

def fib(0), do: 0

def fib(1), do: 1

def fib(n) when n > 1 iex> fib(1)

pattern matching

Guard expressions

def fib(n) when n > 1 do fib(n-1) + fib(n-2) end

guard expression

iex> fib(-3) ** (FunctionClauseError) no function clause matching in fib/1 (fibnew) lib/fib2.ex:2: fib(-3)

Things go wrong

Anonymous functions

fn n -> n + 2 end

&( &1 + 2 )

same thing

Function shortcuts

IO.puts/2

def puts(device, item)

/2 denotes the number of args

Compile-time structural decomposition

def sqrt([h | t]), do: …

iex> sqrt([1, 2, 3, 4 ])

Show me the code Demo

ELIXIR APPLICATION DESIGN APPLICATIONS, SUPERVISORS, PROCESSES

Shared resources Shared state Shared stability

PROCESSSHARED STATE

Shared nothing Message passing

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

Abstractions for ResilienceAgent…abstractions around state GenServer…long-running, messaging Supervisor…let it crash Application…just think component

Abstractions for ResilienceAgent…abstractions around state GenServer…long-running, messaging Supervisor…let it crash Application…just think component

Message-based design using GenServer

BA

GenServer.start_link

{:ok, #PID<0.112.0>}

Message-based design using GenServer

BA

GenServer.call(B, {:sum, 1..3})

Message-based design using GenServer

BA

handle_call({:sum, 1..3}, from, state)

Message-based design using GenServer

BA

{:reply, {:ok, 6}, new_state)

GenServer Demo

Move risk to the bottom of the supervision tree

APPLICATION

SUPERVISOR WORKER C

WORKER A WORKER B Here be dragons…FILE IO DB ACCESS

Supervisors watch their children

APPLICATION

SUPERVISOR WORKER C

WORKER A WORKER B

:one_for_one!

:one_for_one replaces failed process

APPLICATION

SUPERVISOR WORKER C

WORKER A WORKER B WORKER B’ Auto-restart

Supervisor Demo

Processes are distributed across nodes

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

PROCESS

:”one@foo”

:”two@foo”

Nodes and distribution Demo

MORE COOL FEATURES TEASERS ONLY

Testing documentation

@doc """ iex> sieve(10) [2, 3, 5, 7] """ def sieve(n) do ... end

defmodule Test do use ExUnit.Case

doctest … end

Hygienic Macrosdefmacro time([do: body]) do quote do s = :os.system_time(…)

unquote(body)

f = :os.system_time(…)

info(“Took #{s-f} ms") end end

time do IO.puts "Something" :timer.sleep(100) end

[info] Took 101 ms

There is so much more

Protocols Sigils

Umbrella projects Ecto

Phoenix Hot code replacement

SHOULD WE ALL START BUILDING EVERYTHING

WITH ELIXIR?

WELL….MAYBE NOT?!

New insights and ideas Clean patterns

Architecture for IoT Vibrant Community

学⼀一⻔门语⾔言，就是多⼀一个观察世界的窗户。To learn a language is to have one more window from which to look at the world

Elixir Homepage, http://elixir-lang.org/

Dave Thomas, Programming Elixir

Fred Hebert, Stuff Goes Bad: Erlang in Anger

José Valim, Introduction to Elixir https://youtu.be/41PvAPSX0wg

Slides + Code, https://git.io/vKUGc

Do you want to know more?

Thank you very much!<david.schmitz@senacor.com> @koenighotze