{Erlang FTW!

Mahesh Paolini-Subramanya (@dieswaytoofast)V.P. Ubiquiti NetworksJames Aimonetti (@jamesaimonetti)

Erlang Everywhere

Why Erlang?

Horizontal

Scalability

Horizontal

Scalability

Horizontal

Vertical

Scalability

Horizontal

Vertical

Scalability

Live!

Hot Swapping

Live!

Hot Swapping

Asynchronous Processing

Asynchronous Processing

Asynchronous Processing

Supervision

Live Debugging

Stack Traces

Predictability

Why Erlang?

4x – 10x less code

Faster to create

4x – 10x less code

Faster to create

Easier to reason about

4x – 10x less code

Faster to create

Easier to reason about

Fewer bugs

4x – 10x less code

Faster to create

Easier to reason about

Fewer bugs

Speedy refactoring

4x – 10x less code

Scalability

vs

Speed

Reliability

Concurrency by default

Error encapsulation

Fault detection

Fault identification

Code upgrade

Stable Storage

Concurrency Oriented

From http://www.erlang.org/download/armstrong_thesis_2003.pdf

Concurrency Oriented

Concurrency Hell

My Blue Heaven My Blue Heaven

Concurrency Oriented

Concurrency Hell

My Blue Heaven

Deep Problems

My Blue Heaven

Deep Problems

Cheap Actors

Shared vs shared-nothing

OO vs Actors

Shared vs shared-nothing

Inheritance vs Behavior

OO vs Actors

Shared vs shared-nothing

Inheritance vs Behavior

Sync vs Async

OO vs Actors

Why Not Java? (Ruby/…)

Why not assembler?

Trivial thread management (hint: none)

Erlang Architecture

Trivial thread management (hint: none)

Trivial monitoring / load-balancing

Erlang Architecture

Trivial thread management (hint: none)

Trivial monitoring / load-balancing

One process per session

Erlang Architecture

Immutable Variables

X = 1.

Immutable Variables

X = 1.

X = 2.

Huh?

Immutable Variables

X = 1.

X = 2.

X = X + 1.

Huh?

List Comprehensions

[ do_something_with(X) || X <- ListOfItems ]

Functions

function greet( Gender, Name )if Gender == male then

print( "Hello, Mr. %s!", Name )else if Gender == female then

print( "Hello, Mrs. %s!", Name )else

print( "Hello, %s!", Name )end

greet( male, Name ) ->print_out( “Hello Mr. ”, Name );

greet( female, Name ) ->print_out( “Greetings Mrs. ”, Name );

greet( _, Name ) ->print_out( “Wotcher ”, Name ).

vs

From http://learnyousomeerlang.com/

Functions

Module:code_change( OldVersion, OldState, Stuff ) ->

NewState = whatever_you_need_to_do( OldVersion, OldState, Stuff ),

{ ok, NewState }.

vsMonkey Patching?

Really?

You sure?

Bit Syntax

<< Header:16, Checksum:4, Payload/binary >>.

Binary Comprehensions!

[ process_payload(Payload) || <<_Header:16, _Checksum:4, Payload/binary>>

<= BunchOfData ].

Processes

…proc:spawn( fun( X ) -> do_stuff( X ) end ),…

do_stuff( OnePerson ) -> change_the_world( OnePerson ).

Defensive Programming

if ( X instanceof Integer ) {try {

change_position( X );} catch ( ArithmeticException a ) {

// can't happen. ignore} catch ( PositionException p ) {

// why would this happen?} catch ( Exception e ) {

// The other code has this here} catch ( Throwable t ) {

// Dunno why this was in the other code}

}

proc:spawn( fun( X ) -> change_position( X ) end ),

vs

mahesh#dieswaytoofast.com / @dieswaytoofast

james#2600hz.com / @jamesaimonetti

Questions