go is your friend

ROME April 11-12th 2014

Go is your friend

Gianfranco Reppucci Lead Developer at Qurami

giefferre

ROME April 11-12th 2014 - Gianfranco Reppucci

About me

Evolution

As developers, we’ve changed a lot since a decade ago

Evolution

• Monolithic, 100% custom code • Super-complete, MVC frameworks

with tons of built-in features • Simple, bootstrapping frameworks

w/ dependency managers

Context

• There is a lot of different languages available to developers • Some of them are pretty easy, some

others have great performances • We can find frameworks and plugins for

each of them

The big dilemma

I’m starting a new project. Which technology do you think I should use?

There’s no right choice

As developers: • A great idea can be built with

(perhaps) any language • Pros and cons are everywhere • You’ll pay a certain price for whatever

advantages you could have

There’s no right choice

As entrepreneurs: • When choosing a specific technology,

you’ll probably need to justify the decision to yourself, your partners and investors

• Decisions would be based on company’s vision

Start usingsomething modern

Go is an open source programming language that makes it easy to build simple,

reliable and efficient software.

quote from golang.org

What Go is:

• Open source BSD licensed project • Language specification • Runtime components

(garbage collector, scheduler, etc) • Two different compilers (gc or gccgo) • Standard libraries • Documentation

History

• Developed at Google in 2007 as an experiment • Publicly announced in 2009 • Integrated in App Engine in 2011

Who is using Go?

A modern C

Go sits somewhere between C and Python. !

It has the static type checking and bit-twiddling powers of C, yet much of the speed of development and conciseness of Python.

quote from Graham King

Absolutely genuine

• No class inheritance • No method or operator overloading • No circular dependencies among packages • No generic programming • No assertions • No pointer arithmetic

Performance driven

Built-in concurrency primitives: • light-weight threads, called goroutines • channels • select statements

I mean, seriously

Does God exist?

• If you have doubts or issues when styling your Go code, you can use gofmt • gofmt’s aim is to format Go files,

returning a valid and “beautified” version of the code

A little bit of code

Object Oriented Go

A type declaration

! type Name struct {!! ! First string!! ! Middle string!! ! Last string!! }

A method declaration

! func (n Name) String() string {!

! ! return fmt.Sprintf(!

! ! ! “%s %c. %s”,!

! ! ! n.First,!

! ! ! n.Middle[0],!

! ! ! n.Last,!

! ! )!

Instancing a Name

! aName := Name{“John”, “Go”, “White”}!!! fmt.Println(aName.String())

Goroutines

Given the yell function

func yell(word string, seconds int) {!

! time.Sleep(time.Duration(seconds) * time.Second)!

! fmt.Println(word)!

Guess what’s the output

func main() {!! go yell(“2014”, 5)!! go yell(“Codemotion”, 1)!! go yell(“Roma”, 4)!! time.Sleep(10 * time.Second)! }

Channels

• Implement parallelism and synchronization • Channels can be of any type of data

structure, even custom structs • Can be buffered or unbuffered

An example

c := make(chan int)!

! go func() {!

! list.Sort()!

! c <- 1!

! doSomethingForAWhile()!

Select statement

Select

The select statement is like a switch, but it selects over channel operations andchooses exactly one of them

An example ticker := time.NewTicker(250 * time.Millisecond)! boom := time.After(1 * time.Second)!! for {!! select {!! ! case <- ticker.C:!! ! ! fmt.Println(“tick”)!! ! case <- boom:!! ! ! fmt.Println(“BOOM!”)!! ! ! return!! }! }

Start writing yourGo code now

Open your browser and point it to

http://tour.golang.org

for a quick tour, or

http://play.golang.org

to test your own snippets online

Why should I use Go?

• Syntax and environments are similar to dynamic languages • Simple language specification • Powerful and lightweight

Why should I use Go?

• Full development environment (doc, dependencies, formatter, tests) • Static compilation

with NO dependencies binary output • Multi environment build

So, what’s Go about?

Composition

• Go is Object Oriented, BUT not in the usual way! • Simple data models, simple interfaces

Concurrency

• Easily readable concurrency primitives

Gophers

Join us tonight

GOLANGIT Meetup

18:40 - 19.40

Thank you!

Gianfranco Reppucci

giefferre

References

• The gopher images were created by Renee French and they are Creative Commons Attribution 3.0 licensed

• What technology should my startup use? by Matt Aimonetti

• Go after four months by Graham King • Golang on Google’s App Engine

References

• List of organizations that use Go • The gopher look, a photo by Ken Conley • How we went from 30 servers to 2 by Travis

Reeder • Go after 2 years in production by Travis

Reeder • Computer Language Benchmarks Game

References

• Go at Google • Docker and Go: why did we decide to write

docker in Go?

go is your friend

gianfranco

rome april

type

func

fmt

string

aname

python

Software

let’s invite your friend to go with you!

your smartphone is your friend

your friend abroad

unit1 friends welcome what is friend ？ who is your best...

to my friend. your friend is your needs answered

somontano wine, your friend

imagine your customer becomes your friend

your best friend ever

the more we are together, together, together, the more we...

welcome to the early years and ks1 maths workshop for...

money is your friend

your nerdy best friend

database api, your new friend

supertrend is your friend

where did you go on vacation ? my friend, david

your friend - the nerd's...

calf muscles your friend your enemy

go is your friend - reppucci

let’s go! my first trip to the united kingdom letter to my...

valentine, racing...