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


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()!

<-c


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

Software

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