Are we ready to Go?Adam Dudczak

Tomasz Jackowiak

Disclaimer

Who we are?

Why Go?

Heka? Etcd? InfluxDb? JuJu?

Top 10?

Not yet ;-)

Why Go?

Been there, done thatB, C, Java, JavaScript …

• Class free, but object oriented

• Statically-typed - with elem. of duck typing

• Garbage collector

• Compiled - really fast compiler

• Open source from up to bottom (BSD license)

• Write once, run anywhere

Show me the code!!!

package main !import "fmt" !func main() { fmt.Println("Hello, World") }

go run

package main !import "fmt" !func swap(x, y string) (string, string) { return y, x } !func main() { a, b := swap("hello", "world") fmt.Println(a, b) }

package main !import ( "fmt" "math" ) !type Vertex struct { X, Y float64 } !func (v *Vertex) Abs() float64 { return math.Sqrt(v.X*v.X + v.Y*v.Y) } !func main() { v := &Vertex{3, 4} fmt.Println(v.Abs()) }

Microservice!?!

package main !import ( "io" "net/http" ) !func main() { http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { io.WriteString(w, "hello, world\n") }) http.ListenAndServe(":8080", nil) }

type Quote struct { BookTitle string `json:"book_title"` Sentence string `json:"sentence"` } !func NewQuotes(quotesFilePath string) ([]Quote, error) { fileContent, _ := os.Open(quotesFilePath) defer fileContent.Close() ! var quotes []Quote decoder := json.NewDecoder(fileContent) if err := decoder.Decode(&quotes); err != nil { return nil, errors.New("Failed to decode json") } return quotes, nil }

type TwitterClient interface { Tweets(screenName string) []string } !!type FakeClient struct{} !func (fake *FakeClient) Tweets(screenName string) []string { return []string{"test tweet"} } !!func Test_shouldCreateNewPaolo(t *testing.T) { twitterClient := &FakeClient{} paolo := NewTweetingPaolo(twitterClient) assert.NotNil(t, paolo) }

go routines

func sleepySort(number int) { time.Sleep(time.Duration(number)) fmt.Println(number) } !func main() { arrayToSort := []int{12, 14, 3, 6, 1, 2} for _, val := range arrayToSort { sleepySort(val) } }

func sleepySort(number int) { time.Sleep(time.Duration(number)) fmt.Println(number) } !func main() { arrayToSort := []int{12, 14, 3, 6, 1, 2} for _, val := range arrayToSort { sleepySort(val) } }

output: 12, 14, 3, 6, 1, 2

func sleepySort(number int) { time.Sleep(time.Duration(number)) fmt.Println(number) } !func main() { arrayToSort := []int{12, 14, 3, 6, 1, 2} for _, val := range arrayToSort { go sleepySort(val) } }

func sleepySort(number int) { time.Sleep(time.Duration(number)) fmt.Println(number) } !func main() { arrayToSort := []int{12, 14, 3, 6, 1, 2} for _, val := range arrayToSort { go sleepySort(val) } }

output: —

func sleepySort(number int) { time.Sleep(time.Duration(number)) fmt.Println(number) } !func main() { arrayToSort := []int{12, 14, 3, 6, 1, 2} for _, val := range arrayToSort { go sleepySort(val) } time.Sleep(1 * time.Second) }

output: 1, 2, 3, 6, 12, 14

channels

func sleepySort(number int, sort chan<- int) { time.Sleep(time.Duration(number)) sort <- number } !func main() { arrayToSort := []int{12, 14, 3, 6, 1, 2} sort := make(chan int) ! for _, val := range arrayToSort { go sleepySort(val, sort) } ! for i := 0; i < len(arrayToSort); i++ { fmt.Println(<-sort) } }

quote := make(chan Quote) go func() { quote <- localPaolo.RandomQuote() }() go func() { quote <- twittingPaolo.RandomTweet() }() go func() { quote <- wisePaolo.RandomHeartQuote() }() !for i := 0; i < 3; i++ { fmt.Println(<-quote) }

go get github.com/tjackowiak/coelho

Coding standards

gofmt & co

github / Drone.io / coveralls

Are we ready to Go?

Pros• Standing on the shoulders of giant

• Concise and readable - maybe even fun ;-)

• Simple and powerful tooling (go run | install | …)

• Really nice dependency management

• Language spec - with promise of backward compatibility

Cons• Relatively new language

• There is still space to improve how GC works

• Not a JVM language

It is definately worth trying ;-)

@maneo, @kevorin

Questions?