Why we are submitting this talk? Because Go is cool and we would like to hear more about this language ;-). In this talk we would like to tell you about our experience with development of microservices with Go. Go enables devs to create readable, fast and concise code, this - beyond any doubt is important. Apart from this we would like to leverage our test driven habbits to create bulletproof software. We will also explore other aspects important for adoption of a new language.

1. Are we ready to Go?
Adam Dudczak
Tomasz Jackowiak

2. Disclaimer

3. Who we are?

6. Why Go?

7. Heka? Etcd? InfluxDb?
JuJu?

9. Top 10?

10. Not yet ;-)

11. Why Go?

12. Been there, done that
B, C, Java, JavaScript …

13. • 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

14. Show me the code!!!

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

16. go run

17. 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)
}

18. 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())
}

19. Microservice!?!

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

23. 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
}

24. 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)
}

25. go routines

26. 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)
}
}

27. 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

28. 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)
}
}

29. 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: —

30. 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

31. channels

32. 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)
}
}

33. 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)
}

34. go get github.com/tjackowiak/coelho

35. Coding standards

36. gofmt & co

37. github / Drone.io / coveralls

38. Are we ready to Go?

39. 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

40. Cons
• Relatively new language
• There is still space to improve how GC works
• Not a JVM language

41. It is definately worth trying ;-)

42. Questions?
@maneo, @kevorin