Atmosphere 2014: Go, go, go - the one language to try in 2014. (or: "write only an eight of the code" ;-)) - Andrzej Grzesik
You live and breathe http. Most of the things you do with a computer involve it. How many tiny little http-related utils have you already created? Is it time to stop? By no means, we all do it. I'd just like to encourage you to write the next one in Go. It's a fun little language, which feels like a cross-breed between C (pointers!) and ruby (concise, powerful syntax). But how much? Why, yet another language, but my perl/python/.. does all the things? Well, it does. But go has a few things that make it super sweet, is web-scale and real fun to use! Or at least come and listen how did we get rid of 87% of our codebase in a day :-) Andrzej Grzesik - I like programming. I do it a lot, mostly on the JVM, usually writing fancy backends for big, distributed systems. I also display a particular affection to continuous delivery.. UI, unless quickly hacked, is not my play ;-) I believe that most problems we deal with are people problems, so I mix and match tools with technologies to achieve my goals, make people happy and achieve world peace :-) I believe in software quality, and organize GeeCON, Polish JUG, Krakow Software Craftsmanship, Cracow Hadoop User Group. In my free time, I read paper books and cycle, a lot!
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Atmosphere 2014: Go, go, go - the one language to try in 2014. (or: "write only an eight of the code" ;-)) - Andrzej Grzesik
- 1. golang the one language you have to try in 2014
- 2. golang the one language you have to try in 2014
- 4. about:me
- 6. disclaimers
- 7. my opinions are my own
- 10. golang
- 11. gopher
- 12. free and open source
- 13. BSD licensed
- 14. comes from G
- 15. FAST and I mean FAST
- 16. tl;dr; C++ and ruby had a wild time
- 17. play with it tonight
- 18. so, why do I like go?
- 20. more pleasant than C
- 21. go toolchain
- 22. go command
- 24. there is only one formatting
- 25. package main! ! import "fmt"! ! func main() {! !fmt.Println("Hello world")! }!
- 26. types
- 27. types • uint8, uint16, uint32, uint64 • int8, int16, int32, int64 • float32, float64 • complex64, complex128 • byte alias for uint8 • rune alias for int32 • string
- 28. func program() {! var text! text = “zomg"! more := "zomg"! ! fmt.Println(len(text));! }!
- 29. maps
- 30. func main() {! attendees := map[string]bool{! "Phil": true,! "Marcin": true,! }! ! fmt.Println(attendees["Phil"]) // true! fmt.Println(attendees["ags"]) // false! partygoers["ags"] = true! fmt.Println(attendees["ags"]) // true! }!
- 31. structs
- 32. type Rectangle struct {! a, b int32! }! ! func main() {! var rect Rectangle! rect = Rectangle{5, 10}! rect = Rectangle{a: 10, b: 5}! ! HasArea(s).Area()! }
- 33. type Square struct {! side int32! }! ! func (sq Square) Area() int32 {! return sq.side * sq.side! }! ! func main() {! s := Square{16}! area := s.Area()! }
- 34. interfaces
- 35. type Square struct {! side int32! }! ! func (sq Square) Area() int32 {! return sq.side * sq.side! }! ! type HasArea interface {! Area() int32! }! ! func main() {! s := Square{16}! HasArea(s).Area()! }
- 37. func f(i int) {! amt := rand.Intn(1000)! time.Sleep(time.Duration(amt) * time.Millisecond)! fmt.Println(i)! }! ! func main() {! for i := 0; i < 3; i++ {! go f(i)! }! var input string! fmt.Scanln(&input)! }
- 38. how many will run? runtime.GOMAXPROCS(4)
- 39. channels
- 40. channels • communicate between funcs • typed • thread-safe
- 41. channels channel := make(chan int)!
- 42. unbuffered channels • sync • will wait when empty
- 43. buffered channels channel := make(chan int, size)!
- 44. buffered channels • async • return 0 element when empty • will only wait when full
- 45. basics channel := make(chan int)! c <- a! ! <- c! ! a = <- c! ! a, ok = <- c!
- 46. func program() {! channel := make(chan int) ! }! ! func from(connection chan int) {! connection <- rand.Intn(255)! }! ! func to(connection chan int) {! i := <- connection! fmt.Println(“much received", i)! }!
- 47. but that’s not cool yet
- 49. func program() {! channel := make(chan int) ! ! go func() {! close(channel)! // or! channel <- anything! }()! ! <- channel! }!
- 50. func program() {! latch := make(chan int) ! ! go worker()! close(latch)! }! ! func worker() {! <- latch ! }!
- 51. generators
- 52. id := make(chan int64)! go func() {! var counter int64 = 0! for {! id <- counter! counter += 1! } ! }()
- 53. multiple channels at once!
- 54. func program() {! select {! case a := <- channel! ! case b, mkay := other! ! case output <- z! ! default:! }! }!
- 55. ranges
- 56. func fillIn(channel chan int) {! channel <- 1! channel <- 2! channel <- 4! close(channel)! }! ! func main() {! channel := make(chan int)! go fillIn(channel)! ! for s := range channel {! fmt.Printf("%d n", s)! }! }
- 57. packages
- 60. go get
- 61. net
- 62. echo server
- 63. const listenAddr = "localhost:4000"! ! func main() {! l, err := net.Listen("tcp", listenAddr)! if err != nil {! log.Fatal(err)! }! for {! c, err := l.Accept()! if err != nil {! log.Fatal(err)! }! io.Copy(c, c)! }! }
- 65. const listenAddr = "localhost:4000"! ! func main() {! l, err := net.Listen("tcp", listenAddr)! if err != nil {! log.Fatal(err)! }! for {! c, err := l.Accept()! if err != nil {! log.Fatal(err)! }! go io.Copy(c, c)! }! }
- 66. const listenAddr = "localhost:4000"! ! func main() {! l, err := net.Listen("tcp", listenAddr)! if err != nil {! log.Fatal(err)! }! for {! c, err := l.Accept()! if err != nil {! log.Fatal(err)! }! io.Copy(c, c)! }! }
- 67. websockets?
- 68. func main() {! http.Handle("/", websocket.Handler(handler))! http.ListenAndServe("localhost:1984", nil)! }! ! func handler(c *websocket.Conn) {! var s string! fmt.Fscan(c, &s)! fmt.Println("Received:", s)! fmt.Fprint(c, “hey!”)! }!
- 69. so, what looks bad?
- 70. type AssetMetas struct {! !Metas []AssetMeta `json:"assetMetas"`! }! ! type AssetMeta struct {! !ResourceName string `json:"resource_name"`! !Md5 string `json:"md5"`! !Urls []string `json:"urls"`! }!
- 71. so, go code!