Go Programming Language by Google
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Go is a programming language created by Google that aims to be a simple, efficient, and concurrent language. The document provides an overview of the history and features of Go, including its support for garbage collection, concurrency, and ease of programming. Examples are given demonstrating how to write Go code, use interfaces and channels for concurrency, and connect to MongoDB. The document also lists several companies that use Go in production applications.
![Features 2/2
• Slices
– s := []int{2, 3, 5, 7, 11, 13}
– len(s)
• Maps
– var m map[string]string
– m[“index”]
• Func+on values
f1 := func(x, y float64) float64 {
return math.Sqrt(x*x + y*y)
}](https://image.slidesharecdn.com/golang-140118232950-phpapp01/85/Go-Programming-Language-by-Google-12-320.jpg)
![JSON and Go
type Message struct {
Name string
Body string
Time int64
}
m := Message{"Alice", "Hello", 1290090}
b, err := json.Marshal(m)
-----------
b is now
[]byte(`{"Name":"Alice","Body":"Hello","Time
":1290090}`)](https://image.slidesharecdn.com/golang-140118232950-phpapp01/85/Go-Programming-Language-by-Google-14-320.jpg)
Go Programming Language by Google
- 2. History of Go • Robert Griesemer, Rob Pike and Ken Thompson started the idea on Sep 21, 2007 • It became an open source project on Nov 10, 2009 • Go1 was released in March 2012
- 3. Why Go • A good mix of fast compila+on, efficient execu+on and ease of programming • combines best of sta+c language and dynamic language • offers garbage collec+on, concurrency, scalability • Aims to be system programming language for mul+ core machine
- 4. Comparison with C++, Java and Javascript C++ Java Javascript Go Typesafe ✔ ✔ ✖ ✔ Garbage Collec+on ✖ ✔ ✔ ✔ Compila+on Slow Slow NA Very Fast Concurrency ✖ ✔ ✖ ✔ Ease of programming ✖ ✔ ✔ ✔ Efficiency Highest Slow Slowest Close to C++
- 5. Hello World // hello.go package main import ( "fmt” ) func main() { fmt.Println("Hello World”) }
- 6. Sample func+on package main import “fmt” func split(sum int) (x, y int) { x = sum * 4 / 9 y = sum - x return } func main() { var x, y, z int fmt.Println(x,y,z) fmt.Println(split(17)) }
- 7. How to Write Go Code 1/2 • Go tool is designed to work with open source code maintained in public repositories • Workspace – src – pkg – bin • export GOPATH=$HOME/go • go install hello
- 8. How to Write Go Code 2/2 • go install sum (create and put lib pkg) • go install usinglib • go get code.google.com/p/ go.example/hello • go test sum
- 9. Object Oriented Go • No classes, no inheritance • go has duck typing • structs are used for custom types, aggrega+on • Interfaces, abstract type has methods • Any custom type having same methods as interface follows that (and/or other) interface • Interface{}, empty interface is like void in C or Object in Java
- 10. Interface type Printer interface { Print() } type MyFloat float64 func (f MyFloat) Print() { fmt.Println(f); } func main() { var a Printer f := MyFloat(5.5) a = f }
- 11. Features 1/2 • Garbage collec+on • Concurrency • Packages – fmt, net, os, +me, math, zlib – h-p://golang.org/pkg/ has the exhaus+ve list • Types – bool, int, int8, int16, int32, int64, uint …, byte, float32,float64, complex64, complex128 – const • For loop only • struct, access fields using dot • Pointer but no pointer arithme+c
- 12. Features 2/2 • Slices – s := []int{2, 3, 5, 7, 11, 13} – len(s) • Maps – var m map[string]string – m[“index”] • Func+on values f1 := func(x, y float64) float64 { return math.Sqrt(x*x + y*y) }
- 13. Concurrency • go rou+nes – Lightweight thread like rou+ne (may be one or more thread) • Channels and Buffered Channel – Useful for sync between go rou+nes – Send and receive to channel is blocking ( no sync needed) • Range and close – Range used itera+ng over channel – Close used by sender aier sending all values • Select – Lets gorou+ne waits on mul+ple communica+on opera+ons
- 14. JSON and Go type Message struct { Name string Body string Time int64 } m := Message{"Alice", "Hello", 1290090} b, err := json.Marshal(m) ----------- b is now []byte(`{"Name":"Alice","Body":"Hello","Time ":1290090}`)
- 15. Web Server type Hello struct{} func (h Hello) ServeHTTP( w http.ResponseWriter, r *http.Request) { fmt.Fprint(w, "Hello TechNext !") } func main() { var h Hello http.ListenAndServe("localhost:4000", h) }
- 16. MongoDB Driver (mgo) • Mgo Driver can be fetched using – go get gopkg.in/mgo.v2 – go get gopkg.in/mgo.v2/bson • Sample code to connect to mongo session, err := mgo.Dial("localhost”) collection := session.DB(”mydb").C(”mycollection”) err := collection.Find(bson.M{”Name”: “XYZ”}).One(&result)
- 17. Go In Produc+on • Google is using in produc+on for – h-p://golang.org – Vitess system for large-scale SQL installa+ons – Download server dl.google.com • It delivers chrome binaries and apt-get packages • Other companies using Go in produc+on – InfluxData – Canonical – Heroku – Iron.io – Apcera – Docker – h-p://go-lang.cat-v.org/organiza+ons-using-go
- 18. References • FAQ h-p://golang.org/doc/faq • Installa+on h-p://golang.org/doc/install • Code h-p://golang.org/doc/code.html • Videos h-p://blog.golang.org/go-videos-from-google- io-2012 • Tour h-p://tour.golang.org/ • Efficiency BM - JSON Benchmarks
- 19. References • h-p://www.javaworld.com/ar+cle/2080935/ scrip+ng-jvm-languages/go-google-go-a- language-on-full-thro-le.html • h-p://blog.golang.org/json-and-go • h-p://www.drdobbs.com/open-source/geong- going-with-go • h-p://www.drdobbs.com/open-source/why-not- go/240005062 • h-p://www.jellolabs.com/blog/why-golang-is- ready-for-early-stage-startups.html
- 20. References • h-p://stackoverflow.com/ques+ons/11462046/what- is-the-niche-of-go-lang • h-ps://code.google.com/p/go-wiki/wiki/ SuccessStories# • h-p://stackoverflow.com/ques+ons/12168873/cross- compile-go-on-osx • h-p://ma-.aimoneo.net/posts/2012/11/27/real-life- concurrency-in-go/ • h-p://www.golang-book.com/10 • h-p://ma--welsh.blogspot.in/2013/08/rewri+ng- large-produc+on-system-in-go.html