Building REST API with GoLang 14 November 2015 Burak AYDIN 4PPS 

Why Go Micro services hype Easy deployment Performance blog.parse.com/learn/how-we-moved-our-api-from-ruby-to-go-and-saved-our- sanity/ (http://blog.parse.com/learn/how-we-moved-our-api-from-ruby-to-go-and-saved-our-sanity/) 

Comparing Go and Java 

Commons Static Types Garbage Collection Variables are always initialized (zero/nil/false) Methods Interfaces 

Differs Go compiles to machine code. Function values, closures Strings UTF-8 Built-in concurreny Go has great tools! 

Go Mentality Do something very well, but don't do so much. No news is good news. Perfect? 

Hello Hello.java p u b l i c c l a s s M a i n { p u b l i c s t a t i c v o i d m a i n ( S t r i n g [ ] a r g s ) { S y s t e m . o u t . p r i n t l n ( " H e l l o , w o r l d ! " ) ; } } Hello.go f u n c m a i n ( ) { f m t . P r i n t l n ( " H e l l o , G o " ) } 

JSON in Go 

Json in Go "encoding/json" Unmarshal/Marshal Encoder/Decoder 

Json in Go p a c k a g e m a i n i m p o r t ( " f m t " " e n c o d i n g / j s o n " ) t y p e U s e r s t r u c t { i d i n t n a m e s t r i n g } f u n c m a i n ( ) { d a t a : = [ ] b y t e ( ` { " i d " : 1 2 3 , " n a m e " : " j i l l " } ` ) u s e r : = U s e r { } e r r : = j s o n . U n m a r s h a l ( d a t a , & u s e r ) i f e r r ! = n i l { p a n i c ( e r r ) } f m t . P r i n t f ( " H e l l o % s " , u s e r . n a m e ) } Run 

Json in Go p a c k a g e m a i n i m p o r t ( " f m t " " e n c o d i n g / j s o n " ) t y p e U s e r s t r u c t { I d i n t ` j s o n : " i d " ` N a m e s t r i n g ` j s o n : " n a m e " ` } f u n c m a i n ( ) { d a t a : = [ ] b y t e ( ` { " i d " : 1 2 3 , " n a m e " : " j i l l " } ` ) u s e r : = U s e r { } e r r : = j s o n . U n m a r s h a l ( d a t a , & u s e r ) i f e r r ! = n i l { p a n i c ( e r r ) } f m t . P r i n t f ( " H e l l o % s " , u s e r . N a m e ) } Run 

Webserver p a c k a g e m a i n i m p o r t ( " f m t " " l o g " " n e t / h t t p " ) f u n c m a i n ( ) { h t t p . H a n d l e F u n c ( " / h e l l o " , h a n d l e H e l l o ) f m t . P r i n t l n ( " s e r v i n g o n h t t p : / / l o c a l h o s t : 8 0 8 0 / h e l l o " ) l o g . F a t a l ( h t t p . L i s t e n A n d S e r v e ( " l o c a l h o s t : 8 0 8 0 " , n i l ) ) } f u n c h a n d l e H e l l o ( w h t t p . R e s p o n s e W r i t e r , r e q * h t t p . R e q u e s t ) { l o g . P r i n t l n ( " s e r v i n g " , r e q . U R L ) f m t . F p r i n t l n ( w , " H e l l o , 世界! " ) } Run 

Mux ServeMux is an HTTP request multiplexer. p a c k a g e m a i n i m p o r t ( " n e t / h t t p " " l o g " " f m t " ) f u n c m a i n ( ) { m u x : = h t t p . N e w S e r v e M u x ( ) m u x . H a n d l e F u n c ( " / h e l l o " , h a n d l e r ) l o g . F a t a l ( h t t p . L i s t e n A n d S e r v e ( " : 8 0 8 0 " , m u x ) ) } f u n c h a n d l e r ( w h t t p . R e s p o n s e W r i t e r , r * h t t p . R e q u e s t ) { f m t . F p r i n t l n ( w , " H e l l o M u x ! " ) } Run 

Needs for REST API Routing Middleware Authentication CORS Hot code reloading Easy db access Context sharing Logging 

Standard packages net/http (routing, middleware, auth, CORS) log 

Web Frameworks Martini Gin Revel 

3rd Party Packages negroni (Middleware) codegangsta/gin (Hot code reload) jmorion/sqlx rs/cors markbates/goth gorilla/pat gorilla/context 

Gorilla Toolkit gorillatoolkit.org/ (http://gorillatoolkit.org/) 

Go tools godoc.org/golang.org/x/tools (https://godoc.org/golang.org/x/tools) go fmt go vet go present 

Go Mobile godoc.org/golang.org/x/mobile (https://godoc.org/golang.org/x/mobile) 

Thank you Burak AYDIN 4PPS [email protected] (mailto:[email protected]) @burakaydn (http://twitter.com/burakaydn) 

No content