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{{tag>Dev Go}}

= Notes go golang

Voir : 
* https://www.redhat.com/sysadmin/learn-go-programming
* https://awesome-go.com/go-generate-tools/

Voir aussi :
* [[https://fr.wikipedia.org/wiki/Zig_(langage)]]
* [[https://linuxfr.org/news/a-la-decouverte-du-langage-v|Le langage V]]
* [[Notes rust lang]]


== Tuto

Voir tuto Api :
* https://www.youtube.com/watch?v=SonwZ6MF5BE
* https://github.com/bradtraversy/go_restapi

Début du tuto

''restapi.go''
<code go>
package main

import(
//	"encoding/json"
	"log"
	"net/http"
//	"math/rand"
//	"strconv"
	"github.com/gorilla/mux"
)

type Book struct {
	ID string `json:"id"`
	Isbn string `json:"isbn"`
	Title string `json:"title"`
	Author *Author `json:"author"`
}

type Author struct {
	Firstname string `json:"fistname"`
	Lastname string `json:"lastname"`
}

func getBooks(w http.ResponseWriter, r *http.Request) {

}

func getBook(w http.ResponseWriter, r *http.Request) {
}
func createBook(w http.ResponseWriter, r *http.Request) {
}
func updateBook(w http.ResponseWriter, r *http.Request) {
}
func deleteBook(w http.ResponseWriter, r *http.Request) {
}

func main() {
	r := mux.NewRouter()

	r.HandleFunc("/api/books", getBooks).Methods("GET")
	r.HandleFunc("/api/books/{id}", getBook).Methods("GET")
	r.HandleFunc("/api/books", createBook).Methods("POST")
	r.HandleFunc("/api/books/{id}", updateBook).Methods("PUT")
	r.HandleFunc("/api/books/{id}", deleteBook).Methods("DELETE")

	log.Fatal(http.ListenAndServe(":8085", r))
}

</code>


== Install & config

<code bash>
sudo apt-get install -t jessie-backports golang
mkdir -p $HOME/go/bin
#export GOPATH=$HOME/go

# go install plop.go
export GOBIN="$HOME/go/bin"

export PATH="$PATH:~/.local/bin/"
export GOHOME="$HOME/go"
export GO111MODULE=on
export PATH="$PATH:$HOME/go/bin/"
</code>

''~/.bashrc''
<code ->
export GOPATH=$HOME/work
export GOBIN=$HOME/work/bin
export PATH=$PATH:$HOME/work/bin
</code>


Exemple avec Terraform

Voir aussi OpenTofu

<code bash>
go get -u github.com/hashicorp/terraform
</code>

Ce qui revient à :
<code bash>
mkdir -p ~/work/src/github.com/hashicorp/
cd ~/work/src/github.com/hashicorp/
git clone https://github.com/hashicorp/terraform
</code>

Puis
<code bash>
cd ~/work/src/github.com/hashicorp/terraform
cat README.md
make updatedeps
make
go install
</code>


== Dev bonnes pratiques

https://go.dev/doc/gopath_code


== Language


=== Types

Struct
https://www.golangprograms.com/how-to-print-struct-variables-data.html



== Lancer des commandes systèmes

Pb voir : http://stackoverflow.com/questions/23723955/how-can-i-pass-a-slice-as-a-variadic-input

''exec.go''
<code go>
// http://www.darrencoxall.com/golang/executing-commands-in-go/

package main

import (
        "fmt"
        "os"
        "os/exec"
        "log"
        //"flag"
        //"strings"
)

func main() {
        s := os.Args[1:]
        fmt.Println(s)
        //cmd := exec.Command(s[:])             // Error !
        cmd := exec.Command(s[0], s[1], s[2])
        //out, err := cmd.Output()              // Whithout Stdout
        out, err := cmd.CombinedOutput()        // Whith StdErr
        if err != nil {
                fmt.Println("Error")
                fmt.Printf("%s", out)
                log.Fatal(err)
        }
        fmt.Printf("%s", out)
}
</code>

<code bash>
go run exec.go ls /tmp/ /
</code>


== Tests unitaire

''fact.go''
<code ->
package main

func fact(x int) int {
        if (x == 0) || (x == 1) {
                return 1
        }
        return x * fact(x-1)
}
</code>

''fact_test.go''
<code ->
package main

import "testing"

func TestFact(t *testing.T) {
        if fact(0) != 1 {
                //t.Fail() // Erreur sans message
                t.Error("Err with 0")
        }
        if fact(1) != 1 {
                t.Error("Err with 1")
        }
        if fact(4) != 24 {
                t.Error("Err with 4")
        }
}
</code>

<code bash>
go test fact.go fact_test.go
</code>

<code ->
ok      command-line-arguments  0.001s
</code>



----


== Outils

Gosh un shell interactif


=== IDE

Vscode / Codium

LiteIDE X
<code bash>
snap install liteide-tpaw
</code>

IntelliJ IDEA


=== Code qualité

Voir https://sparkbox.com/foundry/go_vet_gofmt_golint_to_code_check_in_Go

Golint
Go fmt
Go vet


=== Crosscompil 

OS et architectures supportées  
<code bash>
go tool dist list
</code>

<code bash>
env GOOS=android GOARCH=arm64 go build -o /arm64bins/app
</code>

Pour voir la liste des architectures supportée
<code bash>
go tool dist list
</code>


=== Tour

<code bash>
export GO111MODULE=on
export GOPATH=$HOME/code/go
go install golang.org/x/website/tour@latest
go get golang.org/x/website/tour@latest
~/code/go/bin/tour
</code>

ou : https://go.dev/tour/welcome/1


=== Debuger

Voir dlv :
* https://developers.redhat.com/articles/2023/04/24/how-debug-openshift-operators-live-cluster-using-dlv
* https://github.com/go-delve/delve/blob/master/Documentation/cli/getting_started.md



== Jupyter Notebook

Voir : https://github.com/gopherdata/gophernotes#linux-or-freebsd

== Ordiphone / Android / téléphone mobile

Voir :
* https://github.com/golang/go/wiki/Mobile
* https://betterprogramming.pub/build-native-cross-platform-apps-with-go-70f9572baeb5
* https://rogchap.com/2020/09/14/running-go-code-on-ios-and-android/

Voir GoMobile :
* https://pkg.go.dev/golang.org/x/mobile/cmd/gomobile

Voir Gioui :
* https://gioui.org/
* https://www.gushiciku.cn/pl/pkdc

Voir Fyne :
* https://fyne.io/
* https://www.youtube.com/watch?v=S3T9l9QUa9I

<code bash>
go get fyne.io/fyne/cmd/fyne
fyne package -os android -appID xyz.acme.plop
</code>

Tuto Fyne notes
* https://www.youtube.com/watch?v=ZYtd6rjP0TM
* https://github.com/fynelabs/notes

Voir aussi
https://www.youtube.com/watch?v=jbsYrrNiqAs