Go workshop

README.md

GO workshop - CLI for news.ycombinator.com

Configuring your editor

• IntelliJ http://go-ide.com/
• Better IntelliJ https://www.jetbrains.com/go/
• Atom https://atom.io/packages/go-plus
• Better Atom https://code.visualstudio.com/
• Emacs https://www.emacswiki.org/emacs/GoLangMode
• Better Emacs https://github.com/fatih/vim-go

Getting started with go itself

Installing: brew install go

Create main.go file:

package main

import "fmt"

func main() {
	fmt.Println("Happy hacking!")
}

Simply run go run main.go

Task at hand

• Grab 10 top stories
• Print title, rating, author to cli of each story
• Write some tests

Easy extra things

• Allow to select a particular story in the list
• Display couple of the comments for the selected story
• Allow to go back to the story list

Funky extra things

• Add a UI (terminal or gui) using one of these:
  • https://github.com/gotk3/gotk3
  • https://github.com/therecipe/qt
  • https://github.com/jroimartin/gocui
  • https://github.com/gizak/termui
  • https://github.com/zserge/webview

Highly recommended to use only stdlib available modules. But no strict rules. Wanna go crazy and pull in dozens of deps? Go for it! vgo get is your friend.

How-to things

Imports that you are gonna need

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
)

Doing http get request

https://golang.org/pkg/net/http/

resp, err := http.Get("http://example.com/")
if err != nil {
	// handle error
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
// body is gonna have []byte type

Parsing json

https://golang.org/pkg/encoding/json/

Into an array:

ids := make([]int, 0)
err := json.Unmarshal(b, &ids)

Into a struct:

type myStruct struct {
	Title string `json:"title"`
	Author string `json:"author"`
}

func main() {
	var body []byte
	var data myStruct
	....
	json.Unmarshal(body, &data)
}

Printint stuff

https://golang.org/pkg/fmt/

fmt.Printf("This is how you print stuff %s", "in go")

Writing tests

https://golang.org/pkg/testing/

package main

import "testing"

func TestMain(t *testing.T) {
	main()
}

Taking n items from an array

subarray := array[0:10]

Sorting a slice/array

https://golang.org/pkg/sort/#Slice

HN Api

Top Stories: https://hacker-news.firebaseio.com/v0/topstories.json

Item: https://hacker-news.firebaseio.com/v0/item/16814671.json

Full api documentation: https://github.com/HackerNews/API/blob/master/README.md

Dependencies

If you decided for some reason to include external dependencies you can do it in 2 ways:

• go get github.com/author/project
• vgo get github.com/author/project

Vgo is the new versioned dependency tool for golang. go get will just pull the dependency master branch in to your $GOPATH (default $GOPATH value is $HOME/go), for the sake of this workshop it should also work fine if you dont want to get distracted by dependency managment tools.

VGO

Getting started with vgo (if you are planning to use external dependencies only):

go get -u golang.org/x/vgo

export PATH=$PATH:$HOME/go/bin

echo > go.mod
echo 'module "/home/myuser/go/src/workshop-project-name"' > go.mod # is optional
vgo build
./workshop-project-name

Now you can replace go command with vgo

Fix for vgo requires Go 1.10 but VGOROOT=/usr/lib/go is not a Go 1.10 source tree:

sudo mkdir /usr/lib/go/api
sudo touch /usr/lib/go/api/go1.10.txt