coins, get the current price of BTC, ETH and LTC from the Coinbase API

main.go

package main

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

type AmountResponse struct {
	Amount   string `json:amount`
	Currency string `json:currency`
}

type DataResponse struct {
	Data AmountResponse `json:data`
}

func price(coin string, ch chan<- string) {
	client := &http.Client{}
	url := fmt.Sprintf("https://api.coinbase.com/v2/prices/%s-USD/spot", coin)
	req, reqErr := http.NewRequest("GET", url, nil)
	if reqErr != nil {
		log.Fatal(reqErr)
	}

	req.Header.Set("CB-VERSION", "2017-03-25")
	res, resErr := client.Do(req)
	if resErr != nil {
		log.Fatal(resErr)
	}

	body, readErr := ioutil.ReadAll(res.Body)
	res.Body.Close()
	if readErr != nil {
		log.Fatal(readErr)
	}

	data := DataResponse{}
	jsonErr := json.Unmarshal(body, &data)
	if jsonErr != nil {
		log.Fatal(jsonErr)
	}

	ch <- fmt.Sprintf("%s $%s", coin, data.Data.Amount)
}

func main() {
	fmt.Println(time.Now().Format("2006/01/02 15:04:05"))

	ch := make(chan string)
	coins := []string{"BTC", "ETH", "LTC"}

	for _, coin := range coins {
		go price(coin, ch)
	}

	for range coins {
		fmt.Println(<-ch)
	}
}