concurrency.go

package main

import (
        "encoding/json"
        "fmt"
        "net"
        "net/http"
)

type IPResponse struct {
        IP net.IP `json:"ip"`
}

func IPRequest(site string) (*IPResponse, error) {
        req, err := http.NewRequest("GET", site, nil)
        if err != nil {
                return nil, err
        }
        req.Header.Add("Accept", "application/json")
        req.Header.Add("User-Agent", "HTTPie/1.0.0-dev")
        resp, err := http.DefaultClient.Do(req)
        if err != nil {
                return nil, err
        }
        defer resp.Body.Close()
        var ip IPResponse
        err = json.NewDecoder(resp.Body).Decode(&ip)
        return &ip, err
}

func mustReturn(site string, out chan *IPResponse) {
        o, _ := IPRequest(site)
        out <- o
}

func main() {
        out := make(chan *IPResponse)
        go mustReturn("http://jsonip.com", out)
        go mustReturn("http://ipinfo.io/", out)
        for i := 0; i < 2; i++ {
                ret := <-out
                fmt.Printf("Got: %s\n", ret.IP)
        }
}