docs/utils/b2d.go

89 lines
1.9 KiB
Go

package utils
import (
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"os"
"path/filepath"
"time"
)
const (
timeout = time.Second * 5
)
func defaultTimeout(network, addr string) (net.Conn, error) {
return net.DialTimeout(network, addr, timeout)
}
func getClient() *http.Client {
transport := http.Transport{
Dial: defaultTimeout,
}
client := http.Client{
Transport: &transport,
}
return &client
}
// Get the latest boot2docker release tag name (e.g. "v0.6.0").
// FIXME: find or create some other way to get the "latest release" of boot2docker since the GitHub API has a pretty low rate limit on API requests
func GetLatestBoot2DockerReleaseURL() (string, error) {
client := getClient()
rsp, err := client.Get("https://api.github.com/repos/boot2docker/boot2docker/releases")
if err != nil {
return "", err
}
defer rsp.Body.Close()
var t []struct {
TagName string `json:"tag_name"`
}
if err := json.NewDecoder(rsp.Body).Decode(&t); err != nil {
return "", err
}
if len(t) == 0 {
return "", fmt.Errorf("no releases found")
}
tag := t[0].TagName
url := fmt.Sprintf("https://github.com/boot2docker/boot2docker/releases/download/%s/boot2docker.iso", tag)
return url, nil
}
// Download boot2docker ISO image for the given tag and save it at dest.
func DownloadISO(dir, file, url string) error {
client := getClient()
rsp, err := client.Get(url)
if err != nil {
return err
}
defer rsp.Body.Close()
// Download to a temp file first then rename it to avoid partial download.
f, err := ioutil.TempFile(dir, file+".tmp")
if err != nil {
return err
}
defer os.Remove(f.Name())
if _, err := io.Copy(f, rsp.Body); err != nil {
// TODO: display download progress?
return err
}
if err := f.Close(); err != nil {
return err
}
if err := os.Rename(f.Name(), filepath.Join(dir, file)); err != nil {
return err
}
return nil
}