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out-of-tree/images.go

83 regels
1.8 KiB
Go

// Copyright 2019 Mikhail Klementev. All rights reserved.
// Use of this source code is governed by a AGPLv3 license
// (or later) that can be found in the LICENSE file.
package main
import (
"fmt"
"io"
"io/ioutil"
"net/http"
"os"
"os/exec"
)
// inspired by Edd Turtle code
func downloadFile(filepath string, url string) (err error) {
out, err := os.Create(filepath)
if err != nil {
return
}
defer out.Close()
resp, err := http.Get(url)
if err != nil {
return
}
defer resp.Body.Close()
switch resp.StatusCode {
case http.StatusOK:
break
case http.StatusForbidden, http.StatusNotFound:
err = fmt.Errorf("Cannot download %s. It looks like you need "+
"to generate it manually and place it "+
"to ~/.out-of-tree/images/. "+
"Check documentation for additional information.", url)
return
default:
err = fmt.Errorf("Something weird happens while "+
"download file: %d", resp.StatusCode)
return
}
_, err = io.Copy(out, resp.Body)
return
}
func unpackTar(archive, destination string) (err error) {
// NOTE: If you're change anything in tar command please check also
// BSD tar (or if you're using macOS, do not forget to check GNU Tar)
// Also make sure that sparse files are extracting correctly
cmd := exec.Command("tar", "-Sxf", archive)
cmd.Dir = destination + "/"
rawOutput, err := cmd.CombinedOutput()
if err != nil {
err = fmt.Errorf("%v: %s", err, rawOutput)
return
}
return
}
func downloadImage(path, file string) (err error) {
tmp, err := ioutil.TempDir("/tmp/", "out-of-tree_")
if err != nil {
return
}
defer os.RemoveAll(tmp)
archive := tmp + "/" + file + ".tar.gz"
url := imagesBaseURL + file + ".tar.gz"
err = downloadFile(archive, url)
if err != nil {
return
}
err = unpackTar(archive, path)
return
}