services/boot/download.go

   1 package main
   2
   3 import (
   4         "archive/zip"
   5         "context"
   6         "fmt"
   7         "io"
   8         "io/ioutil"
   9         "log"
  10         "net/http"
  11         "os"
  12         "path"
  13         "strings"
  14 )
  15
  16 type download struct {
  17         URL  string
  18         Dest string
  19         Size int64
  20         Mode os.FileMode
  21         Hash string
  22 }
  23
  24 func (d *download) Boot(ctx context.Context) error {
  25         fi, err := os.Stat(d.Dest)
  26         if os.IsNotExist(err) {
  27                 // fall through to fix
  28         } else if err != nil {
  29                 return err
  30         } else if d.Size > 0 && fi.Size() != d.Size {
  31                 err = fmt.Errorf("Size mismatch: %q is %d bytes, expected %d", d.Dest, fi.Size(), d.Size)
  32         } else if d.Mode > 0 && fi.Mode() != d.Mode {
  33                 err = fmt.Errorf("Mode mismatch: %q is %s, expected %s", d.Dest, fi.Mode(), d.Mode)
  34         } else {
  35                 return nil
  36         }
  37
  38         defer feedbackf(ctx, "downloading %s", d.URL)()
  39
  40         out, err := ioutil.TempFile(path.Dir(d.Dest), path.Base(d.Dest))
  41         if err != nil {
  42                 return err
  43         }
  44         defer func() {
  45                 if out != nil {
  46                         os.Remove(out.Name())
  47                         out.Close()
  48                 }
  49         }()
  50
  51         resp, err := http.Get(d.URL)
  52         if err != nil {
  53                 return err
  54         }
  55         n, err := io.Copy(out, resp.Body)
  56         resp.Body.Close()
  57         if err != nil {
  58                 return err
  59         }
  60
  61         if strings.HasSuffix(d.URL, ".zip") && !strings.HasSuffix(d.Dest, ".zip") {
  62                 r, err := zip.NewReader(out, n)
  63                 if err != nil {
  64                         return err
  65                 }
  66                 defer os.Remove(out.Name())
  67                 out = nil
  68
  69                 found := false
  70                 for _, f := range r.File {
  71                         if !strings.HasSuffix(d.Dest, "/"+f.Name) {
  72                                 continue
  73                         }
  74                         rc, err := f.Open()
  75                         if err != nil {
  76                                 return err
  77                         }
  78                         defer rc.Close()
  79
  80                         out, err = ioutil.TempFile(path.Dir(d.Dest), path.Base(d.Dest))
  81                         if err != nil {
  82                                 return err
  83                         }
  84
  85                         n, err = io.Copy(out, rc)
  86                         if err != nil {
  87                                 return err
  88                         }
  89                         found = true
  90                         break
  91                 }
  92                 if !found {
  93                         return fmt.Errorf("File not found in archive")
  94                 }
  95         }
  96
  97         if d.Size > 0 && d.Size != n {
  98                 return fmt.Errorf("Size mismatch: got %d bytes, expected %d", n, d.Size)
  99         } else if d.Size == 0 {
 100                 log.Printf("%s: size was %d", d, n)
 101         }
 102         if err = out.Close(); err != nil {
 103                 return err
 104         }
 105         if err = os.Chmod(out.Name(), d.Mode); err != nil {
 106                 return err
 107         }
 108         err = os.Rename(out.Name(), d.Dest)
 109         if err == nil {
 110                 // skip deferred os.Remove(out.Name())
 111                 out = nil
 112         }
 113         return err
 114 }