builder/virtualbox: download ISO

builder/virtualbox/builder.go

 package virtualbox
 
 import (
+	"errors"
 	"fmt"
 	"github.com/mitchellh/mapstructure"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
 	"log"
+	"net/url"
+	"os"
 	"os/exec"
+	"strings"
 )
 
 const BuilderId = "mitchellh.virtualbox"
@@ -19,6 +23,8 @@ type Builder struct {
 
 type config struct {
 	GuestOSType string `mapstructure:"guest_os_type"`
+	ISOMD5 string `mapstructure:"iso_md5"`
+	ISOUrl string `mapstructure:"iso_url"`
 	OutputDir string `mapstructure:"output_directory"`
 	VMName string `mapstructure:"vm_name"`
 }
@@ -43,6 +49,51 @@ func (b *Builder) Prepare(raw interface{}) error {
 
 	errs := make([]error, 0)
 
+	if b.config.ISOMD5 == "" {
+		errs = append(errs, errors.New("Due to large file sizes, an iso_md5 is required"))
+	} else {
+		b.config.ISOMD5 = strings.ToLower(b.config.ISOMD5)
+	}
+
+	if b.config.ISOUrl == "" {
+		errs = append(errs, errors.New("An iso_url must be specified."))
+	} else {
+		url, err := url.Parse(b.config.ISOUrl)
+		if err != nil {
+			errs = append(errs, fmt.Errorf("iso_url is not a valid URL: %s", err))
+		} else {
+			if url.Scheme == "" {
+				url.Scheme = "file"
+			}
+
+			if url.Scheme == "file" {
+				if _, err := os.Stat(b.config.ISOUrl); err != nil {
+					errs = append(errs, fmt.Errorf("iso_url points to bad file: %s", err))
+				}
+			} else {
+				supportedSchemes := []string{"file", "http", "https"}
+				scheme := strings.ToLower(url.Scheme)
+
+				found := false
+				for _, supported := range supportedSchemes {
+					if scheme == supported {
+						found = true
+						break
+					}
+				}
+
+				if !found {
+					errs = append(errs, fmt.Errorf("Unsupported URL scheme in iso_url: %s", scheme))
+				}
+			}
+		}
+
+		if len(errs) == 0 {
+			// Put the URL back together since we may have modified it
+			b.config.ISOUrl = url.String()
+		}
+	}
+
 	b.driver, err = b.newDriver()
 	if err != nil {
 		errs = append(errs, fmt.Errorf("Failed creating VirtualBox driver: %s", err))
@@ -57,6 +108,7 @@ func (b *Builder) Prepare(raw interface{}) error {
 
 func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) packer.Artifact {
 	steps := []multistep.Step{
+		new(stepDownloadISO),
 		new(stepPrepareOutputDir),
 		new(stepSuppressMessages),
 		new(stepCreateVM),

builder/virtualbox/builder_test.go

@@ -2,11 +2,16 @@ package virtualbox
 
 import (
 	"github.com/mitchellh/packer/packer"
+	"io/ioutil"
+	"os"
 	"testing"
 )
 
 func testConfig() map[string]interface{} {
-	return map[string]interface{}{}
+	return map[string]interface{}{
+		"iso_md5": "foo",
+		"iso_url": "http://www.google.com/",
+	}
 }
 
 func TestBuilder_ImplementsBuilder(t *testing.T) {
@@ -37,3 +42,71 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 		t.Errorf("bad vm name: %s", b.config.VMName)
 	}
 }
+
+func TestBuilderPrepare_ISOMD5(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// Test bad
+	config["iso_md5"] = ""
+	err := b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	// Test good
+	config["iso_md5"] = "FOo"
+	err = b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+
+	if b.config.ISOMD5 != "foo" {
+		t.Fatalf("should've lowercased: %s", b.config.ISOMD5)
+	}
+}
+
+func TestBuilderPrepare_ISOUrl(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	config["iso_url"] = ""
+	err := b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	config["iso_url"] = "i/am/a/file/that/doesnt/exist"
+	err = b.Prepare(config)
+	if err == nil {
+		t.Error("should have error")
+	}
+
+	config["iso_url"] = "file:i/am/a/file/that/doesnt/exist"
+	err = b.Prepare(config)
+	if err == nil {
+		t.Error("should have error")
+	}
+
+	config["iso_url"] = "http://www.packer.io"
+	err = b.Prepare(config)
+	if err != nil {
+		t.Errorf("should not have error: %s", err)
+	}
+
+	tf, err := ioutil.TempFile("", "packer")
+	if err != nil {
+		t.Fatalf("error tempfile: %s", err)
+	}
+	defer os.Remove(tf.Name())
+
+	config["iso_url"] = tf.Name()
+	err = b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+
+	if b.config.ISOUrl != "file://"+tf.Name() {
+		t.Fatalf("iso_url should be modified: %s", b.config.ISOUrl)
+	}
+}

builder/virtualbox/step_download_iso.go

+package virtualbox
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"fmt"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"time"
+)
+
+// This step downloads the ISO specified.
+//
+// Uses:
+//   cache packer.Cache
+//   config *config
+//   ui     packer.Ui
+//
+// Produces:
+//   iso_path string
+type stepDownloadISO struct{}
+
+func (s stepDownloadISO) Run(state map[string]interface{}) multistep.StepAction {
+	cache := state["cache"].(packer.Cache)
+	config := state["config"].(*config)
+	ui := state["ui"].(packer.Ui)
+
+	log.Printf("Acquiring lock to download the ISO.")
+	cachePath := cache.Lock(config.ISOUrl)
+	defer cache.Unlock(config.ISOUrl)
+
+	err := s.checkMD5(cachePath, config.ISOMD5)
+	haveFile := err == nil
+	if err != nil {
+		if !os.IsNotExist(err) {
+			ui.Say(fmt.Sprintf("Error validating MD5 of ISO: %s", err))
+			return multistep.ActionHalt
+		}
+	}
+
+	if !haveFile {
+		url, err := url.Parse(config.ISOUrl)
+		if err != nil {
+			ui.Error(fmt.Sprintf("Error parsing iso_url: %s", err))
+			return multistep.ActionHalt
+		}
+
+		// Start the download in a goroutine so that we cancel it and such.
+		var progress uint
+		downloadComplete := make(chan bool, 1)
+		go func() {
+			ui.Say("Copying or downloading ISO. Progress will be shown periodically.")
+			cachePath, err = s.downloadUrl(cachePath, url, &progress)
+			downloadComplete <- true
+		}()
+
+		progressTimer := time.NewTicker(15 * time.Second)
+		defer progressTimer.Stop()
+
+	DownloadWaitLoop:
+		for {
+			select {
+			case <-downloadComplete:
+				log.Println("Download of ISO completed.")
+				break DownloadWaitLoop
+			case <-progressTimer.C:
+				ui.Say(fmt.Sprintf("Download progress: %d%%", progress))
+			case <-time.After(1 * time.Second):
+				if _, ok := state[multistep.StateCancelled]; ok {
+					ui.Say("Interrupt received. Cancelling download...")
+					return multistep.ActionHalt
+				}
+			}
+		}
+
+		if err != nil {
+			ui.Error(fmt.Sprintf("Error downloading ISO: %s", err))
+			return multistep.ActionHalt
+		}
+
+		if err = s.checkMD5(cachePath, config.ISOMD5); err != nil {
+			ui.Say(fmt.Sprintf("Error validating MD5 of ISO: %s", err))
+			return multistep.ActionHalt
+		}
+	}
+
+	log.Printf("Path to ISO on disk: %s", cachePath)
+	state["iso_path"] = cachePath
+
+	return multistep.ActionContinue
+}
+
+func (stepDownloadISO) Cleanup(map[string]interface{}) {}
+
+func (stepDownloadISO) checkMD5(path string, expected string) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+
+	hash := md5.New()
+	io.Copy(hash, f)
+	result := strings.ToLower(hex.EncodeToString(hash.Sum(nil)))
+	if result != expected {
+		return fmt.Errorf("result != expected: %s != %s", result, expected)
+	}
+
+	return nil
+}
+
+func (stepDownloadISO) downloadUrl(path string, url *url.URL, progress *uint) (string, error) {
+	if url.Scheme == "file" {
+		// If it is just a file URL, then we already have the ISO
+		return url.Path, nil
+	}
+
+	// Otherwise, it is an HTTP URL, and we must download it.
+	f, err := os.Create(path)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	log.Printf("Beginning download of ISO: %s", url.String())
+	resp, err := http.Get(url.String())
+	if err != nil {
+		return "", err
+	}
+
+	var buffer [4096]byte
+	var totalRead int64
+	for {
+		n, err := resp.Body.Read(buffer[:])
+		if err != nil && err != io.EOF {
+			return "", err
+		}
+
+		totalRead += int64(n)
+		*progress = uint((float64(totalRead) / float64(resp.ContentLength)) * 100)
+
+		if _, werr := f.Write(buffer[:n]); werr != nil {
+			return "", werr
+		}
+
+		if err == io.EOF {
+			break
+		}
+	}
+
+	return path, nil
+}