Some googlecompute fixes and cleanup. Addresses https://github.com/mitchellh/packer/issues/3829. Changes:

- startup scripts don't run for Windows since it is isn't implemented yet.
- startup scripts use instance metadata instead of serial port output to flag when they are done.
- added licenses to Image data type (to check if an Image is a  Windows Image).
- added GetImage and GetImageFromProject to googlecompute Drivers.
- changed some of the builder/googlecompute tests to use github.com/stretchr/testify/assert.

Tests:
- (in the Packer directory) `go test .`, `go test ./builder/googlecompute`, and `go test ./post-processor/googlecompute-export`
- manual run of `packer build packer_template.json` with the following files

--packer_template.json--
{
  "builders": [
    {
      "type": "googlecompute",
      "account_file": "creds.json",
      "project_id": "google.com:packer-test",
      "source_image": "debian-8-jessie-v20160629",
      "zone": "us-central1-a",
      "startup_script_file": "startup_script.sh",
      "metadata": {
        "startup-script": "#!/bin/sh\necho \"This should be overwritten.\"",
        "startup-script-log-dest": "gs://packer-test.google.com.a.appspot.com/startup-script.log"
      },
      "image_name": "test-packer-modifications",
      "ssh_username": "foo"
    }
  ],
  "post-processors": [
    {
      "type": "googlecompute-export",
      "paths": [
        "gs://packer-test.google.com.a.appspot.com/foo.tar.gz",
        "gs://packer-test.google.com.a.appspot.com/bar.tar.gz"
      ],
      "keep_input_artifact": true
    }
  ]
}

--startup_script.sh--
\#!/bin/sh
echo "Hi, my name is Scott. I'm waiting 60 seconds!" >> /scott
sleep 60
echo "I'm done waiting!" >> /scott

builder/googlecompute/artifact.go

@@ -7,7 +7,7 @@ import (
 
 // Artifact represents a GCE image as the result of a Packer build.
 type Artifact struct {
-	image  Image
+	image  *Image
 	driver Driver
 	config *Config
 }

builder/googlecompute/builder.go

@@ -93,7 +93,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	artifact := &Artifact{
-		image:  state.Get("image").(Image),
+		image:  state.Get("image").(*Image),
 		driver: driver,
 		config: b.config,
 	}

builder/googlecompute/driver.go

@@ -4,13 +4,9 @@ package googlecompute
 // with GCE. The Driver interface exists mostly to allow a mock implementation
 // to be used to test the steps.
 type Driver interface {
-	// ImageExists returns true if the specified image exists. If an error
-	// occurs calling the API, this method returns false.
-	ImageExists(name string) bool
-
 	// CreateImage creates an image from the given disk in Google Compute
 	// Engine.
-	CreateImage(name, description, family, zone, disk string) (<-chan Image, <-chan error)
+	CreateImage(name, description, family, zone, disk string) (<-chan *Image, <-chan error)
 
 	// DeleteImage deletes the image with the given name.
 	DeleteImage(name string) <-chan error
@@ -21,6 +17,15 @@ type Driver interface {
 	// DeleteDisk deletes the disk with the given name.
 	DeleteDisk(zone, name string) (<-chan error, error)
 
+	// GetImage gets an image; tries the default and public projects.
+	GetImage(name string) (*Image, error)
+
+	// GetImageFromProject gets an image from a specific project.
+	GetImageFromProject(project, name string) (*Image, error)
+
+	// GetInstanceMetadata gets a metadata variable for the instance, name.
+	GetInstanceMetadata(zone, name, key string) (string, error)
+
 	// GetInternalIP gets the GCE-internal IP address for the instance.
 	GetInternalIP(zone, name string) (string, error)
 
@@ -30,6 +35,10 @@ type Driver interface {
 	// GetSerialPortOutput gets the Serial Port contents for the instance.
 	GetSerialPortOutput(zone, name string) (string, error)
 
+	// ImageExists returns true if the specified image exists. If an error
+	// occurs calling the API, this method returns false.
+	ImageExists(name string) bool
+
 	// RunInstance takes the given config and launches an instance.
 	RunInstance(*InstanceConfig) (<-chan error, error)
 
@@ -37,18 +46,12 @@ type Driver interface {
 	WaitForInstance(state, zone, name string) <-chan error
 }
 
-type Image struct {
-	Name      string
-	ProjectId string
-	SizeGb    int64
-}
-
 type InstanceConfig struct {
 	Address             string
 	Description         string
 	DiskSizeGb          int64
 	DiskType            string
-	Image               Image
+	Image               *Image
 	MachineType         string
 	Metadata            map[string]string
 	Name                string

builder/googlecompute/driver_gce.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"net/http"
 	"runtime"
+	"strings"
 
 	"github.com/mitchellh/packer/packer"
 	"github.com/mitchellh/packer/version"
@@ -13,7 +14,6 @@ import (
 	"golang.org/x/oauth2/google"
 	"golang.org/x/oauth2/jwt"
 	"google.golang.org/api/compute/v1"
-	"strings"
 )
 
 // driverGCE is a Driver implementation that actually talks to GCE.
@@ -88,15 +88,8 @@ func NewDriverGCE(ui packer.Ui, p string, a *AccountFile) (Driver, error) {
 	}, nil
 }
 
-func (d *driverGCE) ImageExists(name string) bool {
+func (d *driverGCE) CreateImage(name, description, family, zone, disk string) (<-chan *Image, <-chan error) {
-	_, err := d.service.Images.Get(d.projectId, name).Do()
+	gce_image := &compute.Image{
-	// The API may return an error for reasons other than the image not
-	// existing, but this heuristic is sufficient for now.
-	return err == nil
-}
-
-func (d *driverGCE) CreateImage(name, description, family, zone, disk string) (<-chan Image, <-chan error) {
-	image := &compute.Image{
 		Description: description,
 		Name:        name,
 		Family:      family,
@@ -104,9 +97,9 @@ func (d *driverGCE) CreateImage(name, description, family, zone, disk string) (<
 		SourceType:  "RAW",
 	}
 
-	imageCh := make(chan Image, 1)
+	imageCh := make(chan *Image, 1)
 	errCh := make(chan error, 1)
-	op, err := d.service.Images.Insert(d.projectId, image).Do()
+	op, err := d.service.Images.Insert(d.projectId, gce_image).Do()
 	if err != nil {
 		errCh <- err
 	} else {
@@ -114,17 +107,17 @@ func (d *driverGCE) CreateImage(name, description, family, zone, disk string) (<
 			err = waitForState(errCh, "DONE", d.refreshGlobalOp(op))
 			if err != nil {
 				close(imageCh)
+				errCh <- err
+				return
 			}
-			image, err = d.getImage(name, d.projectId)
+			var image *Image
+			image, err = d.GetImageFromProject(d.projectId, name)
 			if err != nil {
 				close(imageCh)
 				errCh <- err
+				return
 			}
-			imageCh <- Image{
+			imageCh <- image
-				Name:      name,
-				ProjectId: d.projectId,
-				SizeGb:    image.DiskSizeGb,
-			}
 			close(imageCh)
 		}()
 	}
@@ -166,6 +159,57 @@ func (d *driverGCE) DeleteDisk(zone, name string) (<-chan error, error) {
 	return errCh, nil
 }
 
+func (d *driverGCE) GetImage(name string) (*Image, error) {
+	projects := []string{d.projectId, "centos-cloud", "coreos-cloud", "debian-cloud", "google-containers", "opensuse-cloud", "rhel-cloud", "suse-cloud", "ubuntu-os-cloud", "windows-cloud"}
+	var errs error
+	for _, project := range projects {
+		image, err := d.GetImageFromProject(project, name)
+		if err != nil {
+			errs = packer.MultiErrorAppend(errs, err)
+		}
+		if image != nil {
+			return image, nil
+		}
+	}
+
+	return nil, fmt.Errorf(
+		"Could not find image, %s, in projects, %s: %s", name,
+		projects, errs)
+}
+
+func (d *driverGCE) GetImageFromProject(project, name string) (*Image, error) {
+	image, err := d.service.Images.Get(project, name).Do()
+
+	if err != nil {
+		return nil, err
+	} else if image == nil || image.SelfLink == "" {
+		return nil, fmt.Errorf("Image, %s, could not be found in project: %s", name, project)
+	} else {
+		return &Image{
+			Licenses: image.Licenses,
+			Name: image.Name,
+			ProjectId: project,
+			SelfLink: image.SelfLink,
+			SizeGb: image.DiskSizeGb,
+		}, nil
+	}
+}
+
+func (d *driverGCE) GetInstanceMetadata(zone, name, key string) (string, error) {
+	instance, err := d.service.Instances.Get(d.projectId, zone, name).Do()
+	if err != nil {
+		return "", err
+	}
+
+	for _, item := range instance.Metadata.Items {
+		if item.Key == key {
+			return *item.Value, nil
+		}
+	}
+
+	return "", fmt.Errorf("Instance metadata key, %s, not found.", key)
+}
+
 func (d *driverGCE) GetNatIP(zone, name string) (string, error) {
 	instance, err := d.service.Instances.Get(d.projectId, zone, name).Do()
 	if err != nil {
@@ -211,6 +255,13 @@ func (d *driverGCE) GetSerialPortOutput(zone, name string) (string, error) {
 	return output.Contents, nil
 }
 
+func (d *driverGCE) ImageExists(name string) bool {
+	_, err := d.GetImageFromProject(d.projectId, name)
+	// The API may return an error for reasons other than the image not
+	// existing, but this heuristic is sufficient for now.
+	return err == nil
+}
+
 func (d *driverGCE) RunInstance(c *InstanceConfig) (<-chan error, error) {
 	// Get the zone
 	d.ui.Message(fmt.Sprintf("Loading zone: %s", c.Zone))
@@ -219,13 +270,6 @@ func (d *driverGCE) RunInstance(c *InstanceConfig) (<-chan error, error) {
 		return nil, err
 	}
 
-	// Get the image
-	d.ui.Message(fmt.Sprintf("Loading image: %s in project %s", c.Image.Name, c.Image.ProjectId))
-	image, err := d.getImage(c.Image.Name, c.Image.ProjectId)
-	if err != nil {
-		return nil, err
-	}
-
 	// Get the machine type
 	d.ui.Message(fmt.Sprintf("Loading machine type: %s", c.MachineType))
 	machineType, err := d.service.MachineTypes.Get(
@@ -302,7 +346,7 @@ func (d *driverGCE) RunInstance(c *InstanceConfig) (<-chan error, error) {
 				Boot:       true,
 				AutoDelete: false,
 				InitializeParams: &compute.AttachedDiskInitializeParams{
-					SourceImage: image.SelfLink,
+					SourceImage: c.Image.SelfLink,
 					DiskSizeGb:  c.DiskSizeGb,
 					DiskType:    fmt.Sprintf("zones/%s/diskTypes/%s", zone.Name, c.DiskType),
 				},
@@ -355,20 +399,6 @@ func (d *driverGCE) WaitForInstance(state, zone, name string) <-chan error {
 	return errCh
 }
 
-func (d *driverGCE) getImage(name, projectId string) (image *compute.Image, err error) {
-	projects := []string{projectId, "centos-cloud", "coreos-cloud", "debian-cloud", "google-containers", "opensuse-cloud", "rhel-cloud", "suse-cloud", "ubuntu-os-cloud", "windows-cloud"}
-	for _, project := range projects {
-		image, err = d.service.Images.Get(project, name).Do()
-		if err == nil && image != nil && image.SelfLink != "" {
-			return
-		}
-		image = nil
-	}
-
-	err = fmt.Errorf("Image %s could not be found in any of these projects: %s", name, projects)
-	return
-}
-
 func (d *driverGCE) refreshInstanceState(zone, name string) stateRefreshFunc {
 	return func() (string, error) {
 		instance, err := d.service.Instances.Get(d.projectId, zone, name).Do()

builder/googlecompute/driver_mock.go

@@ -1,20 +1,21 @@
 package googlecompute
 
+import "fmt"
+
 // DriverMock is a Driver implementation that is a mocked out so that
 // it can be used for tests.
 type DriverMock struct {
-	ImageExistsName   string
+	CreateImageName            string
-	ImageExistsResult bool
+	CreateImageDesc            string
-
+	CreateImageFamily          string
-	CreateImageName      string
+	CreateImageZone            string
-	CreateImageDesc      string
+	CreateImageDisk            string
-	CreateImageFamily    string
+	CreateImageResultLicenses  []string
-	CreateImageZone      string
+	CreateImageResultProjectId string
-	CreateImageDisk      string
+	CreateImageResultSelfLink  string
-	CreateImageProjectId string
+	CreateImageResultSizeGb    int64
-	CreateImageSizeGb    int64
+	CreateImageErrCh           <-chan error
-	CreateImageErrCh     <-chan error
+	CreateImageResultCh        <-chan *Image
-	CreateImageResultCh  <-chan Image
 
 	DeleteImageName  string
 	DeleteImageErrCh <-chan error
@@ -29,6 +30,21 @@ type DriverMock struct {
 	DeleteDiskErrCh <-chan error
 	DeleteDiskErr   error
 
+	GetImageName   string
+	GetImageResult *Image
+	GetImageErr    error
+
+	GetImageFromProjectProject string
+	GetImageFromProjectName    string
+	GetImageFromProjectResult  *Image
+	GetImageFromProjectErr     error
+
+	GetInstanceMetadataZone   string
+	GetInstanceMetadataName   string
+	GetInstanceMetadataKey    string
+	GetInstanceMetadataResult string
+	GetInstanceMetadataErr    error
+
 	GetNatIPZone   string
 	GetNatIPName   string
 	GetNatIPResult string
@@ -44,6 +60,9 @@ type DriverMock struct {
 	GetSerialPortOutputResult string
 	GetSerialPortOutputErr    error
 
+	ImageExistsName   string
+	ImageExistsResult bool
+
 	RunInstanceConfig *InstanceConfig
 	RunInstanceErrCh  <-chan error
 	RunInstanceErr    error
@@ -54,31 +73,33 @@ type DriverMock struct {
 	WaitForInstanceErrCh <-chan error
 }
 
-func (d *DriverMock) ImageExists(name string) bool {
+func (d *DriverMock) CreateImage(name, description, family, zone, disk string) (<-chan *Image, <-chan error) {
-	d.ImageExistsName = name
-	return d.ImageExistsResult
-}
-
-func (d *DriverMock) CreateImage(name, description, family, zone, disk string) (<-chan Image, <-chan error) {
 	d.CreateImageName = name
 	d.CreateImageDesc = description
 	d.CreateImageFamily = family
 	d.CreateImageZone = zone
 	d.CreateImageDisk = disk
-	if d.CreateImageSizeGb == 0 {
+	if d.CreateImageResultProjectId == "" {
-		d.CreateImageSizeGb = 10
+		d.CreateImageResultProjectId = "test"
 	}
-	if d.CreateImageProjectId == "" {
+	if d.CreateImageResultSelfLink == "" {
-		d.CreateImageProjectId = "test"
+		d.CreateImageResultSelfLink = fmt.Sprintf(
+			"http://content.googleapis.com/compute/v1/%s/global/licenses/test",
+			d.CreateImageResultProjectId)
+	}
+	if d.CreateImageResultSizeGb == 0 {
+		d.CreateImageResultSizeGb = 10
 	}
 
 	resultCh := d.CreateImageResultCh
 	if resultCh == nil {
-		ch := make(chan Image, 1)
+		ch := make(chan *Image, 1)
-		ch <- Image{
+		ch <- &Image{
+			Licenses:  d.CreateImageResultLicenses,
 			Name:      name,
-			ProjectId: d.CreateImageProjectId,
+			ProjectId: d.CreateImageResultProjectId,
-			SizeGb:    d.CreateImageSizeGb,
+			SelfLink:  d.CreateImageResultSelfLink,
+			SizeGb:    d.CreateImageResultSizeGb,
 		}
 		close(ch)
 		resultCh = ch
@@ -135,6 +156,24 @@ func (d *DriverMock) DeleteDisk(zone, name string) (<-chan error, error) {
 	return resultCh, d.DeleteDiskErr
 }
 
+func (d *DriverMock) GetImage(name string) (*Image, error) {
+	d.GetImageName = name
+	return d.GetImageResult, d.GetImageErr
+}
+
+func (d *DriverMock) GetImageFromProject(project, name string) (*Image, error) {
+	d.GetImageFromProjectProject = project
+	d.GetImageFromProjectName = name
+	return d.GetImageFromProjectResult, d.GetImageFromProjectErr
+}
+
+func (d *DriverMock) GetInstanceMetadata(zone, name, key string) (string, error) {
+	d.GetInstanceMetadataZone = zone
+	d.GetInstanceMetadataName = name
+	d.GetInstanceMetadataKey = key
+	return d.GetInstanceMetadataResult, d.GetInstanceMetadataErr
+}
+
 func (d *DriverMock) GetNatIP(zone, name string) (string, error) {
 	d.GetNatIPZone = zone
 	d.GetNatIPName = name
@@ -153,6 +192,11 @@ func (d *DriverMock) GetSerialPortOutput(zone, name string) (string, error) {
 	return d.GetSerialPortOutputResult, d.GetSerialPortOutputErr
 }
 
+func (d *DriverMock) ImageExists(name string) bool {
+	d.ImageExistsName = name
+	return d.ImageExistsResult
+}
+
 func (d *DriverMock) RunInstance(c *InstanceConfig) (<-chan error, error) {
 	d.RunInstanceConfig = c
 

builder/googlecompute/image.go

@@ -0,0 +1,22 @@
+package googlecompute
+
+import (
+	"strings"
+)
+
+type Image struct {
+	Licenses  []string
+	Name      string
+	ProjectId string
+	SelfLink  string
+	SizeGb    int64
+}
+
+func (i *Image) IsWindows() bool {
+	for _, license := range i.Licenses {
+		if strings.Contains(license, "windows") {
+			return true
+		}
+	}
+	return false
+}

builder/googlecompute/image_test.go

@@ -0,0 +1,26 @@
+package googlecompute
+
+import(
+	"testing"
+	"fmt"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func StubImage(name, project string, licenses []string, sizeGb int64) *Image {
+	return &Image{
+		Licenses: licenses,
+		Name: name,
+		ProjectId: project,
+		SelfLink: fmt.Sprintf("https://www.googleapis.com/compute/v1/projects/%s/global/images/%s", project, name),
+		SizeGb: sizeGb,
+	}
+}
+
+func TestImage_IsWindows(t *testing.T) {
+	i := StubImage("foo", "foo-project", []string{"license-foo", "license-bar"}, 100)
+	assert.False(t, i.IsWindows())
+
+	i = StubImage("foo", "foo-project", []string{"license-foo", "windows-license"}, 100)
+	assert.True(t, i.IsWindows())
+}

builder/googlecompute/startup.go

@@ -1,37 +1,40 @@
 package googlecompute
 
 import (
-	"encoding/base64"
 	"fmt"
 )
 
-const StartupScriptStartLog string = "Packer startup script starting."
-const StartupScriptDoneLog string = "Packer startup script done."
 const StartupScriptKey string = "startup-script"
+const StartupScriptStatusKey string = "startup-script-status"
 const StartupWrappedScriptKey string = "packer-wrapped-startup-script"
 
-// We have to encode StartupScriptDoneLog because we use it as a sentinel value to indicate
+const StartupScriptStatusDone string = "done"
-// that the user-provided startup script is done. If we pass StartupScriptDoneLog as-is, it
+const StartupScriptStatusError string = "error"
-// will be printed early in the instance console log (before the startup script even runs;
+const StartupScriptStatusNotDone string = "notdone"
-// we print out instance creation metadata which contains this wrapper script).
-var StartupScriptDoneLogBase64 string = base64.StdEncoding.EncodeToString([]byte(StartupScriptDoneLog))
 
-var StartupScript string = fmt.Sprintf(`#!/bin/bash
+var StartupScriptLinux string = fmt.Sprintf(`#!/bin/bash
-echo %s
+echo "Packer startup script starting."
 RETVAL=0
+BASEMETADATAURL=http://metadata/computeMetadata/v1/instance/
 
 GetMetadata () {
-	echo "$(curl -f -H "Metadata-Flavor: Google" http://metadata/computeMetadata/v1/instance/attributes/$1 2> /dev/null)"
+	echo "$(curl -f -H "Metadata-Flavor: Google" ${BASEMETADATAURL}/${1} 2> /dev/null)"
 }
 
-STARTUPSCRIPT=$(GetMetadata %s)
+ZONE=$(GetMetadata zone | grep -oP "[^/]*$")
+
+SetMetadata () {
+	gcloud compute instances add-metadata ${HOSTNAME} --metadata ${1}=${2} --zone ${ZONE}
+}
+
+STARTUPSCRIPT=$(GetMetadata attributes/%s)
 STARTUPSCRIPTPATH=/packer-wrapped-startup-script
 if [ -f "/var/log/startupscript.log" ]; then
   STARTUPSCRIPTLOGPATH=/var/log/startupscript.log
 else
   STARTUPSCRIPTLOGPATH=/var/log/daemon.log
 fi
-STARTUPSCRIPTLOGDEST=$(GetMetadata startup-script-log-dest)
+STARTUPSCRIPTLOGDEST=$(GetMetadata attributes/startup-script-log-dest)
 
 if [[ ! -z $STARTUPSCRIPT ]]; then
   echo "Executing user-provided startup script..."
@@ -48,6 +51,9 @@ if [[ ! -z $STARTUPSCRIPT ]]; then
   rm ${STARTUPSCRIPTPATH}
 fi
 
-echo $(echo %s | base64 --decode)
+echo "Packer startup script done."
+SetMetadata %s %s
 exit $RETVAL
-`, StartupScriptStartLog, StartupWrappedScriptKey, StartupScriptDoneLogBase64)
+`, StartupWrappedScriptKey, StartupScriptStatusKey, StartupScriptStatusDone)
+
+var StartupScriptWindows string = ""

builder/googlecompute/step_check_existing_image.go

@@ -13,14 +13,14 @@ type StepCheckExistingImage int
 
 // Run executes the Packer build step that checks if the image already exists.
 func (s *StepCheckExistingImage) Run(state multistep.StateBag) multistep.StepAction {
-	config := state.Get("config").(*Config)
+	c := state.Get("config").(*Config)
-	driver := state.Get("driver").(Driver)
+	d := state.Get("driver").(Driver)
 	ui := state.Get("ui").(packer.Ui)
 
 	ui.Say("Checking image does not exist...")
-	exists := driver.ImageExists(config.ImageName)
+	exists := d.ImageExists(c.ImageName)
 	if exists {
-		err := fmt.Errorf("Image %s already exists", config.ImageName)
+		err := fmt.Errorf("Image %s already exists", c.ImageName)
 		state.Put("error", err)
 		ui.Error(err.Error())
 		return multistep.ActionHalt

builder/googlecompute/step_create_image.go

@@ -24,7 +24,9 @@ func (s *StepCreateImage) Run(state multistep.StateBag) multistep.StepAction {
 
 	ui.Say("Creating image...")
 
-	imageCh, errCh := driver.CreateImage(config.ImageName, config.ImageDescription, config.ImageFamily, config.Zone, config.DiskName)
+	imageCh, errCh := driver.CreateImage(
+		config.ImageName, config.ImageDescription, config.ImageFamily, config.Zone,
+		config.DiskName)
 	var err error
 	select {
 	case err = <-errCh:

builder/googlecompute/step_create_image_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/mitchellh/multistep"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestStepCreateImage_impl(t *testing.T) {
@@ -16,52 +17,35 @@ func TestStepCreateImage(t *testing.T) {
 	step := new(StepCreateImage)
 	defer step.Cleanup(state)
 
-	config := state.Get("config").(*Config)
+	c := state.Get("config").(*Config)
-	driver := state.Get("driver").(*DriverMock)
+	d := state.Get("driver").(*DriverMock)
-	driver.CreateImageProjectId = "createimage-project"
+
-	driver.CreateImageSizeGb = 100
+	// These are the values of the image the driver will return.
+	d.CreateImageResultLicenses = []string{"test-license"}
+	d.CreateImageResultProjectId = "test-project"
+	d.CreateImageResultSizeGb = 100
 
 	// run the step
-	if action := step.Run(state); action != multistep.ActionContinue {
+	action := step.Run(state)
-		t.Fatalf("bad action: %#v", action)
+	assert.Equal(t, action, multistep.ActionContinue, "Step did not pass.")
-	}
 	
 	uncastImage, ok := state.GetOk("image")
-	if !ok {
+	assert.True(t, ok, "State does not have resulting image.")
-		t.Fatal("should have image")
+	image, ok := uncastImage.(*Image)
-	}
+	assert.True(t, ok, "Image in state is not an Image.")
-	image, ok := uncastImage.(Image)
-	if !ok {
-		t.Fatal("image is not an Image")
-	}
 	
 	// Verify created Image results.
-	if image.Name != config.ImageName {
+	assert.Equal(t, image.Licenses, d.CreateImageResultLicenses, "Created image licenses don't match the licenses returned by the driver.")
-		t.Fatalf("Created image name, %s, does not match config name, %s.", image.Name, config.ImageName)
+	assert.Equal(t, image.Name, c.ImageName, "Created image does not match config name.")
-	}
+	assert.Equal(t, image.ProjectId, d.CreateImageResultProjectId, "Created image project does not match driver project.")
-	if driver.CreateImageProjectId != image.ProjectId {
+	assert.Equal(t, image.SizeGb, d.CreateImageResultSizeGb, "Created image size does not match the size returned by the driver.")
-		t.Fatalf("Created image project ID, %s, does not match driver project ID, %s.", image.ProjectId, driver.CreateImageProjectId)
-	}
-	if driver.CreateImageSizeGb != image.SizeGb {
-		t.Fatalf("Created image size, %d, does not match the expected test value, %d.", image.SizeGb, driver.CreateImageSizeGb)
-	}
 
 	// Verify proper args passed to driver.CreateImage.
-	if driver.CreateImageName != config.ImageName {
+	assert.Equal(t, d.CreateImageName, c.ImageName, "Incorrect image name passed to driver.")
-		t.Fatalf("bad: %#v", driver.CreateImageName)
+	assert.Equal(t, d.CreateImageDesc, c.ImageDescription, "Incorrect image description passed to driver.")
-	}
+	assert.Equal(t, d.CreateImageFamily, c.ImageFamily, "Incorrect image family passed to driver.")
-	if driver.CreateImageDesc != config.ImageDescription {
+	assert.Equal(t, d.CreateImageZone, c.Zone, "Incorrect image zone passed to driver.")
-		t.Fatalf("bad: %#v", driver.CreateImageDesc)
+	assert.Equal(t, d.CreateImageDisk, c.DiskName, "Incorrect disk passed to driver.")
-	}
-	if driver.CreateImageFamily != config.ImageFamily {
-		t.Fatalf("bad: %#v", driver.CreateImageFamily)
-	}
-	if driver.CreateImageZone != config.Zone {
-		t.Fatalf("bad: %#v", driver.CreateImageZone)
-	}
-	if driver.CreateImageDisk != config.DiskName {
-		t.Fatalf("bad: %#v", driver.CreateImageDisk)
-	}
 }
 
 func TestStepCreateImage_errorOnChannel(t *testing.T) {
@@ -76,14 +60,10 @@ func TestStepCreateImage_errorOnChannel(t *testing.T) {
 	driver.CreateImageErrCh = errCh
 
 	// run the step
-	if action := step.Run(state); action != multistep.ActionHalt {
+	action := step.Run(state)
-		t.Fatalf("bad action: %#v", action)
+	assert.Equal(t, action, multistep.ActionHalt, "Step should not have passed.")
-	}
+	_, ok := state.GetOk("error")
-
+	assert.True(t, ok, "State should have an error.")
-	if _, ok := state.GetOk("error"); !ok {
+	_, ok = state.GetOk("image_name")
-		t.Fatal("should have error")
+	assert.False(t, ok, "State should not have a resulting image.")
-	}
-	if _, ok := state.GetOk("image_name"); ok {
-		t.Fatal("should NOT have image")
-	}
 }

builder/googlecompute/step_create_instance.go

@@ -15,82 +15,97 @@ type StepCreateInstance struct {
 	Debug bool
 }
 
-func (config *Config) getImage() Image {
+func (c *Config) createInstanceMetadata(sourceImage *Image, sshPublicKey string) (map[string]string, error) {
-	project := config.ProjectId
-	if config.SourceImageProjectId != "" {
-		project = config.SourceImageProjectId
-	}
-	return Image{Name: config.SourceImage, ProjectId: project}
-}
-
-func (config *Config) getInstanceMetadata(sshPublicKey string) (map[string]string, error) {
 	instanceMetadata := make(map[string]string)
 	var err error
 
 	// Copy metadata from config.
-	for k, v := range config.Metadata {
+	for k, v := range c.Metadata {
 		instanceMetadata[k] = v
 	}
 
 	// Merge any existing ssh keys with our public key.
 	sshMetaKey := "sshKeys"
-	sshKeys := fmt.Sprintf("%s:%s", config.Comm.SSHUsername, sshPublicKey)
+	sshKeys := fmt.Sprintf("%s:%s", c.Comm.SSHUsername, sshPublicKey)
 	if confSshKeys, exists := instanceMetadata[sshMetaKey]; exists {
 		sshKeys = fmt.Sprintf("%s\n%s", sshKeys, confSshKeys)
 	}
 	instanceMetadata[sshMetaKey] = sshKeys
 	
 	// Wrap any startup script with our own startup script.
-	if config.StartupScriptFile != "" {
+	if c.StartupScriptFile != "" {
 		var content []byte
-		content, err = ioutil.ReadFile(config.StartupScriptFile)
+		content, err = ioutil.ReadFile(c.StartupScriptFile)
 		instanceMetadata[StartupWrappedScriptKey] = string(content)
 	} else if wrappedStartupScript, exists := instanceMetadata[StartupScriptKey]; exists {
 		instanceMetadata[StartupWrappedScriptKey] = wrappedStartupScript
 	}
-	instanceMetadata[StartupScriptKey] = StartupScript
+	if sourceImage.IsWindows() {
+		// Windows startup script support is not yet implemented.
+		// Mark the startup script as done.
+		instanceMetadata[StartupScriptKey] = StartupScriptWindows
+		instanceMetadata[StartupScriptStatusKey] = StartupScriptStatusDone
+	} else {
+		instanceMetadata[StartupScriptKey] = StartupScriptLinux
+		instanceMetadata[StartupScriptStatusKey] = StartupScriptStatusNotDone
+	}
 
 	return instanceMetadata, err
 }
 
+func getImage(c *Config, d Driver) (*Image, error) {
+	if c.SourceImageProjectId == "" {
+		return d.GetImage(c.SourceImage)
+	} else {
+		return d.GetImageFromProject(c.SourceImageProjectId, c.SourceImage)
+	}
+}
+
 // Run executes the Packer build step that creates a GCE instance.
 func (s *StepCreateInstance) Run(state multistep.StateBag) multistep.StepAction {
-	config := state.Get("config").(*Config)
+	c := state.Get("config").(*Config)
-	driver := state.Get("driver").(Driver)
+	d := state.Get("driver").(Driver)
 	sshPublicKey := state.Get("ssh_public_key").(string)
 	ui := state.Get("ui").(packer.Ui)
 
+	sourceImage, err := getImage(c, d)
+	if err != nil {
+		err := fmt.Errorf("Error getting source image for instance creation: %s", err)
+		state.Put("error", err)
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+
 	ui.Say("Creating instance...")
-	name := config.InstanceName
+	name := c.InstanceName
 
 	var errCh <-chan error
-	var err error
 	var metadata map[string]string
-	metadata, err = config.getInstanceMetadata(sshPublicKey)
+	metadata, err = c.createInstanceMetadata(sourceImage, sshPublicKey)
-	errCh, err = driver.RunInstance(&InstanceConfig{
+	errCh, err = d.RunInstance(&InstanceConfig{
-		Address:             config.Address,
+		Address:             c.Address,
 		Description:         "New instance created by Packer",
-		DiskSizeGb:          config.DiskSizeGb,
+		DiskSizeGb:          c.DiskSizeGb,
-		DiskType:            config.DiskType,
+		DiskType:            c.DiskType,
-		Image:               config.getImage(),
+		Image:               sourceImage,
-		MachineType:         config.MachineType,
+		MachineType:         c.MachineType,
 		Metadata:            metadata,
 		Name:                name,
-		Network:             config.Network,
+		Network:             c.Network,
-		OmitExternalIP:      config.OmitExternalIP,
+		OmitExternalIP:      c.OmitExternalIP,
-		Preemptible:         config.Preemptible,
+		Preemptible:         c.Preemptible,
-		Region:              config.Region,
+		Region:              c.Region,
-		ServiceAccountEmail: config.Account.ClientEmail,
+		ServiceAccountEmail: c.Account.ClientEmail,
-		Subnetwork:          config.Subnetwork,
+		Subnetwork:          c.Subnetwork,
-		Tags:                config.Tags,
+		Tags:                c.Tags,
-		Zone:                config.Zone,
+		Zone:                c.Zone,
 	})
 
 	if err == nil {
 		ui.Message("Waiting for creation operation to complete...")
 		select {
 		case err = <-errCh:
-		case <-time.After(config.stateTimeout):
+		case <-time.After(c.stateTimeout):
 			err = errors.New("time out while waiting for instance to create")
 		}
 	}
@@ -106,7 +121,7 @@ func (s *StepCreateInstance) Run(state multistep.StateBag) multistep.StepAction
 
 	if s.Debug {
 		if name != "" {
-			ui.Message(fmt.Sprintf("Instance: %s started in %s", name, config.Zone))
+			ui.Message(fmt.Sprintf("Instance: %s started in %s", name, c.Zone))
 		}
 	}
 

builder/googlecompute/step_create_instance_test.go

@@ -2,9 +2,11 @@ package googlecompute
 
 import (
 	"errors"
-	"github.com/mitchellh/multistep"
 	"testing"
 	"time"
+
+	"github.com/mitchellh/multistep"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestStepCreateInstance_impl(t *testing.T) {
@@ -18,36 +20,25 @@ func TestStepCreateInstance(t *testing.T) {
 
 	state.Put("ssh_public_key", "key")
 
-	config := state.Get("config").(*Config)
+	c := state.Get("config").(*Config)
-	driver := state.Get("driver").(*DriverMock)
+	d := state.Get("driver").(*DriverMock)
+	d.GetImageResult = StubImage("test-image", "test-project", []string{}, 100)
 
 	// run the step
-	if action := step.Run(state); action != multistep.ActionContinue {
+	assert.Equal(t, step.Run(state), multistep.ActionContinue, "Step should have passed and continued.")
-		t.Fatalf("bad action: %#v", action)
-	}
 
 	// Verify state
 	nameRaw, ok := state.GetOk("instance_name")
-	if !ok {
+	assert.True(t, ok, "State should have an instance name.")
-		t.Fatal("should have instance name")
-	}
 
 	// cleanup
 	step.Cleanup(state)
 
-	if driver.DeleteInstanceName != nameRaw.(string) {
+	// Check args passed to the driver.
-		t.Fatal("should've deleted instance")
+	assert.Equal(t, d.DeleteInstanceName, nameRaw.(string), "Incorrect instance name passed to driver.")
-	}
+	assert.Equal(t, d.DeleteInstanceZone, c.Zone, "Incorrect instance zone passed to driver.")
-	if driver.DeleteInstanceZone != config.Zone {
+	assert.Equal(t, d.DeleteDiskName, c.InstanceName, "Incorrect disk name passed to driver.")
-		t.Fatalf("bad instance zone: %#v", driver.DeleteInstanceZone)
+	assert.Equal(t, d.DeleteDiskZone, c.Zone, "Incorrect disk zone passed to driver.")
-	}
-
-	if driver.DeleteDiskName != config.InstanceName {
-		t.Fatal("should've deleted disk")
-	}
-	if driver.DeleteDiskZone != config.Zone {
-		t.Fatalf("bad disk zone: %#v", driver.DeleteDiskZone)
-	}
 }
 
 func TestStepCreateInstance_error(t *testing.T) {
@@ -57,21 +48,18 @@ func TestStepCreateInstance_error(t *testing.T) {
 
 	state.Put("ssh_public_key", "key")
 
-	driver := state.Get("driver").(*DriverMock)
+	d := state.Get("driver").(*DriverMock)
-	driver.RunInstanceErr = errors.New("error")
+	d.RunInstanceErr = errors.New("error")
+	d.GetImageResult = StubImage("test-image", "test-project", []string{}, 100)
 
 	// run the step
-	if action := step.Run(state); action != multistep.ActionHalt {
+	assert.Equal(t, step.Run(state), multistep.ActionHalt, "Step should have failed and halted.")
-		t.Fatalf("bad action: %#v", action)
-	}
 
 	// Verify state
-	if _, ok := state.GetOk("error"); !ok {
+	_, ok := state.GetOk("error")
-		t.Fatal("should have error")
+	assert.True(t, ok, "State should have an error.")
-	}
+	_, ok = state.GetOk("instance_name")
-	if _, ok := state.GetOk("instance_name"); ok {
+	assert.False(t, ok, "State should not have an instance name.")
-		t.Fatal("should NOT have instance name")
-	}
 }
 
 func TestStepCreateInstance_errorOnChannel(t *testing.T) {
@@ -79,26 +67,23 @@ func TestStepCreateInstance_errorOnChannel(t *testing.T) {
 	step := new(StepCreateInstance)
 	defer step.Cleanup(state)
 
+	state.Put("ssh_public_key", "key")
+
 	errCh := make(chan error, 1)
 	errCh <- errors.New("error")
 
-	state.Put("ssh_public_key", "key")
+	d := state.Get("driver").(*DriverMock)
-
+	d.RunInstanceErrCh = errCh
-	driver := state.Get("driver").(*DriverMock)
+	d.GetImageResult = StubImage("test-image", "test-project", []string{}, 100)
-	driver.RunInstanceErrCh = errCh
 
 	// run the step
-	if action := step.Run(state); action != multistep.ActionHalt {
+	assert.Equal(t, step.Run(state), multistep.ActionHalt, "Step should have failed and halted.")
-		t.Fatalf("bad action: %#v", action)
-	}
 
 	// Verify state
-	if _, ok := state.GetOk("error"); !ok {
+	_, ok := state.GetOk("error")
-		t.Fatal("should have error")
+	assert.True(t, ok, "State should have an error.")
-	}
+	_, ok = state.GetOk("instance_name")
-	if _, ok := state.GetOk("instance_name"); ok {
+	assert.False(t, ok, "State should not have an instance name.")
-		t.Fatal("should NOT have instance name")
-	}
 }
 
 func TestStepCreateInstance_errorTimeout(t *testing.T) {
@@ -106,30 +91,27 @@ func TestStepCreateInstance_errorTimeout(t *testing.T) {
 	step := new(StepCreateInstance)
 	defer step.Cleanup(state)
 
+	state.Put("ssh_public_key", "key")
+
 	errCh := make(chan error, 1)
 	go func() {
 		<-time.After(10 * time.Millisecond)
 		errCh <- nil
 	}()
 
-	state.Put("ssh_public_key", "key")
-
 	config := state.Get("config").(*Config)
 	config.stateTimeout = 1 * time.Microsecond
 
-	driver := state.Get("driver").(*DriverMock)
+	d := state.Get("driver").(*DriverMock)
-	driver.RunInstanceErrCh = errCh
+	d.RunInstanceErrCh = errCh
+	d.GetImageResult = StubImage("test-image", "test-project", []string{}, 100)
 
 	// run the step
-	if action := step.Run(state); action != multistep.ActionHalt {
+	assert.Equal(t, step.Run(state), multistep.ActionHalt, "Step should have failed and halted.")
-		t.Fatalf("bad action: %#v", action)
-	}
 
 	// Verify state
-	if _, ok := state.GetOk("error"); !ok {
+	_, ok := state.GetOk("error")
-		t.Fatal("should have error")
+	assert.True(t, ok, "State should have an error.")
-	}
+	_, ok = state.GetOk("instance_name")
-	if _, ok := state.GetOk("instance_name"); ok {
+	assert.False(t, ok, "State should not have an instance name.")
-		t.Fatal("should NOT have instance name")
-	}
 }

builder/googlecompute/step_test.go

@@ -2,9 +2,10 @@ package googlecompute
 
 import (
 	"bytes"
+	"testing"
+
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
-	"testing"
 )
 
 func testState(t *testing.T) multistep.StateBag {

builder/googlecompute/step_wait_instance_startup.go

@@ -1,8 +1,8 @@
 package googlecompute
 
 import(
+	"errors"
 	"fmt"
-	"strings"
 
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
@@ -10,7 +10,8 @@ import(
 
 type StepWaitInstanceStartup int
 
-// Run reads the instance serial port output and looks for the log entry indicating the startup script finished.
+// Run reads the instance metadata and looks for the log entry
+// indicating the startup script finished.
 func (s *StepWaitInstanceStartup) Run(state multistep.StateBag) multistep.StepAction {
 	config := state.Get("config").(*Config)
 	driver := state.Get("driver").(Driver)
@@ -21,14 +22,20 @@ func (s *StepWaitInstanceStartup) Run(state multistep.StateBag) multistep.StepAc
 
 	// Keep checking the serial port output to see if the startup script is done.
 	err := Retry(10, 60, 0, func() (bool, error) {
-		output, err := driver.GetSerialPortOutput(config.Zone, instanceName)
+		status, err := driver.GetInstanceMetadata(config.Zone,
+			instanceName, StartupScriptStatusKey)
 
 		if err != nil {
-			err := fmt.Errorf("Error getting serial port output: %s", err)
+			err := fmt.Errorf("Error getting startup script status: %s", err)
 			return false, err
 		}
-		
+
-		done := strings.Contains(output, StartupScriptDoneLog)
+		if status == StartupScriptStatusError {
+			err = errors.New("Startup script error.")
+			return false, err
+		}
+
+		done := status == StartupScriptStatusDone
 		if !done {
 			ui.Say("Startup script not finished yet. Waiting...")
 		}

builder/googlecompute/step_wait_instance_startup_test.go

@@ -3,36 +3,28 @@ package googlecompute
 import (
 	"github.com/mitchellh/multistep"
 	"testing"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestStepWaitInstanceStartup(t *testing.T) {
 	state := testState(t)
 	step := new(StepWaitInstanceStartup)
-	config := state.Get("config").(*Config)
+	c := state.Get("config").(*Config)
-	driver := state.Get("driver").(*DriverMock)
+	d := state.Get("driver").(*DriverMock)
 	
 	testZone := "test-zone"
 	testInstanceName := "test-instance-name"
 
-	config.Zone = testZone
+	c.Zone = testZone
 	state.Put("instance_name", testInstanceName)
-	// The done log triggers step completion.
+
-	driver.GetSerialPortOutputResult = StartupScriptDoneLog
+	// This step stops when it gets Done back from the metadata.
+	d.GetInstanceMetadataResult = StartupScriptStatusDone
 	
 	// Run the step.
-	if action := step.Run(state); action != multistep.ActionContinue {
+	assert.Equal(t, step.Run(state), multistep.ActionContinue, "Step should have passed and continued.")
-		t.Fatalf("StepWaitInstanceStartup did not return a Continue action: %#v", action)
-	}
 	
-	// Check that GetSerialPortOutput was called properly.
+	// Check that GetInstanceMetadata was called properly.
-	if driver.GetSerialPortOutputZone != testZone {
+	assert.Equal(t, d.GetInstanceMetadataZone, testZone, "Incorrect zone passed to GetInstanceMetadata.")
-		t.Fatalf(
+	assert.Equal(t, d.GetInstanceMetadataName, testInstanceName, "Incorrect instance name passed to GetInstanceMetadata.")
-			"GetSerialPortOutput wrong zone. Expected: %s, Actual: %s", driver.GetSerialPortOutputZone,
-			testZone)
-	}
-	if driver.GetSerialPortOutputName != testInstanceName {
-		t.Fatalf(
-			"GetSerialPortOutput wrong instance name. Expected: %s, Actual: %s", driver.GetSerialPortOutputName,
-			testInstanceName)
-	}
 }