builder/googlecompute: support source image family

Closes #4100

builder/googlecompute/config.go

@@ -43,6 +43,7 @@ type Config struct {
 	Region               string            `mapstructure:"region"`
 	Scopes               []string          `mapstructure:"scopes"`
 	SourceImage          string            `mapstructure:"source_image"`
+	SourceImageFamily    string            `mapstructure:"source_image_family"`
 	SourceImageProjectId string            `mapstructure:"source_image_project_id"`
 	StartupScriptFile    string            `mapstructure:"startup_script_file"`
 	Subnetwork           string            `mapstructure:"subnetwork"`
@@ -152,9 +153,9 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		}
 	}
 
-	if c.SourceImage == "" {
+	if c.SourceImage == "" && c.SourceImageFamily == "" {
 		errs = packer.MultiErrorAppend(
-			errs, errors.New("a source_image must be specified"))
+			errs, errors.New("a source_image or source_image_family must be specified"))
 	}
 
 	if c.Zone == "" {

builder/googlecompute/config_test.go

@@ -46,6 +46,17 @@ func TestConfigPrepare(t *testing.T) {
 			false,
 		},
 
+		{
+			"source_image_family",
+			nil,
+			false,
+		},
+		{
+			"source_image_family",
+			"foo",
+			false,
+		},
+
 		{
 			"zone",
 			nil,

builder/googlecompute/driver.go

@@ -22,11 +22,14 @@ 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)
+	// GetImage gets an image; tries the default and public projects. If
+	// fromFamily is true, name designates an image family instead of a
+	// particular image.
+	GetImage(name string, fromFamily bool) (*Image, error)
 
-	// GetImageFromProject gets an image from a specific project.
-	GetImageFromProject(project, name string) (*Image, error)
+	// GetImageFromProject gets an image from a specific project. If fromFamily
+	// is true, name designates an image family instead of a particular image.
+	GetImageFromProject(project, name string, fromFamily bool) (*Image, error)
 
 	// GetInstanceMetadata gets a metadata variable for the instance, name.
 	GetInstanceMetadata(zone, name, key string) (string, error)

builder/googlecompute/driver_gce.go

@@ -119,7 +119,7 @@ func (d *driverGCE) CreateImage(name, description, family, zone, disk string) (<
 				return
 			}
 			var image *Image
-			image, err = d.GetImageFromProject(d.projectId, name)
+			image, err = d.GetImageFromProject(d.projectId, name, false)
 			if err != nil {
 				close(imageCh)
 				errCh <- err
@@ -167,11 +167,11 @@ func (d *driverGCE) DeleteDisk(zone, name string) (<-chan error, error) {
 	return errCh, nil
 }
 
-func (d *driverGCE) GetImage(name string) (*Image, error) {
+func (d *driverGCE) GetImage(name string, fromFamily bool) (*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", "gce-nvme"}
 	var errs error
 	for _, project := range projects {
-		image, err := d.GetImageFromProject(project, name)
+		image, err := d.GetImageFromProject(project, name, fromFamily)
 		if err != nil {
 			errs = packer.MultiErrorAppend(errs, err)
 		}
@@ -185,8 +185,17 @@ func (d *driverGCE) GetImage(name string) (*Image, error) {
 		projects, errs)
 }
 
-func (d *driverGCE) GetImageFromProject(project, name string) (*Image, error) {
-	image, err := d.service.Images.Get(project, name).Do()
+func (d *driverGCE) GetImageFromProject(project, name string, fromFamily bool) (*Image, error) {
+	var (
+		image *compute.Image
+		err   error
+	)
+
+	if fromFamily {
+		image, err = d.service.Images.GetFromFamily(project, name).Do()
+	} else {
+		image, err = d.service.Images.Get(project, name).Do()
+	}
 
 	if err != nil {
 		return nil, err
@@ -264,7 +273,7 @@ func (d *driverGCE) GetSerialPortOutput(zone, name string) (string, error) {
 }
 
 func (d *driverGCE) ImageExists(name string) bool {
-	_, err := d.GetImageFromProject(d.projectId, name)
+	_, err := d.GetImageFromProject(d.projectId, name, false)
 	// The API may return an error for reasons other than the image not
 	// existing, but this heuristic is sufficient for now.
 	return err == nil

builder/googlecompute/driver_mock.go

@@ -31,11 +31,13 @@ type DriverMock struct {
 	DeleteDiskErr   error
 
 	GetImageName       string
+	GetImageFromFamily bool
 	GetImageResult     *Image
 	GetImageErr        error
 
 	GetImageFromProjectProject    string
 	GetImageFromProjectName       string
+	GetImageFromProjectFromFamily bool
 	GetImageFromProjectResult     *Image
 	GetImageFromProjectErr        error
 
@@ -162,14 +164,16 @@ func (d *DriverMock) DeleteDisk(zone, name string) (<-chan error, error) {
 	return resultCh, d.DeleteDiskErr
 }
 
-func (d *DriverMock) GetImage(name string) (*Image, error) {
+func (d *DriverMock) GetImage(name string, fromFamily bool) (*Image, error) {
 	d.GetImageName = name
+	d.GetImageFromFamily = fromFamily
 	return d.GetImageResult, d.GetImageErr
 }
 
-func (d *DriverMock) GetImageFromProject(project, name string) (*Image, error) {
+func (d *DriverMock) GetImageFromProject(project, name string, fromFamily bool) (*Image, error) {
 	d.GetImageFromProjectProject = project
 	d.GetImageFromProjectName = name
+	d.GetImageFromProjectFromFamily = fromFamily
 	return d.GetImageFromProjectResult, d.GetImageFromProjectErr
 }
 

builder/googlecompute/step_create_instance.go

@@ -58,10 +58,16 @@ func (c *Config) createInstanceMetadata(sourceImage *Image, sshPublicKey string)
 }
 
 func getImage(c *Config, d Driver) (*Image, error) {
+	name := c.SourceImageFamily
+	fromFamily := true
+	if c.SourceImage != "" {
+		name = c.SourceImage
+		fromFamily = false
+	}
 	if c.SourceImageProjectId == "" {
-		return d.GetImage(c.SourceImage)
+		return d.GetImage(name, fromFamily)
 	} else {
-		return d.GetImageFromProject(c.SourceImageProjectId, c.SourceImage)
+		return d.GetImageFromProject(c.SourceImageProjectId, c.SourceImage, fromFamily)
 	}
 }
 

builder/googlecompute/step_create_instance_test.go

@@ -42,6 +42,45 @@ func TestStepCreateInstance(t *testing.T) {
 	assert.Equal(t, d.DeleteDiskZone, c.Zone, "Incorrect disk zone passed to driver.")
 }
 
+func TestStepCreateInstance_fromFamily(t *testing.T) {
+	cases := []struct {
+		Name   string
+		Family string
+		Expect bool
+	}{
+		{"test-image", "", false},
+		{"test-image", "test-family", false}, // name trumps family
+		{"", "test-family", true},
+	}
+
+	for _, tc := range cases {
+		state := testState(t)
+		step := new(StepCreateInstance)
+		defer step.Cleanup(state)
+
+		state.Put("ssh_public_key", "key")
+
+		c := state.Get("config").(*Config)
+		c.SourceImage = tc.Name
+		c.SourceImageFamily = tc.Family
+		d := state.Get("driver").(*DriverMock)
+		d.GetImageResult = StubImage("test-image", "test-project", []string{}, 100)
+
+		// run the step
+		assert.Equal(t, step.Run(state), multistep.ActionContinue, "Step should have passed and continued.")
+
+		// cleanup
+		step.Cleanup(state)
+
+		// Check args passed to the driver.
+		if tc.Expect {
+			assert.True(t, d.GetImageFromFamily, "Driver wasn't instructed to use an image family")
+		} else {
+			assert.False(t, d.GetImageFromFamily, "Driver was unexpectedly instructed to use an image family")
+		}
+	}
+}
+
 func TestStepCreateInstance_windowsNeedsPassword(t *testing.T) {
 
 	state := testState(t)

website/source/docs/builders/googlecompute.html.md

@@ -125,8 +125,11 @@ builder.
 -   `project_id` (string) - The project ID that will be used to launch instances
     and store images.
 
--   `source_image` (string) - The source image to use to create the new
-    image from. Example: `"debian-7-wheezy-v20150127"`
+-   `source_image` or `source_image_family` (string) - The source image or
+    family to use to create the new image from. The image family always returns
+    its latest image that is not deprecated. If both `source_image` and
+    `source_image_family` are specified, `source_image` takes precedence.
+    Example: `"debian-7-wheezy-v20150127"`, `"debian-7"`.
 
 -   `zone` (string) - The zone in which to launch the instance used to create
     the image. Example: `"us-central1-a"`
@@ -147,7 +150,10 @@ builder.
 
 -   `image_description` (string) - The description of the resulting image.
 
--   `image_family` (string) - The name of the image family to which the resulting image belongs. You can create disks by specifying an image family instead of a specific image name. The image family always returns its latest image that is not deprecated.
+-   `image_family` (string) - The name of the image family to which the
+    resulting image belongs. You can create disks by specifying an image family
+    instead of a specific image name. The image family always returns its
+    latest image that is not deprecated.
 
 -   `image_name` (string) - The unique name of the resulting image. Defaults to
     `"packer-{{timestamp}}"`.