builder/googlecompute: -force

builder/googlecompute/config.go

@@ -49,10 +49,11 @@ type Config struct {
 	UseInternalIP        bool              `mapstructure:"use_internal_ip"`
 	Zone                 string            `mapstructure:"zone"`
 
-	Account         AccountFile
-	privateKeyBytes []byte
-	stateTimeout    time.Duration
-	ctx             interpolate.Context
+	Account            AccountFile
+	privateKeyBytes    []byte
+	stateTimeout       time.Duration
+	imageAlreadyExists bool
+	ctx                interpolate.Context
 }
 
 func NewConfig(raws ...interface{}) (*Config, []string, error) {

builder/googlecompute/step_check_existing_image.go

@@ -17,15 +17,17 @@ func (s *StepCheckExistingImage) Run(state multistep.StateBag) multistep.StepAct
 	d := state.Get("driver").(Driver)
 	ui := state.Get("ui").(packer.Ui)
 
-	ui.Say("Checking image does not exist...")
-	exists := d.ImageExists(c.ImageName)
-	if exists {
-		err := fmt.Errorf("Image %s already exists", c.ImageName)
-		state.Put("error", err)
-		ui.Error(err.Error())
-		return multistep.ActionHalt
+	if !c.PackerForce {
+		ui.Say("Checking image does not exist...")
+		c.imageAlreadyExists = d.ImageExists(c.ImageName)
+		if c.imageAlreadyExists {
+			err := fmt.Errorf("Image %s already exists.\n"+
+				"Use the force flag to delete it prior to building.", c.ImageName)
+			state.Put("error", err)
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
 	}
-
 	return multistep.ActionContinue
 }
 

builder/googlecompute/step_create_image.go

@@ -22,6 +22,19 @@ func (s *StepCreateImage) Run(state multistep.StateBag) multistep.StepAction {
 	driver := state.Get("driver").(Driver)
 	ui := state.Get("ui").(packer.Ui)
 
+	if config.PackerForce && config.imageAlreadyExists {
+		ui.Say("Deleting previous image...")
+
+		errCh := driver.DeleteImage(config.ImageName)
+		err := <-errCh
+		if err != nil {
+			err := fmt.Errorf("Error deleting image: %s", err)
+			state.Put("error", err)
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
+	}
+
 	ui.Say("Creating image...")
 
 	imageCh, errCh := driver.CreateImage(