Merge pull request #3918 from nouney/f-googlecompute-force

builder/googlecompute: -force option

builder/googlecompute/config.go

@@ -52,6 +52,7 @@ type Config struct {
 	Account            AccountFile
 	privateKeyBytes    []byte
 	stateTimeout       time.Duration
+	imageAlreadyExists bool
 	ctx                interpolate.Context
 }
 

builder/googlecompute/step_check_existing_image.go

@@ -18,14 +18,14 @@ func (s *StepCheckExistingImage) Run(state multistep.StateBag) multistep.StepAct
 	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)
+	c.imageAlreadyExists = d.ImageExists(c.ImageName)
+	if !c.PackerForce && 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(