support '-force': replace existing vm (#186)

clone/builder.go

@@ -39,6 +39,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		&StepCloneVM{
 			Config:   &b.config.CloneConfig,
 			Location: &b.config.LocationConfig,
+			Force:    b.config.PackerConfig.PackerForce,
 		},
 		&common.StepConfigureHardware{
 			Config: &b.config.HardwareConfig,

clone/step_clone.go

@@ -33,14 +33,27 @@ func (c *CloneConfig) Prepare() []error {
 type StepCloneVM struct {
 	Config   *CloneConfig
 	Location *common.LocationConfig
+	Force    bool
 }
 
 func (s *StepCloneVM) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
 	ui := state.Get("ui").(packer.Ui)
 	d := state.Get("driver").(*driver.Driver)
 
-	ui.Say("Cloning VM...")
+	find_vm, err := d.FindVM(s.Location.VMName)
 
+	if s.Force == false && err == nil {
+		state.Put("error", fmt.Errorf("%s already exists, you can use -force flag to destroy it: %v", s.Location.VMName, err))
+		return multistep.ActionHalt
+	} else if s.Force == true && err == nil {
+		ui.Say(fmt.Sprintf("the vm/template %s already exists, but deleting it due to -force flag", s.Location.VMName))
+		err := find_vm.Destroy()
+		if err != nil {
+			state.Put("error", fmt.Errorf("error destroying %s: %v", s.Location.VMName, err))
+		}
+	}
+
+	ui.Say("Cloning VM...")
 	template, err := d.FindVM(s.Config.Template)
 	if err != nil {
 		state.Put("error", err)

iso/builder.go

@@ -39,6 +39,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		&StepCreateVM{
 			Config:   &b.config.CreateConfig,
 			Location: &b.config.LocationConfig,
+			Force:    b.config.PackerConfig.PackerForce,
 		},
 		&common.StepConfigureHardware{
 			Config: &b.config.HardwareConfig,

iso/step_create.go

@@ -46,12 +46,26 @@ func (c *CreateConfig) Prepare() []error {
 type StepCreateVM struct {
 	Config   *CreateConfig
 	Location *common.LocationConfig
+	Force    bool
 }
 
 func (s *StepCreateVM) Run(_ context.Context, state multistep.StateBag) multistep.StepAction {
 	ui := state.Get("ui").(packer.Ui)
 	d := state.Get("driver").(*driver.Driver)
 
+	find_vm, err := d.FindVM(s.Location.VMName)
+
+	if s.Force == false && err == nil {
+		state.Put("error", fmt.Errorf("%s already exists, you can use -force flag to destroy it: %v", s.Location.VMName, err))
+		return multistep.ActionHalt
+	} else if s.Force == true && err == nil {
+		ui.Say(fmt.Sprintf("the vm/template %s already exists, but deleting it due to -force flag", s.Location.VMName))
+		err := find_vm.Destroy()
+		if err != nil {
+			state.Put("error", fmt.Errorf("error destroying %s: %v", s.Location.VMName, err))
+		}
+	}
+
 	ui.Say("Creating VM...")
 	vm, err := d.CreateVM(&driver.CreateConfig{
 		DiskThinProvisioned: s.Config.DiskThinProvisioned,