Wait for detach optimization

builder/azure/chroot/diskattacher.go

@@ -20,9 +20,10 @@ import (
 
 type DiskAttacher interface {
 	AttachDisk(ctx context.Context, disk string) (lun int32, err error)
-	DetachDisk(ctx context.Context, disk string) (err error)
-	WaitForDevice(ctx context.Context, i int32) (device string, err error)
 	DiskPathForLun(lun int32) string
+	WaitForDevice(ctx context.Context, i int32) (device string, err error)
+	DetachDisk(ctx context.Context, disk string) (err error)
+	WaitForDetach(ctx context.Context, diskID string) error
 }
 
 func NewDiskAttacher(azureClient client.AzureClientSet) DiskAttacher {
@@ -89,7 +90,10 @@ func (da *diskAttacher) DetachDisk(ctx context.Context, diskID string) error {
 		return err
 	}
 
-	// waiting for VM update to finish takes way to long
+	return nil
+}
+
+func (da *diskAttacher) WaitForDetach(ctx context.Context, diskID string) error {
 	for { // loop until disk is not attached, timeout or error
 		list, err := da.getDisks(ctx)
 		if err != nil {

builder/azure/chroot/step_create_new_disk.go

@@ -83,9 +83,12 @@ func (s StepCreateNewDisk) Run(ctx context.Context, state multistep.StateBag) mu
 func (s StepCreateNewDisk) Cleanup(state multistep.StateBag) {
 	azcli := state.Get("azureclient").(client.AzureClientSet)
 	ui := state.Get("ui").(packer.Ui)
-	diskResourceID := state.Get("os_disk_resource_id")
+	diskResourceID := state.Get("os_disk_resource_id").(string)
 
-	ui.Say(fmt.Sprintf("Deleting disk '%s'", diskResourceID))
+	ui.Say(fmt.Sprintf("Waiting for disk %q detach to complete", diskResourceID))
+	err := NewDiskAttacher(azcli).WaitForDetach(context.Background(), diskResourceID)
+
+	ui.Say(fmt.Sprintf("Deleting disk %q", diskResourceID))
 
 	f, err := azcli.DisksClient().Delete(context.TODO(), s.ResourceGroup, s.DiskName)
 	if err == nil {