builder/virtualbox: retry removing floppy controller

builder/virtualbox/common/step_remove_devices.go

@@ -2,7 +2,10 @@ package common
 
 import (
 	"fmt"
+	"log"
+
 	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/common"
 	"github.com/mitchellh/packer/packer"
 )
 
@@ -39,14 +42,25 @@ func (s *StepRemoveDevices) Run(state multistep.StateBag) multistep.StepAction {
 			return multistep.ActionHalt
 		}
 
-		// Don't forget to remove the floppy controller as well
-		command = []string{
-			"storagectl", vmName,
-			"--name", "Floppy Controller",
-			"--remove",
-		}
-		if err := driver.VBoxManage(command...); err != nil {
-			err := fmt.Errorf("Error removing floppy controller: %s", err)
+		var vboxErr error
+		// Retry for 10 minutes to remove the floppy controller.
+		log.Printf("Trying for 10 minutes to remove floppy controller.")
+		err := common.Retry(15, 15, 40, func() (bool, error) {
+			// Don't forget to remove the floppy controller as well
+			command = []string{
+				"storagectl", vmName,
+				"--name", "Floppy Controller",
+				"--remove",
+			}
+			vboxErr = driver.VBoxManage(command...)
+			if vboxErr != nil {
+				log.Printf("Error removing floppy controller. Retrying")
+				return false, nil
+			}
+			return true, nil
+		})
+		if err == common.RetryExhaustedError {
+			err := fmt.Errorf("Error removing floppy controller: %s", vboxErr)
 			state.Put("error", err)
 			ui.Error(err.Error())
 			return multistep.ActionHalt

common/retry.go

@@ -8,13 +8,15 @@ import (
 
 var RetryExhaustedError error = fmt.Errorf("Function never succeeded in Retry")
 
+type RetryableFunc func() (bool, error)
+
 // Retry retries a function up to numTries times with exponential backoff.
 // If numTries == 0, retry indefinitely. If interval == 0, Retry will not delay retrying and there will be
 // no exponential backoff. If maxInterval == 0, maxInterval is set to +Infinity.
 // Intervals are in seconds.
 // Returns an error if initial > max intervals, if retries are exhausted, or if the passed function returns
 // an error.
-func Retry(initialInterval float64, maxInterval float64, numTries uint, function func() (bool, error)) error {
+func Retry(initialInterval float64, maxInterval float64, numTries uint, function RetryableFunc) error {
 	if maxInterval == 0 {
 		maxInterval = math.Inf(1)
 	} else if initialInterval < 0 || initialInterval > maxInterval {