Fixing some error handling issues

driver/driver.go

@@ -51,8 +51,9 @@ var (
 	// All registred machines
 	machines map[string]InitFunc
 
-	ErrNotSupported    = errors.New("machine not supported")
+	ErrNotSupported    = errors.New("driver not supported")
 	ErrMachineNotExist = errors.New("machine not exist")
+	ErrMachineExist    = errors.New("machine already exists")
 	ErrPrerequisites   = errors.New("prerequisites for machine not satisfied (hypervisor installed?)")
 )
 

virtualbox/machine.go

@@ -330,7 +330,7 @@ func GetMachine(id string) (*Machine, error) {
 	stdout, stderr, err := vbmOutErr("showvminfo", id, "--machinereadable")
 	if err != nil {
 		if reMachineNotFound.FindString(stderr) != "" {
-			return nil, ErrMachineNotExist
+			return nil, driver.ErrMachineNotExist
 		}
 		return nil, err
 	}
@@ -443,7 +443,7 @@ func CreateMachine(mc *driver.MachineConfig) (*Machine, error) {
 	}
 	for _, m := range machineNames {
 		if m == mc.VM {
-			return nil, ErrMachineExist
+			return nil, driver.ErrMachineExist
 		}
 	}
 

virtualbox/vbm.go

@@ -25,9 +25,7 @@ var (
 )
 
 var (
-	ErrMachineExist    = errors.New("machine already exists")
-	ErrMachineNotExist = errors.New("machine does not exist")
-	ErrVBMNotFound     = errors.New("VBoxManage not found")
+	ErrVBMNotFound = errors.New("VBoxManage not found")
 )
 
 func vbm(args ...string) error {