builder/amazon/chroot: switch func type to interface

Was getting weird behavior... see
https://groups.google.com/d/msg/golang-nuts/a1kymwSVt2M/FwcCuBl1_48

builder/amazon/chroot/builder.go

@@ -18,10 +18,6 @@ import (
 // The unique ID for this builder
 const BuilderId = "mitchellh.amazon.chroot"
 
-// CleanupFunc is a type that is strung throughout the state bag in
-// order to perform cleanup at earlier points.
-type CleanupFunc func(map[string]interface{}) error
-
 // Config is the configuration that is chained through the steps and
 // settable from the template.
 type Config struct {

builder/amazon/chroot/cleanup.go

@@ -0,0 +1,6 @@
+package chroot
+
+// Cleanup is an interface that some steps implement for early cleanup.
+type Cleanup interface {
+	CleanupFunc(map[string]interface{}) error
+}

builder/amazon/chroot/step_attach_volume.go

@@ -71,7 +71,7 @@ func (s *StepAttachVolume) Run(state map[string]interface{}) multistep.StepActio
 	}
 
 	state["device"] = config.AttachedDevicePath
-	state["attach_cleanup"] = s.CleanupFunc
+	state["attach_cleanup"] = s
 	return multistep.ActionContinue
 }
 

builder/amazon/chroot/step_attach_volume_test.go

@@ -0,0 +1,11 @@
+package chroot
+
+import "testing"
+
+func TestAttachVolumeCleanupFunc_ImplementsCleanupFunc(t *testing.T) {
+	var raw interface{}
+	raw = new(StepAttachVolume)
+	if _, ok := raw.(Cleanup); !ok {
+		t.Fatalf("cleanup func should be a CleanupFunc")
+	}
+}

builder/amazon/chroot/step_copy_files.go

@@ -43,7 +43,7 @@ func (s *StepCopyFiles) Run(state map[string]interface{}) multistep.StepAction {
 		}
 	}
 
-	state["copy_files_cleanup"] = s.CleanupFunc
+	state["copy_files_cleanup"] = s
 	return multistep.ActionContinue
 }
 

builder/amazon/chroot/step_copy_files_test.go

@@ -0,0 +1,11 @@
+package chroot
+
+import "testing"
+
+func TestCopyFilesCleanupFunc_ImplementsCleanupFunc(t *testing.T) {
+	var raw interface{}
+	raw = new(StepCopyFiles)
+	if _, ok := raw.(Cleanup); !ok {
+		t.Fatalf("cleanup func should be a CleanupFunc")
+	}
+}

builder/amazon/chroot/step_early_cleanup.go

@@ -21,9 +21,9 @@ func (s *StepEarlyCleanup) Run(state map[string]interface{}) multistep.StepActio
 	}
 
 	for _, key := range cleanupKeys {
-		f := state[key].(CleanupFunc)
+		c := state[key].(Cleanup)
 		log.Printf("Running cleanup func: %s", key)
-		if err := f(state); err != nil {
+		if err := c.CleanupFunc(state); err != nil {
 			err := fmt.Errorf("Error cleaning up: %s", err)
 			state["error"] = err
 			ui.Error(err.Error())

builder/amazon/chroot/step_mount_device.go

@@ -62,7 +62,7 @@ func (s *StepMountDevice) Run(state map[string]interface{}) multistep.StepAction
 	// Set the mount path so we remember to unmount it later
 	s.mountPath = mountPath
 	state["mount_path"] = s.mountPath
-	state["mount_device_cleanup"] = s.CleanupFunc
+	state["mount_device_cleanup"] = s
 
 	return multistep.ActionContinue
 }

builder/amazon/chroot/step_mount_device_test.go

@@ -0,0 +1,11 @@
+package chroot
+
+import "testing"
+
+func TestMountDeviceCleanupFunc_ImplementsCleanupFunc(t *testing.T) {
+	var raw interface{}
+	raw = new(StepMountDevice)
+	if _, ok := raw.(Cleanup); !ok {
+		t.Fatalf("cleanup func should be a CleanupFunc")
+	}
+}

builder/amazon/chroot/step_mount_extra.go

@@ -61,7 +61,7 @@ func (s *StepMountExtra) Run(state map[string]interface{}) multistep.StepAction
 		s.mounts = append(s.mounts, innerPath)
 	}
 
-	state["mount_extra_cleanup"] = s.CleanupFunc
+	state["mount_extra_cleanup"] = s
 	return multistep.ActionContinue
 }
 

builder/amazon/chroot/step_mount_extra_test.go

@@ -0,0 +1,11 @@
+package chroot
+
+import "testing"
+
+func TestMountExtraCleanupFunc_ImplementsCleanupFunc(t *testing.T) {
+	var raw interface{}
+	raw = new(StepMountExtra)
+	if _, ok := raw.(Cleanup); !ok {
+		t.Fatalf("cleanup func should be a CleanupFunc")
+	}
+}