From 21b6d2a43525362e0344cce3ea3f5393feddd9da Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Fri, 14 Jun 2013 15:47:06 -0700
Subject: [PATCH] builder/common: multistep debug fn gracefully exits during an
 interrupt

---
 builder/common/multistep_debug.go | 20 +++++++++++++++++---
 builder/vmware/builder.go         |  2 +-
 packer/rpc/ui_test.go             |  4 ++--
 packer/ui.go                      |  2 +-
 4 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/builder/common/multistep_debug.go b/builder/common/multistep_debug.go
index 3b3a10af2..f0ac31029 100644
--- a/builder/common/multistep_debug.go
+++ b/builder/common/multistep_debug.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
+	"time"
 )
 
 // MultistepDebugFn will return a proper multistep.DebugPauseFn to
@@ -21,10 +22,23 @@ func MultistepDebugFn(ui packer.Ui) multistep.DebugPauseFn {
 		}
 
 		message := fmt.Sprintf(
-			"Pausing %s step '%s'. Press any key to continue.\n",
+			"Pausing %s step '%s'. Press any key to continue.",
 			locationString, name)
 
-		ui.Say(message)
-		ui.Ask("")
+		result := make(chan string, 1)
+		go func() {
+			result <- ui.Ask(message)
+		}()
+
+		for {
+			select {
+			case <-result:
+				return
+			case <-time.After(100 * time.Millisecond):
+				if _, ok := state[multistep.StateCancelled]; ok {
+					return
+				}
+			}
+		}
 	}
 }
diff --git a/builder/vmware/builder.go b/builder/vmware/builder.go
index 2503b6786..41f6365c4 100644
--- a/builder/vmware/builder.go
+++ b/builder/vmware/builder.go
@@ -219,7 +219,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	// Run!
 	if b.config.PackerDebug {
 		b.runner = &multistep.DebugRunner{
-			Steps: steps,
+			Steps:   steps,
 			PauseFn: common.MultistepDebugFn(ui),
 		}
 	} else {
diff --git a/packer/rpc/ui_test.go b/packer/rpc/ui_test.go
index 384b959f2..f267bf512 100644
--- a/packer/rpc/ui_test.go
+++ b/packer/rpc/ui_test.go
@@ -7,8 +7,8 @@ import (
 )
 
 type testUi struct {
-	askCalled bool
-	askQuery string
+	askCalled      bool
+	askQuery       string
 	errorCalled    bool
 	errorMessage   string
 	messageCalled  bool
diff --git a/packer/ui.go b/packer/ui.go
index c702b09f5..c191df9b7 100644
--- a/packer/ui.go
+++ b/packer/ui.go
@@ -110,7 +110,7 @@ func (rw *ReaderWriterUi) Ask(query string) string {
 
 	var line string
 	if _, err := fmt.Fscanln(rw.Reader, &line); err != nil {
-		panic(err)
+		log.Printf("ui: scan err: %s", err)
 	}
 
 	return line