builder/virtualbox,vmware: warning if shutdown_command is not specified

builder/virtualbox/builder.go

@@ -84,8 +84,9 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 	}
 	b.config.tpl.UserVars = b.config.PackerUserVars
 
-	// Accumulate any errors
+	// Accumulate any errors and warnings
 	errs := common.CheckUnusedConfig(md)
+	warnings := make([]string, 0)
 
 	if b.config.DiskSize == 0 {
 		b.config.DiskSize = 40000
@@ -363,11 +364,18 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		}
 	}
 
+	// Warnings
+	if b.config.ShutdownCommand == "" {
+		warnings = append(warnings,
+			"A shutdown_command was not specified. Without a shutdown command, Packer\n"+
+				"will forcibly halt the virtual machine, which may result in data loss.")
+	}
+
 	if errs != nil && len(errs.Errors) > 0 {
-		return nil, errs
+		return warnings, errs
 	}
 
-	return nil, nil
+	return warnings, nil
 }
 
 func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packer.Artifact, error) {

builder/virtualbox/builder_test.go

@@ -43,6 +43,7 @@ func testConfig() map[string]interface{} {
 		"iso_checksum":      "foo",
 		"iso_checksum_type": "md5",
 		"iso_url":           "http://www.google.com/",
+		"shutdown_command":  "yes",
 		"ssh_username":      "foo",
 
 		packer.BuildNameConfigKey: "foo",
@@ -645,6 +646,21 @@ func TestBuilderPrepare_OutputDir(t *testing.T) {
 	}
 }
 
+func TestBuilderPrepare_ShutdownCommand(t *testing.T) {
+	var b Builder
+	config := testConfig()
+	delete(config, "shutdown_command")
+
+	warns, err := b.Prepare(config)
+	if err != nil {
+		t.Fatalf("bad: %s", err)
+	}
+
+	if len(warns) != 1 {
+		t.Fatalf("bad: %#v", warns)
+	}
+}
+
 func TestBuilderPrepare_ShutdownTimeout(t *testing.T) {
 	var b Builder
 	config := testConfig()

builder/vmware/builder.go

@@ -80,6 +80,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 
 	// Accumulate any errors
 	errs := common.CheckUnusedConfig(md)
+	warnings := make([]string, 0)
 
 	if b.config.DiskName == "" {
 		b.config.DiskName = "disk"
@@ -326,11 +327,18 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 			errs, fmt.Errorf("vnc_port_min must be less than vnc_port_max"))
 	}
 
+	// Warnings
+	if b.config.ShutdownCommand == "" {
+		warnings = append(warnings,
+			"A shutdown_command was not specified. Without a shutdown command, Packer\n"+
+				"will forcibly halt the virtual machine, which may result in data loss.")
+	}
+
 	if errs != nil && len(errs.Errors) > 0 {
-		return nil, errs
+		return warnings, errs
 	}
 
-	return nil, nil
+	return warnings, nil
 }
 
 func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packer.Artifact, error) {

builder/vmware/builder_test.go

@@ -44,6 +44,7 @@ func testConfig() map[string]interface{} {
 		"iso_checksum":      "foo",
 		"iso_checksum_type": "md5",
 		"iso_url":           "http://www.packer.io",
+		"shutdown_command":  "foo",
 		"ssh_username":      "foo",
 
 		packer.BuildNameConfigKey: "foo",
@@ -418,6 +419,21 @@ func TestBuilderPrepare_OutputDir(t *testing.T) {
 	}
 }
 
+func TestBuilderPrepare_ShutdownCommand(t *testing.T) {
+	var b Builder
+	config := testConfig()
+	delete(config, "shutdown_command")
+
+	warns, err := b.Prepare(config)
+	if err != nil {
+		t.Fatalf("bad: %s", err)
+	}
+
+	if len(warns) != 1 {
+		t.Fatalf("bad: %#v", warns)
+	}
+}
+
 func TestBuilderPrepare_ShutdownTimeout(t *testing.T) {
 	var b Builder
 	config := testConfig()