From 95d6795ec8de3718964275311b5ff1274adc1e46 Mon Sep 17 00:00:00 2001
From: Dongyu Zheng <garydzheng@gmail.com>
Date: Fri, 28 Oct 2016 10:51:05 -0700
Subject: [PATCH] Allow clone_template to use uuid://

---
 builder/xenserver/iso/step_create_instance.go | 36 +++++++++++++------
 docs/builders/xenserver-iso.html.markdown     |  3 +-
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/builder/xenserver/iso/step_create_instance.go b/builder/xenserver/iso/step_create_instance.go
index a973af45..5bda5bd0 100644
--- a/builder/xenserver/iso/step_create_instance.go
+++ b/builder/xenserver/iso/step_create_instance.go
@@ -22,19 +22,35 @@ func (self *stepCreateInstance) Run(state multistep.StateBag) multistep.StepActi
 	ui.Say("Step: Create Instance")
 
 	// Get the template to clone from
+	var template *xsclient.VM
+	var err error
 
-	vms, err := client.GetVMByNameLabel(config.CloneTemplate)
+	if len(config.CloneTemplate) >= 7 && config.CloneTemplate[:7] == "uuid://" {
+		templateUuid := config.CloneTemplate[7:]
 
-	switch {
-	case len(vms) == 0:
-		ui.Error(fmt.Sprintf("Couldn't find a template with the name-label '%s'. Aborting.", config.CloneTemplate))
-		return multistep.ActionHalt
-	case len(vms) > 1:
-		ui.Error(fmt.Sprintf("Found more than one template with the name '%s'. The name must be unique. Aborting.", config.CloneTemplate))
-		return multistep.ActionHalt
-	}
+		template, err = client.GetVMByUuid(templateUuid)
+		if err != nil {
+			ui.Error(fmt.Sprintf("Could not get template with UUID '%s': %s", templateUuid, err.Error()))
+			return multistep.ActionHalt
+		}
+	} else {
+		templates, err := client.GetVMByNameLabel(config.CloneTemplate)
+		if err != nil {
+			ui.Error(fmt.Sprintf("Error getting template: %s", err.Error()))
+			return multistep.ActionHalt
+		}
 
-	template := vms[0]
+		switch {
+		case len(templates) == 0:
+			ui.Error(fmt.Sprintf("Couldn't find a template with the name-label '%s'.", config.CloneTemplate))
+			return multistep.ActionHalt
+		case len(templates) > 1:
+			ui.Error(fmt.Sprintf("Found more than one template with the name '%s'. The name must be unique. Aborting.", config.CloneTemplate))
+			return multistep.ActionHalt
+		}
+
+		template = templates[0]
+	}
 
 	// Clone that VM template
 	instance, err := template.Clone(config.VMName)
diff --git a/docs/builders/xenserver-iso.html.markdown b/docs/builders/xenserver-iso.html.markdown
index bc7c00e3..75818c98 100644
--- a/docs/builders/xenserver-iso.html.markdown
+++ b/docs/builders/xenserver-iso.html.markdown
@@ -98,7 +98,8 @@ each category, the available options are alphabetized and described.
   media", this is "other", but you can get _dramatic_ performance improvements
   by setting this to the proper value. To view all available values for this
   run `xe template-list`. Setting the correct value hints to XenServer how to
-  optimize the virtual hardware to work best with that operating system.
+  optimize the virtual hardware to work best with that operating system. Setting
+  this to a template's UUID is also acceptable: "uuid://c6a9dee0-0069-24a5-d45d-4a4101a9d7f4".
 
 * `disk_size` (integer) - The size, in megabytes, of the hard disk to create
   for the VM. By default, this is 40000 (about 40 GB).