From 31bdb4853c6d5aa69462c6e03f07da0635791ac5 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Wed, 27 May 2015 12:59:14 -0700
Subject: [PATCH] builder/null: interpolations

---
 builder/null/config.go | 38 +++++++++++---------------------------
 1 file changed, 11 insertions(+), 27 deletions(-)

diff --git a/builder/null/config.go b/builder/null/config.go
index 4823df8ae..7665aec51 100644
--- a/builder/null/config.go
+++ b/builder/null/config.go
@@ -3,7 +3,9 @@ package null
 import (
 	"fmt"
 	"github.com/mitchellh/packer/common"
+	"github.com/mitchellh/packer/helper/config"
 	"github.com/mitchellh/packer/packer"
+	"github.com/mitchellh/packer/template/interpolate"
 )
 
 type Config struct {
@@ -14,46 +16,28 @@ type Config struct {
 	SSHUsername       string `mapstructure:"ssh_username"`
 	SSHPassword       string `mapstructure:"ssh_password"`
 	SSHPrivateKeyFile string `mapstructure:"ssh_private_key_file"`
-
-	tpl *packer.ConfigTemplate
 }
 
 func NewConfig(raws ...interface{}) (*Config, []string, error) {
 	c := new(Config)
-	md, err := common.DecodeConfig(c, raws...)
-	if err != nil {
-		return nil, nil, err
-	}
 
-	c.tpl, err = packer.NewConfigTemplate()
+	err := config.Decode(&c, &config.DecodeOpts{
+		Interpolate: true,
+		InterpolateFilter: &interpolate.RenderFilter{
+			Exclude: []string{
+				"run_command",
+			},
+		},
+	}, raws...)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	c.tpl.UserVars = c.PackerUserVars
-
 	if c.Port == 0 {
 		c.Port = 22
 	}
 
-	errs := common.CheckUnusedConfig(md)
-
-	templates := map[string]*string{
-		"host":                 &c.Host,
-		"ssh_username":         &c.SSHUsername,
-		"ssh_password":         &c.SSHPassword,
-		"ssh_private_key_file": &c.SSHPrivateKeyFile,
-	}
-
-	for n, ptr := range templates {
-		var err error
-		*ptr, err = c.tpl.Process(*ptr, nil)
-		if err != nil {
-			errs = packer.MultiErrorAppend(
-				errs, fmt.Errorf("Error processing %s: %s", n, err))
-		}
-	}
-
+	var errs *packer.MultiError
 	if c.Host == "" {
 		errs = packer.MultiErrorAppend(errs,
 			fmt.Errorf("host must be specified"))