command/build,validate: pass user vars to Prepare

command/build/command.go

@@ -46,6 +46,14 @@ func (c Command) Run(env packer.Environment, args []string) int {
 		return 1
 	}
 
+	userVars, err := buildOptions.AllUserVars()
+	if err != nil {
+		env.Ui().Error(fmt.Sprintf("Error compiling user variables: %s", err))
+		env.Ui().Error("")
+		env.Ui().Error(c.Help())
+		return 1
+	}
+
 	// Read the file into a byte array so that we can parse the template
 	log.Printf("Reading template: %s", args[0])
 	tpl, err := packer.ParseTemplateFile(args[0])
@@ -104,7 +112,7 @@ func (c Command) Run(env packer.Environment, args []string) int {
 		log.Printf("Preparing build: %s", b.Name())
 		b.SetDebug(cfgDebug)
 		b.SetForce(cfgForce)
-		err := b.Prepare(nil)
+		err := b.Prepare(userVars)
 		if err != nil {
 			env.Ui().Error(err.Error())
 			return 1

command/build/help.go

@@ -12,4 +12,5 @@ Options:
   -force                     Force a build to continue if artifacts exist, deletes existing artifacts
   -except=foo,bar,baz        Build all builds other than these
   -only=foo,bar,baz          Only build the given builds by name
+  -var 'key=value'           Variable for templates, can be used multiple times.
 `

command/validate/command.go

@@ -40,6 +40,14 @@ func (c Command) Run(env packer.Environment, args []string) int {
 		return 1
 	}
 
+	userVars, err := buildOptions.AllUserVars()
+	if err != nil {
+		env.Ui().Error(fmt.Sprintf("Error compiling user variables: %s", err))
+		env.Ui().Error("")
+		env.Ui().Error(c.Help())
+		return 1
+	}
+
 	// Parse the template into a machine-usable format
 	log.Printf("Reading template: %s", args[0])
 	tpl, err := packer.ParseTemplateFile(args[0])
@@ -73,7 +81,7 @@ func (c Command) Run(env packer.Environment, args []string) int {
 	// Check the configuration of all builds
 	for _, b := range builds {
 		log.Printf("Preparing build: %s", b.Name())
-		err := b.Prepare(nil)
+		err := b.Prepare(userVars)
 		if err != nil {
 			errs = append(errs, fmt.Errorf("Errors validating build '%s'. %s", b.Name(), err))
 		}

command/validate/help.go

@@ -15,4 +15,5 @@ Options:
   -syntax-only           Only check syntax. Do not verify config of the template.
   -except=foo,bar,baz    Validate all builds other than these
   -only=foo,bar,baz      Validate only these builds
+  -var 'key=value'           Variable for templates, can be used multiple times.
 `

common/command/template.go

@@ -24,6 +24,19 @@ func (f *BuildOptions) Validate() error {
 	return nil
 }
 
+// AllUserVars returns the user variables, compiled from both the
+// file paths and the vars on the command line.
+func (f *BuildOptions) AllUserVars() (map[string]string, error) {
+	all := make(map[string]string)
+
+	// Copy in the command-line vars
+	for k, v := range f.UserVars {
+		all[k] = v
+	}
+
+	return all, nil
+}
+
 // Builds returns the builds out of the given template that pass the
 // configured options.
 func (f *BuildOptions) Builds(t *packer.Template, cf *packer.ComponentFinder) ([]packer.Build, error) {