packer: Template takes a component finder

command/build/command.go

@@ -31,12 +31,18 @@ func (Command) Run(env packer.Environment, args []string) int {
 		return 1
 	}
 
+	// The component finder for our builds
+	components := &packer.ComponentFinder{
+		Builder: env.Builder,
+		Hook: env.Hook,
+	}
+
 	// Go through each builder and compile the builds that we care about
 	buildNames := tpl.BuildNames()
 	builds := make([]packer.Build, 0, len(buildNames))
 	for _, buildName := range buildNames {
 		log.Printf("Creating build: %s\n", buildName)
-		build, err := tpl.Build(buildName, env.Builder)
+		build, err := tpl.Build(buildName, components)
 		if err != nil {
 			env.Ui().Error("Failed to create build '%s': \n\n%s\n", buildName, err.Error())
 			return 1

packer/template.go

@@ -96,14 +96,14 @@ func (t *Template) BuildNames() []string {
 //
 // If the build does not exist as part of this template, an error is
 // returned.
-func (t *Template) Build(name string, bf BuilderFunc) (b Build, err error) {
+func (t *Template) Build(name string, components *ComponentFinder) (b Build, err error) {
 	builderConfig, ok := t.Builders[name]
 	if !ok {
 		err = fmt.Errorf("No such build found in template: %s", name)
 		return
 	}
 
-	builder, err := bf(builderConfig.builderName)
+	builder, err := components.Builder(builderConfig.builderName)
 	if err != nil {
 		return
 	}

packer/template_test.go

@@ -181,7 +181,8 @@ func TestTemplate_BuildUnknownBuilder(t *testing.T) {
 	assert.Nil(err, "should not error")
 
 	builderFactory := func(string) (Builder, error) { return nil, nil }
-	build, err := template.Build("test1", builderFactory)
+	components := &ComponentFinder{Builder: builderFactory}
+	build, err := template.Build("test1", components)
 	assert.Nil(build, "build should be nil")
 	assert.NotNil(err, "should have error")
 }
@@ -215,10 +216,11 @@ func TestTemplate_Build(t *testing.T) {
 	}
 
 	builderFactory := func(n string) (Builder, error) { return builderMap[n], nil }
+	components := &ComponentFinder{Builder: builderFactory}
 
 	// Get the build, verifying we can get it without issue, but also
 	// that the proper builder was looked up and used for the build.
-	build, err := template.Build("test1", builderFactory)
+	build, err := template.Build("test1", components)
 	assert.Nil(err, "should not error")
 
 	build.Prepare()