packer/rpc: Get RPC compliant with Environment again

packer/rpc/environment.go

@@ -73,6 +73,22 @@ func (e *Environment) Hook(name string) (h packer.Hook, err error) {
 	return
 }
 
+func (e *Environment) PostProcessor(name string) (p packer.PostProcessor, err error) {
+	var reply string
+	err = e.client.Call("Environment.PostProcessor", name, &reply)
+	if err != nil {
+		return
+	}
+
+	_, err = rpc.Dial("tcp", reply)
+	if err != nil {
+		return
+	}
+
+	p = nil
+	return
+}
+
 func (e *Environment) Provisioner(name string) (p packer.Provisioner, err error) {
 	var reply string
 	err = e.client.Call("Environment.Provisioner", name, &reply)
@@ -143,6 +159,18 @@ func (e *EnvironmentServer) Hook(name *string, reply *string) error {
 	return nil
 }
 
+func (e *EnvironmentServer) PostProcessor(name *string, reply *string) error {
+	_, err := e.env.PostProcessor(*name)
+	if err != nil {
+		return err
+	}
+
+	server := rpc.NewServer()
+
+	*reply = serveSingleConn(server)
+	return nil
+}
+
 func (e *EnvironmentServer) Provisioner(name *string, reply *string) error {
 	prov, err := e.env.Provisioner(*name)
 	if err != nil {

packer/rpc/environment_test.go

@@ -18,6 +18,8 @@ type testEnvironment struct {
 	cliArgs       []string
 	hookCalled    bool
 	hookName      string
+	ppCalled      bool
+	ppName        string
 	provCalled    bool
 	provName      string
 	uiCalled      bool
@@ -45,6 +47,12 @@ func (e *testEnvironment) Hook(name string) (packer.Hook, error) {
 	return nil, nil
 }
 
+func (e *testEnvironment) PostProcessor(name string) (packer.PostProcessor, error) {
+	e.ppCalled = true
+	e.ppName = name
+	return nil, nil
+}
+
 func (e *testEnvironment) Provisioner(name string) (packer.Provisioner, error) {
 	e.provCalled = true
 	e.provName = name