rpc.Ui

packer/rpc/environment.go

+package rpc
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"net/rpc"
+)
+
+// A EnvironmentClient is an implementation of the packer.Environment interface
+// where the actual environment is executed over an RPC connection.
+type EnvironmentClient struct {
+	client *rpc.Client
+}
+
+// A EnvironmentServer wraps a packer.Environment and makes it exportable
+// as part of a Golang RPC server.
+type EnvironmentServer struct {
+	env packer.Environment
+}

packer/rpc/rpc_test.go

+package rpc
+
+import (
+	"net"
+	"net/rpc"
+)
+
+// This starts a RPC server for the given interface listening on the
+// given address. The RPC server is ready when "readyChan" receives a message
+// and the RPC server will quit when "stopChan" receives a message.
+//
+// This function should be run in a goroutine.
+func testRPCServer(laddr string, name string, iface interface{}, readyChan chan int, stopChan <-chan int) {
+	listener, err := net.Listen("tcp", laddr)
+	if err != nil {
+		panic(err)
+	}
+
+	// Close the listener when we exit so that the RPC server ends
+	defer listener.Close()
+
+	// Start the RPC server
+	server := rpc.NewServer()
+	server.RegisterName(name, iface)
+
+	go func() {
+		for {
+			conn, err := listener.Accept()
+			if err != nil {
+				// If there is an error, just ignore it.
+				break
+			}
+
+			go server.ServeConn(conn)
+		}
+	}()
+
+	// We're ready!
+	readyChan <- 1
+
+	// Block on waiting to receive from the channel
+	<-stopChan
+}

packer/rpc/ui.go

+package rpc
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"net/rpc"
+)
+
+// An implementation of packer.Ui where the Ui is actually executed
+// over an RPC connection.
+type Ui struct {
+	client *rpc.Client
+}
+
+// UiServer wraps a packer.Ui implementation and makes it exportable
+// as part of a Golang RPC server.
+type UiServer struct {
+	ui packer.Ui
+}
+
+type UiSayArgs struct {
+	Format string
+	Vars []interface{}
+}
+
+func (u *Ui) Say(format string, a ...interface{}) {
+	args := &UiSayArgs{format, a}
+	u.client.Call("Ui.Say", args, new(interface{}))
+}
+
+func (u *UiServer) Say(args *UiSayArgs, reply *interface{}) error {
+	u.ui.Say(args.Format, args.Vars...)
+
+	*reply = nil
+	return nil
+}

packer/rpc/ui_test.go

+package rpc
+
+import (
+	"cgl.tideland.biz/asserts"
+	"net/rpc"
+	"testing"
+)
+
+type testUi struct {
+	sayCalled bool
+	sayFormat string
+	sayVars []interface{}
+}
+
+func (u *testUi) Say(format string, a ...interface{}) {
+	u.sayCalled = true
+	u.sayFormat = format
+	u.sayVars = a
+}
+
+func TestUiRPC(t *testing.T) {
+	assert := asserts.NewTestingAsserts(t, true)
+
+	// Create the UI to test
+	ui := new(testUi)
+	uiServer := &UiServer{ui}
+
+	// Start the RPC server
+	readyChan := make(chan int)
+	stopChan := make(chan int)
+	defer func() { stopChan <- 1 }()
+	go testRPCServer(":1234", "Ui", uiServer, readyChan, stopChan)
+	<-readyChan
+
+	// Create the client over RPC and run some methods to verify it works
+	client, err := rpc.Dial("tcp", ":1234")
+	if err != nil {
+		panic(err)
+	}
+
+	uiClient := &Ui{client}
+	uiClient.Say("format", "arg0", 42)
+
+	assert.Equal(ui.sayFormat, "format", "format should be correct")
+}