packer: Return artifact from build

packer/build.go

@@ -7,7 +7,7 @@ import "log"
 type Build interface {
 	Name() string
 	Prepare() error
-	Run(Ui)
+	Run(Ui) Artifact
 }
 
 // A build struct represents a single build job, the result of which should
@@ -41,11 +41,11 @@ func (b *coreBuild) Prepare() (err error) {
 }
 
 // Runs the actual build. Prepare must be called prior to running this.
-func (b *coreBuild) Run(ui Ui) {
+func (b *coreBuild) Run(ui Ui) Artifact {
 	if !b.prepareCalled {
 		panic("Prepare must be called first")
 	}
 
 	hook := &DispatchHook{b.hooks}
-	b.builder.Run(ui, hook)
+	return b.builder.Run(ui, hook)
 }

packer/rpc/build.go

@@ -7,7 +7,7 @@ import (
 
 // An implementation of packer.Build where the build is actually executed
 // over an RPC connection.
-type Build struct {
+type build struct {
 	client *rpc.Client
 }
 
@@ -23,23 +23,38 @@ type BuildRunArgs struct {
 	UiRPCAddress string
 }
 
-func (b *Build) Name() (result string) {
+func Build(client *rpc.Client) *build {
+	return &build{client}
+}
+
+func (b *build) Name() (result string) {
 	b.client.Call("Build.Name", new(interface{}), &result)
 	return
 }
 
-func (b *Build) Prepare() (err error) {
+func (b *build) Prepare() (err error) {
 	b.client.Call("Build.Prepare", new(interface{}), &err)
 	return
 }
 
-func (b *Build) Run(ui packer.Ui) {
+func (b *build) Run(ui packer.Ui) packer.Artifact {
 	// Create and start the server for the UI
 	// TODO: Error handling
 	server := rpc.NewServer()
 	RegisterUi(server, ui)
 	args := &BuildRunArgs{serveSingleConn(server)}
-	b.client.Call("Build.Run", args, new(interface{}))
+
+	var reply string
+	if err := b.client.Call("Build.Run", args, &reply); err != nil {
+		panic(err)
+	}
+
+	client, err := rpc.Dial("tcp", reply)
+	if err != nil {
+		panic(err)
+	}
+
+	return Artifact(client)
 }
 
 func (b *BuildServer) Name(args *interface{}, reply *string) error {
@@ -52,14 +67,18 @@ func (b *BuildServer) Prepare(args *BuildPrepareArgs, reply *error) error {
 	return nil
 }
 
-func (b *BuildServer) Run(args *BuildRunArgs, reply *interface{}) error {
+func (b *BuildServer) Run(args *BuildRunArgs, reply *string) error {
 	client, err := rpc.Dial("tcp", args.UiRPCAddress)
 	if err != nil {
 		return err
 	}
 
-	b.build.Run(&Ui{client})
+	artifact := b.build.Run(&Ui{client})
 
-	*reply = nil
+	// Wrap the artifact
+	server := rpc.NewServer()
+	RegisterArtifact(server, artifact)
+
+	*reply = serveSingleConn(server)
 	return nil
 }

packer/rpc/build_test.go

@@ -7,6 +7,8 @@ import (
 	"testing"
 )
 
+var testBuildArtifact = &testArtifact{}
+
 type testBuild struct {
 	nameCalled    bool
 	prepareCalled bool
@@ -24,32 +26,27 @@ func (b *testBuild) Prepare() error {
 	return nil
 }
 
-func (b *testBuild) Run(ui packer.Ui) {
+func (b *testBuild) Run(ui packer.Ui) packer.Artifact {
 	b.runCalled = true
 	b.runUi = ui
+	return testBuildArtifact
 }
 
 func TestBuildRPC(t *testing.T) {
 	assert := asserts.NewTestingAsserts(t, true)
 
-	// Create the UI to test
+	// Create the interface to test
 	b := new(testBuild)
-	bServer := &BuildServer{b}
 
-	// Start the RPC server
-	readyChan := make(chan int)
-	stopChan := make(chan int)
-	defer func() { stopChan <- 1 }()
-	go testRPCServer(":1234", "Build", bServer, readyChan, stopChan)
-	<-readyChan
+	// Start the server
+	server := rpc.NewServer()
+	RegisterBuild(server, b)
+	address := serveSingleConn(server)
 
 	// Create the client over RPC and run some methods to verify it works
-	client, err := rpc.Dial("tcp", ":1234")
-	if err != nil {
-		panic(err)
-	}
-
-	bClient := &Build{client}
+	client, err := rpc.Dial("tcp", address)
+	assert.Nil(err, "should be able to connect")
+	bClient := Build(client)
 
 	// Test Name
 	bClient.Name()
@@ -76,7 +73,7 @@ func TestBuild_ImplementsBuild(t *testing.T) {
 	assert := asserts.NewTestingAsserts(t, true)
 
 	var realBuild packer.Build
-	b := &Build{nil}
+	b := Build(nil)
 
 	assert.Implementor(b, &realBuild, "should be a Build")
 }