packer: Environment has Cache method, RPC implements

packer/environment.go

@@ -39,6 +39,7 @@ type ComponentFinder struct {
 // list of available builders, and more.
 type Environment interface {
 	Builder(string) (Builder, error)
+	Cache() Cache
 	Cli([]string) (int, error)
 	Hook(string) (Hook, error)
 	Provisioner(string) (Provisioner, error)
@@ -48,6 +49,7 @@ type Environment interface {
 // An implementation of an Environment that represents the Packer core
 // environment.
 type coreEnvironment struct {
+	cache      Cache
 	commands   []string
 	components ComponentFinder
 	ui         Ui
@@ -55,6 +57,7 @@ type coreEnvironment struct {
 
 // This struct configures new environments.
 type EnvironmentConfig struct {
+	Cache      Cache
 	Commands   []string
 	Components ComponentFinder
 	Ui         Ui
@@ -77,6 +80,7 @@ func NewEnvironment(config *EnvironmentConfig) (resultEnv Environment, err error
 	}
 
 	env := &coreEnvironment{}
+	env.cache = config.Cache
 	env.commands = config.Commands
 	env.components = config.Components
 	env.ui = config.Ui
@@ -119,6 +123,11 @@ func (e *coreEnvironment) Builder(name string) (b Builder, err error) {
 	return
 }
 
+// Returns the cache for this environment
+func (e *coreEnvironment) Cache() Cache {
+	return e.cache
+}
+
 // Returns a hook of the given name that is registered with this
 // environment.
 func (e *coreEnvironment) Hook(name string) (h Hook, err error) {

packer/rpc/environment.go

@@ -37,6 +37,20 @@ func (e *Environment) Builder(name string) (b packer.Builder, err error) {
 	return
 }
 
+func (e *Environment) Cache() packer.Cache {
+	var reply string
+	if err := e.client.Call("Environment.Cache", new(interface{}), &reply); err != nil{
+		panic(err)
+	}
+
+	client, err := rpc.Dial("tcp", reply)
+	if err != nil {
+		panic(err)
+	}
+
+	return Cache(client)
+}
+
 func (e *Environment) Cli(args []string) (result int, err error) {
 	rpcArgs := &EnvironmentCliArgs{args}
 	err = e.client.Call("Environment.Cli", rpcArgs, &result)
@@ -98,6 +112,15 @@ func (e *EnvironmentServer) Builder(name *string, reply *string) error {
 	return nil
 }
 
+func (e *EnvironmentServer) Cache(args *interface{}, reply *string) error {
+	cache := e.env.Cache()
+
+	server := rpc.NewServer()
+	RegisterCache(server, cache)
+	*reply = serveSingleConn(server)
+	return nil
+}
+
 func (e *EnvironmentServer) Cli(args *EnvironmentCliArgs, reply *int) (err error) {
 	*reply, err = e.env.Cli(args.Args)
 	return

packer/rpc/environment_test.go

@@ -8,6 +8,7 @@ import (
 )
 
 var testEnvBuilder = &testBuilder{}
+var testEnvCache = &testCache{}
 var testEnvUi = &testUi{}
 
 type testEnvironment struct {
@@ -28,6 +29,10 @@ func (e *testEnvironment) Builder(name string) (packer.Builder, error) {
 	return testEnvBuilder, nil
 }
 
+func (e *testEnvironment) Cache() packer.Cache {
+	return testEnvCache
+}
+
 func (e *testEnvironment) Cli(args []string) (int, error) {
 	e.cliCalled = true
 	e.cliArgs = args
@@ -75,6 +80,11 @@ func TestEnvironmentRPC(t *testing.T) {
 	builder.Prepare(nil)
 	assert.True(testEnvBuilder.prepareCalled, "Prepare should be called")
 
+	// Test Cache
+	cache := eClient.Cache()
+	cache.Lock("foo")
+	assert.True(testEnvCache.lockCalled, "lock should be called")
+
 	// Test Cli
 	cliArgs := []string{"foo", "bar"}
 	result, _ := eClient.Cli(cliArgs)