packer/plugin: use new RPC API

packer/plugin/client.go

@@ -10,7 +10,6 @@ import (
 	"io/ioutil"
 	"log"
 	"net"
-	"net/rpc"
 	"os"
 	"os/exec"
 	"strings"
@@ -130,56 +129,56 @@ func (c *Client) Exited() bool {
 // Returns a builder implementation that is communicating over this
 // client. If the client hasn't been started, this will start it.
 func (c *Client) Builder() (packer.Builder, error) {
-	client, err := c.rpcClient()
+	client, err := c.packrpcClient()
 	if err != nil {
 		return nil, err
 	}
 
-	return &cmdBuilder{packrpc.Builder(client), c}, nil
+	return &cmdBuilder{client.Builder(), c}, nil
 }
 
 // Returns a command implementation that is communicating over this
 // client. If the client hasn't been started, this will start it.
 func (c *Client) Command() (packer.Command, error) {
-	client, err := c.rpcClient()
+	client, err := c.packrpcClient()
 	if err != nil {
 		return nil, err
 	}
 
-	return &cmdCommand{packrpc.Command(client), c}, nil
+	return &cmdCommand{client.Command(), c}, nil
 }
 
 // Returns a hook implementation that is communicating over this
 // client. If the client hasn't been started, this will start it.
 func (c *Client) Hook() (packer.Hook, error) {
-	client, err := c.rpcClient()
+	client, err := c.packrpcClient()
 	if err != nil {
 		return nil, err
 	}
 
-	return &cmdHook{packrpc.Hook(client), c}, nil
+	return &cmdHook{client.Hook(), c}, nil
 }
 
 // Returns a post-processor implementation that is communicating over
 // this client. If the client hasn't been started, this will start it.
 func (c *Client) PostProcessor() (packer.PostProcessor, error) {
-	client, err := c.rpcClient()
+	client, err := c.packrpcClient()
 	if err != nil {
 		return nil, err
 	}
 
-	return &cmdPostProcessor{packrpc.PostProcessor(client), c}, nil
+	return &cmdPostProcessor{client.PostProcessor(), c}, nil
 }
 
 // Returns a provisioner implementation that is communicating over this
 // client. If the client hasn't been started, this will start it.
 func (c *Client) Provisioner() (packer.Provisioner, error) {
-	client, err := c.rpcClient()
+	client, err := c.packrpcClient()
 	if err != nil {
 		return nil, err
 	}
 
-	return &cmdProvisioner{packrpc.Provisioner(client), c}, nil
+	return &cmdProvisioner{client.Provisioner(), c}, nil
 }
 
 // End the executing subprocess (if it is running) and perform any cleanup
@@ -361,7 +360,7 @@ func (c *Client) logStderr(r io.Reader) {
 	close(c.doneLogging)
 }
 
-func (c *Client) rpcClient() (*rpc.Client, error) {
+func (c *Client) packrpcClient() (*packrpc.Client, error) {
 	address, err := c.Start()
 	if err != nil {
 		return nil, err
@@ -376,5 +375,11 @@ func (c *Client) rpcClient() (*rpc.Client, error) {
 	tcpConn := conn.(*net.TCPConn)
 	tcpConn.SetKeepAlive(true)
 
-	return rpc.NewClient(tcpConn), nil
+	client, err := packrpc.NewClient(tcpConn)
+	if err != nil {
+		tcpConn.Close()
+		return nil, err
+	}
+
+	return client, nil
 }

packer/plugin/plugin.go

@@ -14,7 +14,6 @@ import (
 	packrpc "github.com/mitchellh/packer/packer/rpc"
 	"log"
 	"net"
-	"net/rpc"
 	"os"
 	"os/signal"
 	"runtime"
@@ -35,13 +34,14 @@ const MagicCookieValue = "d602bf8f470bc67ca7faa0386276bbdd4330efaf76d1a219cb4d69
 // know how to speak it.
 const APIVersion = "1"
 
-// This serves a single RPC connection on the given RPC server on
-// a random port.
-func serve(server *rpc.Server) (err error) {
+// Server waits for a connection to this plugin and returns a Packer
+// RPC server that you can use to register components and serve them.
+func Server() (*packrpc.Server, error) {
 	log.Printf("Plugin build against Packer '%s'", packer.GitCommit)
 
 	if os.Getenv(MagicCookieKey) != MagicCookieValue {
-		return errors.New("Please do not execute plugins directly. Packer will execute these for you.")
+		return nil, errors.New(
+			"Please do not execute plugins directly. Packer will execute these for you.")
 	}
 
 	// If there is no explicit number of Go threads to use, then set it
@@ -51,12 +51,12 @@ func serve(server *rpc.Server) (err error) {
 
 	minPort, err := strconv.ParseInt(os.Getenv("PACKER_PLUGIN_MIN_PORT"), 10, 32)
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	maxPort, err := strconv.ParseInt(os.Getenv("PACKER_PLUGIN_MAX_PORT"), 10, 32)
 	if err != nil {
-		return
+		return nil, err
 	}
 
 	log.Printf("Plugin minimum port: %d\n", minPort)
@@ -77,7 +77,6 @@ func serve(server *rpc.Server) (err error) {
 
 		break
 	}
-
 	defer listener.Close()
 
 	// Output the address to stdout
@@ -90,13 +89,12 @@ func serve(server *rpc.Server) (err error) {
 	conn, err := listener.Accept()
 	if err != nil {
 		log.Printf("Error accepting connection: %s\n", err.Error())
-		return
+		return nil, err
 	}
 
 	// Serve a single connection
 	log.Println("Serving a plugin connection...")
-	server.ServeConn(conn)
-	return
+	return packrpc.NewServer(conn), nil
 }
 
 // Registers a signal handler to swallow and count interrupts so that the
@@ -115,76 +113,6 @@ func countInterrupts() {
 	}()
 }
 
-// Serves a builder from a plugin.
-func ServeBuilder(builder packer.Builder) {
-	log.Println("Preparing to serve a builder plugin...")
-
-	server := rpc.NewServer()
-	packrpc.RegisterBuilder(server, builder)
-
-	countInterrupts()
-	if err := serve(server); err != nil {
-		log.Printf("ERROR: %s", err)
-		os.Exit(1)
-	}
-}
-
-// Serves a command from a plugin.
-func ServeCommand(command packer.Command) {
-	log.Println("Preparing to serve a command plugin...")
-
-	server := rpc.NewServer()
-	packrpc.RegisterCommand(server, command)
-
-	countInterrupts()
-	if err := serve(server); err != nil {
-		log.Printf("ERROR: %s", err)
-		os.Exit(1)
-	}
-}
-
-// Serves a hook from a plugin.
-func ServeHook(hook packer.Hook) {
-	log.Println("Preparing to serve a hook plugin...")
-
-	server := rpc.NewServer()
-	packrpc.RegisterHook(server, hook)
-
-	countInterrupts()
-	if err := serve(server); err != nil {
-		log.Printf("ERROR: %s", err)
-		os.Exit(1)
-	}
-}
-
-// Serves a post-processor from a plugin.
-func ServePostProcessor(p packer.PostProcessor) {
-	log.Println("Preparing to serve a post-processor plugin...")
-
-	server := rpc.NewServer()
-	packrpc.RegisterPostProcessor(server, p)
-
-	countInterrupts()
-	if err := serve(server); err != nil {
-		log.Printf("ERROR: %s", err)
-		os.Exit(1)
-	}
-}
-
-// Serves a provisioner from a plugin.
-func ServeProvisioner(p packer.Provisioner) {
-	log.Println("Preparing to serve a provisioner plugin...")
-
-	server := rpc.NewServer()
-	packrpc.RegisterProvisioner(server, p)
-
-	countInterrupts()
-	if err := serve(server); err != nil {
-		log.Printf("ERROR: %s", err)
-		os.Exit(1)
-	}
-}
-
 // Tests whether or not the plugin was interrupted or not.
 func Interrupted() bool {
 	return atomic.LoadInt32(&Interrupts) > 0

packer/plugin/plugin_test.go

@@ -54,20 +54,50 @@ func TestHelperProcess(*testing.T) {
 		fmt.Printf("%s1|:1234\n", APIVersion)
 		<-make(chan int)
 	case "builder":
-		ServeBuilder(new(packer.MockBuilder))
+		server, err := Server()
+		if err != nil {
+			log.Printf("[ERR] %s", err)
+			os.Exit(1)
+		}
+		server.RegisterBuilder(new(packer.MockBuilder))
+		server.Serve()
 	case "command":
-		ServeCommand(new(helperCommand))
+		server, err := Server()
+		if err != nil {
+			log.Printf("[ERR] %s", err)
+			os.Exit(1)
+		}
+		server.RegisterCommand(new(helperCommand))
+		server.Serve()
 	case "hook":
-		ServeHook(new(packer.MockHook))
+		server, err := Server()
+		if err != nil {
+			log.Printf("[ERR] %s", err)
+			os.Exit(1)
+		}
+		server.RegisterHook(new(packer.MockHook))
+		server.Serve()
 	case "invalid-rpc-address":
 		fmt.Println("lolinvalid")
 	case "mock":
 		fmt.Printf("%s|:1234\n", APIVersion)
 		<-make(chan int)
 	case "post-processor":
-		ServePostProcessor(new(helperPostProcessor))
+		server, err := Server()
+		if err != nil {
+			log.Printf("[ERR] %s", err)
+			os.Exit(1)
+		}
+		server.RegisterPostProcessor(new(helperPostProcessor))
+		server.Serve()
 	case "provisioner":
-		ServeProvisioner(new(packer.MockProvisioner))
+		server, err := Server()
+		if err != nil {
+			log.Printf("[ERR] %s", err)
+			os.Exit(1)
+		}
+		server.RegisterProvisioner(new(packer.MockProvisioner))
+		server.Serve()
 	case "start-timeout":
 		time.Sleep(1 * time.Minute)
 		os.Exit(1)