`packer build` now communicates through RPC!

Makefile

@@ -3,6 +3,8 @@ OK_COLOR=\x1b[32;01m
 ERROR_COLOR=\x1b[31;01m
 WARN_COLOR=\x1b[33;01m
 
+export ROOTDIR=$(CURDIR)
+
 all:
 	@mkdir -p bin/
 	go get -d -v ./...

packer.go

@@ -3,12 +3,18 @@ package main
 
 import (
 	"github.com/mitchellh/packer/packer"
+	"github.com/mitchellh/packer/packer/plugin"
 	"fmt"
 	"os"
+	"os/exec"
 )
 
 func main() {
 	envConfig := packer.DefaultEnvironmentConfig()
+	envConfig.Commands = []string{"build"}
+	envConfig.CommandFunc = func(n string) packer.Command {
+		return plugin.Command(exec.Command("bin/packer-build"))
+	}
 
 	env, err := packer.NewEnvironment(envConfig)
 	if err != nil {

packer/plugin/command.go

@@ -11,7 +11,13 @@ import (
 )
 
 func Command(cmd *exec.Cmd) packer.Command {
+	env := []string{
+		"PACKER_PLUGIN_MIN_PORT=10000",
+		"PACKER_PLUGIN_MAX_PORT=25000",
+	}
+
 	out := new(bytes.Buffer)
+	cmd.Env = append(cmd.Env, env...)
 	cmd.Stdout = out
 	cmd.Start()
 

plugin/command-build/Makefile

 plugin:
 	go get -d -v ./...
-	go build -v -o $(CURDIR)/bin/packer-build
+	go build -v -o $(ROOTDIR)/bin/packer-build
 
 format:
 	go fmt ./...