Merge pull request #2854 from mitchellh/f-integrated-plugins-rebase

Implemented internal plugins

command/plugin.go

@@ -0,0 +1,181 @@
+//
+// This file is automatically generated by scripts/generate-plugins.go -- Do not edit!
+//
+
+package command
+
+import (
+	"fmt"
+	"log"
+	"regexp"
+	"strings"
+
+	"github.com/mitchellh/packer/packer"
+	"github.com/mitchellh/packer/packer/plugin"
+
+	amazonchrootbuilder "github.com/mitchellh/packer/builder/amazon/chroot"
+	amazonebsbuilder "github.com/mitchellh/packer/builder/amazon/ebs"
+	amazoninstancebuilder "github.com/mitchellh/packer/builder/amazon/instance"
+	ansiblelocalprovisioner "github.com/mitchellh/packer/provisioner/ansible-local"
+	artificepostprocessor "github.com/mitchellh/packer/post-processor/artifice"
+	atlaspostprocessor "github.com/mitchellh/packer/post-processor/atlas"
+	chefclientprovisioner "github.com/mitchellh/packer/provisioner/chef-client"
+	chefsoloprovisioner "github.com/mitchellh/packer/provisioner/chef-solo"
+	compresspostprocessor "github.com/mitchellh/packer/post-processor/compress"
+	digitaloceanbuilder "github.com/mitchellh/packer/builder/digitalocean"
+	dockerbuilder "github.com/mitchellh/packer/builder/docker"
+	dockerimportpostprocessor "github.com/mitchellh/packer/post-processor/docker-import"
+	dockerpushpostprocessor "github.com/mitchellh/packer/post-processor/docker-push"
+	dockersavepostprocessor "github.com/mitchellh/packer/post-processor/docker-save"
+	dockertagpostprocessor "github.com/mitchellh/packer/post-processor/docker-tag"
+	filebuilder "github.com/mitchellh/packer/builder/file"
+	fileprovisioner "github.com/mitchellh/packer/provisioner/file"
+	googlecomputebuilder "github.com/mitchellh/packer/builder/googlecompute"
+	nullbuilder "github.com/mitchellh/packer/builder/null"
+	openstackbuilder "github.com/mitchellh/packer/builder/openstack"
+	parallelsisobuilder "github.com/mitchellh/packer/builder/parallels/iso"
+	parallelspvmbuilder "github.com/mitchellh/packer/builder/parallels/pvm"
+	powershellprovisioner "github.com/mitchellh/packer/provisioner/powershell"
+	puppetmasterlessprovisioner "github.com/mitchellh/packer/provisioner/puppet-masterless"
+	puppetserverprovisioner "github.com/mitchellh/packer/provisioner/puppet-server"
+	qemubuilder "github.com/mitchellh/packer/builder/qemu"
+	saltmasterlessprovisioner "github.com/mitchellh/packer/provisioner/salt-masterless"
+	shelllocalprovisioner "github.com/mitchellh/packer/provisioner/shell-local"
+	shellprovisioner "github.com/mitchellh/packer/provisioner/shell"
+	vagrantcloudpostprocessor "github.com/mitchellh/packer/post-processor/vagrant-cloud"
+	vagrantpostprocessor "github.com/mitchellh/packer/post-processor/vagrant"
+	virtualboxisobuilder "github.com/mitchellh/packer/builder/virtualbox/iso"
+	virtualboxovfbuilder "github.com/mitchellh/packer/builder/virtualbox/ovf"
+	vmwareisobuilder "github.com/mitchellh/packer/builder/vmware/iso"
+	vmwarevmxbuilder "github.com/mitchellh/packer/builder/vmware/vmx"
+	vspherepostprocessor "github.com/mitchellh/packer/post-processor/vsphere"
+	windowsrestartprovisioner "github.com/mitchellh/packer/provisioner/windows-restart"
+	windowsshellprovisioner "github.com/mitchellh/packer/provisioner/windows-shell"
+
+)
+
+type PluginCommand struct {
+	Meta
+}
+
+var Builders = map[string]packer.Builder{
+	"amazon-chroot":   new(amazonchrootbuilder.Builder),
+	"amazon-ebs":   new(amazonebsbuilder.Builder),
+	"amazon-instance":   new(amazoninstancebuilder.Builder),
+	"digitalocean":   new(digitaloceanbuilder.Builder),
+	"docker":   new(dockerbuilder.Builder),
+	"file":   new(filebuilder.Builder),
+	"googlecompute":   new(googlecomputebuilder.Builder),
+	"null":   new(nullbuilder.Builder),
+	"openstack":   new(openstackbuilder.Builder),
+	"parallels-iso":   new(parallelsisobuilder.Builder),
+	"parallels-pvm":   new(parallelspvmbuilder.Builder),
+	"qemu":   new(qemubuilder.Builder),
+	"virtualbox-iso":   new(virtualboxisobuilder.Builder),
+	"virtualbox-ovf":   new(virtualboxovfbuilder.Builder),
+	"vmware-iso":   new(vmwareisobuilder.Builder),
+	"vmware-vmx":   new(vmwarevmxbuilder.Builder),
+}
+
+
+var Provisioners = map[string]packer.Provisioner{
+	"ansible-local":   new(ansiblelocalprovisioner.Provisioner),
+	"chef-client":   new(chefclientprovisioner.Provisioner),
+	"chef-solo":   new(chefsoloprovisioner.Provisioner),
+	"file":   new(fileprovisioner.Provisioner),
+	"powershell":   new(powershellprovisioner.Provisioner),
+	"puppet-masterless":   new(puppetmasterlessprovisioner.Provisioner),
+	"puppet-server":   new(puppetserverprovisioner.Provisioner),
+	"salt-masterless":   new(saltmasterlessprovisioner.Provisioner),
+	"shell":   new(shellprovisioner.Provisioner),
+	"shell-local":   new(shelllocalprovisioner.Provisioner),
+	"windows-restart":   new(windowsrestartprovisioner.Provisioner),
+	"windows-shell":   new(windowsshellprovisioner.Provisioner),
+}
+
+
+var PostProcessors = map[string]packer.PostProcessor{
+	"artifice":   new(artificepostprocessor.PostProcessor),
+	"atlas":   new(atlaspostprocessor.PostProcessor),
+	"compress":   new(compresspostprocessor.PostProcessor),
+	"docker-import":   new(dockerimportpostprocessor.PostProcessor),
+	"docker-push":   new(dockerpushpostprocessor.PostProcessor),
+	"docker-save":   new(dockersavepostprocessor.PostProcessor),
+	"docker-tag":   new(dockertagpostprocessor.PostProcessor),
+	"vagrant":   new(vagrantpostprocessor.PostProcessor),
+	"vagrant-cloud":   new(vagrantcloudpostprocessor.PostProcessor),
+	"vsphere":   new(vspherepostprocessor.PostProcessor),
+}
+
+
+var pluginRegexp = regexp.MustCompile("packer-(builder|post-processor|provisioner)-(.+)")
+
+func (c *PluginCommand) Run(args []string) int {
+	// This is an internal call (users should not call this directly) so we're
+	// not going to do much input validation. If there's a problem we'll often
+	// just crash. Error handling should be added to facilitate debugging.
+	log.Printf("args: %#v", args)
+	if len(args) != 1 {
+		c.Ui.Error("Wrong number of args")
+		return 1
+	}
+
+	// Plugin will match something like "packer-builder-amazon-ebs"
+	parts := pluginRegexp.FindStringSubmatch(args[0])
+	if len(parts) != 3 {
+		c.Ui.Error(fmt.Sprintf("Error parsing plugin argument [DEBUG]: %#v", parts))
+		return 1
+	}
+	pluginType := parts[1] // capture group 1 (builder|post-processor|provisioner)
+	pluginName := parts[2] // capture group 2 (.+)
+
+	server, err := plugin.Server()
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Error starting plugin server: %s", err))
+		return 1
+	}
+
+	switch pluginType {
+	case "builder":
+		builder, found := Builders[pluginName]
+		if !found {
+			c.Ui.Error(fmt.Sprintf("Could not load builder: %s", pluginName))
+			return 1
+		}
+		server.RegisterBuilder(builder)
+	case "provisioner":
+		provisioner, found := Provisioners[pluginName]
+		if !found {
+			c.Ui.Error(fmt.Sprintf("Could not load provisioner: %s", pluginName))
+			return 1
+		}
+		server.RegisterProvisioner(provisioner)
+	case "post-processor":
+		postProcessor, found := PostProcessors[pluginName]
+		if !found {
+			c.Ui.Error(fmt.Sprintf("Could not load post-processor: %s", pluginName))
+			return 1
+		}
+		server.RegisterPostProcessor(postProcessor)
+	}
+
+	server.Serve()
+
+	return 0
+}
+
+func (*PluginCommand) Help() string {
+	helpText := `
+Usage: packer plugin PLUGIN
+
+  Runs an internally-compiled version of a plugin from the packer binary.
+
+  NOTE: this is an internal command and you should not call it yourself.
+`
+
+	return strings.TrimSpace(helpText)
+}
+
+func (c *PluginCommand) Synopsis() string {
+	return "internal plugin command"
+}

command/version.go

@@ -1,5 +1,7 @@
 package command
 
+//go:generate go run ../scripts/generate-plugins.go
+
 import (
 	"bytes"
 	"fmt"

commands.go

@@ -59,6 +59,12 @@ func init() {
 				CheckFunc:         commandVersionCheck,
 			}, nil
 		},
+
+		"plugin": func() (cli.Command, error) {
+			return &command.PluginCommand{
+				Meta: *CommandMeta,
+			}, nil
+		},
 	}
 }
 

config.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 	"log"
 	"os/exec"
@@ -10,10 +11,15 @@ import (
 	"strings"
 
 	"github.com/mitchellh/osext"
+	"github.com/mitchellh/packer/command"
 	"github.com/mitchellh/packer/packer"
 	"github.com/mitchellh/packer/packer/plugin"
 )
 
+// PACKERSPACE is used to represent the spaces that separate args for a command
+// without being confused with spaces in the path to the command itself.
+const PACKERSPACE = "-PACKERSPACE-"
+
 type config struct {
 	DisableCheckpoint          bool `json:"disable_checkpoint"`
 	DisableCheckpointSignature bool `json:"disable_checkpoint_signature"`
@@ -73,11 +79,17 @@ func (c *config) Discover() error {
 		}
 	}
 
-	// Last, look in the CWD.
+	// Next, look in the CWD.
 	if err := c.discover("."); err != nil {
 		return err
 	}
 
+	// Finally, try to use an internal plugin. Note that this will not override
+	// any previously-loaded plugins.
+	if err := c.discoverInternal(); err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -196,6 +208,46 @@ func (c *config) discoverSingle(glob string, m *map[string]string) error {
 	return nil
 }
 
+func (c *config) discoverInternal() error {
+	// Get the packer binary path
+	packerPath, err := osext.Executable()
+	if err != nil {
+		log.Printf("[ERR] Error loading exe directory: %s", err)
+		return err
+	}
+
+	for builder := range command.Builders {
+		_, found := (c.Builders)[builder]
+		if !found {
+			log.Printf("Using internal plugin for %s", builder)
+			(c.Builders)[builder] = fmt.Sprintf("%s%splugin%spacker-builder-%s",
+				packerPath, PACKERSPACE, PACKERSPACE, builder)
+		}
+	}
+
+	for provisioner := range command.Provisioners {
+		_, found := (c.Provisioners)[provisioner]
+		if !found {
+			log.Printf("Using internal plugin for %s", provisioner)
+			(c.Provisioners)[provisioner] = fmt.Sprintf(
+				"%s%splugin%spacker-provisioner-%s",
+				packerPath, PACKERSPACE, PACKERSPACE, provisioner)
+		}
+	}
+
+	for postProcessor := range command.PostProcessors {
+		_, found := (c.PostProcessors)[postProcessor]
+		if !found {
+			log.Printf("Using internal plugin for %s", postProcessor)
+			(c.PostProcessors)[postProcessor] = fmt.Sprintf(
+				"%s%splugin%spacker-post-processor-%s",
+				packerPath, PACKERSPACE, PACKERSPACE, postProcessor)
+		}
+	}
+
+	return nil
+}
+
 func (c *config) pluginClient(path string) *plugin.Client {
 	originalPath := path
 
@@ -214,6 +266,14 @@ func (c *config) pluginClient(path string) *plugin.Client {
 		}
 	}
 
+	// Check for special case using `packer plugin PLUGIN`
+	args := []string{}
+	if strings.Contains(path, PACKERSPACE) {
+		parts := strings.Split(path, PACKERSPACE)
+		path = parts[0]
+		args = parts[1:]
+	}
+
 	// If everything failed, just use the original path and let the error
 	// bubble through.
 	if path == "" {
@@ -222,7 +282,7 @@ func (c *config) pluginClient(path string) *plugin.Client {
 
 	log.Printf("Creating plugin client for path: %s", path)
 	var config plugin.ClientConfig
-	config.Cmd = exec.Command(path)
+	config.Cmd = exec.Command(path, args...)
 	config.Managed = true
 	config.MinPort = c.PluginMinPort
 	config.MaxPort = c.PluginMaxPort

main.go

@@ -181,7 +181,7 @@ func wrappedMain() int {
 	cli := &cli.CLI{
 		Args:       args,
 		Commands:   Commands,
-		HelpFunc:   cli.BasicHelpFunc("packer"),
+		HelpFunc:   excludeHelpFunc(Commands, []string{"plugin"}),
 		HelpWriter: os.Stdout,
 		Version:    Version,
 	}
@@ -195,6 +195,27 @@ func wrappedMain() int {
 	return exitCode
 }
 
+// excludeHelpFunc filters commands we don't want to show from the list of
+// commands displayed in packer's help text.
+func excludeHelpFunc(commands map[string]cli.CommandFactory, exclude []string) cli.HelpFunc {
+	// Make search slice into a map so we can use use the `if found` idiom
+	// instead of a nested loop.
+	var excludes = make(map[string]interface{}, len(exclude))
+	for _, item := range exclude {
+		excludes[item] = nil
+	}
+
+	// Create filtered list of commands
+	helpCommands := []string{}
+	for command := range commands {
+		if _, found := excludes[command]; !found {
+			helpCommands = append(helpCommands, command)
+		}
+	}
+
+	return cli.FilteredHelpFunc(helpCommands, cli.BasicHelpFunc("packer"))
+}
+
 // extractMachineReadable checks the args for the machine readable
 // flag and returns whether or not it is on. It modifies the args
 // to remove this flag.

main_test.go

@@ -3,9 +3,36 @@ package main
 import (
 	"math/rand"
 	"reflect"
+	"strings"
 	"testing"
+
+	"github.com/mitchellh/cli"
+	"github.com/mitchellh/packer/command"
 )
 
+func TestExcludeHelpFunc(t *testing.T) {
+	commands := map[string]cli.CommandFactory{
+		"build": func() (cli.Command, error) {
+			return &command.BuildCommand{
+				Meta: command.Meta{},
+			}, nil
+		},
+
+		"fix": func() (cli.Command, error) {
+			return &command.FixCommand{
+				Meta: command.Meta{},
+			}, nil
+		},
+	}
+
+	helpFunc := excludeHelpFunc(commands, []string{"fix"})
+	helpText := helpFunc(commands)
+
+	if strings.Contains(helpText, "fix") {
+		t.Fatalf("Found fix in help text even though we excluded it: \n\n%s\n\n", helpText)
+	}
+}
+
 func TestExtractMachineReadable(t *testing.T) {
 	var args, expected, result []string
 	var mr bool

scripts/build.sh

@@ -42,18 +42,10 @@ gox \
     -os="${XC_OS}" \
     -arch="${XC_ARCH}" \
     -ldflags "-X main.GitCommit ${GIT_COMMIT}${GIT_DIRTY}" \
-    -output "pkg/{{.OS}}_{{.Arch}}/packer-{{.Dir}}" \
+    -output "pkg/{{.OS}}_{{.Arch}}/packer" \
-    ./...
+    .
 set -e
 
-# Make sure "packer-packer" is renamed properly
-for PLATFORM in $(find ./pkg -mindepth 1 -maxdepth 1 -type d); do
-    set +e
-    mv ${PLATFORM}/packer-packer.exe ${PLATFORM}/packer.exe 2>/dev/null
-    mv ${PLATFORM}/packer-packer ${PLATFORM}/packer 2>/dev/null
-    set -e
-done
-
 # Move all the compiled things to the $GOPATH/bin
 GOPATH=${GOPATH:-$(go env GOPATH)}
 case $(uname) in

scripts/generate-plugins.go

@@ -0,0 +1,335 @@
+// Generate Plugins is a small program that updates the lists of plugins in
+// command/plugin.go so they will be compiled into the main packer binary.
+//
+// See https://github.com/mitchellh/packer/pull/2608 for details.
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+const target = "command/plugin.go"
+
+func main() {
+	// Normally this is run via go:generate from the command folder so we need
+	// to cd .. first. But when developing it's easier to use go run, so we'll
+	// support that too.
+	wd, _ := os.Getwd()
+	if filepath.Base(wd) != "packer" {
+		os.Chdir("..")
+		wd, _ = os.Getwd()
+		if filepath.Base(wd) != "packer" {
+			log.Fatalf("This program must be invoked in the packer project root; in %s", wd)
+		}
+	}
+
+	// Collect all of the data we need about plugins we have in the project
+	builders, err := discoverBuilders()
+	if err != nil {
+		log.Fatalf("Failed to discover builders: %s", err)
+	}
+
+	provisioners, err := discoverProvisioners()
+	if err != nil {
+		log.Fatalf("Failed to discover provisioners: %s", err)
+	}
+
+	postProcessors, err := discoverPostProcessors()
+	if err != nil {
+		log.Fatalf("Failed to discover post processors: %s", err)
+	}
+
+	// Do some simple code generation and templating
+	output := source
+	output = strings.Replace(output, "IMPORTS", makeImports(builders, provisioners, postProcessors), 1)
+	output = strings.Replace(output, "BUILDERS", makeMap("Builders", "Builder", builders), 1)
+	output = strings.Replace(output, "PROVISIONERS", makeMap("Provisioners", "Provisioner", provisioners), 1)
+	output = strings.Replace(output, "POSTPROCESSORS", makeMap("PostProcessors", "PostProcessor", postProcessors), 1)
+
+	// TODO sort the lists of plugins so we are not subjected to random OS ordering of the plugin lists
+	// TODO format the file
+
+	// Write our generated code to the command/plugin.go file
+	file, err := os.Create(target)
+	defer file.Close()
+	if err != nil {
+		log.Fatalf("Failed to open %s for writing: %s", target, err)
+	}
+
+	_, err = file.WriteString(output)
+	if err != nil {
+		log.Fatalf("Failed writing to %s: %s", target, err)
+	}
+
+	log.Printf("Generated %s", target)
+}
+
+type plugin struct {
+	Package    string // This plugin's package name (iso)
+	PluginName string // Name of plugin (vmware-iso)
+	TypeName   string // Type of plugin (builder)
+	Path       string // Path relative to packer root (builder/vmware/iso)
+	ImportName string // PluginName+TypeName (vmwareisobuilder)
+}
+
+// makeMap creates a map named Name with type packer.Name that looks something
+// like this:
+//
+// var Builders = map[string]packer.Builder{
+// 	"amazon-chroot":   new(chroot.Builder),
+// 	"amazon-ebs":      new(ebs.Builder),
+// 	"amazon-instance": new(instance.Builder),
+func makeMap(varName, varType string, items []plugin) string {
+	output := ""
+
+	output += fmt.Sprintf("var %s = map[string]packer.%s{\n", varName, varType)
+	for _, item := range items {
+		output += fmt.Sprintf("\t\"%s\":   new(%s.%s),\n", item.PluginName, item.ImportName, item.TypeName)
+	}
+	output += "}\n"
+	return output
+}
+
+func makeImports(builders, provisioners, postProcessors []plugin) string {
+	plugins := []string{}
+
+	for _, builder := range builders {
+		plugins = append(plugins, fmt.Sprintf("\t%s \"github.com/mitchellh/packer/%s\"\n", builder.ImportName, builder.Path))
+	}
+
+	for _, provisioner := range provisioners {
+		plugins = append(plugins, fmt.Sprintf("\t%s \"github.com/mitchellh/packer/%s\"\n", provisioner.ImportName, provisioner.Path))
+	}
+
+	for _, postProcessor := range postProcessors {
+		plugins = append(plugins, fmt.Sprintf("\t%s \"github.com/mitchellh/packer/%s\"\n", postProcessor.ImportName, postProcessor.Path))
+	}
+
+	// Make things pretty
+	sort.Strings(plugins)
+
+	return strings.Join(plugins, "")
+}
+
+// listDirectories recursively lists directories under the specified path
+func listDirectories(path string) ([]string, error) {
+	names := []string{}
+	items, err := ioutil.ReadDir(path)
+	if err != nil {
+		return names, err
+	}
+
+	for _, item := range items {
+		// We only want directories
+		if item.IsDir() {
+			currentDir := filepath.Join(path, item.Name())
+			names = append(names, currentDir)
+
+			// Do some recursion
+			subNames, err := listDirectories(currentDir)
+			if err == nil {
+				names = append(names, subNames...)
+			}
+		}
+	}
+
+	return names, nil
+}
+
+// deriveName determines the name of the plugin (what you'll see in a packer
+// template) based on the filesystem path. We use two rules:
+//
+// Start with                     -> builder/virtualbox/iso
+//
+// 1. Strip the root              -> virtualbox/iso
+// 2. Switch slash / to dash -    -> virtualbox-iso
+func deriveName(root, full string) string {
+	short, _ := filepath.Rel(root, full)
+	bits := strings.Split(short, string(os.PathSeparator))
+	return strings.Join(bits, "-")
+}
+
+// deriveImport will build a unique import identifier based on packageName and
+// the result of deriveName()
+//
+// This will be something like    -> virtualboxisobuilder
+//
+// Which is long, but deterministic and unique.
+func deriveImport(typeName, derivedName string) string {
+	return strings.Replace(derivedName, "-", "", -1) + strings.ToLower(typeName)
+}
+
+// discoverTypesInPath searches for types of typeID in path and returns a list
+// of plugins it finds.
+func discoverTypesInPath(path, typeID string) ([]plugin, error) {
+	postProcessors := []plugin{}
+
+	dirs, err := listDirectories(path)
+	if err != nil {
+		return postProcessors, err
+	}
+
+	for _, dir := range dirs {
+		fset := token.NewFileSet()
+		goPackages, err := parser.ParseDir(fset, dir, nil, parser.AllErrors)
+		if err != nil {
+			return postProcessors, fmt.Errorf("Failed parsing directory %s: %s", dir, err)
+		}
+
+		for _, goPackage := range goPackages {
+			ast.PackageExports(goPackage)
+			ast.Inspect(goPackage, func(n ast.Node) bool {
+				switch x := n.(type) {
+				case *ast.TypeSpec:
+					if x.Name.Name == typeID {
+						derivedName := deriveName(path, dir)
+						postProcessors = append(postProcessors, plugin{
+							Package:    goPackage.Name,
+							PluginName: derivedName,
+							ImportName: deriveImport(x.Name.Name, derivedName),
+							TypeName:   x.Name.Name,
+							Path:       dir,
+						})
+						// The AST stops parsing when we return false. Once we
+						// find the symbol we want we can stop parsing.
+
+						// DEBUG:
+						// fmt.Printf("package %#v\n", goPackage)
+						return false
+					}
+				}
+				return true
+			})
+		}
+	}
+
+	return postProcessors, nil
+}
+
+func discoverBuilders() ([]plugin, error) {
+	path := "./builder"
+	typeID := "Builder"
+	return discoverTypesInPath(path, typeID)
+}
+
+func discoverProvisioners() ([]plugin, error) {
+	path := "./provisioner"
+	typeID := "Provisioner"
+	return discoverTypesInPath(path, typeID)
+}
+
+func discoverPostProcessors() ([]plugin, error) {
+	path := "./post-processor"
+	typeID := "PostProcessor"
+	return discoverTypesInPath(path, typeID)
+}
+
+const source = `//
+// This file is automatically generated by scripts/generate-plugins.go -- Do not edit!
+//
+
+package command
+
+import (
+	"fmt"
+	"log"
+	"regexp"
+	"strings"
+
+	"github.com/mitchellh/packer/packer"
+	"github.com/mitchellh/packer/packer/plugin"
+
+IMPORTS
+)
+
+type PluginCommand struct {
+	Meta
+}
+
+BUILDERS
+
+PROVISIONERS
+
+POSTPROCESSORS
+
+var pluginRegexp = regexp.MustCompile("packer-(builder|post-processor|provisioner)-(.+)")
+
+func (c *PluginCommand) Run(args []string) int {
+	// This is an internal call (users should not call this directly) so we're
+	// not going to do much input validation. If there's a problem we'll often
+	// just crash. Error handling should be added to facilitate debugging.
+	log.Printf("args: %#v", args)
+	if len(args) != 1 {
+		c.Ui.Error("Wrong number of args")
+		return 1
+	}
+
+	// Plugin will match something like "packer-builder-amazon-ebs"
+	parts := pluginRegexp.FindStringSubmatch(args[0])
+	if len(parts) != 3 {
+		c.Ui.Error(fmt.Sprintf("Error parsing plugin argument [DEBUG]: %#v", parts))
+		return 1
+	}
+	pluginType := parts[1] // capture group 1 (builder|post-processor|provisioner)
+	pluginName := parts[2] // capture group 2 (.+)
+
+	server, err := plugin.Server()
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Error starting plugin server: %s", err))
+		return 1
+	}
+
+	switch pluginType {
+	case "builder":
+		builder, found := Builders[pluginName]
+		if !found {
+			c.Ui.Error(fmt.Sprintf("Could not load builder: %s", pluginName))
+			return 1
+		}
+		server.RegisterBuilder(builder)
+	case "provisioner":
+		provisioner, found := Provisioners[pluginName]
+		if !found {
+			c.Ui.Error(fmt.Sprintf("Could not load provisioner: %s", pluginName))
+			return 1
+		}
+		server.RegisterProvisioner(provisioner)
+	case "post-processor":
+		postProcessor, found := PostProcessors[pluginName]
+		if !found {
+			c.Ui.Error(fmt.Sprintf("Could not load post-processor: %s", pluginName))
+			return 1
+		}
+		server.RegisterPostProcessor(postProcessor)
+	}
+
+	server.Serve()
+
+	return 0
+}
+
+func (*PluginCommand) Help() string {
+	helpText := ` + "`" + `
+Usage: packer plugin PLUGIN
+
+  Runs an internally-compiled version of a plugin from the packer binary.
+
+  NOTE: this is an internal command and you should not call it yourself.
+` + "`" + `
+
+	return strings.TrimSpace(helpText)
+}
+
+func (c *PluginCommand) Synopsis() string {
+	return "internal plugin command"
+}
+`