Merge pull request #432 from mwhooker/chroot_cmd

build/amazon/chroot: command_wrapper to support sudo-less

builder/amazon/chroot/builder.go

@@ -13,6 +13,7 @@ import (
 	"github.com/mitchellh/packer/common"
 	"github.com/mitchellh/packer/packer"
 	"log"
+	"os/exec"
 	"runtime"
 )
 
@@ -29,14 +30,17 @@ type Config struct {
 	ChrootMounts   [][]string `mapstructure:"chroot_mounts"`
 	CopyFiles      []string   `mapstructure:"copy_files"`
 	DevicePath     string     `mapstructure:"device_path"`
-	MountCommand   string     `mapstructure:"mount_command"`
+	CommandWrapper string     `mapstructure:"command_wrapper"`
 	MountPath      string     `mapstructure:"mount_path"`
 	SourceAmi      string     `mapstructure:"source_ami"`
-	UnmountCommand string     `mapstructure:"unmount_command"`
 
 	tpl *packer.ConfigTemplate
 }
 
+type wrappedCommandTemplate struct {
+	Command string
+}
+
 type Builder struct {
 	config Config
 	runner multistep.Runner
@@ -78,18 +82,14 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		b.config.CopyFiles = []string{"/etc/resolv.conf"}
 	}
 
-	if b.config.MountCommand == "" {
+	if b.config.CommandWrapper == "" {
-		b.config.MountCommand = "mount"
+		b.config.CommandWrapper = "{{.Command}}"
 	}
 
 	if b.config.MountPath == "" {
 		b.config.MountPath = "packer-amazon-chroot-volumes/{{.Device}}"
 	}
 
-	if b.config.UnmountCommand == "" {
-		b.config.UnmountCommand = "umount"
-	}
-
 	// Accumulate any errors
 	errs := common.CheckUnusedConfig(md)
 	errs = packer.MultiErrorAppend(errs, b.config.AccessConfig.Prepare(b.config.tpl)...)
@@ -127,10 +127,8 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 	}
 
 	templates := map[string]*string{
-		"device_path":     &b.config.DevicePath,
+		"device_path": &b.config.DevicePath,
-		"mount_command":   &b.config.MountCommand,
+		"source_ami":  &b.config.SourceAmi,
-		"source_ami":      &b.config.SourceAmi,
-		"unmount_command": &b.config.UnmountCommand,
 	}
 
 	for n, ptr := range templates {
@@ -167,12 +165,24 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 
 	ec2conn := ec2.New(auth, region)
 
+	wrappedCommand := func(command string) *exec.Cmd {
+		wrapped, err := b.config.tpl.Process(
+			b.config.CommandWrapper, &wrappedCommandTemplate{
+				Command: command,
+			})
+		if err != nil {
+			ui.Error(err.Error())
+		}
+		return ShellCommand(wrapped)
+	}
+
 	// Setup the state bag and initial state for the steps
 	state := new(multistep.BasicStateBag)
 	state.Put("config", &b.config)
 	state.Put("ec2", ec2conn)
 	state.Put("hook", hook)
 	state.Put("ui", ui)
+	state.Put("wrappedCommand", Command(wrappedCommand))
 
 	// Build the steps
 	steps := []multistep.Step{

builder/amazon/chroot/builder_test.go

@@ -82,3 +82,14 @@ func TestBuilderPrepare_SourceAmi(t *testing.T) {
 		t.Errorf("err: %s", err)
 	}
 }
+
+func TestBuilderPrepare_CommandWrapper(t *testing.T) {
+	b := &Builder{}
+	config := testConfig()
+
+	config["command_wrapper"] = "echo hi; {{.Command}}"
+	err := b.Prepare(config)
+	if err != nil {
+		t.Errorf("err: %s", err)
+	}
+}

builder/amazon/chroot/communicator.go

@@ -1,8 +1,12 @@
 package chroot
 
+//  pf := func () { somefunc("a str", 1) } 
+
 import (
+	"fmt"
 	"github.com/mitchellh/packer/packer"
 	"io"
+	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -10,19 +14,18 @@ import (
 	"syscall"
 )
 
+type Command func(string) *exec.Cmd
+
 // Communicator is a special communicator that works by executing
 // commands locally but within a chroot.
 type Communicator struct {
-	Chroot string
+	Chroot         string
+	ChrootCmd      Command
+	WrappedCommand Command
 }
 
 func (c *Communicator) Start(cmd *packer.RemoteCmd) error {
-	chrootCmdPath, err := exec.LookPath("chroot")
+	localCmd := c.ChrootCmd(cmd.Command)
-	if err != nil {
-		return err
-	}
-
-	localCmd := exec.Command(chrootCmdPath, c.Chroot, "/bin/sh", "-c", cmd.Command)
 	localCmd.Stdin = cmd.Stdin
 	localCmd.Stdout = cmd.Stdout
 	localCmd.Stderr = cmd.Stderr
@@ -46,7 +49,7 @@ func (c *Communicator) Start(cmd *packer.RemoteCmd) error {
 		}
 
 		log.Printf(
-			"Chroot executation ended with '%d': '%s'",
+			"Chroot executation exited with '%d': '%s'",
 			exitStatus, cmd.Command)
 		cmd.SetExited(exitStatus)
 	}()
@@ -57,49 +60,47 @@ func (c *Communicator) Start(cmd *packer.RemoteCmd) error {
 func (c *Communicator) Upload(dst string, r io.Reader) error {
 	dst = filepath.Join(c.Chroot, dst)
 	log.Printf("Uploading to chroot dir: %s", dst)
-	f, err := os.Create(dst)
+	tf, err := ioutil.TempFile("", "packer-amazon-chroot")
 	if err != nil {
-		return err
+		return fmt.Errorf("Error preparing shell script: %s", err)
 	}
-	defer f.Close()
+	defer os.Remove(tf.Name())
-
+	io.Copy(tf, r)
-	if _, err := io.Copy(f, r); err != nil {
+	cpCmd := fmt.Sprintf("cp %s %s", tf.Name(), dst)
-		return err
+	return (c.WrappedCommand(cpCmd)).Run()
-	}
-
-	return nil
 }
 
 func (c *Communicator) UploadDir(dst string, src string, exclude []string) error {
-	walkFn := func(fullPath string, info os.FileInfo, err error) error {
+	/*
-		if err != nil {
+		walkFn := func(fullPath string, info os.FileInfo, err error) error {
-			return err
+			if err != nil {
-		}
+				return err
-
-		path, err := filepath.Rel(src, fullPath)
-		if err != nil {
-			return err
-		}
-
-		for _, e := range exclude {
-			if e == path {
-				log.Printf("Skipping excluded file: %s", path)
-				return nil
 			}
+
+			path, err := filepath.Rel(src, fullPath)
+			if err != nil {
+				return err
+			}
+
+			for _, e := range exclude {
+				if e == path {
+					log.Printf("Skipping excluded file: %s", path)
+					return nil
+				}
+			}
+
+			chrootDest := filepath.Join(c.Chroot, dst, path)
+			log.Printf("Uploading dir %s to chroot dir: %s", src, dst)
+			cpCmd := fmt.Sprintf("cp %s %s", fullPath, chrootDest)
+			return c.WrappedCommand(cpCmd).Run()
 		}
+	*/
 
-		dstPath := filepath.Join(dst, path)
+	// TODO: remove any file copied if it appears in `exclude`
-		f, err := os.Open(fullPath)
+	chrootDest := filepath.Join(c.Chroot, dst)
-		if err != nil {
+	log.Printf("Uploading directory '%s' to '%s'", src, chrootDest)
-			return err
+	cpCmd := fmt.Sprintf("cp -R %s* %s", src, chrootDest)
-		}
+	return c.WrappedCommand(cpCmd).Run()
-		defer f.Close()
-
-		return c.Upload(dstPath, f)
-	}
-
-	log.Printf("Uploading directory '%s' to '%s'", src, dst)
-	return filepath.Walk(src, walkFn)
 }
 
 func (c *Communicator) Download(src string, w io.Writer) error {

builder/amazon/chroot/copy_files.go

@@ -0,0 +1,19 @@
+package chroot
+
+import (
+	"fmt"
+	"log"
+	"os/exec"
+)
+
+func ChrootCommand(chroot string, command string) *exec.Cmd {
+	cmd := fmt.Sprintf("sudo chroot %s", chroot)
+	return ShellCommand(cmd, command)
+}
+
+func ShellCommand(commands ...string) *exec.Cmd {
+	cmds := append([]string{"-c"}, commands...)
+	cmd := exec.Command("/bin/sh", cmds...)
+	log.Printf("ShellCommand: %s %v", cmd.Path, cmd.Args[1:])
+	return cmd
+}

builder/amazon/chroot/copy_files_test.go

@@ -0,0 +1,44 @@
+package chroot
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestCopyFile(t *testing.T) {
+	first, err := ioutil.TempFile("", "copy_files_test")
+	if err != nil {
+		t.Fatalf("couldn't create temp file.")
+	}
+	defer os.Remove(first.Name())
+	newName := first.Name() + "-new"
+
+	payload := "copy_files_test.go payload"
+	if _, err = first.WriteString(payload); err != nil {
+		t.Fatalf("Couldn't write payload to first file.")
+	}
+	first.Sync()
+
+	cmd := ShellCommand(fmt.Sprintf("cp %s %s", first.Name(), newName))
+	if err := cmd.Run(); err != nil {
+		t.Fatalf("Couldn't copy file")
+	}
+	defer os.Remove(newName)
+
+	second, err := os.Open(newName)
+	if err != nil {
+		t.Fatalf("Couldn't open copied file.")
+	}
+	defer second.Close()
+
+	var copiedPayload = make([]byte, len(payload))
+	if _, err := second.Read(copiedPayload); err != nil {
+		t.Fatalf("Couldn't open copied file for reading.")
+	}
+
+	if string(copiedPayload) != payload {
+		t.Fatalf("payload not copied.")
+	}
+}

builder/amazon/chroot/step_chroot_provision.go

@@ -4,6 +4,7 @@ import (
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
 	"log"
+	"os/exec"
 )
 
 // StepChrootProvision provisions the instance within a chroot.
@@ -15,10 +16,16 @@ func (s *StepChrootProvision) Run(state multistep.StateBag) multistep.StepAction
 	hook := state.Get("hook").(packer.Hook)
 	mountPath := state.Get("mount_path").(string)
 	ui := state.Get("ui").(packer.Ui)
+	wrappedCommand := state.Get("wrappedCommand").(Command)
+	chrootCmd := func(command string) *exec.Cmd {
+		return ChrootCommand(mountPath, command)
+	}
 
 	// Create our communicator
 	comm := &Communicator{
-		Chroot: mountPath,
+		Chroot:         mountPath,
+		ChrootCmd:      chrootCmd,
+		WrappedCommand: wrappedCommand,
 	}
 
 	// Provision

builder/amazon/chroot/step_copy_files.go

@@ -1,12 +1,11 @@
 package chroot
 
 import (
+	"bytes"
 	"fmt"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
-	"io"
 	"log"
-	"os"
 	"path/filepath"
 )
 
@@ -23,6 +22,8 @@ func (s *StepCopyFiles) Run(state multistep.StateBag) multistep.StepAction {
 	config := state.Get("config").(*Config)
 	mountPath := state.Get("mount_path").(string)
 	ui := state.Get("ui").(packer.Ui)
+	wrappedCommand := state.Get("wrappedCommand").(Command)
+	stderr := new(bytes.Buffer)
 
 	s.files = make([]string, 0, len(config.CopyFiles))
 	if len(config.CopyFiles) > 0 {
@@ -32,8 +33,12 @@ func (s *StepCopyFiles) Run(state multistep.StateBag) multistep.StepAction {
 			chrootPath := filepath.Join(mountPath, path)
 			log.Printf("Copying '%s' to '%s'", path, chrootPath)
 
-			if err := s.copySingle(chrootPath, path); err != nil {
+			cmd := wrappedCommand(fmt.Sprintf("cp %s %s", path, chrootPath))
-				err := fmt.Errorf("Error copying file: %s", err)
+			stderr.Reset()
+			cmd.Stderr = stderr
+			if err := cmd.Run(); err != nil {
+				err := fmt.Errorf(
+					"Error copying file: %s\nnStderr: %s", err, stderr.String())
 				state.Put("error", err)
 				ui.Error(err.Error())
 				return multistep.ActionHalt
@@ -54,11 +59,13 @@ func (s *StepCopyFiles) Cleanup(state multistep.StateBag) {
 	}
 }
 
-func (s *StepCopyFiles) CleanupFunc(multistep.StateBag) error {
+func (s *StepCopyFiles) CleanupFunc(state multistep.StateBag) error {
+	wrappedCommand := state.Get("wrappedCommand").(Command)
 	if s.files != nil {
 		for _, file := range s.files {
 			log.Printf("Removing: %s", file)
-			if err := os.Remove(file); err != nil {
+			localCmd := wrappedCommand(fmt.Sprintf("rm -f %s", file))
+			if err := localCmd.Run(); err != nil {
 				return err
 			}
 		}
@@ -67,41 +74,3 @@ func (s *StepCopyFiles) CleanupFunc(multistep.StateBag) error {
 	s.files = nil
 	return nil
 }
-
-func (s *StepCopyFiles) copySingle(dst, src string) error {
-	// Stat the src file so we can copy the mode later
-	srcInfo, err := os.Stat(src)
-	if err != nil {
-		return err
-	}
-
-	// Remove any existing destination file
-	if err := os.Remove(dst); err != nil {
-		return err
-	}
-
-	// Copy the files
-	srcF, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	defer srcF.Close()
-
-	dstF, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-	defer dstF.Close()
-
-	if _, err := io.Copy(dstF, srcF); err != nil {
-		return err
-	}
-	dstF.Close()
-
-	// Match the mode
-	if err := os.Chmod(dst, srcInfo.Mode()); err != nil {
-		return err
-	}
-
-	return nil
-}

builder/amazon/chroot/step_mount_device.go

@@ -7,7 +7,6 @@ import (
 	"github.com/mitchellh/packer/packer"
 	"log"
 	"os"
-	"os/exec"
 	"path/filepath"
 )
 
@@ -59,8 +58,9 @@ func (s *StepMountDevice) Run(state multistep.StateBag) multistep.StepAction {
 
 	ui.Say("Mounting the root device...")
 	stderr := new(bytes.Buffer)
-	mountCommand := fmt.Sprintf("%s %s %s", config.MountCommand, device, mountPath)
+	mountCommand := fmt.Sprintf("mount %s %s", device, mountPath)
-	cmd := exec.Command("/bin/sh", "-c", mountCommand)
+	wrappedCommand := state.Get("wrappedCommand").(Command)
+	cmd := wrappedCommand(mountCommand)
 	cmd.Stderr = stderr
 	if err := cmd.Run(); err != nil {
 		err := fmt.Errorf(
@@ -90,12 +90,12 @@ func (s *StepMountDevice) CleanupFunc(state multistep.StateBag) error {
 		return nil
 	}
 
-	config := state.Get("config").(*Config)
 	ui := state.Get("ui").(packer.Ui)
 	ui.Say("Unmounting the root device...")
 
-	unmountCommand := fmt.Sprintf("%s %s", config.UnmountCommand, s.mountPath)
+	unmountCommand := fmt.Sprintf("umount %s", s.mountPath)
-	cmd := exec.Command("/bin/sh", "-c", unmountCommand)
+	wrappedCommand := state.Get("wrappedCommand").(Command)
+	cmd := wrappedCommand(unmountCommand)
 	if err := cmd.Run(); err != nil {
 		return fmt.Errorf("Error unmounting root device: %s", err)
 	}

builder/amazon/chroot/step_mount_extra.go

@@ -6,7 +6,6 @@ import (
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
 	"os"
-	"os/exec"
 )
 
 // StepMountExtra mounts the attached device.
@@ -21,6 +20,7 @@ func (s *StepMountExtra) Run(state multistep.StateBag) multistep.StepAction {
 	config := state.Get("config").(*Config)
 	mountPath := state.Get("mount_path").(string)
 	ui := state.Get("ui").(packer.Ui)
+	wrappedCommand := state.Get("wrappedCommand").(Command)
 
 	s.mounts = make([]string, 0, len(config.ChrootMounts))
 
@@ -43,12 +43,11 @@ func (s *StepMountExtra) Run(state multistep.StateBag) multistep.StepAction {
 		ui.Message(fmt.Sprintf("Mounting: %s", mountInfo[2]))
 		stderr := new(bytes.Buffer)
 		mountCommand := fmt.Sprintf(
-			"%s %s %s %s",
+			"mount %s %s %s",
-			config.MountCommand,
 			flags,
 			mountInfo[1],
 			innerPath)
-		cmd := exec.Command("/bin/sh", "-c", mountCommand)
+		cmd := wrappedCommand(mountCommand)
 		cmd.Stderr = stderr
 		if err := cmd.Run(); err != nil {
 			err := fmt.Errorf(
@@ -79,15 +78,15 @@ func (s *StepMountExtra) CleanupFunc(state multistep.StateBag) error {
 		return nil
 	}
 
-	config := state.Get("config").(*Config)
+	wrappedCommand := state.Get("wrappedCommand").(Command)
 	for len(s.mounts) > 0 {
 		var path string
 		lastIndex := len(s.mounts) - 1
 		path, s.mounts = s.mounts[lastIndex], s.mounts[:lastIndex]
-		unmountCommand := fmt.Sprintf("%s %s", config.UnmountCommand, path)
+		unmountCommand := fmt.Sprintf("umount %s", path)
 
 		stderr := new(bytes.Buffer)
-		cmd := exec.Command("/bin/sh", "-c", unmountCommand)
+		cmd := wrappedCommand(unmountCommand)
 		cmd.Stderr = stderr
 		if err := cmd.Run(); err != nil {
 			return fmt.Errorf(

website/source/docs/builders/amazon-chroot.html.markdown

@@ -111,9 +111,11 @@ Optional:
   of the source AMI will be attached. This defaults to "" (empty string),
   which forces Packer to find an open device automatically.
 
-* `mount_command` (string) - The command to use to mount devices. This
+* `command_wrapper` (string) - How to run shell commands. This
-  defaults to "mount". This may be useful to set if you want to set
+  defaults to "{{.Command}}". This may be useful to set if you want to set
-  environmental variables or perhaps run it with `sudo` or so on.
+  environmental variables or perhaps run it with `sudo` or so on. This is a
+  configuration template where the `.Command` variable is replaced with the
+  command to be run..
 
 * `mount_path` (string) - The path where the volume will be mounted. This is
   where the chroot environment will be. This defaults to
@@ -123,9 +125,6 @@ Optional:
 
 * `tags` (object of key/value strings) - Tags applied to the AMI.
 
-* `unmount_command` (string) - Just like `mount_command`, except this is
-  the command to unmount devices.
-
 ## Basic Example
 
 Here is a basic example. It is completely valid except for the access keys: