Merge pull request #432 from mwhooker/chroot_cmd

build/amazon/chroot: command_wrapper to support sudo-less
This commit is contained in:
Mitchell Hashimoto 2013-09-30 09:00:22 -07:00
commit 707fe57edd
10 changed files with 178 additions and 119 deletions

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@ -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 == "" {
b.config.MountCommand = "mount"
if b.config.CommandWrapper == "" {
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,
"mount_command": &b.config.MountCommand,
"source_ami": &b.config.SourceAmi,
"unmount_command": &b.config.UnmountCommand,
"device_path": &b.config.DevicePath,
"source_ami": &b.config.SourceAmi,
}
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{

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@ -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)
}
}

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@ -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")
if err != nil {
return err
}
localCmd := exec.Command(chrootCmdPath, c.Chroot, "/bin/sh", "-c", cmd.Command)
localCmd := c.ChrootCmd(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()
if _, err := io.Copy(f, r); err != nil {
return err
}
return nil
defer os.Remove(tf.Name())
io.Copy(tf, r)
cpCmd := fmt.Sprintf("cp %s %s", tf.Name(), dst)
return (c.WrappedCommand(cpCmd)).Run()
}
func (c *Communicator) UploadDir(dst string, src string, exclude []string) error {
walkFn := func(fullPath string, info os.FileInfo, err error) error {
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
/*
walkFn := func(fullPath string, info os.FileInfo, err error) error {
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
}
}
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)
f, err := os.Open(fullPath)
if err != nil {
return err
}
defer f.Close()
return c.Upload(dstPath, f)
}
log.Printf("Uploading directory '%s' to '%s'", src, dst)
return filepath.Walk(src, walkFn)
// TODO: remove any file copied if it appears in `exclude`
chrootDest := filepath.Join(c.Chroot, dst)
log.Printf("Uploading directory '%s' to '%s'", src, chrootDest)
cpCmd := fmt.Sprintf("cp -R %s* %s", src, chrootDest)
return c.WrappedCommand(cpCmd).Run()
}
func (c *Communicator) Download(src string, w io.Writer) error {

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@ -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
}

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@ -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.")
}
}

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@ -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

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@ -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 {
err := fmt.Errorf("Error copying file: %s", err)
cmd := wrappedCommand(fmt.Sprintf("cp %s %s", path, chrootPath))
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
}

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@ -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)
cmd := exec.Command("/bin/sh", "-c", mountCommand)
mountCommand := fmt.Sprintf("mount %s %s", device, mountPath)
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)
cmd := exec.Command("/bin/sh", "-c", unmountCommand)
unmountCommand := fmt.Sprintf("umount %s", s.mountPath)
wrappedCommand := state.Get("wrappedCommand").(Command)
cmd := wrappedCommand(unmountCommand)
if err := cmd.Run(); err != nil {
return fmt.Errorf("Error unmounting root device: %s", err)
}

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@ -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",
config.MountCommand,
"mount %s %s %s",
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(

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@ -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
defaults to "mount". This may be useful to set if you want to set
environmental variables or perhaps run it with `sudo` or so on.
* `command_wrapper` (string) - How to run shell commands. This
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. 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: