builder/amazon/chroot: provision within the chroot

builder/amazon/chroot/communicator.go

@@ -0,0 +1,82 @@
+package chroot
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+)
+
+// Communicator is a special communicator that works by executing
+// commands locally but within a chroot.
+type Communicator struct {
+	Chroot string
+}
+
+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.Stdin = cmd.Stdin
+	localCmd.Stdout = cmd.Stdout
+	localCmd.Stderr = cmd.Stderr
+	log.Printf("Executing: %s %#v", localCmd.Path, localCmd.Args)
+	if err := localCmd.Start(); err != nil {
+		return err
+	}
+
+	go func() {
+		exitStatus := 0
+		if err := localCmd.Wait(); err != nil {
+			if exitErr, ok := err.(*exec.ExitError); ok {
+				exitStatus = 1
+
+				// There is no process-independent way to get the REAL
+				// exit status so we just try to go deeper.
+				if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
+					exitStatus = status.ExitStatus()
+				}
+			}
+		}
+
+		cmd.SetExited(exitStatus)
+	}()
+
+	return nil
+}
+
+func (c *Communicator) Upload(dst string, r io.Reader) error {
+	dst = filepath.Join(c.Chroot, dst)
+	f, err := os.Open(dst)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if _, err := io.Copy(f, r); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *Communicator) Download(src string, w io.Writer) error {
+	src = filepath.Join(c.Chroot, src)
+	f, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if _, err := io.Copy(w, f); err != nil {
+		return err
+	}
+
+	return nil
+}

builder/amazon/chroot/communicator_test.go

@@ -0,0 +1,14 @@
+package chroot
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"testing"
+)
+
+func TestCommunicator_ImplementsCommunicator(t *testing.T) {
+	var raw interface{}
+	raw = &Communicator{}
+	if _, ok := raw.(packer.Communicator); !ok {
+		t.Fatalf("Communicator should be a communicator")
+	}
+}

builder/amazon/chroot/step_chroot_provision.go

@@ -0,0 +1,34 @@
+package chroot
+
+import (
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"log"
+)
+
+// StepChrootProvision provisions the instance within a chroot.
+type StepChrootProvision struct {
+	mounts []string
+}
+
+func (s *StepChrootProvision) Run(state map[string]interface{}) multistep.StepAction {
+	hook := state["hook"].(packer.Hook)
+	mountPath := state["mount_path"].(string)
+	ui := state["ui"].(packer.Ui)
+
+	// Create our communicator
+	comm := &Communicator{
+		Chroot: mountPath,
+	}
+
+	// Provision
+	log.Println("Running the provision hook")
+	if err := hook.Run(packer.HookProvision, ui, comm, nil); err != nil {
+		state["error"] = err
+		return multistep.ActionHalt
+	}
+
+	return multistep.ActionContinue
+}
+
+func (s *StepChrootProvision) Cleanup(state map[string]interface{}) {}