builder/docker: start a container

builder/docker/builder.go

@@ -38,6 +38,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packer.Artifact, error) {
 	steps := []multistep.Step{
 		&StepPull{},
+		&StepRun{},
 	}
 
 	// Setup the state bag and initial state for the steps

builder/docker/step_run.go

@@ -0,0 +1,53 @@
+package docker
+
+import (
+	"bytes"
+	"fmt"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"os/exec"
+	"strings"
+)
+
+type StepRun struct {
+	containerId string
+}
+
+func (s *StepRun) Run(state multistep.StateBag) multistep.StepAction {
+	config := state.Get("config").(*Config)
+	ui := state.Get("ui").(packer.Ui)
+
+	ui.Say("Starting docker container with /bin/bash")
+
+	var stdout, stderr bytes.Buffer
+	cmd := exec.Command("docker", "run", "-d", "-i", "-t", config.Image, "/bin/bash")
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	if err := cmd.Start(); err != nil {
+		err := fmt.Errorf("Error running container: %s", err)
+		state.Put("error", err)
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+
+	if err := cmd.Wait(); err != nil {
+		err := fmt.Errorf("Error running container: %s", err)
+		state.Put("error", err)
+		ui.Error(err.Error())
+		return multistep.ActionHalt
+	}
+
+	s.containerId = strings.TrimSpace(stdout.String())
+	ui.Message(fmt.Sprintf("Container ID: %s", s.containerId))
+
+	return multistep.ActionContinue
+}
+
+func (s *StepRun) Cleanup(state multistep.StateBag) {
+	if s.containerId == "" {
+		return
+	}
+
+	// TODO(mitchellh): handle errors
+	exec.Command("docker", "kill", s.containerId).Run()
+}