builder/docker: make Import part of this Driver for reuse

builder/docker/driver.go

@@ -14,6 +14,9 @@ type Driver interface {
 	// Export exports the container with the given ID to the given writer.
 	Export(id string, dst io.Writer) error
 
+	// Import imports a container from a tar file
+	Import(path, repo string) (string, error)
+
 	// Pull should pull down the given image.
 	Pull(image string) error
 

builder/docker/driver_docker.go

@@ -6,6 +6,7 @@ import (
 	"github.com/mitchellh/packer/packer"
 	"io"
 	"log"
+	"os"
 	"os/exec"
 	"strings"
 )
@@ -54,6 +55,39 @@ func (d *DockerDriver) Export(id string, dst io.Writer) error {
 	return nil
 }
 
+func (d *DockerDriver) Import(path string, repo string) (string, error) {
+	var stdout bytes.Buffer
+	cmd := exec.Command("docker", "import", "-", repo)
+	cmd.Stdout = &stdout
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		return "", err
+	}
+
+	// There should be only one artifact of the Docker builder
+	file, err := os.Open(path)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	if err := cmd.Start(); err != nil {
+		return "", err
+	}
+
+	go func() {
+		defer stdin.Close()
+		io.Copy(stdin, file)
+	}()
+
+	if err := cmd.Wait(); err != nil {
+		err = fmt.Errorf("Error importing container: %s", err)
+		return "", err
+	}
+
+	return strings.TrimSpace(stdout.String()), nil
+}
+
 func (d *DockerDriver) Pull(image string) error {
 	cmd := exec.Command("docker", "pull", image)
 	return runAndStream(cmd, d.Ui)

builder/docker/driver_mock.go

@@ -10,6 +10,12 @@ type MockDriver struct {
 	DeleteImageId     string
 	DeleteImageErr    error
 
+	ImportCalled bool
+	ImportPath   string
+	ImportRepo   string
+	ImportId     string
+	ImportErr    error
+
 	ExportReader io.Reader
 	ExportError  error
 	PullError    error
@@ -49,6 +55,13 @@ func (d *MockDriver) Export(id string, dst io.Writer) error {
 	return d.ExportError
 }
 
+func (d *MockDriver) Import(path, repo string) (string, error) {
+	d.ImportCalled = true
+	d.ImportPath = path
+	d.ImportRepo = repo
+	return d.ImportId, d.ImportErr
+}
+
 func (d *MockDriver) Pull(image string) error {
 	d.PullCalled = true
 	d.PullImage = image

post-processor/docker-import/post-processor.go

 package dockerimport
 
 import (
-	"bytes"
 	"fmt"
 	"github.com/mitchellh/packer/builder/docker"
 	"github.com/mitchellh/packer/common"
 	"github.com/mitchellh/packer/packer"
-	"io"
-	"os"
-	"os/exec"
-	"strings"
 )
 
 const BuilderId = "packer.post-processor.docker-import"
@@ -74,43 +69,18 @@ func (p *PostProcessor) PostProcess(ui packer.Ui, artifact packer.Artifact) (pac
 		importRepo += ":" + p.config.Tag
 	}
 
-	var stdout bytes.Buffer
-	cmd := exec.Command("docker", "import", "-", importRepo)
-	cmd.Stdout = &stdout
-	stdin, err := cmd.StdinPipe()
-	if err != nil {
-		return nil, false, err
-	}
-
-	// There should be only one artifact of the Docker builder
-	file, err := os.Open(artifact.Files()[0])
-	if err != nil {
-		return nil, false, err
-	}
-	defer file.Close()
+	driver := &docker.DockerDriver{Tpl: p.config.tpl, Ui: ui}
 
 	ui.Message("Importing image: " + artifact.Id())
 	ui.Message("Repository: " + importRepo)
-
-	if err := cmd.Start(); err != nil {
-		return nil, false, err
-	}
-
-	go func() {
-		defer stdin.Close()
-		io.Copy(stdin, file)
-	}()
-
-	if err := cmd.Wait(); err != nil {
-		err = fmt.Errorf("Error importing container: %s", err)
+	id, err := driver.Import(artifact.Files()[0], importRepo)
+	if err != nil {
 		return nil, false, err
 	}
 
-	id := strings.TrimSpace(stdout.String())
 	ui.Message("Imported ID: " + id)
 
 	// Build the artifact
-	driver := &docker.DockerDriver{Tpl: p.config.tpl, Ui: ui}
 	artifact = &docker.ImportArtifact{
 		BuilderIdValue: BuilderId,
 		Driver:         driver,