builder/docker: support volumes

CHANGELOG.md

@@ -16,6 +16,7 @@ FEATURES:
       binaries named `packer-TYPE-NAME`.
   * builder/docker: Images can now be committed instead of exported. [GH-1198]
   * builder/docker: Can now specify login credentials to pull images.
+  * builder/docker: Support mounting additional volumes. [GH-1430]
   * builder/virtualbox-ovf: New `import_flags` setting can be used to add
       new command line flags to `VBoxManage import` to allow things such
       as EULAs to be accepted. [GH-1383]

builder/docker/config.go

@@ -14,6 +14,7 @@ type Config struct {
 	Image      string
 	Pull       bool
 	RunCommand []string `mapstructure:"run_command"`
+	Volumes    map[string]string
 
 	Login         bool
 	LoginEmail    string `mapstructure:"login_email"`
@@ -41,9 +42,7 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 	// Defaults
 	if len(c.RunCommand) == 0 {
 		c.RunCommand = []string{
-			"run",
 			"-d", "-i", "-t",
-			"-v", "{{.Volumes}}",
 			"{{.Image}}",
 			"/bin/bash",
 		}
@@ -82,6 +81,17 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		}
 	}
 
+	for k, v := range c.Volumes {
+		var err error
+		v, err = c.tpl.Process(v, nil)
+		if err != nil {
+			errs = packer.MultiErrorAppend(
+				errs, fmt.Errorf("Error processing volumes[%s]: %s", k, err))
+		}
+
+		c.Volumes[k] = v
+	}
+
 	if c.Image == "" {
 		errs = packer.MultiErrorAppend(errs,
 			fmt.Errorf("image must be specified"))

builder/docker/driver.go

@@ -60,5 +60,4 @@ type ContainerConfig struct {
 // This is the template that is used for the RunCommand in the ContainerConfig.
 type startContainerTemplate struct {
 	Image   string
-	Volumes string
 }

builder/docker/driver_docker.go

@@ -185,23 +185,19 @@ func (d *DockerDriver) StartContainer(config *ContainerConfig) (string, error) {
 	// Build up the template data
 	var tplData startContainerTemplate
 	tplData.Image = config.Image
-	if len(config.Volumes) > 0 {
-		volumes := make([]string, 0, len(config.Volumes))
-		for host, guest := range config.Volumes {
-			volumes = append(volumes, fmt.Sprintf("%s:%s", host, guest))
-		}
-
-		tplData.Volumes = strings.Join(volumes, ",")
-	}
 
 	// Args that we're going to pass to Docker
-	args := config.RunCommand
-	for i, v := range args {
-		var err error
-		args[i], err = d.Tpl.Process(v, &tplData)
+	args := []string{"run"}
+	for host, guest := range config.Volumes {
+		args = append(args, "-v", fmt.Sprintf("%s:%s", host, guest))
+	}
+	for _, v := range config.RunCommand {
+		v, err := d.Tpl.Process(v, &tplData)
 		if err != nil {
 			return "", err
 		}
+
+		args = append(args, v)
 	}
 	d.Ui.Message(fmt.Sprintf(
 		"Run command: docker %s", strings.Join(args, " ")))

builder/docker/step_run.go

@@ -19,11 +19,14 @@ func (s *StepRun) Run(state multistep.StateBag) multistep.StepAction {
 	runConfig := ContainerConfig{
 		Image:      config.Image,
 		RunCommand: config.RunCommand,
-		Volumes: map[string]string{
-			tempDir: "/packer-files",
-		},
+		Volumes:    make(map[string]string),
 	}
 
+	for host, container := range config.Volumes {
+		runConfig.Volumes[host] = container
+	}
+	runConfig.Volumes[tempDir] = "/packer-files"
+
 	ui.Say("Starting docker container...")
 	containerId, err := driver.StartContainer(&runConfig)
 	if err != nil {

website/source/docs/builders/docker.html.markdown

@@ -95,6 +95,10 @@ described.
   `["run", "-d", "-i", "-t", "-v", "{{.Volumes}}", "{{.Image}}", "/bin/bash"]`.
   As you can see, you have a couple template variables to customize, as well.
 
+* `volumes` (map of strings to strings) - A mapping of additional volumes
+   to mount into this container. The key of the object is the host path,
+   the value is the container path.
+
 ## Using the Artifact: Export
 
 Once the tar artifact has been generated, you will likely want to import, tag,