provider/docker: Mount named volumes in containers

This adds support for specifying named volumes for mounting in a
`docker_container` resource.

builtin/providers/docker/resource_docker_container.go

@@ -137,6 +137,20 @@ func resourceDockerContainer() *schema.Resource {
 							Type:     schema.TypeString,
 							Optional: true,
 							ForceNew: true,
+							ValidateFunc: func(v interface{}, k string) (ws []string, es []error) {
+								value := v.(string)
+								if !regexp.MustCompile(`^/`).MatchString(value) {
+									es = append(es, fmt.Errorf(
+										"%q must be an absolute path", k))
+								}
+								return
+							},
+						},
+
+						"volume_name": &schema.Schema{
+							Type:     schema.TypeString,
+							Optional: true,
+							ForceNew: true,
 						},
 
 						"read_only": &schema.Schema{
@@ -383,6 +397,10 @@ func resourceDockerVolumesHash(v interface{}) int {
 		buf.WriteString(fmt.Sprintf("%v-", v.(string)))
 	}
 
+	if v, ok := m["volume_name"]; ok {
+		buf.WriteString(fmt.Sprintf("%v-", v.(string)))
+	}
+
 	if v, ok := m["read_only"]; ok {
 		buf.WriteString(fmt.Sprintf("%v-", v.(bool)))
 	}

builtin/providers/docker/resource_docker_container_funcs.go

@@ -353,7 +353,10 @@ func volumeSetToDockerVolumes(volumes *schema.Set) (map[string]struct{}, []strin
 		volume := volumeInt.(map[string]interface{})
 		fromContainer := volume["from_container"].(string)
 		containerPath := volume["container_path"].(string)
-		hostPath := volume["host_path"].(string)
+		volumeName := volume["volume_name"].(string)
+		if len(volumeName) == 0 {
+			volumeName = volume["host_path"].(string)
+		}
 		readOnly := volume["read_only"].(bool)
 
 		switch {
@@ -363,13 +366,13 @@ func volumeSetToDockerVolumes(volumes *schema.Set) (map[string]struct{}, []strin
 			return retVolumeMap, retHostConfigBinds, retVolumeFromContainers, errors.New("Both a container and a path specified in a volume entry")
 		case len(fromContainer) != 0:
 			retVolumeFromContainers = append(retVolumeFromContainers, fromContainer)
-		case len(hostPath) != 0:
+		case len(volumeName) != 0:
 			readWrite := "rw"
 			if readOnly {
 				readWrite = "ro"
 			}
 			retVolumeMap[containerPath] = struct{}{}
-			retHostConfigBinds = append(retHostConfigBinds, hostPath+":"+containerPath+":"+readWrite)
+			retHostConfigBinds = append(retHostConfigBinds, volumeName+":"+containerPath+":"+readWrite)
 		default:
 			retVolumeMap[containerPath] = struct{}{}
 		}

builtin/providers/docker/resource_docker_container_test.go

@@ -25,6 +25,48 @@ func TestAccDockerContainer_basic(t *testing.T) {
 	})
 }
 
+func TestAccDockerContainer_volume(t *testing.T) {
+	var c dc.Container
+
+	testCheck := func(*terraform.State) error {
+		if len(c.Mounts) != 2 {
+			return fmt.Errorf("Incorrect number of mounts: expected 2, got %d", len(c.Mounts))
+		}
+
+		for _, v := range c.Mounts {
+			if v.Name != "testAccDockerContainerVolume_volume" {
+				continue
+			}
+
+			if v.Destination != "/tmp/volume" {
+				return fmt.Errorf("Bad destination on mount: expected /tmp/volume, got %q", v.Destination)
+			}
+
+			if v.Mode != "rw" {
+				return fmt.Errorf("Bad mode on mount: expected rw, got %q", v.Mode)
+			}
+
+			return nil
+		}
+
+		return fmt.Errorf("Mount for testAccDockerContainerVolume_volume not found")
+	}
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccDockerContainerVolumeConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccContainerRunning("docker_container.foo", &c),
+					testCheck,
+				),
+			},
+		},
+	})
+}
+
 func TestAccDockerContainer_customized(t *testing.T) {
 	var c dc.Container
 
@@ -145,6 +187,27 @@ resource "docker_container" "foo" {
 }
 `
 
+const testAccDockerContainerVolumeConfig = `
+resource "docker_image" "foo" {
+	name = "nginx:latest"
+}
+
+resource "docker_volume" "foo" {
+    name = "testAccDockerContainerVolume_volume"
+}
+
+resource "docker_container" "foo" {
+	name = "tf-test"
+	image = "${docker_image.foo.latest}"
+
+    volumes {
+        volume_name = "${docker_volume.foo.name}"
+        container_path = "/tmp/volume"
+        read_only = false
+    }
+}
+`
+
 const testAccDockerContainerCustomizedConfig = `
 resource "docker_image" "foo" {
 	name = "nginx:latest"

website/source/docs/providers/docker/r/container.html.markdown

@@ -107,13 +107,17 @@ the following:
 
 * `from_container` - (Optional, string) The container where the volume is
   coming from.
-* `container_path` - (Optional, string) The path in the container where the
-  volume will be mounted.
 * `host_path` - (Optional, string) The path on the host where the volume
   is coming from.
+* `volume_name` - (Optional, string) The name of the docker volume which
+  should be mounted.
+* `container_path` - (Optional, string) The path in the container where the
+  volume will be mounted.
 * `read_only` - (Optional, bool) If true, this volume will be readonly.
   Defaults to false.
   
+One of `from_container`, `host_path` or `volume_name` must be set.
+
 ## Attributes Reference
 
 The following attributes are exported: