Cleanup: applyVolumesFrom

Docker-DCO-1.1-Signed-off-by: Brian Goff <cpuguy83@gmail.com> (github: cpuguy83)

daemon/container.go

@@ -1145,3 +1145,47 @@ func (container *Container) getNetworkedContainer() (*Container, error) {
 		return nil, fmt.Errorf("network mode not set to container")
 	}
 }
+
+func (container *Container) GetVolumes() (map[string]*Volume, error) {
+	// Get all the bind-mounts
+	volumes, err := container.getBindMap()
+	if err != nil {
+		return nil, err
+	}
+
+	// Get all the normal volumes
+	for volPath, hostPath := range container.Volumes {
+		if _, exists := volumes[volPath]; exists {
+			continue
+		}
+		volumes[volPath] = &Volume{VolPath: volPath, HostPath: hostPath, isReadWrite: container.VolumesRW[volPath]}
+	}
+
+	return volumes, nil
+}
+
+func (container *Container) getBindMap() (map[string]*Volume, error) {
+	var (
+		// Create the requested bind mounts
+		volumes = map[string]*Volume{}
+		// Define illegal container destinations
+		illegalDsts = []string{"/", "."}
+	)
+
+	for _, bind := range container.hostConfig.Binds {
+		vol, err := parseBindVolumeSpec(bind)
+		if err != nil {
+			return nil, err
+		}
+		vol.isBindMount = true
+		// Bail if trying to mount to an illegal destination
+		for _, illegal := range illegalDsts {
+			if vol.VolPath == illegal {
+				return nil, fmt.Errorf("Illegal bind destination: %s", vol.VolPath)
+			}
+		}
+
+		volumes[filepath.Clean(vol.VolPath)] = &vol
+	}
+	return volumes, nil
+}

daemon/volumes.go

@@ -16,14 +16,10 @@ import (
 type Volume struct {
 	HostPath    string
 	VolPath     string
-	Mode        string
+	isReadWrite bool
 	isBindMount bool
 }
 
-func (v *Volume) isRw() bool {
-	return v.Mode == "" || strings.ToLower(v.Mode) == "rw"
-}
-
 func (v *Volume) isDir() (bool, error) {
 	stat, err := os.Stat(v.HostPath)
 	if err != nil {
@@ -42,10 +38,7 @@ func prepareVolumesForContainer(container *Container) error {
 		}
 	}
 
-	if err := createVolumes(container); err != nil {
-		return err
-	}
-	return nil
+	return createVolumes(container)
 }
 
 func setupMountsForContainer(container *Container) error {
@@ -74,87 +67,82 @@ func setupMountsForContainer(container *Container) error {
 	return nil
 }
 
+func parseVolumesFromSpec(container *Container, spec string) (map[string]*Volume, error) {
+	specParts := strings.SplitN(spec, ":", 2)
+	if len(specParts) == 0 {
+		return nil, fmt.Errorf("Malformed volumes-from specification: %s", spec)
+	}
+
+	c := container.daemon.Get(specParts[0])
+	if c == nil {
+		return nil, fmt.Errorf("Container %s not found. Impossible to mount its volumes", specParts[0])
+	}
+
+	volumes, err := c.GetVolumes()
+	if err != nil {
+		return nil, err
+	}
+
+	if len(specParts) == 2 {
+		mode := specParts[1]
+		if validVolumeMode(mode) {
+			return nil, fmt.Errorf("Invalid mode for volumes-from: %s", mode)
+		}
+
+		// Set the mode for the inheritted volume
+		for _, v := range volumes {
+			v.isReadWrite = mode != "ro"
+		}
+	}
+
+	return volumes, nil
+}
+
 func applyVolumesFrom(container *Container) error {
 	volumesFrom := container.hostConfig.VolumesFrom
-	if len(volumesFrom) > 0 {
-		for _, containerSpec := range volumesFrom {
-			var (
-				mountRW   = true
-				specParts = strings.SplitN(containerSpec, ":", 2)
-			)
-
-			switch len(specParts) {
-			case 0:
-				return fmt.Errorf("Malformed volumes-from specification: %s", containerSpec)
-			case 2:
-				switch specParts[1] {
-				case "ro":
-					mountRW = false
-				case "rw": // mountRW is already true
-				default:
-					return fmt.Errorf("Malformed volumes-from specification: %s", containerSpec)
-				}
-			}
 
-			c := container.daemon.Get(specParts[0])
-			if c == nil {
-				return fmt.Errorf("Container %s not found. Impossible to mount its volumes", specParts[0])
-			}
+	for _, spec := range volumesFrom {
+		volumes, err := parseVolumesFromSpec(container, spec)
+		if err != nil {
+			return err
+		}
 
-			if err := c.Mount(); err != nil {
-				return fmt.Errorf("Container %s failed to mount. Impossible to mount its volumes", specParts[0])
-			}
-			defer c.Unmount()
-
-			for volPath, id := range c.Volumes {
-				if _, exists := container.Volumes[volPath]; exists {
-					continue
-				}
-
-				pth, err := c.getResourcePath(volPath)
-				if err != nil {
-					return err
-				}
-
-				stat, err := os.Stat(pth)
-				if err != nil {
-					return err
-				}
-
-				if err := createIfNotExists(pth, stat.IsDir()); err != nil {
-					return err
-				}
-
-				container.Volumes[volPath] = id
-				if isRW, exists := c.VolumesRW[volPath]; exists {
-					container.VolumesRW[volPath] = isRW && mountRW
-				}
+		for _, v := range volumes {
+			if err = v.initialize(container); err != nil {
+				return err
 			}
-
 		}
 	}
 	return nil
 }
 
+func validVolumeMode(mode string) bool {
+	validModes := map[string]bool{
+		"rw": true,
+		"ro": true,
+	}
+
+	return validModes[mode]
+}
+
 func parseBindVolumeSpec(spec string) (Volume, error) {
 	var (
 		arr = strings.Split(spec, ":")
 		vol Volume
 	)
 
-	vol.isBindMount = true
 	switch len(arr) {
 	case 1:
 		vol.VolPath = spec
-		vol.Mode = "rw"
+		vol.isReadWrite = true
 	case 2:
 		vol.HostPath = arr[0]
 		vol.VolPath = arr[1]
-		vol.Mode = "rw"
+		vol.isReadWrite = true
 	case 3:
 		vol.HostPath = arr[0]
 		vol.VolPath = arr[1]
-		vol.Mode = arr[2]
+		vol.isReadWrite = validVolumeMode(arr[2]) && arr[2] == "rw"
 	default:
 		return vol, fmt.Errorf("Invalid volume specification: %s", spec)
 	}
@@ -166,34 +154,9 @@ func parseBindVolumeSpec(spec string) (Volume, error) {
 	return vol, nil
 }
 
-func getBindMap(container *Container) (map[string]Volume, error) {
-	var (
-		// Create the requested bind mounts
-		volumes = map[string]Volume{}
-		// Define illegal container destinations
-		illegalDsts = []string{"/", "."}
-	)
-
-	for _, bind := range container.hostConfig.Binds {
-		vol, err := parseBindVolumeSpec(bind)
-		if err != nil {
-			return volumes, err
-		}
-		// Bail if trying to mount to an illegal destination
-		for _, illegal := range illegalDsts {
-			if vol.VolPath == illegal {
-				return nil, fmt.Errorf("Illegal bind destination: %s", vol.VolPath)
-			}
-		}
-
-		volumes[filepath.Clean(vol.VolPath)] = vol
-	}
-	return volumes, nil
-}
-
 func createVolumes(container *Container) error {
 	// Get all the bindmounts
-	volumes, err := getBindMap(container)
+	volumes, err := container.GetVolumes()
 	if err != nil {
 		return err
 	}
@@ -202,9 +165,9 @@ func createVolumes(container *Container) error {
 	for volPath := range container.Config.Volumes {
 		// Make sure the the volume isn't already specified as a bindmount
 		if _, exists := volumes[volPath]; !exists {
-			volumes[volPath] = Volume{
+			volumes[volPath] = &Volume{
 				VolPath:     volPath,
-				Mode:        "rw",
+				isReadWrite: true,
 				isBindMount: false,
 			}
 		}
@@ -215,8 +178,8 @@ func createVolumes(container *Container) error {
 			return err
 		}
 	}
-	return nil
 
+	return nil
 }
 
 func createVolumeHostPath(container *Container) (string, error) {
@@ -247,7 +210,7 @@ func (v *Volume) initialize(container *Container) error {
 	}
 
 	// If it's not a bindmount we need to create the dir on the host
-	if !v.isBindMount {
+	if !v.isBindMount && v.HostPath == "" {
 		v.HostPath, err = createVolumeHostPath(container)
 		if err != nil {
 			return err
@@ -269,7 +232,7 @@ func (v *Volume) initialize(container *Container) error {
 	}
 
 	container.Volumes[v.VolPath] = hostPath
-	container.VolumesRW[v.VolPath] = v.isRw()
+	container.VolumesRW[v.VolPath] = v.isReadWrite
 
 	volIsDir, err := v.isDir()
 	if err != nil {
@@ -280,7 +243,7 @@ func (v *Volume) initialize(container *Container) error {
 	}
 
 	// Do not copy or change permissions if we are mounting from the host
-	if v.isRw() && !v.isBindMount {
+	if v.isReadWrite && !v.isBindMount {
 		return copyExistingContents(fullVolPath, hostPath)
 	}
 	return nil

integration-cli/docker_cli_run_test.go

@@ -374,6 +374,23 @@ func TestVolumesFromInReadWriteMode(t *testing.T) {
 	logDone("run - volumes from as read write mount")
 }
 
+func TestVolumesFromInheritsReadOnly(t *testing.T) {
+	cmd := exec.Command(dockerBinary, "run", "--name", "parent", "-v", "/test:/test:ro", "busybox", "true")
+	if _, err := runCommand(cmd); err != nil {
+		t.Fatal(err)
+	}
+
+	// Expect this "rw" mode to be be ignored since the inheritted volume is "ro"
+	cmd = exec.Command(dockerBinary, "run", "--volumes-from", "parent:rw", "busybox", "touch", "/test/file")
+	if _, err := runCommand(cmd); err == nil {
+		t.Fatal("Expected to inherit read-only volume even when passing in `rw`")
+	}
+
+	deleteAllContainers()
+
+	logDone("run - volumes from ignores `rw` if inherrited volume is `ro`")
+}
+
 // Test for #1351
 func TestApplyVolumesFromBeforeVolumes(t *testing.T) {
 	cmd := exec.Command(dockerBinary, "run", "--name", "parent", "-v", "/test", "busybox", "touch", "/test/foo")
@@ -1181,7 +1198,7 @@ func TestDockerRunWithVolumesIsRecursive(t *testing.T) {
 
 	deleteAllContainers()
 
-	logDone("run - volumes are bind mounted recuursively")
+	logDone("run - volumes are bind mounted recursively")
 }
 
 func TestDnsDefaultOptions(t *testing.T) {