Merge pull request #15181 from Microsoft/10662-registermountpoints

Windows: Tidy/godoc volume*.go

daemon/volumes.go

@@ -17,8 +17,9 @@ import (
 // a volume mount that is not writable.
 var ErrVolumeReadonly = errors.New("mounted volume is marked read-only")
 
-// TODO Windows. Further platform refactoring can still be done in volumes*.go
-
+// mountPoint is the intersection point between a volume and a container. It
+// specifies which volume is to be used and where inside a container it should
+// be mounted.
 type mountPoint struct {
 	Name        string
 	Destination string
@@ -29,6 +30,8 @@ type mountPoint struct {
 	Mode        string `json:"Relabel"` // Originally field was `Relabel`"
 }
 
+// Setup sets up a mount point by either mounting the volume if it is
+// configured, or creating the source directory if supplied.
 func (m *mountPoint) Setup() (string, error) {
 	if m.Volume != nil {
 		return m.Volume.Mount()
@@ -59,6 +62,7 @@ func (m *mountPoint) hasResource(absolutePath string) bool {
 	return err == nil && relPath != ".." && !strings.HasPrefix(relPath, fmt.Sprintf("..%c", filepath.Separator))
 }
 
+// Path returns the path of a volume in a mount point.
 func (m *mountPoint) Path() string {
 	if m.Volume != nil {
 		return m.Volume.Path()
@@ -67,6 +71,8 @@ func (m *mountPoint) Path() string {
 	return m.Source
 }
 
+// copyExistingContents copies from the source to the destination and
+// ensures the ownership is appropriately set.
 func copyExistingContents(source, destination string) error {
 	volList, err := ioutil.ReadDir(source)
 	if err != nil {

daemon/volumes_unix.go

@@ -21,7 +21,7 @@ import (
 )
 
 // copyOwnership copies the permissions and uid:gid of the source file
-// into the destination file
+// to the destination file
 func copyOwnership(source, destination string) error {
 	stat, err := system.Stat(source)
 	if err != nil {
@@ -35,6 +35,9 @@ func copyOwnership(source, destination string) error {
 	return os.Chmod(destination, os.FileMode(stat.Mode()))
 }
 
+// setupMounts iterates through each of the mount points for a container and
+// calls Setup() on each. It also looks to see if is a network mount such as
+// /etc/resolv.conf, and if it is not, appends it to the array of mounts.
 func (container *Container) setupMounts() ([]execdriver.Mount, error) {
 	var mounts []execdriver.Mount
 	for _, m := range container.MountPoints {
@@ -55,6 +58,7 @@ func (container *Container) setupMounts() ([]execdriver.Mount, error) {
 	return append(mounts, container.networkMounts()...), nil
 }
 
+// parseBindMount validates the configuration of mount information in runconfig is valid.
 func parseBindMount(spec string, mountLabel string, config *runconfig.Config) (*mountPoint, error) {
 	bind := &mountPoint{
 		RW: true,
@@ -97,6 +101,9 @@ func parseBindMount(spec string, mountLabel string, config *runconfig.Config) (*
 	return bind, nil
 }
 
+// sortMounts sorts an array of mounts in lexicographic order. This ensure that
+// when mounting, the mounts don't shadow other mounts. For example, if mounting
+// /etc and /etc/resolv.conf, /etc/resolv.conf must not be mounted first.
 func sortMounts(m []execdriver.Mount) []execdriver.Mount {
 	sort.Sort(mounts(m))
 	return m
@@ -104,18 +111,24 @@ func sortMounts(m []execdriver.Mount) []execdriver.Mount {
 
 type mounts []execdriver.Mount
 
+// Len returns the number of mounts
 func (m mounts) Len() int {
 	return len(m)
 }
 
+// Less returns true if the number of parts (a/b/c would be 3 parts) in the
+// mount indexed by parameter 1 is less than that of the mount indexed by
+// parameter 2.
 func (m mounts) Less(i, j int) bool {
 	return m.parts(i) < m.parts(j)
 }
 
+// Swap swaps two items in an array of mounts.
 func (m mounts) Swap(i, j int) {
 	m[i], m[j] = m[j], m[i]
 }
 
+// parts returns the number of parts in the destination of a mount.
 func (m mounts) parts(i int) int {
 	return len(strings.Split(filepath.Clean(m[i].Destination), string(os.PathSeparator)))
 }
@@ -243,6 +256,7 @@ func (daemon *Daemon) verifyVolumesInfo(container *Container) error {
 	return nil
 }
 
+// parseVolumesFrom ensure that the supplied volumes-from is valid.
 func parseVolumesFrom(spec string) (string, string, error) {
 	if len(spec) == 0 {
 		return "", "", fmt.Errorf("malformed volumes-from specification: %s", spec)
@@ -361,6 +375,7 @@ func (daemon *Daemon) registerMountPoints(container *Container, hostConfig *runc
 	return nil
 }
 
+// createVolume creates a volume.
 func createVolume(name, driverName string) (volume.Volume, error) {
 	vd, err := getVolumeDriver(driverName)
 	if err != nil {
@@ -369,6 +384,7 @@ func createVolume(name, driverName string) (volume.Volume, error) {
 	return vd.Create(name)
 }
 
+// removeVolume removes a volume.
 func removeVolume(v volume.Volume) error {
 	vd, err := getVolumeDriver(v.DriverName())
 	if err != nil {
@@ -377,6 +393,7 @@ func removeVolume(v volume.Volume) error {
 	return vd.Remove(v)
 }
 
+// getVolumeDriver returns the volume driver for the supplied name.
 func getVolumeDriver(name string) (volume.Driver, error) {
 	if name == "" {
 		name = volume.DefaultDriverName
@@ -384,6 +401,7 @@ func getVolumeDriver(name string) (volume.Driver, error) {
 	return volumedrivers.Lookup(name)
 }
 
+// parseVolumeSource parses the origin sources that's mounted into the container.
 func parseVolumeSource(spec string) (string, string, error) {
 	if !filepath.IsAbs(spec) {
 		return spec, "", nil

daemon/volumes_windows.go

@@ -7,11 +7,17 @@ import (
 	"github.com/docker/docker/runconfig"
 )
 
-// Not supported on Windows
+// copyOwnership copies the permissions and group of a source file to the
+// destination file. This is a no-op on Windows.
 func copyOwnership(source, destination string) error {
 	return nil
 }
 
+// setupMounts configures the mount points for a container.
+// setupMounts on Linux iterates through each of the mount points for a
+// container and calls Setup() on each. It also looks to see if is a network
+// mount such as /etc/resolv.conf, and if it is not, appends it to the array
+// of mounts. As Windows does not support mount points, this is a no-op.
 func (container *Container) setupMounts() ([]execdriver.Mount, error) {
 	return nil, nil
 }
@@ -22,7 +28,9 @@ func (daemon *Daemon) verifyVolumesInfo(container *Container) error {
 	return nil
 }
 
-// TODO Windows: This can be further factored out. Called from daemon\daemon.go
+// registerMountPoints initializes the container mount points with the
+// configured volumes and bind mounts. Windows does not support volumes or
+// mount points.
 func (daemon *Daemon) registerMountPoints(container *Container, hostConfig *runconfig.HostConfig) error {
 	return nil
 }