Move responsibility of ls/inspect to volume driver

Makes `docker volume ls` and `docker volume inspect` ask the volume
drivers rather than only using what is cached locally.

Previously in order to use a volume from an external driver, one would
either have to use `docker volume create` or have a container that is
already using that volume for it to be visible to the other volume
API's.

For keeping uniqueness of volume names in the daemon, names are bound to
a driver on a first come first serve basis. If two drivers have a volume
with the same name, the first one is chosen, and a warning is logged
about the second one.

Adds 2 new methods to the plugin API, `List` and `Get`.
If a plugin does not implement these endpoints, a user will not be able
to find the specified volumes as well requests go through the drivers.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

Author: cpuguy83

api/client/volume.go

@@ -65,6 +65,9 @@ func (cli *DockerCli) CmdVolumeLs(args ...string) error {
 
 	w := tabwriter.NewWriter(cli.out, 20, 1, 3, ' ', 0)
 	if !*quiet {
+		for _, warn := range volumes.Warnings {
+			fmt.Fprintln(cli.err, warn)
+		}
 		fmt.Fprintf(w, "DRIVER \tVOLUME NAME")
 		fmt.Fprintf(w, "\n")
 	}
@@ -102,7 +105,7 @@ func (cli *DockerCli) CmdVolumeInspect(args ...string) error {
 	return cli.inspectElements(*tmplStr, cmd.Args(), inspectSearcher)
 }
 
-// CmdVolumeCreate creates a new container from a given image.
+// CmdVolumeCreate creates a new volume.
 //
 // Usage: docker volume create [OPTIONS]
 func (cli *DockerCli) CmdVolumeCreate(args ...string) error {
@@ -131,7 +134,7 @@ func (cli *DockerCli) CmdVolumeCreate(args ...string) error {
 	return nil
 }
 
-// CmdVolumeRm removes one or more containers.
+// CmdVolumeRm removes one or more volumes.
 //
 // Usage: docker volume rm VOLUME [VOLUME...]
 func (cli *DockerCli) CmdVolumeRm(args ...string) error {
@@ -140,6 +143,7 @@ func (cli *DockerCli) CmdVolumeRm(args ...string) error {
 	cmd.ParseFlags(args, true)
 
 	var status = 0
+
 	for _, name := range cmd.Args() {
 		if err := cli.client.VolumeRemove(name); err != nil {
 			fmt.Fprintf(cli.err, "%s\n", err)

api/server/router/volume/backend.go

@@ -8,7 +8,7 @@ import (
 // Backend is the methods that need to be implemented to provide
 // volume specific functionality
 type Backend interface {
-	Volumes(filter string) ([]*types.Volume, error)
+	Volumes(filter string) ([]*types.Volume, []string, error)
 	VolumeInspect(name string) (*types.Volume, error)
 	VolumeCreate(name, driverName string,
 		opts map[string]string) (*types.Volume, error)

api/server/router/volume/volume_routes.go

@@ -14,11 +14,11 @@ func (v *volumeRouter) getVolumesList(ctx context.Context, w http.ResponseWriter
 		return err
 	}
 
-	volumes, err := v.backend.Volumes(r.Form.Get("filters"))
+	volumes, warnings, err := v.backend.Volumes(r.Form.Get("filters"))
 	if err != nil {
 		return err
 	}
-	return httputils.WriteJSON(w, http.StatusOK, &types.VolumesListResponse{Volumes: volumes})
+	return httputils.WriteJSON(w, http.StatusOK, &types.VolumesListResponse{Volumes: volumes, Warnings: warnings})
 }
 
 func (v *volumeRouter) getVolumeByName(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

api/types/types.go

@@ -366,7 +366,8 @@ type Volume struct {
 // VolumesListResponse contains the response for the remote API:
 // GET "/volumes"
 type VolumesListResponse struct {
-	Volumes []*Volume // Volumes is the list of volumes being returned
+	Volumes  []*Volume // Volumes is the list of volumes being returned
+	Warnings []string  // Warnings is a list of warnings that occurred when getting the list from the volume drivers
 }
 
 // VolumeCreateRequest contains the response for the remote API:

daemon/create.go

@@ -10,7 +10,7 @@ import (
 	"github.com/docker/docker/layer"
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/stringid"
-	"github.com/docker/docker/volume"
+	volumestore "github.com/docker/docker/volume/store"
 	"github.com/opencontainers/runc/libcontainer/label"
 )
 
@@ -162,17 +162,12 @@ func (daemon *Daemon) VolumeCreate(name, driverName string, opts map[string]stri
 
 	v, err := daemon.volumes.Create(name, driverName, opts)
 	if err != nil {
+		if volumestore.IsNameConflict(err) {
+			return nil, derr.ErrorVolumeNameTaken.WithArgs(name)
+		}
 		return nil, err
 	}
 
-	// keep "docker run -v existing_volume:/foo --volume-driver other_driver" work
-	if (driverName != "" && v.DriverName() != driverName) || (driverName == "" && v.DriverName() != volume.DefaultDriverName) {
-		return nil, derr.ErrorVolumeNameTaken.WithArgs(name, v.DriverName())
-	}
-
-	if driverName == "" {
-		driverName = volume.DefaultDriverName
-	}
-	daemon.LogVolumeEvent(name, "create", map[string]string{"driver": driverName})
+	daemon.LogVolumeEvent(v.Name(), "create", map[string]string{"driver": v.DriverName()})
 	return volumeToAPIType(v), nil
 }

daemon/create_unix.go

@@ -51,7 +51,7 @@ func (daemon *Daemon) createContainerPlatformSpecificSettings(container *contain
 			}
 		}
 
-		v, err := daemon.createVolume(name, volumeDriver, nil)
+		v, err := daemon.volumes.CreateWithRef(name, volumeDriver, container.ID, nil)
 		if err != nil {
 			return err
 		}

daemon/create_windows.go

@@ -42,7 +42,7 @@ func (daemon *Daemon) createContainerPlatformSpecificSettings(container *contain
 
 		// Create the volume in the volume driver. If it doesn't exist,
 		// a new one will be created.
-		v, err := daemon.createVolume(mp.Name, volumeDriver, nil)
+		v, err := daemon.volumes.CreateWithRef(mp.Name, volumeDriver, container.ID, nil)
 		if err != nil {
 			return err
 		}

daemon/daemon.go

@@ -1470,10 +1470,7 @@ func configureVolumes(config *Config, rootUID, rootGID int) (*store.VolumeStore,
 	}
 
 	volumedrivers.Register(volumesDriver, volumesDriver.Name())
-	s := store.New()
-	s.AddAll(volumesDriver.List())
-
-	return s, nil
+	return store.New(), nil
 }
 
 // AuthenticateToRegistry checks the validity of credentials in authConfig

daemon/delete.go

@@ -151,6 +151,7 @@ func (daemon *Daemon) VolumeRm(name string) error {
 	if err != nil {
 		return err
 	}
+
 	if err := daemon.volumes.Remove(v); err != nil {
 		if volumestore.IsInUse(err) {
 			return derr.ErrorCodeRmVolumeInUse.WithArgs(err)

daemon/list.go

@@ -392,24 +392,27 @@ func (daemon *Daemon) transformContainer(container *container.Container, ctx *li
 
 // Volumes lists known volumes, using the filter to restrict the range
 // of volumes returned.
-func (daemon *Daemon) Volumes(filter string) ([]*types.Volume, error) {
+func (daemon *Daemon) Volumes(filter string) ([]*types.Volume, []string, error) {
 	var volumesOut []*types.Volume
 	volFilters, err := filters.FromParam(filter)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	filterUsed := volFilters.Include("dangling") &&
 		(volFilters.ExactMatch("dangling", "true") || volFilters.ExactMatch("dangling", "1"))
 
-	volumes := daemon.volumes.List()
+	volumes, warnings, err := daemon.volumes.List()
+	if err != nil {
+		return nil, nil, err
+	}
+	if filterUsed {
+		volumes = daemon.volumes.FilterByUsed(volumes)
+	}
 	for _, v := range volumes {
-		if filterUsed && daemon.volumes.Count(v) > 0 {
-			continue
-		}
 		volumesOut = append(volumesOut, volumeToAPIType(v))
 	}
-	return volumesOut, nil
+	return volumesOut, warnings, nil
 }
 
 func populateImageFilterByParents(ancestorMap map[image.ID]bool, imageID image.ID, getChildren func(image.ID) []image.ID) {

daemon/mounts.go

@@ -11,10 +11,11 @@ import (
 func (daemon *Daemon) prepareMountPoints(container *container.Container) error {
 	for _, config := range container.MountPoints {
 		if len(config.Driver) > 0 {
-			v, err := daemon.createVolume(config.Name, config.Driver, nil)
+			v, err := daemon.volumes.GetWithRef(config.Name, config.Driver, container.ID)
 			if err != nil {
 				return err
 			}
+
 			config.Volume = v
 		}
 	}
@@ -27,10 +28,10 @@ func (daemon *Daemon) removeMountPoints(container *container.Container, rm bool)
 		if m.Volume == nil {
 			continue
 		}
-		daemon.volumes.Decrement(m.Volume)
+		daemon.volumes.Dereference(m.Volume, container.ID)
 		if rm {
 			err := daemon.volumes.Remove(m.Volume)
-			// ErrVolumeInUse is ignored because having this
+			// Ignore volume in use errors because having this
 			// volume being referenced by other container is
 			// not an error, but an implementation detail.
 			// This prevents docker from logging "ERROR: Volume in use"

daemon/volumes.go

@@ -32,16 +32,6 @@ func volumeToAPIType(v volume.Volume) *types.Volume {
 	}
 }
 
-// createVolume creates a volume.
-func (daemon *Daemon) createVolume(name, driverName string, opts map[string]string) (volume.Volume, error) {
-	v, err := daemon.volumes.Create(name, driverName, opts)
-	if err != nil {
-		return nil, err
-	}
-	daemon.volumes.Increment(v)
-	return v, nil
-}
-
 // Len returns the number of mounts. Used in sorting.
 func (m mounts) Len() int {
 	return len(m)
@@ -103,7 +93,7 @@ func (daemon *Daemon) registerMountPoints(container *container.Container, hostCo
 			}
 
 			if len(cp.Source) == 0 {
-				v, err := daemon.createVolume(cp.Name, cp.Driver, nil)
+				v, err := daemon.volumes.GetWithRef(cp.Name, cp.Driver, container.ID)
 				if err != nil {
 					return err
 				}
@@ -128,7 +118,7 @@ func (daemon *Daemon) registerMountPoints(container *container.Container, hostCo
 
 		if len(bind.Name) > 0 && len(bind.Driver) > 0 {
 			// create the volume
-			v, err := daemon.createVolume(bind.Name, bind.Driver, nil)
+			v, err := daemon.volumes.CreateWithRef(bind.Name, bind.Driver, container.ID, nil)
 			if err != nil {
 				return err
 			}
@@ -153,7 +143,7 @@ func (daemon *Daemon) registerMountPoints(container *container.Container, hostCo
 	for _, m := range mountPoints {
 		if m.BackwardsCompatible() {
 			if mp, exists := container.MountPoints[m.Destination]; exists && mp.Volume != nil {
-				daemon.volumes.Decrement(mp.Volume)
+				daemon.volumes.Dereference(mp.Volume, container.ID)
 			}
 		}
 	}

errors/daemon.go

@@ -908,7 +908,7 @@ var (
 	// trying to create a volume that has existed using different driver.
 	ErrorVolumeNameTaken = errcode.Register(errGroup, errcode.ErrorDescriptor{
 		Value:          "VOLUME_NAME_TAKEN",
-		Message:        "A volume named %q already exists with the %q driver. Choose a different volume name.",
+		Message:        "A volume named %s already exists. Choose a different volume name.",
 		Description:    "An attempt to create a volume using a driver but the volume already exists with a different driver",
 		HTTPStatusCode: http.StatusInternalServerError,
 	})

integration-cli/docker_cli_daemon_test.go

@@ -1733,8 +1733,8 @@ func (s *DockerDaemonSuite) TestDaemonRestartRmVolumeInUse(c *check.C) {
 	c.Assert(s.d.Restart(), check.IsNil)
 
 	out, err = s.d.Cmd("volume", "rm", "test")
-	c.Assert(err, check.Not(check.IsNil), check.Commentf("should not be able to remove in use volume after daemon restart"))
-	c.Assert(strings.Contains(out, "in use"), check.Equals, true)
+	c.Assert(err, check.NotNil, check.Commentf("should not be able to remove in use volume after daemon restart"))
+	c.Assert(out, checker.Contains, "in use")
 }
 
 func (s *DockerDaemonSuite) TestDaemonRestartLocalVolumes(c *check.C) {