+ Support for data volumes

commands.go

@@ -10,6 +10,7 @@ import (
 	"log"
 	"net/http"
 	"net/url"
+	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"
@@ -400,7 +401,8 @@ func (srv *Server) CmdHistory(stdin io.ReadCloser, stdout io.Writer, args ...str
 }
 
 func (srv *Server) CmdRm(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
-	cmd := rcli.Subcmd(stdout, "rm", "CONTAINER [CONTAINER...]", "Remove a container")
+	cmd := rcli.Subcmd(stdout, "rm", "[OPTIONS] CONTAINER [CONTAINER...]", "Remove a container")
+	v := cmd.Bool("v", false, "Remove the volumes associated to the container")
 	if err := cmd.Parse(args); err != nil {
 		return nil
 	}
@@ -408,15 +410,40 @@ func (srv *Server) CmdRm(stdin io.ReadCloser, stdout io.Writer, args ...string)
 		cmd.Usage()
 		return nil
 	}
+	volumes := make(map[string]struct{})
 	for _, name := range cmd.Args() {
 		container := srv.runtime.Get(name)
 		if container == nil {
 			return fmt.Errorf("No such container: %s", name)
 		}
+		// Store all the deleted containers volumes
+		for _, volumeId := range container.Volumes {
+			volumes[volumeId] = struct{}{}
+		}
 		if err := srv.runtime.Destroy(container); err != nil {
 			fmt.Fprintln(stdout, "Error destroying container "+name+": "+err.Error())
 		}
 	}
+	if *v {
+		// Retrieve all volumes from all remaining containers
+		usedVolumes := make(map[string]*Container)
+		for _, container := range srv.runtime.List() {
+			for _, containerVolumeId := range container.Volumes {
+				usedVolumes[containerVolumeId] = container
+			}
+		}
+
+		for volumeId := range volumes {
+			// If the requested volu
+			if c, exists := usedVolumes[volumeId]; exists {
+				fmt.Fprintf(stdout, "The volume %s is used by the container %s. Impossible to remove it. Skipping.\n", volumeId, c.Id)
+				continue
+			}
+			if err := srv.runtime.volumes.Delete(volumeId); err != nil {
+				return err
+			}
+		}
+	}
 	return nil
 }
 
@@ -913,6 +940,25 @@ func (opts AttachOpts) Get(val string) bool {
 	return false
 }
 
+// PathOpts stores a unique set of absolute paths
+type PathOpts map[string]struct{}
+
+func NewPathOpts() PathOpts {
+	return make(PathOpts)
+}
+
+func (opts PathOpts) String() string {
+	return fmt.Sprintf("%v", map[string]struct{}(opts))
+}
+
+func (opts PathOpts) Set(val string) error {
+	if !filepath.IsAbs(val) {
+		return fmt.Errorf("%s is not an absolute path", val)
+	}
+	opts[filepath.Clean(val)] = struct{}{}
+	return nil
+}
+
 func (srv *Server) CmdTag(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
 	cmd := rcli.Subcmd(stdout, "tag", "[OPTIONS] IMAGE REPOSITORY [TAG]", "Tag an image into a repository")
 	force := cmd.Bool("f", false, "Force")

container.go

@@ -48,6 +48,7 @@ type Container struct {
 	runtime *Runtime
 
 	waitLock chan struct{}
+	Volumes  map[string]string
 }
 
 type Config struct {
@@ -66,6 +67,8 @@ type Config struct {
 	Cmd          []string
 	Dns          []string
 	Image        string // Name of the image as it was passed by the operator (eg. could be symbolic)
+	Volumes      map[string]struct{}
+	VolumesFrom  string
 }
 
 func ParseRun(args []string, stdout io.Writer, capabilities *Capabilities) (*Config, error) {
@@ -97,6 +100,11 @@ func ParseRun(args []string, stdout io.Writer, capabilities *Capabilities) (*Con
 	var flDns ListOpts
 	cmd.Var(&flDns, "dns", "Set custom dns servers")
 
+	flVolumes := NewPathOpts()
+	cmd.Var(flVolumes, "v", "Attach a data volume")
+
+	flVolumesFrom := cmd.String("volumes-from", "", "Mount volumes from the specified container")
+
 	if err := cmd.Parse(args); err != nil {
 		return nil, err
 	}
@@ -136,6 +144,8 @@ func ParseRun(args []string, stdout io.Writer, capabilities *Capabilities) (*Con
 		Cmd:          runCmd,
 		Dns:          flDns,
 		Image:        image,
+		Volumes:      flVolumes,
+		VolumesFrom:  *flVolumesFrom,
 	}
 
 	if *flMemory > 0 && !capabilities.SwapLimit {
@@ -394,10 +404,40 @@ func (container *Container) Start() error {
 		log.Printf("WARNING: Your kernel does not support swap limit capabilities. Limitation discarded.\n")
 		container.Config.MemorySwap = -1
 	}
+	container.Volumes = make(map[string]string)
+
+	// Create the requested volumes volumes
+	for volPath := range container.Config.Volumes {
+		if c, err := container.runtime.volumes.Create(nil, container, "", "", nil); err != nil {
+			return err
+		} else {
+			if err := os.MkdirAll(path.Join(container.RootfsPath(), volPath), 0755); err != nil {
+				return nil
+			}
+			container.Volumes[volPath] = c.Id
+		}
+	}
+
+	if container.Config.VolumesFrom != "" {
+		c := container.runtime.Get(container.Config.VolumesFrom)
+		if c == nil {
+			return fmt.Errorf("Container %s not found. Impossible to mount its volumes", container.Id)
+		}
+		for volPath, id := range c.Volumes {
+			if _, exists := container.Volumes[volPath]; exists {
+				return fmt.Errorf("The requested volume %s overlap one of the volume of the container %s", volPath, c.Id)
+			}
+			if err := os.MkdirAll(path.Join(container.RootfsPath(), volPath), 0755); err != nil {
+				return nil
+			}
+			container.Volumes[volPath] = id
+		}
+	}
 
 	if err := container.generateLXCConfig(); err != nil {
 		return err
 	}
+
 	params := []string{
 		"-n", container.Id,
 		"-f", container.lxcConfigPath(),
@@ -456,6 +496,7 @@ func (container *Container) Start() error {
 
 	// Init the lock
 	container.waitLock = make(chan struct{})
+
 	container.ToDisk()
 	go container.monitor()
 	return nil
@@ -787,6 +828,22 @@ func (container *Container) RootfsPath() string {
 	return path.Join(container.root, "rootfs")
 }
 
+func (container *Container) GetVolumes() (map[string]string, error) {
+	ret := make(map[string]string)
+	for volPath, id := range container.Volumes {
+		volume, err := container.runtime.volumes.Get(id)
+		if err != nil {
+			return nil, err
+		}
+		root, err := volume.root()
+		if err != nil {
+			return nil, err
+		}
+		ret[volPath] = path.Join(root, "layer")
+	}
+	return ret, nil
+}
+
 func (container *Container) rwPath() string {
 	return path.Join(container.root, "rw")
 }

docs/sources/commandline/command/run.rst

@@ -17,3 +17,5 @@
       -p=[]: Map a network port to the container
       -t=false: Allocate a pseudo-tty
       -u="": Username or UID
+      -d=[]: Set custom dns servers for the container
+      -v=[]: Creates a new volumes and mount it at the specified path. A container ID can be passed instead of a path in order to mount all volumes from the given container.

lxc_template.go

@@ -79,7 +79,11 @@ lxc.mount.entry = {{.SysInitPath}} {{$ROOTFS}}/sbin/init none bind,ro 0 0
 
 # In order to get a working DNS environment, mount bind (ro) the host's /etc/resolv.conf into the container
 lxc.mount.entry = {{.ResolvConfPath}} {{$ROOTFS}}/etc/resolv.conf none bind,ro 0 0
-
+{{if .Volumes}}
+{{range $virtualPath, $realPath := .GetVolumes}}
+lxc.mount.entry = {{$realPath}} {{$ROOTFS}}/{{$virtualPath}} none bind,rw 0 0
+{{end}}
+{{end}}
 
 # drop linux capabilities (apply mainly to the user root in the container)
 lxc.cap.drop = audit_control audit_write mac_admin mac_override mknod setfcap setpcap sys_admin sys_boot sys_module sys_nice sys_pacct sys_rawio sys_resource sys_time sys_tty_config

runtime.go

@@ -32,6 +32,7 @@ type Runtime struct {
 	capabilities   *Capabilities
 	kernelVersion  *KernelVersionInfo
 	autoRestart    bool
+	volumes        *Graph
 }
 
 var sysInitPath string
@@ -405,6 +406,10 @@ func NewRuntimeFromDirectory(root string, autoRestart bool) (*Runtime, error) {
 	if err != nil {
 		return nil, err
 	}
+	volumes, err := NewGraph(path.Join(root, "volumes"))
+	if err != nil {
+		return nil, err
+	}
 	repositories, err := NewTagStore(path.Join(root, "repositories"), g)
 	if err != nil {
 		return nil, fmt.Errorf("Couldn't create Tag store: %s", err)
@@ -432,6 +437,7 @@ func NewRuntimeFromDirectory(root string, autoRestart bool) (*Runtime, error) {
 		idIndex:        NewTruncIndex(),
 		capabilities:   &Capabilities{},
 		autoRestart:    autoRestart,
+		volumes:        volumes,
 	}
 
 	if err := runtime.restore(); err != nil {