package volume import ( "fmt" "os" "strings" "syscall" "github.com/docker/docker/pkg/stringid" "github.com/docker/docker/pkg/system" "github.com/opencontainers/runc/libcontainer/label" ) // DefaultDriverName is the driver name used for the driver // implemented in the local package. const DefaultDriverName = "local" // Scopes define if a volume has is cluster-wide (global) or local only. // Scopes are returned by the volume driver when it is queried for capabilities and then set on a volume const ( LocalScope = "local" GlobalScope = "global" ) // Driver is for creating and removing volumes. type Driver interface { // Name returns the name of the volume driver. Name() string // Create makes a new volume with the given id. Create(name string, opts map[string]string) (Volume, error) // Remove deletes the volume. Remove(vol Volume) (err error) // List lists all the volumes the driver has List() ([]Volume, error) // Get retrieves the volume with the requested name Get(name string) (Volume, error) // Scope returns the scope of the driver (e.g. `global` or `local`). // Scope determines how the driver is handled at a cluster level Scope() string } // Capability defines a set of capabilities that a driver is able to handle. type Capability struct { // Scope is the scope of the driver, `global` or `local` // A `global` scope indicates that the driver manages volumes across the cluster // A `local` scope indicates that the driver only manages volumes resources local to the host // Scope is declared by the driver Scope string } // Volume is a place to store data. It is backed by a specific driver, and can be mounted. type Volume interface { // Name returns the name of the volume Name() string // DriverName returns the name of the driver which owns this volume. DriverName() string // Path returns the absolute path to the volume. Path() string // Mount mounts the volume and returns the absolute path to // where it can be consumed. Mount(id string) (string, error) // Unmount unmounts the volume when it is no longer in use. Unmount(id string) error // Status returns low-level status information about a volume Status() map[string]interface{} } // LabeledVolume wraps a Volume with user-defined labels type LabeledVolume interface { Labels() map[string]string Volume } // ScopedVolume wraps a volume with a cluster scope (e.g., `local` or `global`) type ScopedVolume interface { Scope() string Volume } // 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 { Source string // Container host directory Destination string // Inside the container RW bool // True if writable Name string // Name set by user Driver string // Volume driver to use Volume Volume `json:"-"` // Note Mode is not used on Windows Mode string `json:"Relabel"` // Originally field was `Relabel`" // Note Propagation is not used on Windows Propagation string // Mount propagation string Named bool // specifies if the mountpoint was specified by name // Specifies if data should be copied from the container before the first mount // Use a pointer here so we can tell if the user set this value explicitly // This allows us to error out when the user explicitly enabled copy but we can't copy due to the volume being populated CopyData bool `json:"-"` // ID is the opaque ID used to pass to the volume driver. // This should be set by calls to `Mount` and unset by calls to `Unmount` ID string } // 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(mountLabel string) (string, error) { if m.Volume != nil { if m.ID == "" { m.ID = stringid.GenerateNonCryptoID() } return m.Volume.Mount(m.ID) } if len(m.Source) == 0 { return "", fmt.Errorf("Unable to setup mount point, neither source nor volume defined") } // system.MkdirAll() produces an error if m.Source exists and is a file (not a directory), if err := system.MkdirAll(m.Source, 0755); err != nil { if perr, ok := err.(*os.PathError); ok { if perr.Err != syscall.ENOTDIR { return "", err } } } if label.RelabelNeeded(m.Mode) { if err := label.Relabel(m.Source, mountLabel, label.IsShared(m.Mode)); err != nil { return "", err } } return m.Source, nil } // Path returns the path of a volume in a mount point. func (m *MountPoint) Path() string { if m.Volume != nil { return m.Volume.Path() } return m.Source } // Type returns the type of mount point func (m *MountPoint) Type() string { if m.Name != "" { return "volume" } if m.Source != "" { return "bind" } return "ephemeral" } // ParseVolumesFrom ensures that the supplied volumes-from is valid. func ParseVolumesFrom(spec string) (string, string, error) { if len(spec) == 0 { return "", "", fmt.Errorf("volumes-from specification cannot be an empty string") } specParts := strings.SplitN(spec, ":", 2) id := specParts[0] mode := "rw" if len(specParts) == 2 { mode = specParts[1] if !ValidMountMode(mode) { return "", "", errInvalidMode(mode) } // For now don't allow propagation properties while importing // volumes from data container. These volumes will inherit // the same propagation property as of the original volume // in data container. This probably can be relaxed in future. if HasPropagation(mode) { return "", "", errInvalidMode(mode) } // Do not allow copy modes on volumes-from if _, isSet := getCopyMode(mode); isSet { return "", "", errInvalidMode(mode) } } return id, mode, nil } func errInvalidMode(mode string) error { return fmt.Errorf("invalid mode: %v", mode) } func errInvalidSpec(spec string) error { return fmt.Errorf("Invalid volume specification: '%s'", spec) }