graphdriver

package
Version: v20.10.7+incompatible Latest Latest
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Published: Jun 1, 2021 License: Apache-2.0 Imports: 22 Imported by: 721

Documentation

Index

Constants

View Source
const (
	// FsMagicAufs filesystem id for Aufs
	FsMagicAufs = FsMagic(0x61756673)
	// FsMagicBtrfs filesystem id for Btrfs
	FsMagicBtrfs = FsMagic(0x9123683E)
	// FsMagicCramfs filesystem id for Cramfs
	FsMagicCramfs = FsMagic(0x28cd3d45)
	// FsMagicEcryptfs filesystem id for eCryptfs
	FsMagicEcryptfs = FsMagic(0xf15f)
	// FsMagicExtfs filesystem id for Extfs
	FsMagicExtfs = FsMagic(0x0000EF53)
	// FsMagicF2fs filesystem id for F2fs
	FsMagicF2fs = FsMagic(0xF2F52010)
	// FsMagicGPFS filesystem id for GPFS
	FsMagicGPFS = FsMagic(0x47504653)
	// FsMagicJffs2Fs filesystem if for Jffs2Fs
	FsMagicJffs2Fs = FsMagic(0x000072b6)
	// FsMagicJfs filesystem id for Jfs
	FsMagicJfs = FsMagic(0x3153464a)
	// FsMagicNfsFs filesystem id for NfsFs
	FsMagicNfsFs = FsMagic(0x00006969)
	// FsMagicRAMFs filesystem id for RamFs
	FsMagicRAMFs = FsMagic(0x858458f6)
	// FsMagicReiserFs filesystem id for ReiserFs
	FsMagicReiserFs = FsMagic(0x52654973)
	// FsMagicSmbFs filesystem id for SmbFs
	FsMagicSmbFs = FsMagic(0x0000517B)
	// FsMagicSquashFs filesystem id for SquashFs
	FsMagicSquashFs = FsMagic(0x73717368)
	// FsMagicTmpFs filesystem id for TmpFs
	FsMagicTmpFs = FsMagic(0x01021994)
	// FsMagicVxFS filesystem id for VxFs
	FsMagicVxFS = FsMagic(0xa501fcf5)
	// FsMagicXfs filesystem id for Xfs
	FsMagicXfs = FsMagic(0x58465342)
	// FsMagicZfs filesystem id for Zfs
	FsMagicZfs = FsMagic(0x2fc12fc1)
	// FsMagicOverlay filesystem id for overlay
	FsMagicOverlay = FsMagic(0x794C7630)
	// FsMagicFUSE filesystem id for FUSE
	FsMagicFUSE = FsMagic(0x65735546)
)
View Source
const (
	// FsMagicUnsupported is a predefined constant value other than a valid filesystem id.
	FsMagicUnsupported = FsMagic(0x00000000)
)

Variables

View Source
var (
	// ApplyUncompressedLayer defines the unpack method used by the graph
	// driver.
	ApplyUncompressedLayer = chrootarchive.ApplyUncompressedLayer
)
View Source
var (

	// FsNames maps filesystem id to name of the filesystem.
	FsNames = map[FsMagic]string{
		FsMagicAufs:        "aufs",
		FsMagicBtrfs:       "btrfs",
		FsMagicCramfs:      "cramfs",
		FsMagicEcryptfs:    "ecryptfs",
		FsMagicExtfs:       "extfs",
		FsMagicF2fs:        "f2fs",
		FsMagicFUSE:        "fuse",
		FsMagicGPFS:        "gpfs",
		FsMagicJffs2Fs:     "jffs2",
		FsMagicJfs:         "jfs",
		FsMagicNfsFs:       "nfs",
		FsMagicOverlay:     "overlayfs",
		FsMagicRAMFs:       "ramfs",
		FsMagicReiserFs:    "reiserfs",
		FsMagicSmbFs:       "smb",
		FsMagicSquashFs:    "squashfs",
		FsMagicTmpFs:       "tmpfs",
		FsMagicUnsupported: "unsupported",
		FsMagicVxFS:        "vxfs",
		FsMagicXfs:         "xfs",
		FsMagicZfs:         "zfs",
	}
)

Functions

func IsDriverNotSupported

func IsDriverNotSupported(err error) bool

IsDriverNotSupported returns true if the error initializing the graph driver is a non-supported error.

func IsInitialized

func IsInitialized(driverHome string) bool

IsInitialized checks if the driver's home-directory exists and is non-empty.

func Mounted

func Mounted(fsType FsMagic, mountPath string) (bool, error)

Mounted checks if the given path is mounted as the fs type

func Register

func Register(name string, initFunc InitFunc) error

Register registers an InitFunc for the driver.

Types

type Capabilities

type Capabilities struct {
	// Flags that this driver is capable of reproducing exactly equivalent
	// diffs for read-only layers. If set, clients can rely on the driver
	// for consistent tar streams, and avoid extra processing to account
	// for potential differences (eg: the layer store's use of tar-split).
	ReproducesExactDiffs bool
}

Capabilities defines a list of capabilities a driver may implement. These capabilities are not required; however, they do determine how a graphdriver can be used.

type CapabilityDriver

type CapabilityDriver interface {
	Capabilities() Capabilities
}

CapabilityDriver is the interface for layered file system drivers that can report on their Capabilities.

type Checker

type Checker interface {
	// IsMounted returns true if the provided path is mounted for the specific checker
	IsMounted(path string) bool
}

Checker makes checks on specified filesystems.

func NewDefaultChecker

func NewDefaultChecker() Checker

NewDefaultChecker returns a check that parses /proc/mountinfo to check if the specified path is mounted.

func NewFsChecker

func NewFsChecker(t FsMagic) Checker

NewFsChecker returns a checker configured for the provided FsMagic

type CreateOpts

type CreateOpts struct {
	MountLabel string
	StorageOpt map[string]string
}

CreateOpts contains optional arguments for Create() and CreateReadWrite() methods.

type DiffDriver

type DiffDriver interface {
	// Diff produces an archive of the changes between the specified
	// layer and its parent layer which may be "".
	Diff(id, parent string) (io.ReadCloser, error)
	// Changes produces a list of changes between the specified layer
	// and its parent layer. If parent is "", then all changes will be ADD changes.
	Changes(id, parent string) ([]archive.Change, error)
	// ApplyDiff extracts the changeset from the given diff into the
	// layer with the specified id and parent, returning the size of the
	// new layer in bytes.
	// The archive.Reader must be an uncompressed stream.
	ApplyDiff(id, parent string, diff io.Reader) (size int64, err error)
	// DiffSize calculates the changes between the specified id
	// and its parent and returns the size in bytes of the changes
	// relative to its base filesystem directory.
	DiffSize(id, parent string) (size int64, err error)
}

DiffDriver is the interface to use to implement graph diffs

type DiffGetterDriver

type DiffGetterDriver interface {
	Driver
	// DiffGetter returns an interface to efficiently retrieve the contents
	// of files in a layer.
	DiffGetter(id string) (FileGetCloser, error)
}

DiffGetterDriver is the interface for layered file system drivers that provide a specialized function for getting file contents for tar-split.

type Driver

type Driver interface {
	ProtoDriver
	DiffDriver
}

Driver is the interface for layered/snapshot file system drivers.

func GetDriver

func GetDriver(name string, pg plugingetter.PluginGetter, config Options) (Driver, error)

GetDriver initializes and returns the registered driver

func New

func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, error)

New creates the driver and initializes it at the specified root.

func NewNaiveDiffDriver

func NewNaiveDiffDriver(driver ProtoDriver, uidMaps, gidMaps []idtools.IDMap) Driver

NewNaiveDiffDriver returns a fully functional driver that wraps the given ProtoDriver and adds the capability of the following methods which it may or may not support on its own:

Diff(id, parent string) (archive.Archive, error)
Changes(id, parent string) ([]archive.Change, error)
ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)
DiffSize(id, parent string) (size int64, err error)

type ErrUnSupported

type ErrUnSupported interface {
	NotSupported()
}

ErrUnSupported signals that the graph-driver is not supported on the current configuration

type FileGetCloser

type FileGetCloser interface {
	storage.FileGetter
	// Close cleans up any resources associated with the FileGetCloser.
	Close() error
}

FileGetCloser extends the storage.FileGetter interface with a Close method for cleaning up.

type FsMagic

type FsMagic uint32

FsMagic unsigned id of the filesystem in use.

func GetFSMagic

func GetFSMagic(rootpath string) (FsMagic, error)

GetFSMagic returns the filesystem id given the path.

type InitFunc

type InitFunc func(root string, options []string, uidMaps, gidMaps []idtools.IDMap) (Driver, error)

InitFunc initializes the storage driver.

type NaiveDiffDriver

type NaiveDiffDriver struct {
	ProtoDriver
	// contains filtered or unexported fields
}

NaiveDiffDriver takes a ProtoDriver and adds the capability of the Diffing methods on the local file system, which it may or may not support on its own. See the comment on the exported NewNaiveDiffDriver function below. Notably, the AUFS driver doesn't need to be wrapped like this.

func (*NaiveDiffDriver) ApplyDiff

func (gdw *NaiveDiffDriver) ApplyDiff(id, parent string, diff io.Reader) (size int64, err error)

ApplyDiff extracts the changeset from the given diff into the layer with the specified id and parent, returning the size of the new layer in bytes.

func (*NaiveDiffDriver) Changes

func (gdw *NaiveDiffDriver) Changes(id, parent string) ([]archive.Change, error)

Changes produces a list of changes between the specified layer and its parent layer. If parent is "", then all changes will be ADD changes.

func (*NaiveDiffDriver) Diff

func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch io.ReadCloser, err error)

Diff produces an archive of the changes between the specified layer and its parent layer which may be "".

func (*NaiveDiffDriver) DiffSize

func (gdw *NaiveDiffDriver) DiffSize(id, parent string) (size int64, err error)

DiffSize calculates the changes between the specified layer and its parent and returns the size in bytes of the changes relative to its base filesystem directory.

type NotSupportedError

type NotSupportedError string

NotSupportedError signals that the graph-driver is not supported on the current configuration

const (
	// ErrNotSupported returned when driver is not supported.
	ErrNotSupported NotSupportedError = "driver not supported"
	// ErrPrerequisites returned when driver does not meet prerequisites.
	ErrPrerequisites NotSupportedError = "prerequisites for driver not satisfied (wrong filesystem?)"
	// ErrIncompatibleFS returned when file system is not supported.
	ErrIncompatibleFS NotSupportedError = "backing file system is unsupported for this graph driver"
)

func (NotSupportedError) Error

func (e NotSupportedError) Error() string

func (NotSupportedError) NotSupported

func (e NotSupportedError) NotSupported()

NotSupported signals that a graph-driver is not supported.

type Options

type Options struct {
	Root                string
	DriverOptions       []string
	UIDMaps             []idtools.IDMap
	GIDMaps             []idtools.IDMap
	ExperimentalEnabled bool
}

Options is used to initialize a graphdriver

type ProtoDriver

type ProtoDriver interface {
	// String returns a string representation of this driver.
	String() string
	// CreateReadWrite creates a new, empty filesystem layer that is ready
	// to be used as the storage for a container. Additional options can
	// be passed in opts. parent may be "" and opts may be nil.
	CreateReadWrite(id, parent string, opts *CreateOpts) error
	// Create creates a new, empty, filesystem layer with the
	// specified id and parent and options passed in opts. Parent
	// may be "" and opts may be nil.
	Create(id, parent string, opts *CreateOpts) error
	// Remove attempts to remove the filesystem layer with this id.
	Remove(id string) error
	// Get returns the mountpoint for the layered filesystem referred
	// to by this id. You can optionally specify a mountLabel or "".
	// Returns the absolute path to the mounted layered filesystem.
	Get(id, mountLabel string) (fs containerfs.ContainerFS, err error)
	// Put releases the system resources for the specified id,
	// e.g, unmounting layered filesystem.
	Put(id string) error
	// Exists returns whether a filesystem layer with the specified
	// ID exists on this driver.
	Exists(id string) bool
	// Status returns a set of key-value pairs which give low
	// level diagnostic status about this driver.
	Status() [][2]string
	// Returns a set of key-value pairs which give low level information
	// about the image/container driver is managing.
	GetMetadata(id string) (map[string]string, error)
	// Cleanup performs necessary tasks to release resources
	// held by the driver, e.g., unmounting all layered filesystems
	// known to this driver.
	Cleanup() error
}

ProtoDriver defines the basic capabilities of a driver. This interface exists solely to be a minimum set of methods for client code which choose not to implement the entire Driver interface and use the NaiveDiffDriver wrapper constructor.

Use of ProtoDriver directly by client code is not recommended.

type RefCounter

type RefCounter struct {
	// contains filtered or unexported fields
}

RefCounter is a generic counter for use by graphdriver Get/Put calls

func NewRefCounter

func NewRefCounter(c Checker) *RefCounter

NewRefCounter returns a new RefCounter

func (*RefCounter) Decrement

func (c *RefCounter) Decrement(path string) int

Decrement decreases the ref count for the given id and returns the current count

func (*RefCounter) Increment

func (c *RefCounter) Increment(path string) int

Increment increases the ref count for the given id and returns the current count

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