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moby--moby/vendor/github.com/mistifyio/go-zfs/zfs.go
Alexander Morozov f2614f2107 project: use vndr for vendoring
Signed-off-by: Alexander Morozov <lk4d4@docker.com>
2016-11-03 15:31:46 -07:00

451 lines
12 KiB
Go

// Package zfs provides wrappers around the ZFS command line tools.
package zfs
import (
"errors"
"fmt"
"io"
"strconv"
"strings"
)
// ZFS dataset types, which can indicate if a dataset is a filesystem,
// snapshot, or volume.
const (
DatasetFilesystem = "filesystem"
DatasetSnapshot = "snapshot"
DatasetVolume = "volume"
)
// Dataset is a ZFS dataset. A dataset could be a clone, filesystem, snapshot,
// or volume. The Type struct member can be used to determine a dataset's type.
//
// The field definitions can be found in the ZFS manual:
// http://www.freebsd.org/cgi/man.cgi?zfs(8).
type Dataset struct {
Name string
Origin string
Used uint64
Avail uint64
Mountpoint string
Compression string
Type string
Written uint64
Volsize uint64
Logicalused uint64
Usedbydataset uint64
Quota uint64
}
// InodeType is the type of inode as reported by Diff
type InodeType int
// Types of Inodes
const (
_ = iota // 0 == unknown type
BlockDevice InodeType = iota
CharacterDevice
Directory
Door
NamedPipe
SymbolicLink
EventPort
Socket
File
)
// ChangeType is the type of inode change as reported by Diff
type ChangeType int
// Types of Changes
const (
_ = iota // 0 == unknown type
Removed ChangeType = iota
Created
Modified
Renamed
)
// DestroyFlag is the options flag passed to Destroy
type DestroyFlag int
// Valid destroy options
const (
DestroyDefault DestroyFlag = 1 << iota
DestroyRecursive = 1 << iota
DestroyRecursiveClones = 1 << iota
DestroyDeferDeletion = 1 << iota
DestroyForceUmount = 1 << iota
)
// InodeChange represents a change as reported by Diff
type InodeChange struct {
Change ChangeType
Type InodeType
Path string
NewPath string
ReferenceCountChange int
}
// Logger can be used to log commands/actions
type Logger interface {
Log(cmd []string)
}
type defaultLogger struct{}
func (*defaultLogger) Log(cmd []string) {
return
}
var logger Logger = &defaultLogger{}
// SetLogger set a log handler to log all commands including arguments before
// they are executed
func SetLogger(l Logger) {
if l != nil {
logger = l
}
}
// zfs is a helper function to wrap typical calls to zfs.
func zfs(arg ...string) ([][]string, error) {
c := command{Command: "zfs"}
return c.Run(arg...)
}
// Datasets returns a slice of ZFS datasets, regardless of type.
// A filter argument may be passed to select a dataset with the matching name,
// or empty string ("") may be used to select all datasets.
func Datasets(filter string) ([]*Dataset, error) {
return listByType("all", filter)
}
// Snapshots returns a slice of ZFS snapshots.
// A filter argument may be passed to select a snapshot with the matching name,
// or empty string ("") may be used to select all snapshots.
func Snapshots(filter string) ([]*Dataset, error) {
return listByType(DatasetSnapshot, filter)
}
// Filesystems returns a slice of ZFS filesystems.
// A filter argument may be passed to select a filesystem with the matching name,
// or empty string ("") may be used to select all filesystems.
func Filesystems(filter string) ([]*Dataset, error) {
return listByType(DatasetFilesystem, filter)
}
// Volumes returns a slice of ZFS volumes.
// A filter argument may be passed to select a volume with the matching name,
// or empty string ("") may be used to select all volumes.
func Volumes(filter string) ([]*Dataset, error) {
return listByType(DatasetVolume, filter)
}
// GetDataset retrieves a single ZFS dataset by name. This dataset could be
// any valid ZFS dataset type, such as a clone, filesystem, snapshot, or volume.
func GetDataset(name string) (*Dataset, error) {
out, err := zfs("list", "-Hp", "-o", dsPropListOptions, name)
if err != nil {
return nil, err
}
ds := &Dataset{Name: name}
for _, line := range out {
if err := ds.parseLine(line); err != nil {
return nil, err
}
}
return ds, nil
}
// Clone clones a ZFS snapshot and returns a clone dataset.
// An error will be returned if the input dataset is not of snapshot type.
func (d *Dataset) Clone(dest string, properties map[string]string) (*Dataset, error) {
if d.Type != DatasetSnapshot {
return nil, errors.New("can only clone snapshots")
}
args := make([]string, 2, 4)
args[0] = "clone"
args[1] = "-p"
if properties != nil {
args = append(args, propsSlice(properties)...)
}
args = append(args, []string{d.Name, dest}...)
_, err := zfs(args...)
if err != nil {
return nil, err
}
return GetDataset(dest)
}
// Unmount unmounts currently mounted ZFS file systems.
func (d *Dataset) Unmount(force bool) (*Dataset, error) {
if d.Type == DatasetSnapshot {
return nil, errors.New("cannot unmount snapshots")
}
args := make([]string, 1, 3)
args[0] = "umount"
if force {
args = append(args, "-f")
}
args = append(args, d.Name)
_, err := zfs(args...)
if err != nil {
return nil, err
}
return GetDataset(d.Name)
}
// Mount mounts ZFS file systems.
func (d *Dataset) Mount(overlay bool, options []string) (*Dataset, error) {
if d.Type == DatasetSnapshot {
return nil, errors.New("cannot mount snapshots")
}
args := make([]string, 1, 5)
args[0] = "mount"
if overlay {
args = append(args, "-O")
}
if options != nil {
args = append(args, "-o")
args = append(args, strings.Join(options, ","))
}
args = append(args, d.Name)
_, err := zfs(args...)
if err != nil {
return nil, err
}
return GetDataset(d.Name)
}
// ReceiveSnapshot receives a ZFS stream from the input io.Reader, creates a
// new snapshot with the specified name, and streams the input data into the
// newly-created snapshot.
func ReceiveSnapshot(input io.Reader, name string) (*Dataset, error) {
c := command{Command: "zfs", Stdin: input}
_, err := c.Run("receive", name)
if err != nil {
return nil, err
}
return GetDataset(name)
}
// SendSnapshot sends a ZFS stream of a snapshot to the input io.Writer.
// An error will be returned if the input dataset is not of snapshot type.
func (d *Dataset) SendSnapshot(output io.Writer) error {
if d.Type != DatasetSnapshot {
return errors.New("can only send snapshots")
}
c := command{Command: "zfs", Stdout: output}
_, err := c.Run("send", d.Name)
return err
}
// CreateVolume creates a new ZFS volume with the specified name, size, and
// properties.
// A full list of available ZFS properties may be found here:
// https://www.freebsd.org/cgi/man.cgi?zfs(8).
func CreateVolume(name string, size uint64, properties map[string]string) (*Dataset, error) {
args := make([]string, 4, 5)
args[0] = "create"
args[1] = "-p"
args[2] = "-V"
args[3] = strconv.FormatUint(size, 10)
if properties != nil {
args = append(args, propsSlice(properties)...)
}
args = append(args, name)
_, err := zfs(args...)
if err != nil {
return nil, err
}
return GetDataset(name)
}
// Destroy destroys a ZFS dataset. If the destroy bit flag is set, any
// descendents of the dataset will be recursively destroyed, including snapshots.
// If the deferred bit flag is set, the snapshot is marked for deferred
// deletion.
func (d *Dataset) Destroy(flags DestroyFlag) error {
args := make([]string, 1, 3)
args[0] = "destroy"
if flags&DestroyRecursive != 0 {
args = append(args, "-r")
}
if flags&DestroyRecursiveClones != 0 {
args = append(args, "-R")
}
if flags&DestroyDeferDeletion != 0 {
args = append(args, "-d")
}
if flags&DestroyForceUmount != 0 {
args = append(args, "-f")
}
args = append(args, d.Name)
_, err := zfs(args...)
return err
}
// SetProperty sets a ZFS property on the receiving dataset.
// A full list of available ZFS properties may be found here:
// https://www.freebsd.org/cgi/man.cgi?zfs(8).
func (d *Dataset) SetProperty(key, val string) error {
prop := strings.Join([]string{key, val}, "=")
_, err := zfs("set", prop, d.Name)
return err
}
// GetProperty returns the current value of a ZFS property from the
// receiving dataset.
// A full list of available ZFS properties may be found here:
// https://www.freebsd.org/cgi/man.cgi?zfs(8).
func (d *Dataset) GetProperty(key string) (string, error) {
out, err := zfs("get", key, d.Name)
if err != nil {
return "", err
}
return out[0][2], nil
}
// Rename renames a dataset.
func (d *Dataset) Rename(name string, createParent bool, recursiveRenameSnapshots bool) (*Dataset, error) {
args := make([]string, 3, 5)
args[0] = "rename"
args[1] = d.Name
args[2] = name
if createParent {
args = append(args, "-p")
}
if recursiveRenameSnapshots {
args = append(args, "-r")
}
_, err := zfs(args...)
if err != nil {
return d, err
}
return GetDataset(name)
}
// Snapshots returns a slice of all ZFS snapshots of a given dataset.
func (d *Dataset) Snapshots() ([]*Dataset, error) {
return Snapshots(d.Name)
}
// CreateFilesystem creates a new ZFS filesystem with the specified name and
// properties.
// A full list of available ZFS properties may be found here:
// https://www.freebsd.org/cgi/man.cgi?zfs(8).
func CreateFilesystem(name string, properties map[string]string) (*Dataset, error) {
args := make([]string, 1, 4)
args[0] = "create"
if properties != nil {
args = append(args, propsSlice(properties)...)
}
args = append(args, name)
_, err := zfs(args...)
if err != nil {
return nil, err
}
return GetDataset(name)
}
// Snapshot creates a new ZFS snapshot of the receiving dataset, using the
// specified name. Optionally, the snapshot can be taken recursively, creating
// snapshots of all descendent filesystems in a single, atomic operation.
func (d *Dataset) Snapshot(name string, recursive bool) (*Dataset, error) {
args := make([]string, 1, 4)
args[0] = "snapshot"
if recursive {
args = append(args, "-r")
}
snapName := fmt.Sprintf("%s@%s", d.Name, name)
args = append(args, snapName)
_, err := zfs(args...)
if err != nil {
return nil, err
}
return GetDataset(snapName)
}
// Rollback rolls back the receiving ZFS dataset to a previous snapshot.
// Optionally, intermediate snapshots can be destroyed. A ZFS snapshot
// rollback cannot be completed without this option, if more recent
// snapshots exist.
// An error will be returned if the input dataset is not of snapshot type.
func (d *Dataset) Rollback(destroyMoreRecent bool) error {
if d.Type != DatasetSnapshot {
return errors.New("can only rollback snapshots")
}
args := make([]string, 1, 3)
args[0] = "rollback"
if destroyMoreRecent {
args = append(args, "-r")
}
args = append(args, d.Name)
_, err := zfs(args...)
return err
}
// Children returns a slice of children of the receiving ZFS dataset.
// A recursion depth may be specified, or a depth of 0 allows unlimited
// recursion.
func (d *Dataset) Children(depth uint64) ([]*Dataset, error) {
args := []string{"list"}
if depth > 0 {
args = append(args, "-d")
args = append(args, strconv.FormatUint(depth, 10))
} else {
args = append(args, "-r")
}
args = append(args, "-t", "all", "-Hp", "-o", dsPropListOptions)
args = append(args, d.Name)
out, err := zfs(args...)
if err != nil {
return nil, err
}
var datasets []*Dataset
name := ""
var ds *Dataset
for _, line := range out {
if name != line[0] {
name = line[0]
ds = &Dataset{Name: name}
datasets = append(datasets, ds)
}
if err := ds.parseLine(line); err != nil {
return nil, err
}
}
return datasets[1:], nil
}
// Diff returns changes between a snapshot and the given ZFS dataset.
// The snapshot name must include the filesystem part as it is possible to
// compare clones with their origin snapshots.
func (d *Dataset) Diff(snapshot string) ([]*InodeChange, error) {
args := []string{"diff", "-FH", snapshot, d.Name}[:]
out, err := zfs(args...)
if err != nil {
return nil, err
}
inodeChanges, err := parseInodeChanges(out)
if err != nil {
return nil, err
}
return inodeChanges, nil
}