zrepl/zfs/zfs.go
2017-04-30 23:47:11 +02:00

132 lines
2.2 KiB
Go

package zfs
import (
"bufio"
"errors"
"fmt"
"github.com/zrepl/zrepl/model"
"io"
"io/ioutil"
"os/exec"
"strings"
)
func InitialSend(snapshot string) (io.Reader, error) {
return nil, nil
}
func IncrementalSend(from, to string) (io.Reader, error) {
return nil, nil
}
func FilesystemsAtRoot(root string) (fs model.Filesystem, err error) {
_, _ = zfsList("zroot", func(path DatasetPath) bool {
return true
})
return
}
type DatasetPath []string
func (p DatasetPath) ToString() string {
return strings.Join(p, "/")
}
func (p DatasetPath) Empty() bool {
return len(p) == 0
}
var EmptyDatasetPath DatasetPath = []string{}
func NewDatasetPath(s string) (p DatasetPath, err error) {
if s == "" {
return EmptyDatasetPath, nil // the empty dataset path
}
// TODO validation
return toDatasetPath(s), nil
}
func toDatasetPath(s string) DatasetPath {
return strings.Split(s, "/")
}
type DatasetFilter func(path DatasetPath) bool
type ZFSError struct {
Stderr []byte
WaitErr error
}
func (e ZFSError) Error() string {
return fmt.Sprintf("zfs exited with error: %s", e.WaitErr.Error())
}
var ZFS_BINARY string = "zfs"
func zfsList(root string, filter DatasetFilter) (datasets []DatasetPath, err error) {
const ZFS_LIST_FIELD_COUNT = 1
args := make([]string, 0, 10)
args = append(args,
"list", "-H", "-r",
"-t", "filesystem,volume",
"-o", "name")
if len(root) > 0 {
args = append(args, root)
}
cmd := exec.Command(ZFS_BINARY, args...)
var stdout io.Reader
var stderr io.Reader
if stdout, err = cmd.StdoutPipe(); err != nil {
return
}
if stderr, err = cmd.StderrPipe(); err != nil {
return
}
if err = cmd.Start(); err != nil {
return
}
s := bufio.NewScanner(stdout)
buf := make([]byte, 1024)
s.Buffer(buf, 0)
datasets = make([]DatasetPath, 0)
for s.Scan() {
fields := strings.SplitN(s.Text(), "\t", ZFS_LIST_FIELD_COUNT)
if len(fields) != ZFS_LIST_FIELD_COUNT {
err = errors.New("unexpected output")
return
}
dp := toDatasetPath(fields[0])
if filter(dp) {
datasets = append(datasets, dp)
}
}
stderrOutput, err := ioutil.ReadAll(stderr)
if waitErr := cmd.Wait(); waitErr != nil {
err := ZFSError{
Stderr: stderrOutput,
WaitErr: waitErr,
}
return nil, err
}
return
}