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restic/restorer.go
Sebastian Schmidt bd43e27deb Create parent directories for restore items
When restoring an item fails with ENOENT, create parent directories and
try again. This is needed for restoring partial trees (as in: the Filter
function didn't return true for the paths leading up to this restore
item).
2015-01-01 16:40:36 +01:00

109 lines
2.5 KiB
Go

package restic
import (
"errors"
"fmt"
"os"
"path/filepath"
"syscall"
"github.com/juju/arrar"
"github.com/restic/restic/backend"
)
type Restorer struct {
s Server
ch *ContentHandler
sn *Snapshot
Error func(dir string, node *Node, err error) error
Filter func(item string, dstpath string, node *Node) bool
}
// NewRestorer creates a restorer preloaded with the content from the snapshot snid.
func NewRestorer(s Server, snid backend.ID) (*Restorer, error) {
r := &Restorer{s: s}
var err error
r.ch, err = NewContentHandler(s)
if err != nil {
return nil, arrar.Annotate(err, "create contenthandler for restorer")
}
r.sn, err = r.ch.LoadSnapshot(snid)
if err != nil {
return nil, arrar.Annotate(err, "load snapshot for restorer")
}
// abort on all errors
r.Error = func(string, *Node, error) error { return err }
return r, nil
}
func (res *Restorer) to(dst string, dir string, tree_id backend.ID) error {
tree := Tree{}
err := res.ch.LoadJSON(backend.Tree, tree_id, &tree)
if err != nil {
return res.Error(dir, nil, arrar.Annotate(err, "LoadJSON"))
}
for _, node := range tree {
dstpath := filepath.Join(dst, dir, node.Name)
if res.Filter == nil ||
res.Filter(filepath.Join(res.sn.Dir, dir, node.Name), dstpath, node) {
err := node.CreateAt(res.ch, dstpath)
// Did it fail because of ENOENT?
if arrar.Check(err, func(err error) bool {
if pe, ok := err.(*os.PathError); ok {
errn, ok := pe.Err.(syscall.Errno)
return ok && errn == syscall.ENOENT
}
return false
}) {
// Create parent directories and retry
err = os.MkdirAll(filepath.Dir(dstpath), 0700)
if err == nil || err == os.ErrExist {
err = node.CreateAt(res.ch, dstpath)
}
}
if err != nil {
err = res.Error(dstpath, node, arrar.Annotate(err, "create node"))
if err != nil {
return err
}
}
}
if node.Type == "dir" {
if node.Subtree == nil {
return errors.New(fmt.Sprintf("Dir without subtree in tree %s", tree_id))
}
subp := filepath.Join(dir, node.Name)
err = res.to(dst, subp, node.Subtree)
if err != nil {
err = res.Error(subp, node, arrar.Annotate(err, "restore subtree"))
if err != nil {
return err
}
}
}
}
return nil
}
// RestoreTo creates the directories and files in the snapshot below dir.
// Before an item is created, res.Filter is called.
func (res *Restorer) RestoreTo(dir string) error {
return res.to(dir, "", res.sn.Tree)
}
func (res *Restorer) Snapshot() *Snapshot {
return res.sn
}