restic/restorer.go

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package restic
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import (
"errors"
"fmt"
"os"
"path/filepath"
"syscall"
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"github.com/juju/arrar"
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"github.com/restic/restic/backend"
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)
type Restorer struct {
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s Server
ch *ContentHandler
sn *Snapshot
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Error func(dir string, node *Node, err error) error
Filter func(item string, dstpath string, node *Node) bool
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}
// NewRestorer creates a restorer preloaded with the content from the snapshot snid.
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func NewRestorer(s Server, snid backend.ID) (*Restorer, error) {
r := &Restorer{s: s}
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var err error
r.ch = NewContentHandler(s)
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r.sn, err = r.ch.LoadSnapshot(snid)
if err != nil {
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return nil, arrar.Annotate(err, "load snapshot for restorer")
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}
// 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 {
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tree := Tree{}
err := res.ch.LoadJSON(backend.Tree, tree_id, &tree)
if err != nil {
return res.Error(dir, nil, arrar.Annotate(err, "LoadJSON"))
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}
for _, node := range tree {
dstpath := filepath.Join(dst, dir, node.Name)
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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)
}
}
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if err != nil {
err = res.Error(dstpath, node, arrar.Annotate(err, "create node"))
if err != nil {
return err
}
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}
}
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)
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if err != nil {
err = res.Error(subp, node, arrar.Annotate(err, "restore subtree"))
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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)
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}
func (res *Restorer) Snapshot() *Snapshot {
return res.sn
}