TheArchive/restic
1
0
Fork 0
mirror of https://github.com/restic/restic.git synced 2025-12-03 23:11:47 +00:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #3524 from MichaelEischer/atomic-sftp

Browse Source 
sftp: Implement atomic uploads
This commit is contained in:
Alexander Neumann
2022-03-21 11:08:22 +01:00
committed by GitHub
parent 8388f66c4c 5ec312ca06
commit a350625554
2 changed files with 33 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
internal/backend/sftp/sftp.go
View File

@@ -3,6 +3,8 @@ package sftp
import (
"bufio"
"context"
"crypto/rand"
"encoding/hex"
"fmt"
"hash"
"io"
@@ -252,6 +254,17 @@ func Join(parts ...string) string {
return path.Clean(path.Join(parts...))
}
// tempSuffix generates a random string suffix that should be sufficiently long
// to avoid accidential conflicts
func tempSuffix() string {
var nonce [16]byte
_, err := rand.Read(nonce[:])
if err != nil {
panic(err)
}
return hex.EncodeToString(nonce[:])
}
// Save stores data in the backend at the handle.
func (r *SFTP) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader) error {
debug.Log("Save %v", h)
@@ -264,10 +277,11 @@ func (r *SFTP) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader
}
filename := r.Filename(h)
tmpFilename := filename + "-restic-temp-" + tempSuffix()
dirname := r.Dirname(h)
// create new file
f, err := r.c.OpenFile(filename, os.O_CREATE|os.O_EXCL|os.O_WRONLY)
f, err := r.c.OpenFile(tmpFilename, os.O_CREATE|os.O_EXCL|os.O_WRONLY)
if r.IsNotExist(err) {
// error is caused by a missing directory, try to create it
@@ -276,7 +290,7 @@ func (r *SFTP) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader
debug.Log("error creating dir %v: %v", r.Dirname(h), mkdirErr)
} else {
// try again
f, err = r.c.OpenFile(filename, os.O_CREATE|os.O_EXCL|os.O_WRONLY)
f, err = r.c.OpenFile(tmpFilename, os.O_CREATE|os.O_EXCL|os.O_WRONLY)
}
}
@@ -298,7 +312,7 @@ func (r *SFTP) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader
rmErr := r.c.Remove(f.Name())
if rmErr != nil {
debug.Log("sftp: failed to remove broken file %v: %v",
filename, rmErr)
f.Name(), rmErr)
}
err = r.checkNoSpace(dirname, rd.Length(), err)
@@ -318,7 +332,12 @@ func (r *SFTP) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader
}
err = f.Close()
return errors.Wrap(err, "Close")
if err != nil {
return errors.Wrap(err, "Close")
}
err = r.c.Rename(tmpFilename, filename)
return errors.Wrap(err, "Rename")
}
// checkNoSpace checks if err was likely caused by lack of available space