docker-volume-backup/internal/storage/ssh/ssh.go

192 lines
4.8 KiB
Go

// Copyright 2022 - Offen Authors <hioffen@posteo.de>
// SPDX-License-Identifier: MPL-2.0
package ssh
import (
"fmt"
"io"
"os"
"path"
"path/filepath"
"strings"
"time"
"github.com/offen/docker-volume-backup/internal/errwrap"
"github.com/offen/docker-volume-backup/internal/storage"
"github.com/pkg/sftp"
"golang.org/x/crypto/ssh"
)
type sshStorage struct {
*storage.StorageBackend
client *ssh.Client
sftpClient *sftp.Client
hostName string
}
// Config allows to configure a SSH backend.
type Config struct {
HostName string
Port string
User string
Password string
IdentityFile string
IdentityPassphrase string
RemotePath string
}
// NewStorageBackend creates and initializes a new SSH storage backend.
func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
var authMethods []ssh.AuthMethod
if opts.Password != "" {
authMethods = append(authMethods, ssh.Password(opts.Password))
}
if _, err := os.Stat(opts.IdentityFile); err == nil {
key, err := os.ReadFile(opts.IdentityFile)
if err != nil {
return nil, errwrap.Wrap(nil, "error reading the private key")
}
var signer ssh.Signer
if opts.IdentityPassphrase != "" {
signer, err = ssh.ParsePrivateKeyWithPassphrase(key, []byte(opts.IdentityPassphrase))
if err != nil {
return nil, errwrap.Wrap(nil, "error parsing the encrypted private key")
}
authMethods = append(authMethods, ssh.PublicKeys(signer))
} else {
signer, err = ssh.ParsePrivateKey(key)
if err != nil {
return nil, errwrap.Wrap(nil, "error parsing the private key")
}
authMethods = append(authMethods, ssh.PublicKeys(signer))
}
}
sshClientConfig := &ssh.ClientConfig{
User: opts.User,
Auth: authMethods,
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
}
sshClient, err := ssh.Dial("tcp", fmt.Sprintf("%s:%s", opts.HostName, opts.Port), sshClientConfig)
if err != nil {
return nil, errwrap.Wrap(err, "error creating ssh client")
}
_, _, err = sshClient.SendRequest("keepalive", false, nil)
if err != nil {
return nil, err
}
sftpClient, err := sftp.NewClient(sshClient,
sftp.UseConcurrentReads(true),
sftp.UseConcurrentWrites(true),
sftp.MaxConcurrentRequestsPerFile(64),
)
if err != nil {
return nil, errwrap.Wrap(err, "error creating sftp client")
}
return &sshStorage{
StorageBackend: &storage.StorageBackend{
DestinationPath: opts.RemotePath,
Log: logFunc,
},
client: sshClient,
sftpClient: sftpClient,
hostName: opts.HostName,
}, nil
}
// Name returns the name of the storage backend
func (b *sshStorage) Name() string {
return "SSH"
}
// Copy copies the given file to the SSH storage backend.
func (b *sshStorage) Copy(file string) error {
source, err := os.Open(file)
_, name := path.Split(file)
if err != nil {
return errwrap.Wrap(err, " error reading the file to be uploaded")
}
defer source.Close()
destination, err := b.sftpClient.Create(filepath.Join(b.DestinationPath, name))
if err != nil {
return errwrap.Wrap(err, "error creating file")
}
defer destination.Close()
chunk := make([]byte, 1e9)
for {
num, err := source.Read(chunk)
if err == io.EOF {
tot, err := destination.Write(chunk[:num])
if err != nil {
return errwrap.Wrap(err, "error uploading the file")
}
if tot != len(chunk[:num]) {
return errwrap.Wrap(nil, "failed to write stream")
}
break
}
if err != nil {
return errwrap.Wrap(err, "error uploading the file")
}
tot, err := destination.Write(chunk[:num])
if err != nil {
return errwrap.Wrap(err, "error uploading the file")
}
if tot != len(chunk[:num]) {
return errwrap.Wrap(nil, "failed to write stream")
}
}
b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to '%s' at path '%s'.", file, b.hostName, b.DestinationPath)
return nil
}
// Prune rotates away backups according to the configuration and provided deadline for the SSH storage backend.
func (b *sshStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
candidates, err := b.sftpClient.ReadDir(b.DestinationPath)
if err != nil {
return nil, errwrap.Wrap(err, "error reading directory")
}
var matches []string
for _, candidate := range candidates {
if !strings.HasPrefix(candidate.Name(), pruningPrefix) {
continue
}
if candidate.ModTime().Before(deadline) {
matches = append(matches, candidate.Name())
}
}
stats := &storage.PruneStats{
Total: uint(len(candidates)),
Pruned: uint(len(matches)),
}
pruneErr := b.DoPrune(b.Name(), len(matches), len(candidates), deadline, func() error {
for _, match := range matches {
if err := b.sftpClient.Remove(filepath.Join(b.DestinationPath, match)); err != nil {
return errwrap.Wrap(err, "error removing file")
}
}
return nil
})
return stats, pruneErr
}