package s3 import ( "context" "fmt" "io" "net/http" "os" "path" "strings" "time" "github.com/restic/restic/internal/backend" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/restic" "github.com/minio/minio-go" "github.com/minio/minio-go/pkg/credentials" "github.com/restic/restic/internal/debug" ) // Backend stores data on an S3 endpoint. type Backend struct { client *minio.Client sem *backend.Semaphore cfg Config backend.Layout } // make sure that *Backend implements backend.Backend var _ restic.Backend = &Backend{} const defaultLayout = "default" func open(cfg Config, rt http.RoundTripper) (*Backend, error) { debug.Log("open, config %#v", cfg) if cfg.MaxRetries > 0 { minio.MaxRetry = int(cfg.MaxRetries) } // Chains all credential types, starting with // Static credentials provided by user. // IAM profile based credentials. (performs an HTTP // call to a pre-defined endpoint, only valid inside // configured ec2 instances) // AWS env variables such as AWS_ACCESS_KEY_ID // Minio env variables such as MINIO_ACCESS_KEY creds := credentials.NewChainCredentials([]credentials.Provider{ &credentials.Static{ Value: credentials.Value{ AccessKeyID: cfg.KeyID, SecretAccessKey: cfg.Secret, }, }, &credentials.IAM{ Client: &http.Client{ Transport: http.DefaultTransport, }, }, &credentials.EnvAWS{}, &credentials.EnvMinio{}, }) client, err := minio.NewWithCredentials(cfg.Endpoint, creds, !cfg.UseHTTP, "") if err != nil { return nil, errors.Wrap(err, "minio.NewWithCredentials") } sem, err := backend.NewSemaphore(cfg.Connections) if err != nil { return nil, err } be := &Backend{ client: client, sem: sem, cfg: cfg, } client.SetCustomTransport(rt) l, err := backend.ParseLayout(be, cfg.Layout, defaultLayout, cfg.Prefix) if err != nil { return nil, err } be.Layout = l return be, nil } // Open opens the S3 backend at bucket and region. The bucket is created if it // does not exist yet. func Open(cfg Config, rt http.RoundTripper) (restic.Backend, error) { return open(cfg, rt) } // Create opens the S3 backend at bucket and region and creates the bucket if // it does not exist yet. func Create(cfg Config, rt http.RoundTripper) (restic.Backend, error) { be, err := open(cfg, rt) if err != nil { return nil, errors.Wrap(err, "open") } found, err := be.client.BucketExists(cfg.Bucket) if err != nil { debug.Log("BucketExists(%v) returned err %v", cfg.Bucket, err) return nil, errors.Wrap(err, "client.BucketExists") } if !found { // create new bucket with default ACL in default region err = be.client.MakeBucket(cfg.Bucket, "") if err != nil { return nil, errors.Wrap(err, "client.MakeBucket") } } return be, nil } // IsNotExist returns true if the error is caused by a not existing file. func (be *Backend) IsNotExist(err error) bool { debug.Log("IsNotExist(%T, %#v)", err, err) if os.IsNotExist(errors.Cause(err)) { return true } if e, ok := errors.Cause(err).(minio.ErrorResponse); ok && e.Code == "NoSuchKey" { return true } return false } // Join combines path components with slashes. func (be *Backend) Join(p ...string) string { return path.Join(p...) } type fileInfo struct { name string size int64 mode os.FileMode modTime time.Time isDir bool } func (fi fileInfo) Name() string { return fi.name } // base name of the file func (fi fileInfo) Size() int64 { return fi.size } // length in bytes for regular files; system-dependent for others func (fi fileInfo) Mode() os.FileMode { return fi.mode } // file mode bits func (fi fileInfo) ModTime() time.Time { return fi.modTime } // modification time func (fi fileInfo) IsDir() bool { return fi.isDir } // abbreviation for Mode().IsDir() func (fi fileInfo) Sys() interface{} { return nil } // underlying data source (can return nil) // ReadDir returns the entries for a directory. func (be *Backend) ReadDir(dir string) (list []os.FileInfo, err error) { debug.Log("ReadDir(%v)", dir) // make sure dir ends with a slash if dir[len(dir)-1] != '/' { dir += "/" } done := make(chan struct{}) defer close(done) for obj := range be.client.ListObjects(be.cfg.Bucket, dir, false, done) { if obj.Key == "" { continue } name := strings.TrimPrefix(obj.Key, dir) // Sometimes s3 returns an entry for the dir itself. Ignore it. if name == "" { continue } entry := fileInfo{ name: name, size: obj.Size, modTime: obj.LastModified, } if name[len(name)-1] == '/' { entry.isDir = true entry.mode = os.ModeDir | 0755 entry.name = name[:len(name)-1] } else { entry.mode = 0644 } list = append(list, entry) } return list, nil } // Location returns this backend's location (the bucket name). func (be *Backend) Location() string { return be.Join(be.cfg.Bucket, be.cfg.Prefix) } // Path returns the path in the bucket that is used for this backend. func (be *Backend) Path() string { return be.cfg.Prefix } // nopCloserFile wraps *os.File and overwrites the Close() method with method // that does nothing. In addition, the method Len() is implemented, which // returns the size of the file (filesize - current offset). type nopCloserFile struct { *os.File } func (f nopCloserFile) Close() error { debug.Log("prevented Close()") return nil } // Len returns the remaining length of the file (filesize - current offset). func (f nopCloserFile) Len() int { debug.Log("Len() called") fi, err := f.Stat() if err != nil { panic(err) } pos, err := f.Seek(0, io.SeekCurrent) if err != nil { panic(err) } size := fi.Size() - pos debug.Log("returning file size %v", size) return int(size) } type lenner interface { Len() int io.Reader } // nopCloserLenner wraps a lenner and overwrites the Close() method with method // that does nothing. In addition, the method Size() is implemented, which // returns the size of the file (filesize - current offset). type nopCloserLenner struct { lenner } func (f *nopCloserLenner) Close() error { debug.Log("prevented Close()") return nil } // Save stores data in the backend at the handle. func (be *Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err error) { debug.Log("Save %v", h) if err := h.Valid(); err != nil { return err } objName := be.Filename(h) be.sem.GetToken() defer be.sem.ReleaseToken() // Check key does not already exist _, err = be.client.StatObject(be.cfg.Bucket, objName) if err == nil { debug.Log("%v already exists", h) return errors.New("key already exists") } // FIXME: This is a workaround once we move to minio-go 4.0.x this can be // removed and size can be directly provided. if f, ok := rd.(*os.File); ok { debug.Log("reader is %#T, using nopCloserFile{}", rd) rd = nopCloserFile{f} } else if l, ok := rd.(lenner); ok { debug.Log("reader is %#T, using nopCloserLenner{}", rd) rd = nopCloserLenner{l} } else { debug.Log("reader is %#T, no specific workaround enabled", rd) } debug.Log("PutObject(%v, %v)", be.cfg.Bucket, objName) n, err := be.client.PutObject(be.cfg.Bucket, objName, rd, "application/octet-stream") debug.Log("%v -> %v bytes, err %#v: %v", objName, n, err, err) return errors.Wrap(err, "client.PutObject") } // wrapReader wraps an io.ReadCloser to run an additional function on Close. type wrapReader struct { io.ReadCloser f func() } func (wr wrapReader) Close() error { err := wr.ReadCloser.Close() wr.f() return err } // Load returns a reader that yields the contents of the file at h at the // given offset. If length is nonzero, only a portion of the file is // returned. rd must be closed after use. func (be *Backend) Load(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) { debug.Log("Load %v, length %v, offset %v from %v", h, length, offset, be.Filename(h)) if err := h.Valid(); err != nil { return nil, err } if offset < 0 { return nil, errors.New("offset is negative") } if length < 0 { return nil, errors.Errorf("invalid length %d", length) } objName := be.Filename(h) byteRange := fmt.Sprintf("bytes=%d-", offset) if length > 0 { byteRange = fmt.Sprintf("bytes=%d-%d", offset, offset+int64(length)-1) } headers := minio.NewGetReqHeaders() headers.Add("Range", byteRange) be.sem.GetToken() debug.Log("Load(%v) send range %v", h, byteRange) coreClient := minio.Core{Client: be.client} rd, _, err := coreClient.GetObject(be.cfg.Bucket, objName, headers) if err != nil { be.sem.ReleaseToken() return nil, err } closeRd := wrapReader{ ReadCloser: rd, f: func() { debug.Log("Close()") be.sem.ReleaseToken() }, } return closeRd, err } // Stat returns information about a blob. func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInfo, err error) { debug.Log("%v", h) objName := be.Filename(h) var obj *minio.Object be.sem.GetToken() obj, err = be.client.GetObject(be.cfg.Bucket, objName) if err != nil { debug.Log("GetObject() err %v", err) be.sem.ReleaseToken() return restic.FileInfo{}, errors.Wrap(err, "client.GetObject") } // make sure that the object is closed properly. defer func() { e := obj.Close() be.sem.ReleaseToken() if err == nil { err = errors.Wrap(e, "Close") } }() fi, err := obj.Stat() if err != nil { debug.Log("Stat() err %v", err) return restic.FileInfo{}, errors.Wrap(err, "Stat") } return restic.FileInfo{Size: fi.Size}, nil } // Test returns true if a blob of the given type and name exists in the backend. func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) { found := false objName := be.Filename(h) be.sem.GetToken() _, err := be.client.StatObject(be.cfg.Bucket, objName) be.sem.ReleaseToken() if err == nil { found = true } // If error, then not found return found, nil } // Remove removes the blob with the given name and type. func (be *Backend) Remove(ctx context.Context, h restic.Handle) error { objName := be.Filename(h) be.sem.GetToken() err := be.client.RemoveObject(be.cfg.Bucket, objName) be.sem.ReleaseToken() debug.Log("Remove(%v) at %v -> err %v", h, objName, err) if be.IsNotExist(err) { err = nil } return errors.Wrap(err, "client.RemoveObject") } // List returns a channel that yields all names of blobs of type t. A // goroutine is started for this. If the channel done is closed, sending // stops. func (be *Backend) List(ctx context.Context, t restic.FileType) <-chan string { debug.Log("listing %v", t) ch := make(chan string) prefix := be.Dirname(restic.Handle{Type: t}) // make sure prefix ends with a slash if prefix[len(prefix)-1] != '/' { prefix += "/" } // NB: unfortunately we can't protect this with be.sem.GetToken() here. // Doing so would enable a deadlock situation (gh-1399), as ListObjects() // starts its own goroutine and returns results via a channel. listresp := be.client.ListObjects(be.cfg.Bucket, prefix, true, ctx.Done()) go func() { defer close(ch) for obj := range listresp { m := strings.TrimPrefix(obj.Key, prefix) if m == "" { continue } select { case ch <- path.Base(m): case <-ctx.Done(): return } } }() return ch } // Remove keys for a specified backend type. func (be *Backend) removeKeys(ctx context.Context, t restic.FileType) error { for key := range be.List(ctx, restic.DataFile) { err := be.Remove(ctx, restic.Handle{Type: restic.DataFile, Name: key}) if err != nil { return err } } return nil } // Delete removes all restic keys in the bucket. It will not remove the bucket itself. func (be *Backend) Delete(ctx context.Context) error { alltypes := []restic.FileType{ restic.DataFile, restic.KeyFile, restic.LockFile, restic.SnapshotFile, restic.IndexFile} for _, t := range alltypes { err := be.removeKeys(ctx, t) if err != nil { return nil } } return be.Remove(ctx, restic.Handle{Type: restic.ConfigFile}) } // Close does nothing func (be *Backend) Close() error { return nil } // Rename moves a file based on the new layout l. func (be *Backend) Rename(h restic.Handle, l backend.Layout) error { debug.Log("Rename %v to %v", h, l) oldname := be.Filename(h) newname := l.Filename(h) if oldname == newname { debug.Log(" %v is already renamed", newname) return nil } debug.Log(" %v -> %v", oldname, newname) src := minio.NewSourceInfo(be.cfg.Bucket, oldname, nil) dst, err := minio.NewDestinationInfo(be.cfg.Bucket, newname, nil, nil) if err != nil { return errors.Wrap(err, "NewDestinationInfo") } err = be.client.CopyObject(dst, src) if err != nil && be.IsNotExist(err) { debug.Log("copy failed: %v, seems to already have been renamed", err) return nil } if err != nil { debug.Log("copy failed: %v", err) return err } return be.client.RemoveObject(be.cfg.Bucket, oldname) }