package b2 import ( "context" "io" "path" "strings" "github.com/restic/restic/internal/backend" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/restic" "github.com/kurin/blazer/b2" ) // b2Backend is a backend which stores its data on Backblaze B2. type b2Backend struct { client *b2.Client bucket *b2.Bucket cfg Config listMaxItems int backend.Layout sem *backend.Semaphore } const defaultListMaxItems = 1000 // ensure statically that *b2Backend implements restic.Backend. var _ restic.Backend = &b2Backend{} func newClient(ctx context.Context, cfg Config) (*b2.Client, error) { opts := []b2.ClientOption{b2.Transport(backend.Transport())} c, err := b2.NewClient(ctx, cfg.AccountID, cfg.Key, opts...) if err != nil { return nil, errors.Wrap(err, "b2.NewClient") } return c, nil } // Open opens a connection to the B2 service. func Open(cfg Config) (restic.Backend, error) { debug.Log("cfg %#v", cfg) ctx, cancel := context.WithCancel(context.TODO()) defer cancel() client, err := newClient(ctx, cfg) if err != nil { return nil, err } bucket, err := client.Bucket(ctx, cfg.Bucket) if err != nil { return nil, errors.Wrap(err, "Bucket") } sem, err := backend.NewSemaphore(cfg.Connections) if err != nil { return nil, err } be := &b2Backend{ client: client, bucket: bucket, cfg: cfg, Layout: &backend.DefaultLayout{ Join: path.Join, Path: cfg.Prefix, }, sem: sem, } return be, nil } // Create opens a connection to the B2 service. If the bucket does not exist yet, // it is created. func Create(cfg Config) (restic.Backend, error) { debug.Log("cfg %#v", cfg) ctx, cancel := context.WithCancel(context.TODO()) defer cancel() client, err := newClient(ctx, cfg) if err != nil { return nil, err } attr := b2.BucketAttrs{ Type: b2.Private, } bucket, err := client.NewBucket(ctx, cfg.Bucket, &attr) if err != nil { return nil, errors.Wrap(err, "NewBucket") } sem, err := backend.NewSemaphore(cfg.Connections) if err != nil { return nil, err } be := &b2Backend{ client: client, bucket: bucket, cfg: cfg, Layout: &backend.DefaultLayout{ Join: path.Join, Path: cfg.Prefix, }, sem: sem, } present, err := be.Test(context.TODO(), restic.Handle{Type: restic.ConfigFile}) if err != nil { return nil, err } if present { return nil, errors.New("config already exists") } return be, nil } // SetListMaxItems sets the number of list items to load per request. func (be *b2Backend) SetListMaxItems(i int) { be.listMaxItems = i } // Location returns the location for the backend. func (be *b2Backend) Location() string { return be.cfg.Bucket } // wrapReader wraps an io.ReadCloser to run an additional function on Close. type wrapReader struct { io.ReadCloser eofSeen bool f func() } func (wr *wrapReader) Read(p []byte) (int, error) { if wr.eofSeen { return 0, io.EOF } n, err := wr.ReadCloser.Read(p) if err == io.EOF { wr.eofSeen = true } return n, err } func (wr *wrapReader) Close() error { err := wr.ReadCloser.Close() wr.f() return err } // IsNotExist returns true if the error is caused by a non-existing file. func (be *b2Backend) IsNotExist(err error) bool { return b2.IsNotExist(errors.Cause(err)) } // Load returns the data stored in the backend for h at the given offset // and saves it in p. Load has the same semantics as io.ReaderAt. func (be *b2Backend) 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) } ctx, cancel := context.WithCancel(ctx) be.sem.GetToken() name := be.Layout.Filename(h) obj := be.bucket.Object(name) if offset == 0 && length == 0 { rd := obj.NewReader(ctx) wrapper := &wrapReader{ ReadCloser: rd, f: func() { cancel() be.sem.ReleaseToken() }, } return wrapper, nil } // pass a negative length to NewRangeReader so that the remainder of the // file is read. if length == 0 { length = -1 } rd := obj.NewRangeReader(ctx, offset, int64(length)) wrapper := &wrapReader{ ReadCloser: rd, f: func() { cancel() be.sem.ReleaseToken() }, } return wrapper, nil } // Save stores data in the backend at the handle. func (be *b2Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err error) { ctx, cancel := context.WithCancel(ctx) defer cancel() if err := h.Valid(); err != nil { return err } be.sem.GetToken() defer be.sem.ReleaseToken() name := be.Filename(h) debug.Log("Save %v, name %v", h, name) obj := be.bucket.Object(name) _, err = obj.Attrs(ctx) if err == nil { debug.Log(" %v already exists", h) return errors.New("key already exists") } w := obj.NewWriter(ctx) n, err := io.Copy(w, rd) debug.Log(" saved %d bytes, err %v", n, err) if err != nil { _ = w.Close() return errors.Wrap(err, "Copy") } return errors.Wrap(w.Close(), "Close") } // Stat returns information about a blob. func (be *b2Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInfo, err error) { debug.Log("Stat %v", h) be.sem.GetToken() defer be.sem.ReleaseToken() name := be.Filename(h) obj := be.bucket.Object(name) info, err := obj.Attrs(ctx) if err != nil { debug.Log("Attrs() err %v", err) return restic.FileInfo{}, errors.Wrap(err, "Stat") } return restic.FileInfo{Size: info.Size}, nil } // Test returns true if a blob of the given type and name exists in the backend. func (be *b2Backend) Test(ctx context.Context, h restic.Handle) (bool, error) { debug.Log("Test %v", h) be.sem.GetToken() defer be.sem.ReleaseToken() found := false name := be.Filename(h) obj := be.bucket.Object(name) info, err := obj.Attrs(ctx) if err == nil && info != nil && info.Status == b2.Uploaded { found = true } return found, nil } // Remove removes the blob with the given name and type. func (be *b2Backend) Remove(ctx context.Context, h restic.Handle) error { debug.Log("Remove %v", h) be.sem.GetToken() defer be.sem.ReleaseToken() obj := be.bucket.Object(be.Filename(h)) return errors.Wrap(obj.Delete(ctx), "Delete") } // 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 *b2Backend) List(ctx context.Context, t restic.FileType) <-chan string { debug.Log("List %v", t) ch := make(chan string) ctx, cancel := context.WithCancel(ctx) be.sem.GetToken() go func() { defer close(ch) defer cancel() defer be.sem.ReleaseToken() prefix := be.Dirname(restic.Handle{Type: t}) cur := &b2.Cursor{Prefix: prefix} for { objs, c, err := be.bucket.ListCurrentObjects(ctx, be.listMaxItems, cur) if err != nil && err != io.EOF { return } debug.Log("returned %v items", len(objs)) for _, obj := range objs { // Skip objects returned that do not have the specified prefix. if !strings.HasPrefix(obj.Name(), prefix) { continue } m := path.Base(obj.Name()) if m == "" { continue } select { case ch <- m: case <-ctx.Done(): return } } if err == io.EOF { return } cur = c } }() return ch } // Remove keys for a specified backend type. func (be *b2Backend) removeKeys(ctx context.Context, t restic.FileType) error { debug.Log("removeKeys %v", t) for key := range be.List(ctx, t) { err := be.Remove(ctx, restic.Handle{Type: t, 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 *b2Backend) 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 } } err := be.Remove(ctx, restic.Handle{Type: restic.ConfigFile}) if err != nil && b2.IsNotExist(errors.Cause(err)) { err = nil } return err } // Close does nothing func (be *b2Backend) Close() error { return nil }