package azure import ( "context" "io" "net/http" "os" "path" "strings" "github.com/Azure/azure-sdk-for-go/storage" "github.com/restic/restic/internal/backend" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/restic" ) // Backend stores data on an azure endpoint. type Backend struct { accountName string container *storage.Container sem *backend.Semaphore prefix string listMaxItems int backend.Layout } const defaultListMaxItems = 5000 // make sure that *Backend implements backend.Backend var _ restic.Backend = &Backend{} func open(cfg Config, rt http.RoundTripper) (*Backend, error) { debug.Log("open, config %#v", cfg) client, err := storage.NewBasicClient(cfg.AccountName, cfg.AccountKey) if err != nil { return nil, errors.Wrap(err, "NewBasicClient") } client.HTTPClient = &http.Client{Transport: rt} service := client.GetBlobService() sem, err := backend.NewSemaphore(cfg.Connections) if err != nil { return nil, err } be := &Backend{ container: service.GetContainerReference(cfg.Container), accountName: cfg.AccountName, sem: sem, prefix: cfg.Prefix, Layout: &backend.DefaultLayout{ Path: cfg.Prefix, Join: path.Join, }, listMaxItems: defaultListMaxItems, } return be, nil } // Open opens the Azure backend at specified container. func Open(cfg Config, rt http.RoundTripper) (restic.Backend, error) { return open(cfg, rt) } // Create opens the Azure backend at specified container and creates the container 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") } options := storage.CreateContainerOptions{ Access: storage.ContainerAccessTypePrivate, } _, err = be.container.CreateIfNotExists(&options) if err != nil { return nil, errors.Wrap(err, "container.CreateIfNotExists") } return be, nil } // SetListMaxItems sets the number of list items to load per request. func (be *Backend) SetListMaxItems(i int) { be.listMaxItems = i } // 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) return os.IsNotExist(err) } // Join combines path components with slashes. func (be *Backend) Join(p ...string) string { return path.Join(p...) } // Location returns this backend's location (the container name). func (be *Backend) Location() string { return be.Join(be.container.Name, be.prefix) } // Path returns the path in the bucket that is used for this backend. func (be *Backend) Path() string { return be.prefix } // preventCloser wraps an io.Reader to run a function instead of the original Close() function. type preventCloser struct { io.Reader f func() } func (wr preventCloser) Close() error { wr.f() 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) { if err := h.Valid(); err != nil { return err } objName := be.Filename(h) debug.Log("Save %v at %v", h, objName) // Check key does not already exist found, err := be.container.GetBlobReference(objName).Exists() if err != nil { return errors.Wrap(err, "GetBlobReference().Exists()") } if found { debug.Log("%v already exists", h) return errors.New("key already exists") } be.sem.GetToken() // wrap the reader so that net/http client cannot close the reader, return // the token instead. rd = preventCloser{ Reader: rd, f: func() { debug.Log("Close()") }, } debug.Log("InsertObject(%v, %v)", be.container.Name, objName) err = be.container.GetBlobReference(objName).CreateBlockBlobFromReader(rd, nil) be.sem.ReleaseToken() debug.Log("%v, err %#v", objName, err) return errors.Wrap(err, "CreateBlockBlobFromReader") } // 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) blob := be.container.GetBlobReference(objName) start := uint64(offset) var end uint64 if length > 0 { end = uint64(offset + int64(length) - 1) } else { end = 0 } be.sem.GetToken() rd, err := blob.GetRange(&storage.GetBlobRangeOptions{Range: &storage.BlobRange{Start: start, End: end}}) 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) (restic.FileInfo, error) { debug.Log("%v", h) objName := be.Filename(h) blob := be.container.GetBlobReference(objName) be.sem.GetToken() err := blob.GetProperties(nil) be.sem.ReleaseToken() if err != nil { debug.Log("blob.GetProperties err %v", err) return restic.FileInfo{}, errors.Wrap(err, "blob.GetProperties") } return restic.FileInfo{Size: int64(blob.Properties.ContentLength)}, 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) { objName := be.Filename(h) be.sem.GetToken() found, err := be.container.GetBlobReference(objName).Exists() be.sem.ReleaseToken() if err != nil { return false, err } 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.container.GetBlobReference(objName).DeleteIfExists(nil) be.sem.ReleaseToken() debug.Log("Remove(%v) at %v -> err %v", h, objName, err) 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 += "/" } params := storage.ListBlobsParameters{ MaxResults: uint(be.listMaxItems), Prefix: prefix, } go func() { defer close(ch) for { be.sem.GetToken() obj, err := be.container.ListBlobs(params) be.sem.ReleaseToken() if err != nil { return } debug.Log("got %v objects", len(obj.Blobs)) for _, item := range obj.Blobs { m := strings.TrimPrefix(item.Name, prefix) if m == "" { continue } select { case ch <- path.Base(m): case <-ctx.Done(): return } } if obj.NextMarker == "" { break } params.Marker = obj.NextMarker } }() 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 }