package azure import ( "context" "crypto/md5" "encoding/base64" "hash" "io" "net/http" "os" "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/Azure/azure-sdk-for-go/storage" "github.com/cenkalti/backoff/v4" ) // Backend stores data on an azure endpoint. type Backend struct { accountName string container *storage.Container connections uint 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.Unwrap()) 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, connections: cfg.Connections, 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) (*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) (*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...) } func (be *Backend) Connections() uint { return be.connections } // Location returns this backend's location (the container name). func (be *Backend) Location() string { return be.Join(be.container.Name, be.prefix) } // Hasher may return a hash function for calculating a content hash for the backend func (be *Backend) Hasher() hash.Hash { return md5.New() } // HasAtomicReplace returns whether Save() can atomically replace files func (be *Backend) HasAtomicReplace() bool { return true } // Path returns the path in the bucket that is used for this backend. func (be *Backend) Path() string { return be.prefix } type azureAdapter struct { restic.RewindReader } func (azureAdapter) Close() error { return nil } func (a azureAdapter) Len() int { return int(a.Length()) } // Save stores data in the backend at the handle. func (be *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader) error { if err := h.Valid(); err != nil { return backoff.Permanent(err) } objName := be.Filename(h) debug.Log("Save %v at %v", h, objName) be.sem.GetToken() debug.Log("InsertObject(%v, %v)", be.container.Name, objName) var err error if rd.Length() < 256*1024*1024 { // wrap the reader so that net/http client cannot close the reader // CreateBlockBlobFromReader reads length from `Len()`` dataReader := azureAdapter{rd} // if it's smaller than 256miB, then just create the file directly from the reader ref := be.container.GetBlobReference(objName) ref.Properties.ContentMD5 = base64.StdEncoding.EncodeToString(rd.Hash()) err = ref.CreateBlockBlobFromReader(dataReader, nil) } else { // otherwise use the more complicated method err = be.saveLarge(ctx, objName, rd) } be.sem.ReleaseToken() debug.Log("%v, err %#v", objName, err) return errors.Wrap(err, "CreateBlockBlobFromReader") } func (be *Backend) saveLarge(ctx context.Context, objName string, rd restic.RewindReader) error { // create the file on the server file := be.container.GetBlobReference(objName) err := file.CreateBlockBlob(nil) if err != nil { return errors.Wrap(err, "CreateBlockBlob") } // read the data, in 100 MiB chunks buf := make([]byte, 100*1024*1024) var blocks []storage.Block uploadedBytes := 0 for { n, err := io.ReadFull(rd, buf) if err == io.ErrUnexpectedEOF { err = nil } if err == io.EOF { // end of file reached, no bytes have been read at all break } if err != nil { return errors.Wrap(err, "ReadFull") } buf = buf[:n] uploadedBytes += n // upload it as a new "block", use the base64 hash for the ID h := md5.Sum(buf) id := base64.StdEncoding.EncodeToString(h[:]) debug.Log("PutBlock %v with %d bytes", id, len(buf)) err = file.PutBlock(id, buf, &storage.PutBlockOptions{ContentMD5: id}) if err != nil { return errors.Wrap(err, "PutBlock") } blocks = append(blocks, storage.Block{ ID: id, Status: "Uncommitted", }) } // sanity check if uploadedBytes != int(rd.Length()) { return errors.Errorf("wrote %d bytes instead of the expected %d bytes", uploadedBytes, rd.Length()) } debug.Log("uploaded %d parts: %v", len(blocks), blocks) err = file.PutBlockList(blocks, nil) debug.Log("PutBlockList returned %v", err) return errors.Wrap(err, "PutBlockList") } // Load runs fn with a reader that yields the contents of the file at h at the // given offset. func (be *Backend) Load(ctx context.Context, h restic.Handle, length int, offset int64, fn func(rd io.Reader) error) error { return backend.DefaultLoad(ctx, h, length, offset, be.openReader, fn) } func (be *Backend) openReader(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, backoff.Permanent(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 } return be.sem.ReleaseTokenOnClose(rd, nil), 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") } fi := restic.FileInfo{ Size: int64(blob.Properties.ContentLength), Name: h.Name, } return fi, 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 runs fn for each file in the backend which has the type t. When an // error occurs (or fn returns an error), List stops and returns it. func (be *Backend) List(ctx context.Context, t restic.FileType, fn func(restic.FileInfo) error) error { debug.Log("listing %v", t) prefix, _ := be.Basedir(t) // make sure prefix ends with a slash if !strings.HasSuffix(prefix, "/") { prefix += "/" } params := storage.ListBlobsParameters{ MaxResults: uint(be.listMaxItems), Prefix: prefix, } for { be.sem.GetToken() obj, err := be.container.ListBlobs(params) be.sem.ReleaseToken() if err != nil { return err } debug.Log("got %v objects", len(obj.Blobs)) for _, item := range obj.Blobs { m := strings.TrimPrefix(item.Name, prefix) if m == "" { continue } fi := restic.FileInfo{ Name: path.Base(m), Size: item.Properties.ContentLength, } if ctx.Err() != nil { return ctx.Err() } err := fn(fi) if err != nil { return err } if ctx.Err() != nil { return ctx.Err() } } if obj.NextMarker == "" { break } params.Marker = obj.NextMarker } return ctx.Err() } // Remove keys for a specified backend type. func (be *Backend) removeKeys(ctx context.Context, t restic.FileType) error { return be.List(ctx, t, func(fi restic.FileInfo) error { return be.Remove(ctx, restic.Handle{Type: t, Name: fi.Name}) }) } // 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.PackFile, 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 }