package s3 import ( "context" "fmt" "hash" "io" "io/ioutil" "net/http" "os" "path" "strings" "time" "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/cenkalti/backoff/v4" "github.com/minio/minio-go/v7" "github.com/minio/minio-go/v7/pkg/credentials" ) // 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(ctx context.Context, 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, in the following order: // - Static credentials provided by user // - AWS env vars (i.e. AWS_ACCESS_KEY_ID) // - Minio env vars (i.e. MINIO_ACCESS_KEY) // - AWS creds file (i.e. AWS_SHARED_CREDENTIALS_FILE or ~/.aws/credentials) // - Minio creds file (i.e. MINIO_SHARED_CREDENTIALS_FILE or ~/.mc/config.json) // - IAM profile based credentials. (performs an HTTP // call to a pre-defined endpoint, only valid inside // configured ec2 instances) creds := credentials.NewChainCredentials([]credentials.Provider{ &credentials.EnvAWS{}, &credentials.Static{ Value: credentials.Value{ AccessKeyID: cfg.KeyID, SecretAccessKey: cfg.Secret, }, }, &credentials.EnvMinio{}, &credentials.FileAWSCredentials{}, &credentials.FileMinioClient{}, &credentials.IAM{ Client: &http.Client{ Transport: http.DefaultTransport, }, }, }) c, err := creds.Get() if err != nil { return nil, errors.Wrap(err, "creds.Get") } if c.SignerType == credentials.SignatureAnonymous { debug.Log("using anonymous access for %#v", cfg.Endpoint) } options := &minio.Options{ Creds: creds, Secure: !cfg.UseHTTP, Region: cfg.Region, Transport: rt, } switch strings.ToLower(cfg.BucketLookup) { case "", "auto": options.BucketLookup = minio.BucketLookupAuto case "dns": options.BucketLookup = minio.BucketLookupDNS case "path": options.BucketLookup = minio.BucketLookupPath default: return nil, fmt.Errorf(`bad bucket-lookup style %q must be "auto", "path" or "dns"`, cfg.BucketLookup) } client, err := minio.New(cfg.Endpoint, options) if err != nil { return nil, errors.Wrap(err, "minio.New") } sem, err := backend.NewSemaphore(cfg.Connections) if err != nil { return nil, err } be := &Backend{ client: client, sem: sem, cfg: cfg, } l, err := backend.ParseLayout(ctx, 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(ctx context.Context, cfg Config, rt http.RoundTripper) (restic.Backend, error) { return open(ctx, cfg, rt) } // Create opens the S3 backend at bucket and region and creates the bucket if // it does not exist yet. func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (restic.Backend, error) { be, err := open(ctx, cfg, rt) if err != nil { return nil, errors.Wrap(err, "open") } found, err := be.client.BucketExists(ctx, cfg.Bucket) if err != nil && be.IsAccessDenied(err) { err = nil found = true } 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(ctx, cfg.Bucket, minio.MakeBucketOptions{}) if err != nil { return nil, errors.Wrap(err, "client.MakeBucket") } } return be, nil } // IsAccessDenied returns true if the error is caused by Access Denied. func (be *Backend) IsAccessDenied(err error) bool { debug.Log("IsAccessDenied(%T, %#v)", err, err) if e, ok := errors.Cause(err).(minio.ErrorResponse); ok && e.Code == "AccessDenied" { return true } return false } // 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(ctx context.Context, 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 += "/" } ctx, cancel := context.WithCancel(ctx) defer cancel() debug.Log("using ListObjectsV1(%v)", be.cfg.ListObjectsV1) for obj := range be.client.ListObjects(ctx, be.cfg.Bucket, minio.ListObjectsOptions{ Prefix: dir, Recursive: false, UseV1: be.cfg.ListObjectsV1, }) { if obj.Err != nil { return nil, err } 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) } // Hasher may return a hash function for calculating a content hash for the backend func (be *Backend) Hasher() hash.Hash { return nil } // Path returns the path in the bucket that is used for this backend. func (be *Backend) Path() string { return be.cfg.Prefix } // Save stores data in the backend at the handle. func (be *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader) error { debug.Log("Save %v", h) if err := h.Valid(); err != nil { return backoff.Permanent(err) } objName := be.Filename(h) be.sem.GetToken() defer be.sem.ReleaseToken() opts := minio.PutObjectOptions{StorageClass: be.cfg.StorageClass} opts.ContentType = "application/octet-stream" // the only option with the high-level api is to let the library handle the checksum computation opts.SendContentMd5 = true debug.Log("PutObject(%v, %v, %v)", be.cfg.Bucket, objName, rd.Length()) info, err := be.client.PutObject(ctx, be.cfg.Bucket, objName, ioutil.NopCloser(rd), int64(rd.Length()), opts) debug.Log("%v -> %v bytes, err %#v: %v", objName, info.Size, err, err) // sanity check if err == nil && info.Size != rd.Length() { return errors.Errorf("wrote %d bytes instead of the expected %d bytes", info.Size, rd.Length()) } 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 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) opts := minio.GetObjectOptions{} var err error if length > 0 { debug.Log("range: %v-%v", offset, offset+int64(length)-1) err = opts.SetRange(offset, offset+int64(length)-1) } else if offset > 0 { debug.Log("range: %v-", offset) err = opts.SetRange(offset, 0) } if err != nil { return nil, errors.Wrap(err, "SetRange") } be.sem.GetToken() coreClient := minio.Core{Client: be.client} rd, _, _, err := coreClient.GetObject(ctx, be.cfg.Bucket, objName, opts) 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 opts := minio.GetObjectOptions{} be.sem.GetToken() obj, err = be.client.GetObject(ctx, be.cfg.Bucket, objName, opts) 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, Name: h.Name}, 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(ctx, be.cfg.Bucket, objName, minio.StatObjectOptions{}) 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(ctx, be.cfg.Bucket, objName, minio.RemoveObjectOptions{}) 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 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, recursive := be.Basedir(t) // make sure prefix ends with a slash if !strings.HasSuffix(prefix, "/") { prefix += "/" } ctx, cancel := context.WithCancel(ctx) defer cancel() debug.Log("using ListObjectsV1(%v)", be.cfg.ListObjectsV1) // 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(ctx, be.cfg.Bucket, minio.ListObjectsOptions{ Prefix: prefix, Recursive: recursive, UseV1: be.cfg.ListObjectsV1, }) for obj := range listresp { if obj.Err != nil { return obj.Err } m := strings.TrimPrefix(obj.Key, prefix) if m == "" { continue } fi := restic.FileInfo{ Name: path.Base(m), Size: obj.Size, } if ctx.Err() != nil { return ctx.Err() } err := fn(fi) if err != nil { return err } if ctx.Err() != nil { return ctx.Err() } } 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, restic.PackFile, 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 } // Rename moves a file based on the new layout l. func (be *Backend) Rename(ctx context.Context, 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.CopySrcOptions{ Bucket: be.cfg.Bucket, Object: oldname, } dst := minio.CopyDestOptions{ Bucket: be.cfg.Bucket, Object: newname, } _, err := be.client.CopyObject(ctx, 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(ctx, be.cfg.Bucket, oldname, minio.RemoveObjectOptions{}) }