package s3 import ( "context" "fmt" "hash" "io" "net/http" "os" "path" "strings" "time" "github.com/restic/restic/internal/backend" "github.com/restic/restic/internal/backend/layout" "github.com/restic/restic/internal/backend/location" "github.com/restic/restic/internal/backend/util" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/errors" "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 cfg Config layout.Layout } // make sure that *Backend implements backend.Backend var _ backend.Backend = &Backend{} func NewFactory() location.Factory { return location.NewHTTPBackendFactory("s3", ParseConfig, location.NoPassword, Create, Open) } const defaultLayout = "default" func open(ctx context.Context, cfg Config, rt http.RoundTripper) (*Backend, error) { debug.Log("open, config %#v", cfg) if cfg.KeyID == "" && cfg.Secret.String() != "" { return nil, errors.Fatalf("unable to open S3 backend: Key ID ($AWS_ACCESS_KEY_ID) is empty") } else if cfg.KeyID != "" && cfg.Secret.String() == "" { return nil, errors.Fatalf("unable to open S3 backend: Secret ($AWS_SECRET_ACCESS_KEY) is empty") } if cfg.MaxRetries > 0 { minio.MaxRetry = int(cfg.MaxRetries) } creds, err := getCredentials(cfg) if err != nil { return nil, errors.Wrap(err, "s3.getCredentials") } 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") } be := &Backend{ client: client, cfg: cfg, } l, err := layout.ParseLayout(ctx, be, cfg.Layout, defaultLayout, cfg.Prefix) if err != nil { return nil, err } be.Layout = l return be, nil } // getCredentials -- runs through the various credential types and returns the first one that works. // additionally if the user has specified a role to assume, it will do that as well. func getCredentials(cfg Config) (*credentials.Credentials, error) { // 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.Static{ Value: credentials.Value{ AccessKeyID: cfg.KeyID, SecretAccessKey: cfg.Secret.Unwrap(), }, }, &credentials.EnvAWS{}, &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) } roleArn := os.Getenv("RESTIC_AWS_ASSUME_ROLE_ARN") if roleArn != "" { // use the region provided by the configuration by default awsRegion := cfg.Region // allow the region to be overridden if for some reason it is required if len(os.Getenv("RESTIC_AWS_ASSUME_ROLE_REGION")) > 0 { awsRegion = os.Getenv("RESTIC_AWS_ASSUME_ROLE_REGION") } sessionName := os.Getenv("RESTIC_AWS_ASSUME_ROLE_SESSION_NAME") externalID := os.Getenv("RESTIC_AWS_ASSUME_ROLE_EXTERNAL_ID") policy := os.Getenv("RESTIC_AWS_ASSUME_ROLE_POLICY") stsEndpoint := os.Getenv("RESTIC_AWS_ASSUME_ROLE_STS_ENDPOINT") if stsEndpoint == "" { if len(awsRegion) > 0 { if strings.HasPrefix(awsRegion, "cn-") { stsEndpoint = "https://sts." + awsRegion + ".amazonaws.com.cn" } else { stsEndpoint = "https://sts." + awsRegion + ".amazonaws.com" } } else { stsEndpoint = "https://sts.amazonaws.com" } } opts := credentials.STSAssumeRoleOptions{ RoleARN: roleArn, AccessKey: c.AccessKeyID, SecretKey: c.SecretAccessKey, SessionToken: c.SessionToken, RoleSessionName: sessionName, ExternalID: externalID, Policy: policy, } if len(awsRegion) > 0 { opts.Location = awsRegion } creds, err = credentials.NewSTSAssumeRole(stsEndpoint, opts) if err != nil { return nil, errors.Wrap(err, "creds.AssumeRole") } } return creds, 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) (backend.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) (backend.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 && 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 isAccessDenied(err error) bool { debug.Log("isAccessDenied(%T, %#v)", err, err) var e minio.ErrorResponse return errors.As(err, &e) && e.Code == "AccessDenied" } // IsNotExist returns true if the error is caused by a not existing file. func (be *Backend) IsNotExist(err error) bool { var e minio.ErrorResponse return errors.As(err, &e) && e.Code == "NoSuchKey" } // 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 } func (be *Backend) Connections() uint { return be.cfg.Connections } // 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 } // 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.cfg.Prefix } // Save stores data in the backend at the handle. func (be *Backend) Save(ctx context.Context, h backend.Handle, rd backend.RewindReader) error { objName := be.Filename(h) 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 // only use multipart uploads for very large files opts.PartSize = 200 * 1024 * 1024 info, err := be.client.PutObject(ctx, be.cfg.Bucket, objName, io.NopCloser(rd), int64(rd.Length()), opts) // 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") } // 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 backend.Handle, length int, offset int64, fn func(rd io.Reader) error) error { ctx, cancel := context.WithCancel(ctx) defer cancel() return util.DefaultLoad(ctx, h, length, offset, be.openReader, fn) } func (be *Backend) openReader(ctx context.Context, h backend.Handle, length int, offset int64) (io.ReadCloser, error) { objName := be.Filename(h) opts := minio.GetObjectOptions{} var err error if length > 0 { err = opts.SetRange(offset, offset+int64(length)-1) } else if offset > 0 { err = opts.SetRange(offset, 0) } if err != nil { return nil, errors.Wrap(err, "SetRange") } coreClient := minio.Core{Client: be.client} rd, _, _, err := coreClient.GetObject(ctx, be.cfg.Bucket, objName, opts) if err != nil { return nil, err } return rd, err } // Stat returns information about a blob. func (be *Backend) Stat(ctx context.Context, h backend.Handle) (bi backend.FileInfo, err error) { objName := be.Filename(h) var obj *minio.Object opts := minio.GetObjectOptions{} obj, err = be.client.GetObject(ctx, be.cfg.Bucket, objName, opts) if err != nil { return backend.FileInfo{}, errors.Wrap(err, "client.GetObject") } // make sure that the object is closed properly. defer func() { e := obj.Close() if err == nil { err = errors.Wrap(e, "Close") } }() fi, err := obj.Stat() if err != nil { return backend.FileInfo{}, errors.Wrap(err, "Stat") } return backend.FileInfo{Size: fi.Size, Name: h.Name}, nil } // Remove removes the blob with the given name and type. func (be *Backend) Remove(ctx context.Context, h backend.Handle) error { objName := be.Filename(h) err := be.client.RemoveObject(ctx, be.cfg.Bucket, objName, minio.RemoveObjectOptions{}) 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 backend.FileType, fn func(backend.FileInfo) error) error { 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 := backend.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() } // Delete removes all restic keys in the bucket. It will not remove the bucket itself. func (be *Backend) Delete(ctx context.Context) error { return util.DefaultDelete(ctx, be) } // 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 backend.Handle, l layout.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{}) }