package driver import ( "context" "fmt" "io" "regexp" "strconv" "strings" ) // Version is a string representing the storage driver version, of the form // Major.Minor. // The registry must accept storage drivers with equal major version and greater // minor version, but may not be compatible with older storage driver versions. type Version string // Major returns the major (primary) component of a version. func (version Version) Major() uint { majorPart := strings.Split(string(version), ".")[0] major, _ := strconv.ParseUint(majorPart, 10, 0) return uint(major) } // Minor returns the minor (secondary) component of a version. func (version Version) Minor() uint { minorPart := strings.Split(string(version), ".")[1] minor, _ := strconv.ParseUint(minorPart, 10, 0) return uint(minor) } // CurrentVersion is the current storage driver Version. const CurrentVersion Version = "0.1" // StorageDriver defines methods that a Storage Driver must implement for a // filesystem-like key/value object storage. Storage Drivers are automatically // registered via an internal registration mechanism, and generally created // via the StorageDriverFactory interface (https://godoc.org/github.com/distribution/distribution/registry/storage/driver/factory). // Please see the aforementioned factory package for example code showing how to get an instance // of a StorageDriver type StorageDriver interface { // Name returns the human-readable "name" of the driver, useful in error // messages and logging. By convention, this will just be the registration // name, but drivers may provide other information here. Name() string // GetContent retrieves the content stored at "path" as a []byte. // This should primarily be used for small objects. GetContent(ctx context.Context, path string) ([]byte, error) // PutContent stores the []byte content at a location designated by "path". // This should primarily be used for small objects. PutContent(ctx context.Context, path string, content []byte) error // Reader retrieves an io.ReadCloser for the content stored at "path" // with a given byte offset. // May be used to resume reading a stream by providing a nonzero offset. Reader(ctx context.Context, path string, offset int64) (io.ReadCloser, error) // Writer returns a FileWriter which will store the content written to it // at the location designated by "path" after the call to Commit. Writer(ctx context.Context, path string, append bool) (FileWriter, error) // Stat retrieves the FileInfo for the given path, including the current // size in bytes and the creation time. Stat(ctx context.Context, path string) (FileInfo, error) // List returns a list of the objects that are direct descendants of the //given path. List(ctx context.Context, path string) ([]string, error) // Move moves an object stored at sourcePath to destPath, removing the // original object. // Note: This may be no more efficient than a copy followed by a delete for // many implementations. Move(ctx context.Context, sourcePath string, destPath string) error // Delete recursively deletes all objects stored at "path" and its subpaths. Delete(ctx context.Context, path string) error // URLFor returns a URL which may be used to retrieve the content stored at // the given path, possibly using the given options. // May return an ErrUnsupportedMethod in certain StorageDriver // implementations. URLFor(ctx context.Context, path string, options map[string]interface{}) (string, error) // Walk traverses a filesystem defined within driver, starting // from the given path, calling f on each file. // If the returned error from the WalkFn is ErrSkipDir and fileInfo refers // to a directory, the directory will not be entered and Walk // will continue the traversal. If fileInfo refers to a normal file, processing stops Walk(ctx context.Context, path string, f WalkFn) error } // FileWriter provides an abstraction for an opened writable file-like object in // the storage backend. The FileWriter must flush all content written to it on // the call to Close, but is only required to make its content readable on a // call to Commit. type FileWriter interface { io.WriteCloser // Size returns the number of bytes written to this FileWriter. Size() int64 // Cancel removes any written content from this FileWriter. Cancel() error // Commit flushes all content written to this FileWriter and makes it // available for future calls to StorageDriver.GetContent and // StorageDriver.Reader. Commit() error } // PathRegexp is the regular expression which each file path must match. A // file path is absolute, beginning with a slash and containing a positive // number of path components separated by slashes, where each component is // restricted to alphanumeric characters or a period, underscore, or // hyphen. var PathRegexp = regexp.MustCompile(`^(/[A-Za-z0-9._-]+)+$`) // ErrUnsupportedMethod may be returned in the case where a StorageDriver implementation does not support an optional method. type ErrUnsupportedMethod struct { DriverName string } func (err ErrUnsupportedMethod) Error() string { return fmt.Sprintf("%s: unsupported method", err.DriverName) } // PathNotFoundError is returned when operating on a nonexistent path. type PathNotFoundError struct { Path string DriverName string } func (err PathNotFoundError) Error() string { return fmt.Sprintf("%s: Path not found: %s", err.DriverName, err.Path) } // InvalidPathError is returned when the provided path is malformed. type InvalidPathError struct { Path string DriverName string } func (err InvalidPathError) Error() string { return fmt.Sprintf("%s: invalid path: %s", err.DriverName, err.Path) } // InvalidOffsetError is returned when attempting to read or write from an // invalid offset. type InvalidOffsetError struct { Path string Offset int64 DriverName string } func (err InvalidOffsetError) Error() string { return fmt.Sprintf("%s: invalid offset: %d for path: %s", err.DriverName, err.Offset, err.Path) } // Error is a catch-all error type which captures an error string and // the driver type on which it occurred. type Error struct { DriverName string Enclosed error } func (err Error) Error() string { return fmt.Sprintf("%s: %s", err.DriverName, err.Enclosed) }