Documentation
¶
Index ¶
- Constants
- Variables
- func AlignToTarBlock(o compression.Offset) compression.Offset
- func Marshal(ztoc *Ztoc) (io.Reader, ocispec.Descriptor, error)
- func TarProviderGzip(compressedReader *os.File) (io.Reader, error)
- func TarProviderTar(compressedReader *os.File) (io.Reader, error)
- func TarProviderZstd(compressedReader *os.File) (io.Reader, error)
- func Xattrs(paxHeaders map[string]string) map[string]string
- type BuildOption
- type Builder
- type CompressionInfo
- type FileMetadata
- type MetadataEntry
- type TOC
- type TarProvider
- type TocBuilder
- type Version
- type ZinfoBuilder
- type Ztoc
Constants ¶
const (
// TarBlockSize is the size of a tar block
TarBlockSize = 512
)
Variables ¶
var ErrInvalidTOCEntry = errors.New("invalid toc entry")
Functions ¶
func AlignToTarBlock ¶ added in v0.5.0
func AlignToTarBlock(o compression.Offset) compression.Offset
AlignToTarBlock aligns an offset to the next larger multiple of TarBlockSize
func Marshal ¶
Marshal serializes Ztoc to its flatbuffers schema and returns a reader along with the descriptor (digest and size only). If not successful, it will return an error.
func TarProviderGzip ¶
TarProviderGzip creates a tar reader from gzip reader.
func TarProviderTar ¶ added in v0.3.0
TarProviderTar return the tar file directly as the input to `tar.NewReader`.
func TarProviderZstd ¶
TarProviderZstd creates a tar reader from zstd reader.
Types ¶
type BuildOption ¶
type BuildOption func(opt *buildConfig) error
BuildOption specifies a change to `buildConfig` when building a ztoc.
func WithCompression ¶
func WithCompression(algorithm string) BuildOption
WithCompression specifies which compression algorithm is used by the layer.
type Builder ¶
type Builder struct {
// contains filtered or unexported fields
}
Builder holds a single `TocBuilder` that builds toc, and one `ZinfoBuilder` *per* compression algorithm that builds zinfo. `TocBuilder` is shared by different compression algorithms. Which `ZinfoBuilder` is used depends on the compression algorithm used by the layer.
func NewBuilder ¶
NewBuilder creates a `Builder` used to build ztocs. By default it supports gzip, user can register new compression algorithms by calling `RegisterCompressionAlgorithm`.
func (*Builder) BuildZtoc ¶
BuildZtoc builds a `Ztoc` given the filename of a layer blob. By default it assumes the layer is compressed using `gzip`, unless specified via `WithCompression`.
func (*Builder) CheckCompressionAlgorithm ¶
CheckCompressionAlgorithm checks if a compression algorithm is supported.
The algorithm has to be supported by both (1) `tocBuilder` (straightforward, create a tar reader from the compressed io.reader in compressionFileReader) and (2) `zinfoBuilder` (require zinfo impl, see `compression/gzip_zinfo.go` as an example).
func (*Builder) RegisterCompressionAlgorithm ¶
func (b *Builder) RegisterCompressionAlgorithm(name string, tarProvider TarProvider, zinfoBuilder ZinfoBuilder)
RegisterCompressionAlgorithm supports a new compression algorithm in `ztoc.Builder`.
type CompressionInfo ¶
type CompressionInfo struct { MaxSpanID compression.SpanID //The total number of spans in Ztoc - 1 SpanDigests []digest.Digest Checkpoints []byte CompressionAlgorithm string }
CompressionInfo is the "zinfo" part of ztoc including the `Checkpoints` data and other metadata such as all span digests.
type FileMetadata ¶
type FileMetadata struct { Name string Type string UncompressedOffset compression.Offset UncompressedSize compression.Offset TarHeaderOffset compression.Offset Linkname string // Target name of link (valid for TypeLink or TypeSymlink) Mode int64 // Permission and mode bits UID int // User ID of owner GID int // Group ID of owner Uname string // User name of owner Gname string // Group name of owner ModTime time.Time // Modification time Devmajor int64 // Major device number (valid for TypeChar or TypeBlock) Devminor int64 // Minor device number (valid for TypeChar or TypeBlock) PAXHeaders map[string]string }
FileMetadata contains metadata of a file in the compressed data.
func (FileMetadata) Equal ¶ added in v0.5.0
func (src FileMetadata) Equal(o FileMetadata) bool
func (FileMetadata) FileMode ¶ added in v0.3.0
func (src FileMetadata) FileMode() (m os.FileMode)
FileMode gets file mode for the file metadata
func (FileMetadata) Xattrs ¶
func (src FileMetadata) Xattrs() map[string]string
type MetadataEntry ¶
type MetadataEntry struct { UncompressedSize compression.Offset UncompressedOffset compression.Offset }
MetadataEntry is used to locate a file based on its metadata.
type TOC ¶
type TOC struct {
FileMetadata []FileMetadata
}
TOC is the "ztoc" part of ztoc including metadata of all files in the compressed data (e.g., a gzip tar file).
func (TOC) GetMetadataEntry ¶ added in v0.3.0
func (toc TOC) GetMetadataEntry(filename string) (MetadataEntry, error)
GetMetadataEntry gets MetadataEntry given a filename.
type TarProvider ¶
TarProvider creates a tar reader from a compressed file reader (e.g., a gzip file reader), which can be used by `TocBuilder` to create `TOC` from it.
type TocBuilder ¶
type TocBuilder struct {
// contains filtered or unexported fields
}
TocBuilder builds the `TOC` part of a ztoc and works with different compression algorithms (e.g., gzip, zstd) with a registered `TarProvider`.
func NewTocBuilder ¶
func NewTocBuilder() TocBuilder
NewTocBuilder return a `TocBuilder` struct. Users need to call `RegisterTarProvider` to support a specific compression algorithm.
func (TocBuilder) CheckCompressionAlgorithm ¶
func (tb TocBuilder) CheckCompressionAlgorithm(algorithm string) bool
CheckCompressionAlgorithm checks if a compression algorithm is supported.
func (TocBuilder) RegisterTarProvider ¶
func (tb TocBuilder) RegisterTarProvider(algorithm string, provider TarProvider)
RegisterTarProvider adds a TarProvider for a compression algorithm.
func (TocBuilder) TocFromFile ¶
func (tb TocBuilder) TocFromFile(algorithm, filename string) (TOC, compression.Offset, error)
TocFromFile creates a `TOC` given a layer blob filename and the compression algorithm used by the layer.
type Version ¶ added in v0.3.0
type Version string
Version defines the version of a Ztoc.
const (
Version09 Version = "0.9"
)
Ztoc versions available.
type ZinfoBuilder ¶
type ZinfoBuilder interface { // ZinfoFromFile builds zinfo given a compressed tar filename and span size, and calculate the size of the file. ZinfoFromFile(filename string, spanSize int64) (zinfo CompressionInfo, fs compression.Offset, err error) }
ZinfoBuilder builds the `zinfo` part of a ztoc. This interface should be implemented for each compression algorithm we support.
type Ztoc ¶
type Ztoc struct { TOC CompressionInfo Version Version BuildToolIdentifier string CompressedArchiveSize compression.Offset UncompressedArchiveSize compression.Offset }
Ztoc is a table of contents for compressed data which consists 2 parts:
(1). toc (`TOC`): a table of contents containing file metadata and its offset in the decompressed TAR archive. (2). zinfo (`CompressionInfo`): a collection of "checkpoints" of the state of the compression engine at various points in the layer.
func BuildZtocReader ¶
func BuildZtocReader(_ *testing.T, ents []testutil.TarEntry, compressionLevel int, spanSize int64, opts ...testutil.BuildTarOption) (*Ztoc, *io.SectionReader, error)
BuildZtocReader creates the tar gz file for tar entries. It returns ztoc and io.SectionReader of the file.
func Unmarshal ¶
Unmarshal takes the reader with flatbuffers byte stream and deserializes it ztoc. In case if there's any error situation during deserialization from flatbuffers, there will be an error returned.
func (Ztoc) ExtractFile ¶ added in v0.3.0
ExtractFile extracts a file from compressed data (as a reader) and returns the byte data.
func (Ztoc) ExtractFromTarGz ¶ added in v0.3.0
ExtractFromTarGz extracts data given a gzip tar file (`gz`) and its `ztoc`.