archive

package
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Published: Aug 4, 2015 License: Apache-2.0 Imports: 23 Imported by: 0

README

This code provides helper functions for dealing with archive files.

Documentation

Index

Constants

View Source
const (
	ChangeModify = iota
	ChangeAdd
	ChangeDelete
)

Variables

View Source
var (
	ErrNotDirectory      = errors.New("not a directory")
	ErrDirNotExists      = errors.New("no such directory")
	ErrCannotCopyDir     = errors.New("cannot copy directory")
	ErrInvalidCopySource = errors.New("invalid copy source content")
)

Errors used or returned by this file.

View Source
var (
	ErrNotImplemented = errors.New("Function not implemented")
)

Functions

func ApplyLayer

func ApplyLayer(dest string, layer ArchiveReader) (int64, error)

ApplyLayer parses a diff in the standard layer format from `layer`, and applies it to the directory `dest`. The stream `layer` can be compressed or uncompressed. Returns the size in bytes of the contents of the layer.

func ApplyUncompressedLayer

func ApplyUncompressedLayer(dest string, layer ArchiveReader) (int64, error)

ApplyUncompressedLayer parses a diff in the standard layer format from `layer`, and applies it to the directory `dest`. The stream `layer` can only be uncompressed. Returns the size in bytes of the contents of the layer.

func AssertsDirectory

func AssertsDirectory(path string) bool

AssertsDirectory returns whether the given path is asserted to be a directory, i.e., the path ends with a trailing '/' or `/.`, assuming a path separator of `/`.

func CanonicalTarNameForPath

func CanonicalTarNameForPath(p string) (string, error)

CanonicalTarNameForPath returns platform-specific filepath to canonical posix-style path for tar archival. p is relative path.

func ChangesSize

func ChangesSize(newDir string, changes []Change) int64

ChangesSize calculates the size in bytes of the provided changes, based on newDir.

func CmdStream

func CmdStream(cmd *exec.Cmd, input io.Reader) (io.ReadCloser, error)

CmdStream executes a command, and returns its stdout as a stream. If the command fails to run or doesn't complete successfully, an error will be returned, including anything written on stderr.

func CompressStream

func CompressStream(dest io.WriteCloser, compression Compression) (io.WriteCloser, error)

func CopyFileWithTar

func CopyFileWithTar(src, dst string) (err error)

CopyFileWithTar emulates the behavior of the 'cp' command-line for a single file. It copies a regular file from path `src` to path `dst`, and preserves all its metadata.

Destination handling is in an operating specific manner depending where the daemon is running. If `dst` ends with a trailing slash the final destination path will be `dst/base(src)` (Linux) or `dst\base(src)` (Windows).

func CopyResource

func CopyResource(srcPath, dstPath string) error

CopyResource performs an archive copy from the given source path to the given destination path. The source path MUST exist and the destination path's parent directory must exist.

func CopyTo

func CopyTo(content ArchiveReader, srcInfo CopyInfo, dstPath string) error

CopyTo handles extracting the given content whose entries should be sourced from srcInfo to dstPath.

func CopyWithTar

func CopyWithTar(src, dst string) error

CopyWithTar creates a tar archive of filesystem path `src`, and unpacks it at filesystem path `dst`. The archive is streamed directly with fixed buffering and no intermediary disk IO.

func DecompressStream

func DecompressStream(archive io.Reader) (io.ReadCloser, error)

func HasTrailingPathSeparator

func HasTrailingPathSeparator(path string) bool

HasTrailingPathSeparator returns whether the given path ends with the system's path separator character.

func IsArchive

func IsArchive(header []byte) bool

func PreserveTrailingDotOrSeparator

func PreserveTrailingDotOrSeparator(cleanedPath, originalPath string) string

PreserveTrailingDotOrSeparator returns the given cleaned path (after processing using any utility functions from the path or filepath stdlib packages) and appends a trailing `/.` or `/` if its corresponding original path (from before being processed by utility functions from the path or filepath stdlib packages) ends with a trailing `/.` or `/`. If the cleaned path already ends in a `.` path segment, then another is not added. If the clean path already ends in a path separator, then another is not added.

func SpecifiesCurrentDir

func SpecifiesCurrentDir(path string) bool

SpecifiesCurrentDir returns whether the given path specifies a "current directory", i.e., the last path segment is `.`.

func SplitPathDirEntry

func SplitPathDirEntry(path string) (dir, base string)

SplitPathDirEntry splits the given path between its directory name and its basename by first cleaning the path but preserves a trailing "." if the original path specified the current directory.

func Tar

func Tar(path string, compression Compression) (io.ReadCloser, error)

Tar creates an archive from the directory at `path`, and returns it as a stream of bytes.

func TarUntar

func TarUntar(src, dst string) error

TarUntar is a convenience function which calls Tar and Untar, with the output of one piped into the other. If either Tar or Untar fails, TarUntar aborts and returns the error.

func TarWithOptions

func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error)

TarWithOptions creates an archive from the directory at `path`, only including files whose relative paths are included in `options.IncludeFiles` (if non-nil) or not in `options.ExcludePatterns`.

func Unpack

func Unpack(decompressedArchive io.Reader, dest string, options *TarOptions) error

func UnpackLayer

func UnpackLayer(dest string, layer ArchiveReader) (size int64, err error)

func Untar

func Untar(tarArchive io.Reader, dest string, options *TarOptions) error

Untar reads a stream of bytes from `archive`, parses it as a tar archive, and unpacks it into the directory at `dest`. The archive may be compressed with one of the following algorithms:

identity (uncompressed), gzip, bzip2, xz.

FIXME: specify behavior when target path exists vs. doesn't exist.

func UntarPath

func UntarPath(src, dst string) error

UntarPath is a convenience function which looks for an archive at filesystem path `src`, and unpacks it at `dst`.

func UntarUncompressed

func UntarUncompressed(tarArchive io.Reader, dest string, options *TarOptions) error

Untar reads a stream of bytes from `archive`, parses it as a tar archive, and unpacks it into the directory at `dest`. The archive must be an uncompressed stream.

Types

type Archive

type Archive io.ReadCloser

func ExportChanges

func ExportChanges(dir string, changes []Change) (Archive, error)

ExportChanges produces an Archive from the provided changes, relative to dir.

func Generate

func Generate(input ...string) (Archive, error)

Generate generates a new archive from the content provided as input.

`files` is a sequence of path/content pairs. A new file is added to the archive for each pair. If the last pair is incomplete, the file is created with an empty content. For example:

Generate("foo.txt", "hello world", "emptyfile")

The above call will return an archive with 2 files:

  • ./foo.txt with content "hello world"
  • ./empty with empty content

FIXME: stream content instead of buffering FIXME: specify permissions and other archive metadata

func PrepareArchiveCopy

func PrepareArchiveCopy(srcContent ArchiveReader, srcInfo, dstInfo CopyInfo) (dstDir string, content Archive, err error)

PrepareArchiveCopy prepares the given srcContent archive, which should contain the archived resource described by srcInfo, to the destination described by dstInfo. Returns the possibly modified content archive along with the path to the destination directory which it should be extracted to.

func TarResource

func TarResource(sourceInfo CopyInfo) (content Archive, err error)

TarResource archives the resource described by the given CopyInfo to a Tar archive. A non-nil error is returned if sourcePath does not exist or is asserted to be a directory but exists as another type of file.

This function acts as a convenient wrapper around TarWithOptions, which requires a directory as the source path. TarResource accepts either a directory or a file path and correctly sets the Tar options.

func TarResourceRebase

func TarResourceRebase(sourcePath, rebaseName string) (content Archive, err error)

TarResourceRebase is like TarResource but renames the first path element of items in the resulting tar archive to match the given rebaseName if not "".

type ArchiveReader

type ArchiveReader io.Reader

type Archiver

type Archiver struct {
	Untar func(io.Reader, string, *TarOptions) error
}

Archiver allows the reuse of most utility functions of this package with a pluggable Untar function.

func (*Archiver) CopyFileWithTar

func (archiver *Archiver) CopyFileWithTar(src, dst string) (err error)

func (*Archiver) CopyWithTar

func (archiver *Archiver) CopyWithTar(src, dst string) error

func (*Archiver) TarUntar

func (archiver *Archiver) TarUntar(src, dst string) error

func (*Archiver) UntarPath

func (archiver *Archiver) UntarPath(src, dst string) error

type Change

type Change struct {
	Path string
	Kind ChangeType
}

func Changes

func Changes(layers []string, rw string) ([]Change, error)

Changes walks the path rw and determines changes for the files in the path, with respect to the parent layers

func ChangesDirs

func ChangesDirs(newDir, oldDir string) ([]Change, error)

ChangesDirs compares two directories and generates an array of Change objects describing the changes. If oldDir is "", then all files in newDir will be Add-Changes.

func (*Change) String

func (change *Change) String() string

type ChangeType

type ChangeType int

type Compression

type Compression int
const (
	Uncompressed Compression = iota
	Bzip2
	Gzip
	Xz
)

func DetectCompression

func DetectCompression(source []byte) Compression

func (*Compression) Extension

func (compression *Compression) Extension() string

type CopyInfo

type CopyInfo struct {
	Path       string
	Exists     bool
	IsDir      bool
	RebaseName string
}

CopyInfo holds basic info about the source or destination path of a copy operation.

func CopyInfoDestinationPath

func CopyInfoDestinationPath(path string) (info CopyInfo, err error)

CopyInfoDestinationPath stats the given path to create a CopyInfo struct representing that resource for the destination of an archive copy operation. The given path should be an absolute local path.

func CopyInfoSourcePath

func CopyInfoSourcePath(path string) (CopyInfo, error)

CopyInfoSourcePath stats the given path to create a CopyInfo struct representing that resource for the source of an archive copy operation. The given path should be an absolute local path. A source path has all symlinks evaluated that appear before the last path separator ("/" on Unix). As it is to be a copy source, the path must exist.

type FileInfo

type FileInfo struct {
	// contains filtered or unexported fields
}

func (*FileInfo) Changes

func (info *FileInfo) Changes(oldInfo *FileInfo) []Change

func (*FileInfo) LookUp

func (root *FileInfo) LookUp(path string) *FileInfo

type TarChownOptions

type TarChownOptions struct {
	UID, GID int
}

type TarOptions

type TarOptions struct {
	IncludeFiles     []string
	ExcludePatterns  []string
	Compression      Compression
	NoLchown         bool
	ChownOpts        *TarChownOptions
	IncludeSourceDir bool
	// When unpacking, specifies whether overwriting a directory with a
	// non-directory is allowed and vice versa.
	NoOverwriteDirNonDir bool
	// For each include when creating an archive, the included name will be
	// replaced with the matching name from this map.
	RebaseNames map[string]string
}

type TempArchive

type TempArchive struct {
	*os.File
	Size int64 // Pre-computed from Stat().Size() as a convenience
	// contains filtered or unexported fields
}

func NewTempArchive

func NewTempArchive(src Archive, dir string) (*TempArchive, error)

NewTempArchive reads the content of src into a temporary file, and returns the contents of that file as an archive. The archive can only be read once - as soon as reading completes, the file will be deleted.

func (*TempArchive) Close

func (archive *TempArchive) Close() error

Close closes the underlying file if it's still open, or does a no-op to allow callers to try to close the TempArchive multiple times safely.

func (*TempArchive) Read

func (archive *TempArchive) Read(data []byte) (int, error)

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