overlayfs

README

overlayfs is a composite filesystem (currently only) for Afero with similar but different semantics compared to Afero's copyOnWriteFs. See the GoDoc for more information.

Documentation

Index

• type Dir
  • func (d *Dir) Close() error
  • func (d *Dir) Name() string
  • func (d *Dir) Read(p []byte) (n int, err error)
  • func (d *Dir) ReadAt(p []byte, off int64) (n int, err error)
  • func (d *Dir) ReadDir(n int) ([]fs.DirEntry, error)
  • func (d *Dir) Readdir(n int) ([]os.FileInfo, error)
  • func (d *Dir) Readdirnames(n int) ([]string, error)
  • func (d *Dir) Seek(offset int64, whence int) (int64, error)
  • func (d *Dir) Stat() (os.FileInfo, error)
  • func (d *Dir) Sync() error
  • func (d *Dir) Truncate(size int64) error
  • func (d *Dir) Write(p []byte) (n int, err error)
  • func (d *Dir) WriteAt(p []byte, off int64) (n int, err error)
  • func (d *Dir) WriteString(s string) (ret int, err error)
• type DirsMerger
• type FilesystemIterator
• type Options
• type OverlayFs
  • func New(opts Options) *OverlayFs
  • func (ofs OverlayFs) Append(fss ...afero.Fs) *OverlayFs
  • func (ofs *OverlayFs) Chmod(name string, mode os.FileMode) error
  • func (ofs *OverlayFs) Chown(name string, uid, gid int) error
  • func (ofs *OverlayFs) Chtimes(name string, atime, mtime time.Time) error
  • func (ofs *OverlayFs) Create(name string) (afero.File, error)
  • func (ofs *OverlayFs) Filesystem(i int) afero.Fs
  • func (ofs *OverlayFs) LstatIfPossible(name string) (os.FileInfo, bool, error)
  • func (ofs *OverlayFs) Mkdir(name string, perm os.FileMode) error
  • func (ofs *OverlayFs) MkdirAll(path string, perm os.FileMode) error
  • func (ofs *OverlayFs) Name() string
  • func (ofs *OverlayFs) NumFilesystems() int
  • func (ofs *OverlayFs) Open(name string) (afero.File, error)
  • func (ofs *OverlayFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error)
  • func (ofs *OverlayFs) Remove(name string) error
  • func (ofs *OverlayFs) RemoveAll(path string) error
  • func (ofs *OverlayFs) Rename(oldname, newname string) error
  • func (ofs *OverlayFs) Stat(name string) (os.FileInfo, error)

Types

type Dir

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

Dir is an afero.File that represents list of directories that will be merged in Readdir and Readdirnames.

func (*Dir) Close

func (d *Dir) Close() error

Close implements afero.File.Close. Note that d must not be used after it is closed, as the object may be reused.

func (*Dir) Name

func (d *Dir) Name() string

Name implements afero.File.Name.

func (*Dir) Read

func (d *Dir) Read(p []byte) (n int, err error)

Read is not supported.

func (*Dir) ReadAt

func (d *Dir) ReadAt(p []byte, off int64) (n int, err error)

ReadAt is not supported.

func (*Dir) ReadDir

func (d *Dir) ReadDir(n int) ([]fs.DirEntry, error)

ReadDir implements fs.ReadDirFile.

func (*Dir) Readdir

func (d *Dir) Readdir(n int) ([]os.FileInfo, error)

Readdir implements afero.File.Readdir. If n > 0, Readdir returns at most n. Note that Dir also implements fs.ReadDirFile, which is more efficient.

func (*Dir) Readdirnames

func (d *Dir) Readdirnames(n int) ([]string, error)

Readdirnames implements afero.File.Readdirnames. If n > 0, Readdirnames returns at most n.

func (*Dir) Seek

func (d *Dir) Seek(offset int64, whence int) (int64, error)

Seek is not supported.

func (*Dir) Stat

func (d *Dir) Stat() (os.FileInfo, error)

Stat implements afero.File.Stat.

func (*Dir) Sync

func (d *Dir) Sync() error

Sync is not supported.

func (*Dir) Truncate

func (d *Dir) Truncate(size int64) error

Truncate is not supported.

func (*Dir) Write

func (d *Dir) Write(p []byte) (n int, err error)

Write is not supported.

func (*Dir) WriteAt

func (d *Dir) WriteAt(p []byte, off int64) (n int, err error)

WriteAt is not supported.

func (*Dir) WriteString

func (d *Dir) WriteString(s string) (ret int, err error)

WriteString is not supported.

type DirsMerger

type DirsMerger func(lofi, bofi []fs.DirEntry) []fs.DirEntry

DirsMerger is used to merge two directories.

type FilesystemIterator

type FilesystemIterator interface {
	Filesystem(i int) afero.Fs
	NumFilesystems() int
}

FilesystemIterator is an interface for iterating over the wrapped filesystems in order.

type Options

type Options struct {
	// The filesystems to overlay ordered in priority from left to right.
	Fss []afero.Fs

	// The OverlayFs is by default read-only, but you can nominate the first filesystem to be writable.
	FirstWritable bool

	// The DirsMerger is used to merge the contents of two directories.
	// If not provided, the defaultDirMerger is used.
	DirsMerger DirsMerger
}

Options for the OverlayFs.

type OverlayFs

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

OverlayFs is a filesystem that overlays multiple filesystems. It's by default a read-only filesystem, but you can nominate the first filesystem to be writable. For all operations, the filesystems are checked in order until found. If a filesystem implementes FilesystemIterator, those filesystems will be checked before continuing.

func New

func New(opts Options) *OverlayFs

New creates a new OverlayFs with the given options.

func (OverlayFs) Append

func (ofs OverlayFs) Append(fss ...afero.Fs) *OverlayFs

Append creates a shallow copy of the filesystem and appends the given filesystems to it.

func (*OverlayFs) Chmod

func (ofs *OverlayFs) Chmod(name string, mode os.FileMode) error

Chmod changes the mode of the named file to mode.

func (*OverlayFs) Chown

func (ofs *OverlayFs) Chown(name string, uid, gid int) error

Chown changes the uid and gid of the named file.

func (*OverlayFs) Chtimes

func (ofs *OverlayFs) Chtimes(name string, atime, mtime time.Time) error

Chtimes changes the access and modification times of the named file

func (*OverlayFs) Create

func (ofs *OverlayFs) Create(name string) (afero.File, error)

Create creates a file in the filesystem, returning the file and an error, if any happens.

func (*OverlayFs) Filesystem

func (ofs *OverlayFs) Filesystem(i int) afero.Fs

Filesystem returns filesystem with index i, nil if not found.

func (*OverlayFs) LstatIfPossible

func (ofs *OverlayFs) LstatIfPossible(name string) (os.FileInfo, bool, error)

LstatIfPossible will call Lstat if the filesystem iself is, or it delegates to, the os filesystem. Else it will call Stat.

func (*OverlayFs) Mkdir

func (ofs *OverlayFs) Mkdir(name string, perm os.FileMode) error

Mkdir creates a directory in the filesystem, return an error if any happens.

func (*OverlayFs) MkdirAll

func (ofs *OverlayFs) MkdirAll(path string, perm os.FileMode) error

MkdirAll creates a directory path and all parents that does not exist yet.

func (*OverlayFs) Name

func (ofs *OverlayFs) Name() string

Name returns the name of this filesystem.

func (*OverlayFs) NumFilesystems

func (ofs *OverlayFs) NumFilesystems() int

NumFilesystems returns the number of filesystems in this composite filesystem.

func (*OverlayFs) Open

func (ofs *OverlayFs) Open(name string) (afero.File, error)

Open opens a file, returning it or an error, if any happens. If name is a directory, a *Dir is returned representing all directories matching name. Note that a *Dir must not be used after it's closed.

func (*OverlayFs) OpenFile

func (ofs *OverlayFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error)

OpenFile opens a file using the given flags and the given mode.

func (*OverlayFs) Remove

func (ofs *OverlayFs) Remove(name string) error

Remove removes a file identified by name, returning an error, if any happens.

func (*OverlayFs) RemoveAll

func (ofs *OverlayFs) RemoveAll(path string) error

RemoveAll removes a directory path and any children it contains. It does not fail if the path does not exist (return nil).

func (*OverlayFs) Rename

func (ofs *OverlayFs) Rename(oldname, newname string) error

Rename renames a file.

func (*OverlayFs) Stat

func (ofs *OverlayFs) Stat(name string) (os.FileInfo, error)

Stat returns a FileInfo describing the named file, or an error, if any happens.