atomicfile

README

atomicfile

Package atomicfile implements all-or-nothing file replacement by staging output to a temporary file adjacent to the specified target file, and renaming over the target when the temporary is closed.

Documentation

Overview

Package atomicfile implements all-or-nothing file replacement by staging output to a temporary file adjacent to the target, and renaming over the target when the temporary is closed.

If (and only if) the implementation of rename is atomic the replacement is also atomic. Since IEEE Std 1003.1 requires rename to be atomic, this is ordinarily true on POSIX-compatible filesystems.

Index

• func WriteAll(target string, r io.Reader, mode os.FileMode) (int64, error)
• func WriteData(target string, data []byte, mode os.FileMode) error
• type File
  • func New(target string, mode os.FileMode) (*File, error)
  • func (f *File) Cancel()
  • func (f *File) Close() error
  • func (f *File) Write(data []byte) (int, error)

Functions

func WriteAll

func WriteAll(target string, r io.Reader, mode os.FileMode) (int64, error)

WriteAll copies all the data from r to the specified target path via a File. It reports the total number of bytes copied.

func WriteData

func WriteData(target string, data []byte, mode os.FileMode) error

WriteData copies data to the specified target path via a File.

Types

type File

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

A File is a writable temporary file that will be renamed to a target path when successfully closed.

func New

func New(target string, mode os.FileMode) (*File, error)

New constructs a new writable File with the given mode that, when successfully closed will be renamed to target.

func (*File) Cancel

func (f *File) Cancel()

Cancel closes the temporary associated with f and discards it. It is safe to call Cancel even if f.Close has already succeeded.

func (*File) Close

func (f *File) Close() error

Close closes the temporary associated with f and renames it to the designated target file. If closing the temporary fails, or if the rename fails, the temporary file is unlinked before Close returns.

func (*File) Write

func (f *File) Write(data []byte) (int, error)

Write writes data to f, satisfying io.Writer.