fileutil

Documentation

Overview

Package fileutil implements utility functions related to files and paths.

Index

• Constants
• Variables
• func CreateDirAll(dir string) error
• func Exist(name string) bool
• func Fdatasync(f *os.File) error
• func Fsync(f *os.File) error
• func IsDirWriteable(dir string) error
• func OpenDir(path string) (*os.File, error)
• func Preallocate(f *os.File, sizeInBytes int64, extendFile bool) error
• func PurgeFile(lg *zap.Logger, dirname string, suffix string, max uint, ...) <-chan error
• func ReadDir(dirpath string) ([]string, error)
• func TouchDirAll(dir string) error
• func ZeroToEnd(f *os.File) error
• type LockedFile
  • func LockFile(path string, flag int, perm os.FileMode) (*LockedFile, error)
  • func TryLockFile(path string, flag int, perm os.FileMode) (*LockedFile, error)

Constants

const (
	// PrivateFileMode grants owner to read/write a file.
	PrivateFileMode = 0600
	// PrivateDirMode grants owner to make/remove files inside the directory.
	PrivateDirMode = 0700
)

const (
	F_OFD_GETLK  = 37
	F_OFD_SETLK  = 37
	F_OFD_SETLKW = 38
)

This used to call syscall.Flock() but that call fails with EBADF on NFS. An alternative is lockf() which works on NFS but that call lets a process lock the same file twice. Instead, use Linux's non-standard open file descriptor locks which will block if the process already holds the file lock.

constants from /usr/include/bits/fcntl-linux.h

Variables

var (
	ErrLocked = errors.New("fileutil: file already locked")
)

Functions

func CreateDirAll

func CreateDirAll(dir string) error

CreateDirAll is similar to TouchDirAll but returns error if the deepest directory was not empty.

func Exist

func Exist(name string) bool

Exist returns true if a file or directory exists.

func Fdatasync

func Fdatasync(f *os.File) error

Fdatasync is similar to fsync(), but does not flush modified metadata unless that metadata is needed in order to allow a subsequent data retrieval to be correctly handled.

func Fsync

func Fsync(f *os.File) error

Fsync is a wrapper around file.Sync(). Special handling is needed on darwin platform.

func IsDirWriteable

func IsDirWriteable(dir string) error

IsDirWriteable checks if dir is writable by writing and removing a file to dir. It returns nil if dir is writable.

func OpenDir

func OpenDir(path string) (*os.File, error)

OpenDir opens a directory for syncing.

func Preallocate

func Preallocate(f *os.File, sizeInBytes int64, extendFile bool) error

Preallocate tries to allocate the space for given file. This operation is only supported on linux by a few filesystems (btrfs, ext4, etc.). If the operation is unsupported, no error will be returned. Otherwise, the error encountered will be returned.

func PurgeFile

func PurgeFile(lg *zap.Logger, dirname string, suffix string, max uint, interval time.Duration, stop <-chan struct{}) <-chan error

func ReadDir

func ReadDir(dirpath string) ([]string, error)

ReadDir returns the filenames in the given directory in sorted order.

func TouchDirAll

func TouchDirAll(dir string) error

TouchDirAll is similar to os.MkdirAll. It creates directories with 0700 permission if any directory does not exists. TouchDirAll also ensures the given directory is writable.

func ZeroToEnd

func ZeroToEnd(f *os.File) error

ZeroToEnd zeros a file starting from SEEK_CUR to its SEEK_END. May temporarily shorten the length of the file.

Types

type LockedFile

type LockedFile struct{ *os.File }

func LockFile

func LockFile(path string, flag int, perm os.FileMode) (*LockedFile, error)

func TryLockFile

func TryLockFile(path string, flag int, perm os.FileMode) (*LockedFile, error)