README
¶
safefile
Go package safefile implements safe "atomic" saving of files.
Instead of truncating and overwriting the destination file, it creates a temporary file in the same directory, writes to it, and then renames the temporary file to the original name when calling Commit.
Installation
$ go get github.com/dchest/safefile
Documentation
https://godoc.org/github.com/dchest/safefile
Example
f, err := safefile.Create("/home/ken/report.txt", 0644)
if err != nil {
// ...
}
// Created temporary file /home/ken/sf-ppcyksu5hyw2mfec.tmp
defer f.Close()
_, err = io.WriteString(f, "Hello world")
if err != nil {
// ...
}
// Wrote "Hello world" to /home/ken/sf-ppcyksu5hyw2mfec.tmp
err = f.Commit()
if err != nil {
// ...
}
// Renamed /home/ken/sf-ppcyksu5hyw2mfec.tmp to /home/ken/report.txt
Documentation
¶
Overview ¶
Package safefile implements safe "atomic" saving of files.
Instead of truncating and overwriting the destination file, it creates a temporary file in the same directory, writes to it, and then renames the temporary file to the original name when calling Commit.
Example:
f, err := safefile.Create("/home/ken/report.txt", 0644)
if err != nil {
// ...
}
// Created temporary file /home/ken/sf-ppcyksu5hyw2mfec.tmp
defer f.Close()
_, err = io.WriteString(f, "Hello world")
if err != nil {
// ...
}
// Wrote "Hello world" to /home/ken/sf-ppcyksu5hyw2mfec.tmp
err = f.Commit()
if err != nil {
// ...
}
// Renamed /home/ken/sf-ppcyksu5hyw2mfec.tmp to /home/ken/report.txt
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrAlreadyCommitted = errors.New("file already committed")
ErrAlreadyCommitted error is returned when calling Commit on a file that has been already successfully committed.
Functions ¶
Types ¶
type File ¶
func Create ¶
Create creates a temporary file in the same directory as filename, which will be renamed to the given filename when calling Commit.
func (*File) Close ¶
Close closes temporary file and removes it. If the file has been committed, Close is no-op.
func (*File) Commit ¶
Note that when trying to Commit again after a failed Commit when the file has been closed, but not renamed to its original name (the new commit will try again to rename it), safefile cannot guarantee that the temporary file has not been changed, or that it is the same temporary file we were dealing with. However, since the temporary name is unpredictable, it is unlikely that this happened accidentally. If complete atomicity is needed, do not Commit again after error, write the file again.
Source Files