prometheus/util/flock/flock.go

34 lines
1.0 KiB
Go

// Package flock provides portable file locking. It is essentially ripped out
// from the code of github.com/syndtr/goleveldb. Strange enough that the
// standard library does not provide this functionality. Once this package has
// proven to work as expected, we should probably turn it into a separate
// general purpose package for humanity.
package flock
import (
"os"
"path/filepath"
)
// Releaser provides the Release method to release a file lock.
type Releaser interface {
Release() error
}
// New locks the file with the provided name. If the file does not exist, it is
// created. The returned Releaser is used to release the lock. existed is true
// if the file to lock already existed. A non-nil error is returned if the
// locking has failed. Neither this function nor the returned Releaser is
// goroutine-safe.
func New(fileName string) (r Releaser, existed bool, err error) {
if err = os.MkdirAll(filepath.Dir(fileName), 0755); err != nil {
return
}
_, err = os.Stat(fileName)
existed = err == nil
r, err = newLock(fileName)
return
}