55 lines
1 KiB
Go
55 lines
1 KiB
Go
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package filelock
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import (
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"errors"
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"fmt"
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"os"
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"path"
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"time"
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)
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var ErrLocked = errors.New("failed to get a lock in a timely manner")
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type FileLock struct {
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lockPath string
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}
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func New(filepath string) *FileLock {
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dir, filename := path.Split(filepath)
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lockPath := path.Join(dir, fmt.Sprintf(".%s.lock", filename))
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return &FileLock{
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lockPath: lockPath,
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}
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}
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func (fl *FileLock) lockFileExists() bool {
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if _, err := os.Stat(fl.lockPath); errors.Is(err, os.ErrNotExist) {
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return false
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}
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return true
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}
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func (fl *FileLock) Lock(timeout time.Duration) error {
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start := time.Now().UTC()
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end := start.Add(timeout)
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for {
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if !fl.lockFileExists() {
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if _, err := os.Create(fl.lockPath); err != nil {
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return fmt.Errorf("failed to create lock: %w", err)
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}
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}
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if time.Now().After(end) {
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return ErrLocked
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}
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time.Sleep(100 * time.Millisecond)
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}
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}
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func (fl *FileLock) Unlock() error {
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if err := os.Remove(fl.lockPath); err != nil {
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return fmt.Errorf("failed to remove lock: %w", err)
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}
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return nil
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}
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