observer.go

package lockd

import "time"

// Observer receives lifecycle events so an external package can export metrics
// without the engine core importing any metrics library. All methods must be
// safe for concurrent use and should not block; they run on the caller's
// goroutine right after the corresponding operation.
type Observer interface {
	// AcquireDone fires after an Acquire returns. granted reports whether a
	// lease was handed out; dur is the wall time the call took.
	AcquireDone(granted bool, dur time.Duration)
	// Released fires after a successful Release.
	Released()
	// Expired fires when the timing wheel reclaims a lease.
	Expired()
}

// nopObserver is used when no Observer is configured.
type nopObserver struct{}

func (nopObserver) AcquireDone(bool, time.Duration) {}
func (nopObserver) Released()                       {}
func (nopObserver) Expired()                        {}