Method updateLatency

osscluster.go:515–541

()

const maximumNodeLatency = 1 * time.Minute

func (n *clusterNode) updateLatency() {
	const numProbe = 10
	var dur uint64

	successes := 0
	for i := 0; i < numProbe; i++ {
		time.Sleep(time.Duration(10+rand.Intn(10)) * time.Millisecond)

		start := time.Now()
		err := n.Client.Ping(context.TODO()).Err()
		if err == nil {
			dur += uint64(time.Since(start) / time.Microsecond)
			successes++
		}
	}

	var latency float64
	if successes == 0 {
		// If none of the pings worked, set latency to some arbitrarily high value so this node gets
		// least priority.
		latency = float64(maximumNodeLatency / time.Microsecond)
	} else {
		latency = float64(dur) / float64(successes)
	}
	atomic.StoreUint32(&n.latency, uint32(latency+0.5))
	n.SetLastLatencyMeasurement(time.Now())
}

func (n *clusterNode) Latency() time.Duration {
	latency := atomic.LoadUint32(&n.latency)