Method setNewPrimaryClient

kv/multi.go:154–184

returns true, if primary client has changed

(store string)

// returns true, if primary client has changed
func (m *MultiClient) setNewPrimaryClient(store string) (bool, error) {
	newPrimaryIx := -1
	for ix, c := range m.clients {
		if c.name == store {
			newPrimaryIx = ix
			break
		}
	}

	if newPrimaryIx < 0 {
		return false, fmt.Errorf("KV store not found")
	}

	prev := int(m.primaryID.Swap(int32(newPrimaryIx)))
	if prev == newPrimaryIx {
		return false, nil
	}

	defer m.updatePrimaryStoreGauge() // do as the last thing, after releasing the lock

	// switching to new primary... cancel clients using previous one
	m.inProgressMu.Lock()
	defer m.inProgressMu.Unlock()

	for _, inp := range m.inProgress {
		if inp.client == prev {
			inp.cancel()
		}
	}
	return true, nil
}

func (m *MultiClient) registerMetrics(registerer prometheus.Registerer) {
	m.primaryStoreGauge = promauto.With(registerer).NewGaugeVec(prometheus.GaugeOpts{