Method Masters

pkg/utils/redis/sentinel.go:344–407

(sentinels []string, timeout time.Duration)

}

func (s *Sentinel) Masters(sentinels []string, timeout time.Duration) (map[int]string, error) {
	cntx, cancel := context.WithTimeout(s.Context, timeout)
	defer cancel()

	timeout += time.Second * 5
	results := make(chan map[int]*SentinelMaster, len(sentinels))

	var majority = 1 + len(sentinels)/2

	for i := range sentinels {
		go func(sentinel string) {
			masters, err := s.mastersDispatch(cntx, sentinel, timeout)
			if err != nil {
				s.errorf(err, "sentinel-[%s] masters failed", sentinel)
			}
			results <- masters
		}(sentinels[i])
	}

	masters := make(map[int]string)
	current := make(map[int]*SentinelMaster)

	var voted int
	for alive := len(sentinels); ; alive-- {
		if alive == 0 {
			switch {
			case cntx.Err() != context.DeadlineExceeded && cntx.Err() != nil:
				s.printf("sentinel masters canceled (%v)", cntx.Err())
				return nil, errors.Trace(cntx.Err())
			case voted != len(sentinels):
				s.printf("sentinel masters voted = (%d/%d) masters = %d (%v)", voted, len(sentinels), len(masters), cntx.Err())
			}
			if voted < majority {
				return nil, errors.Errorf("lost majority (%d/%d)", voted, len(sentinels))
			}
			return masters, nil
		}
		select {
		case <-cntx.Done():
			switch {
			case cntx.Err() != context.DeadlineExceeded:
				s.printf("sentinel masters canceled (%v)", cntx.Err())
				return nil, errors.Trace(cntx.Err())
			default:
				s.printf("sentinel masters voted = (%d/%d) masters = %d (%v)", voted, len(sentinels), len(masters), cntx.Err())
			}
			if voted < majority {
				return nil, errors.Errorf("lost majority (%d/%d)", voted, len(sentinels))
			}
			return masters, nil
		case m := <-results:
			if m == nil {
				continue
			}
			for gid, master := range m {
				if current[gid] == nil || current[gid].Epoch < master.Epoch {
					current[gid] = master
					masters[gid] = master.Addr