Method selectNext

internal/services/subgroup_manager.go:145–198

selectNext uses weighted round-robin algorithm to select a sub-group with active keys

()

// selectNext uses weighted round-robin algorithm to select a sub-group with active keys
func (s *selector) selectNext() string {
	s.mu.Lock()
	defer s.mu.Unlock()

	if len(s.subGroups) == 0 {
		return ""
	}

	if len(s.subGroups) == 1 {
		if s.hasActiveKeys(s.subGroups[0].subGroupID) {
			return s.subGroups[0].name
		}
		logrus.WithFields(logrus.Fields{
			"group_id":   s.subGroups[0].subGroupID,
			"group_name": s.subGroups[0].name,
		}).Debug("Single sub-group has no active keys")
		return ""
	}

	attempted := make(map[uint]bool)
	for len(attempted) < len(s.subGroups) {
		item := s.selectByWeight()
		if item == nil {
			break
		}

		if attempted[item.subGroupID] {
			continue
		}
		attempted[item.subGroupID] = true

		if s.hasActiveKeys(item.subGroupID) {
			logrus.WithFields(logrus.Fields{
				"aggregate_group": s.groupName,
				"selected_group":  item.name,
				"attempts":        len(attempted),
			}).Debug("Selected sub-group with active keys")
			return item.name
		}

		logrus.WithFields(logrus.Fields{
			"group_id":   item.subGroupID,
			"group_name": item.name,
			"attempts":   len(attempted),
		}).Debug("Sub-group has no active keys, trying next")
	}

	logrus.WithFields(logrus.Fields{
		"aggregate_group":  s.groupName,
		"total_sub_groups": len(s.subGroups),
	}).Warn("No sub-groups with active keys available")

	return ""
}

// selectByWeight implements smooth weighted round-robin algorithm
func (s *selector) selectByWeight() *subGroupItem {