Method UpdateState

balancer/ringhash/ringhash.go:130–179

UpdateState intercepts child balancer state updates. It updates the per-endpoint state stored in the ring, and also the aggregated state based on the child picker. It also reconciles the endpoint list. It sets `b.shouldRegenerateRing` to true if the new endpoint list is different from the previous,

(state balancer.State)

// - an endpoint's weight was updated
// - the first addresses of the endpoint has changed
func (b *ringhashBalancer) UpdateState(state balancer.State) {
	b.mu.Lock()
	defer b.mu.Unlock()
	childStates := endpointsharding.ChildStatesFromPicker(state.Picker)
	// endpointsSet is the set converted from endpoints, used for quick lookup.
	endpointsSet := resolver.NewEndpointMap[bool]()

	for _, childState := range childStates {
		endpoint := childState.Endpoint
		endpointsSet.Set(endpoint, true)
		newWeight := getWeightAttribute(endpoint)
		hk := hashKey(endpoint)
		es, ok := b.endpointStates.Get(endpoint)
		if !ok {
			es := &endpointState{
				balancer: childState.Balancer,
				hashKey:  hk,
				weight:   newWeight,
				state:    childState.State,
			}
			b.endpointStates.Set(endpoint, es)
			b.shouldRegenerateRing = true
		} else {
			// We have seen this endpoint before and created a `endpointState`
			// object for it. If the weight or the hash key of the endpoint has
			// changed, update the endpoint state map with the new weight or
			// hash key. This will be used when a new ring is created.
			if oldWeight := es.weight; oldWeight != newWeight {
				b.shouldRegenerateRing = true
				es.weight = newWeight
			}
			if es.hashKey != hk {
				b.shouldRegenerateRing = true
				es.hashKey = hk
			}
			es.state = childState.State
		}
	}

	for endpoint := range b.endpointStates.All() {
		if _, ok := endpointsSet.Get(endpoint); ok {
			continue
		}
		// endpoint was removed by resolver.
		b.endpointStates.Delete(endpoint)
		b.shouldRegenerateRing = true
	}

	b.updatePickerLocked()
}

func (b *ringhashBalancer) UpdateClientConnState(ccs balancer.ClientConnState) error {
	if b.logger.V(2) {