Method processServerList

balancer/grpclb/grpclb_remote_balancer.go:59–102

processServerList updates balancer's internal state, create/remove SubConns and regenerates picker using the received serverList.

(l *lbpb.ServerList)

// processServerList updates balancer's internal state, create/remove SubConns
// and regenerates picker using the received serverList.
func (lb *lbBalancer) processServerList(l *lbpb.ServerList) {
	if lb.logger.V(2) {
		lb.logger.Infof("Processing server list: %#v", l)
	}
	lb.mu.Lock()
	defer lb.mu.Unlock()

	// Set serverListReceived to true so fallback will not take effect if it has
	// not hit timeout.
	lb.serverListReceived = true

	// If the new server list == old server list, do nothing.
	if serverListEqual(lb.fullServerList, l.Servers) {
		if lb.logger.V(2) {
			lb.logger.Infof("Ignoring new server list as it is the same as the previous one")
		}
		return
	}
	lb.fullServerList = l.Servers

	var backendAddrs []resolver.Address
	for i, s := range l.Servers {
		if s.Drop {
			continue
		}

		md := metadata.Pairs(lbTokenKey, s.LoadBalanceToken)
		var ipStr string
		if ip, ok := netip.AddrFromSlice(s.IpAddress); ok {
			ipStr = ip.String()
		} else {
			ipStr = fmt.Sprintf("? %x", s.IpAddress)
		}
		addr := imetadata.Set(resolver.Address{Addr: net.JoinHostPort(ipStr, fmt.Sprintf("%d", s.Port))}, md)
		if lb.logger.V(2) {
			lb.logger.Infof("Server list entry:|%d|, ipStr:|%s|, port:|%d|, load balancer token:|%v|", i, ipStr, s.Port, s.LoadBalanceToken)
		}
		backendAddrs = append(backendAddrs, addr)
	}

	// Call refreshSubConns to create/remove SubConns.  If we are in fallback,
	// this is also exiting fallback.
	lb.refreshSubConns(backendAddrs, false, lb.usePickFirst)
}

// refreshSubConns creates/removes SubConns with backendAddrs, and refreshes
// balancer state and picker.