Esempio n. 1
0
func (b *balancer) watchAddrUpdates(w naming.Watcher, ch chan remoteBalancerInfo) error {
	updates, err := w.Next()
	if err != nil {
		return err
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.done {
		return grpc.ErrClientConnClosing
	}
	var bAddr remoteBalancerInfo
	if len(b.rbs) > 0 {
		bAddr = b.rbs[0]
	}
	for _, update := range updates {
		addr := grpc.Address{
			Addr:     update.Addr,
			Metadata: update.Metadata,
		}
		switch update.Op {
		case naming.Add:
			var exist bool
			for _, v := range b.rbs {
				// TODO: Is the same addr with different server name a different balancer?
				if addr == v.addr {
					exist = true
					break
				}
			}
			if exist {
				continue
			}
			b.rbs = append(b.rbs, remoteBalancerInfo{addr: addr})
		case naming.Delete:
			for i, v := range b.rbs {
				if addr == v.addr {
					copy(b.rbs[i:], b.rbs[i+1:])
					b.rbs = b.rbs[:len(b.rbs)-1]
					break
				}
			}
		default:
			grpclog.Println("Unknown update.Op ", update.Op)
		}
	}
	// TODO: Fall back to the basic round-robin load balancing if the resulting address is
	// not a load balancer.
	if len(b.rbs) > 0 {
		// For simplicity, always use the first one now. May revisit this decision later.
		if b.rbs[0] != bAddr {
			select {
			case <-ch:
			default:
			}
			ch <- b.rbs[0]
		}
	}
	return nil
}
Esempio n. 2
0
func (b *balancer) watchAddrUpdates(w naming.Watcher, ch chan remoteBalancerInfo) error {
	updates, err := w.Next()
	if err != nil {
		return err
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	if b.done {
		return grpc.ErrClientConnClosing
	}
	var bAddr remoteBalancerInfo
	if len(b.rbs) > 0 {
		bAddr = b.rbs[0]
	}
	for _, update := range updates {
		switch update.Op {
		case naming.Add:
			var exist bool
			for _, v := range b.rbs {
				// TODO: Is the same addr with different server name a different balancer?
				if update.Addr == v.addr {
					exist = true
					break
				}
			}
			if exist {
				continue
			}
			md, ok := update.Metadata.(*Metadata)
			if !ok {
				// TODO: Revisit the handling here and may introduce some fallback mechanism.
				grpclog.Printf("The name resolution contains unexpected metadata %v", update.Metadata)
				continue
			}
			switch md.AddrType {
			case Backend:
				// TODO: Revisit the handling here and may introduce some fallback mechanism.
				grpclog.Printf("The name resolution does not give grpclb addresses")
				continue
			case GRPCLB:
				b.rbs = append(b.rbs, remoteBalancerInfo{
					addr: update.Addr,
					name: md.ServerName,
				})
			default:
				grpclog.Printf("Received unknow address type %d", md.AddrType)
				continue
			}
		case naming.Delete:
			for i, v := range b.rbs {
				if update.Addr == v.addr {
					copy(b.rbs[i:], b.rbs[i+1:])
					b.rbs = b.rbs[:len(b.rbs)-1]
					break
				}
			}
		default:
			grpclog.Println("Unknown update.Op ", update.Op)
		}
	}
	// TODO: Fall back to the basic round-robin load balancing if the resulting address is
	// not a load balancer.
	if len(b.rbs) > 0 {
		// For simplicity, always use the first one now. May revisit this decision later.
		if b.rbs[0] != bAddr {
			select {
			case <-ch:
			default:
			}
			ch <- b.rbs[0]
		}
	}
	return nil
}