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
}
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
}