fix grpc-go(v1.27.0) incompatible changes to balancer / resolver.

Author: eddycjy

clientv3/balancer/picker/err.go

@@ -34,6 +34,6 @@ func (ep *errPicker) String() string {
 	return ep.p.String()
 }
 
-func (ep *errPicker) Pick(context.Context, balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+func (ep *errPicker) Pick(context.Context, balancer.PickInfo) (balancer.SubConn, func(balancer.DoneInfo), error) {
 	return nil, nil, ep.err
 }

clientv3/balancer/picker/roundrobin_balanced.go

@@ -52,7 +52,7 @@ type rrBalanced struct {
 func (rb *rrBalanced) String() string { return rb.p.String() }
 
 // Pick is called for every client request.
-func (rb *rrBalanced) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
+func (rb *rrBalanced) Pick(ctx context.Context, opts balancer.PickInfo) (balancer.SubConn, func(balancer.DoneInfo), error) {
 	rb.mu.RLock()
 	n := len(rb.scs)
 	rb.mu.RUnlock()

clientv3/balancer/resolver/endpoint/endpoint.go

@@ -111,7 +111,7 @@ func (e *ResolverGroup) Close() {
 }
 
 // Build creates or reuses an etcd resolver for the etcd cluster name identified by the authority part of the target.
-func (b *builder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOption) (resolver.Resolver, error) {
+func (b *builder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
 	if len(target.Authority) < 1 {
 		return nil, fmt.Errorf("'etcd' target scheme requires non-empty authority identifying etcd cluster being routed to")
 	}
@@ -179,7 +179,7 @@ func epsToAddrs(eps ...string) (addrs []resolver.Address) {
 	return addrs
 }
 
-func (*Resolver) ResolveNow(o resolver.ResolveNowOption) {}
+func (*Resolver) ResolveNow(o resolver.ResolveNowOptions) {}
 
 func (r *Resolver) Close() {
 	es, err := bldr.getResolverGroup(r.endpointID)