1/*
2 *
3 * Copyright 2019 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19package grpc
20
21import (
22	"fmt"
23	"net"
24	"testing"
25
26	"google.golang.org/grpc/balancer"
27	"google.golang.org/grpc/balancer/roundrobin"
28	"google.golang.org/grpc/connectivity"
29	"google.golang.org/grpc/resolver"
30	"google.golang.org/grpc/resolver/manual"
31)
32
33var _ balancer.V2Balancer = &funcBalancer{}
34
35type funcBalancer struct {
36	updateClientConnState func(s balancer.ClientConnState) error
37}
38
39func (*funcBalancer) HandleSubConnStateChange(balancer.SubConn, connectivity.State) {
40	panic("unimplemented") // v1 API
41}
42func (*funcBalancer) HandleResolvedAddrs([]resolver.Address, error) {
43	panic("unimplemented") // v1 API
44}
45func (b *funcBalancer) UpdateClientConnState(s balancer.ClientConnState) error {
46	return b.updateClientConnState(s)
47}
48func (*funcBalancer) ResolverError(error) {}
49func (*funcBalancer) UpdateSubConnState(balancer.SubConn, balancer.SubConnState) {
50	panic("unimplemented") // we never have sub-conns
51}
52func (*funcBalancer) Close() {}
53
54type funcBalancerBuilder struct {
55	name     string
56	instance *funcBalancer
57}
58
59func (b *funcBalancerBuilder) Build(balancer.ClientConn, balancer.BuildOptions) balancer.Balancer {
60	return b.instance
61}
62func (b *funcBalancerBuilder) Name() string { return b.name }
63
64// TestBalancerErrorResolverPolling injects balancer errors and verifies
65// ResolveNow is called on the resolver with the appropriate backoff strategy
66// being consulted between ResolveNow calls.
67func (s) TestBalancerErrorResolverPolling(t *testing.T) {
68	// The test balancer will return ErrBadResolverState iff the
69	// ClientConnState contains no addresses.
70	fb := &funcBalancer{
71		updateClientConnState: func(s balancer.ClientConnState) error {
72			if len(s.ResolverState.Addresses) == 0 {
73				return balancer.ErrBadResolverState
74			}
75			return nil
76		},
77	}
78	const balName = "BalancerErrorResolverPolling"
79	balancer.Register(&funcBalancerBuilder{name: balName, instance: fb})
80
81	testResolverErrorPolling(t,
82		func(r *manual.Resolver) {
83			// No addresses so the balancer will fail.
84			r.CC.UpdateState(resolver.State{})
85		}, func(r *manual.Resolver) {
86			// UpdateState will block if ResolveNow is being called (which blocks on
87			// rn), so call it in a goroutine.  Include some address so the balancer
88			// will be happy.
89			go r.CC.UpdateState(resolver.State{Addresses: []resolver.Address{{Addr: "x"}}})
90		},
91		WithDefaultServiceConfig(fmt.Sprintf(`{ "loadBalancingConfig": [{"%v": {}}] }`, balName)))
92}
93
94// TestRoundRobinZeroAddressesResolverPolling reports no addresses to the round
95// robin balancer and verifies ResolveNow is called on the resolver with the
96// appropriate backoff strategy being consulted between ResolveNow calls.
97func (s) TestRoundRobinZeroAddressesResolverPolling(t *testing.T) {
98	// We need to start a real server or else the connecting loop will call
99	// ResolveNow after every iteration, even after a valid resolver result is
100	// returned.
101	lis, err := net.Listen("tcp", "localhost:0")
102	if err != nil {
103		t.Fatalf("Error while listening. Err: %v", err)
104	}
105	defer lis.Close()
106	s := NewServer()
107	defer s.Stop()
108	go s.Serve(lis)
109
110	testResolverErrorPolling(t,
111		func(r *manual.Resolver) {
112			// No addresses so the balancer will fail.
113			r.CC.UpdateState(resolver.State{})
114		}, func(r *manual.Resolver) {
115			// UpdateState will block if ResolveNow is being called (which
116			// blocks on rn), so call it in a goroutine.  Include a valid
117			// address so the balancer will be happy.
118			go r.CC.UpdateState(resolver.State{Addresses: []resolver.Address{{Addr: lis.Addr().String()}}})
119		},
120		WithDefaultServiceConfig(fmt.Sprintf(`{ "loadBalancingConfig": [{"%v": {}}] }`, roundrobin.Name)))
121}
122