1 //
2 // Copyright 2022 gRPC authors.
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16
17 #include <array>
18 #include <memory>
19
20 #include "absl/status/status.h"
21 #include "absl/strings/string_view.h"
22 #include "absl/types/span.h"
23 #include "gtest/gtest.h"
24
25 #include <grpc/grpc.h>
26
27 #include "src/core/lib/gprpp/orphanable.h"
28 #include "src/core/lib/gprpp/ref_counted_ptr.h"
29 #include "src/core/resolver/endpoint_addresses.h"
30 #include "test/core/client_channel/lb_policy/lb_policy_test_lib.h"
31 #include "test/core/util/test_config.h"
32
33 namespace grpc_core {
34 namespace testing {
35 namespace {
36
37 class RoundRobinTest : public LoadBalancingPolicyTest {
38 protected:
RoundRobinTest()39 RoundRobinTest() : LoadBalancingPolicyTest("round_robin") {}
40 };
41
TEST_F(RoundRobinTest,Basic)42 TEST_F(RoundRobinTest, Basic) {
43 const std::array<absl::string_view, 3> kAddresses = {
44 "ipv4:127.0.0.1:441", "ipv4:127.0.0.1:442", "ipv4:127.0.0.1:443"};
45 EXPECT_EQ(ApplyUpdate(BuildUpdate(kAddresses, nullptr), lb_policy()),
46 absl::OkStatus());
47 ExpectRoundRobinStartup(kAddresses);
48 }
49
TEST_F(RoundRobinTest,AddressUpdates)50 TEST_F(RoundRobinTest, AddressUpdates) {
51 const std::array<absl::string_view, 3> kAddresses = {
52 "ipv4:127.0.0.1:441", "ipv4:127.0.0.1:442", "ipv4:127.0.0.1:443"};
53 EXPECT_EQ(ApplyUpdate(BuildUpdate(kAddresses, nullptr), lb_policy()),
54 absl::OkStatus());
55 ExpectRoundRobinStartup(kAddresses);
56 // Send update to remove address 2.
57 EXPECT_EQ(
58 ApplyUpdate(BuildUpdate(absl::MakeSpan(kAddresses).first(2), nullptr),
59 lb_policy()),
60 absl::OkStatus());
61 WaitForRoundRobinListChange(kAddresses, absl::MakeSpan(kAddresses).first(2));
62 // Send update to remove address 0 and re-add address 2.
63 EXPECT_EQ(
64 ApplyUpdate(BuildUpdate(absl::MakeSpan(kAddresses).last(2), nullptr),
65 lb_policy()),
66 absl::OkStatus());
67 WaitForRoundRobinListChange(absl::MakeSpan(kAddresses).first(2),
68 absl::MakeSpan(kAddresses).last(2));
69 }
70
TEST_F(RoundRobinTest,MultipleAddressesPerEndpoint)71 TEST_F(RoundRobinTest, MultipleAddressesPerEndpoint) {
72 constexpr std::array<absl::string_view, 2> kEndpoint1Addresses = {
73 "ipv4:127.0.0.1:443", "ipv4:127.0.0.1:444"};
74 constexpr std::array<absl::string_view, 2> kEndpoint2Addresses = {
75 "ipv4:127.0.0.1:445", "ipv4:127.0.0.1:446"};
76 const std::array<EndpointAddresses, 2> kEndpoints = {
77 MakeEndpointAddresses(kEndpoint1Addresses),
78 MakeEndpointAddresses(kEndpoint2Addresses)};
79 EXPECT_EQ(ApplyUpdate(BuildUpdate(kEndpoints, nullptr), lb_policy_.get()),
80 absl::OkStatus());
81 // RR should have created a subchannel for each address.
82 auto* subchannel1_0 = FindSubchannel(kEndpoint1Addresses[0]);
83 ASSERT_NE(subchannel1_0, nullptr) << "Address: " << kEndpoint1Addresses[0];
84 auto* subchannel1_1 = FindSubchannel(kEndpoint1Addresses[1]);
85 ASSERT_NE(subchannel1_1, nullptr) << "Address: " << kEndpoint1Addresses[1];
86 auto* subchannel2_0 = FindSubchannel(kEndpoint2Addresses[0]);
87 ASSERT_NE(subchannel2_0, nullptr) << "Address: " << kEndpoint2Addresses[0];
88 auto* subchannel2_1 = FindSubchannel(kEndpoint2Addresses[1]);
89 ASSERT_NE(subchannel2_1, nullptr) << "Address: " << kEndpoint2Addresses[1];
90 // PF for each endpoint should try to connect to the first subchannel.
91 EXPECT_TRUE(subchannel1_0->ConnectionRequested());
92 EXPECT_FALSE(subchannel1_1->ConnectionRequested());
93 EXPECT_TRUE(subchannel2_0->ConnectionRequested());
94 EXPECT_FALSE(subchannel2_1->ConnectionRequested());
95 // In the first endpoint, the first subchannel reports CONNECTING.
96 // This causes RR to report CONNECTING.
97 subchannel1_0->SetConnectivityState(GRPC_CHANNEL_CONNECTING);
98 ExpectConnectingUpdate();
99 // In the second endpoint, the first subchannel reports CONNECTING.
100 subchannel2_0->SetConnectivityState(GRPC_CHANNEL_CONNECTING);
101 // In the first endpoint, the first subchannel fails to connect.
102 // This causes PF to start a connection attempt on the second subchannel.
103 subchannel1_0->SetConnectivityState(GRPC_CHANNEL_TRANSIENT_FAILURE,
104 absl::UnavailableError("ugh"));
105 EXPECT_TRUE(subchannel1_1->ConnectionRequested());
106 subchannel1_1->SetConnectivityState(GRPC_CHANNEL_CONNECTING);
107 // In the second endpoint, the first subchannel becomes connected.
108 // This causes RR to report READY with all RPCs going to a single address.
109 subchannel2_0->SetConnectivityState(GRPC_CHANNEL_READY);
110 auto picker = WaitForConnected();
111 ExpectRoundRobinPicks(picker.get(), {kEndpoint2Addresses[0]});
112 // In the first endpoint, the second subchannel becomes connected.
113 // This causes RR to add it to the rotation.
114 subchannel1_1->SetConnectivityState(GRPC_CHANNEL_READY);
115 WaitForRoundRobinListChange({kEndpoint2Addresses[0]},
116 {kEndpoint1Addresses[1], kEndpoint2Addresses[0]});
117 // No more connection attempts triggered.
118 EXPECT_FALSE(subchannel1_0->ConnectionRequested());
119 EXPECT_FALSE(subchannel1_1->ConnectionRequested());
120 EXPECT_FALSE(subchannel2_0->ConnectionRequested());
121 EXPECT_FALSE(subchannel2_1->ConnectionRequested());
122 // First endpoint first subchannel finishes backoff, but this doesn't
123 // affect anything -- in fact, PF isn't even watching this subchannel
124 // anymore, since it's connected to the other one. However, this
125 // ensures that the subchannel is in the right state when we try to
126 // reconnect below.
127 subchannel1_0->SetConnectivityState(GRPC_CHANNEL_IDLE);
128 EXPECT_FALSE(subchannel1_0->ConnectionRequested());
129 // Endpoint 1 switches to a different address.
130 ExpectEndpointAddressChange(kEndpoint1Addresses, 1, 0, [&]() {
131 // RR will remove the endpoint from the rotation when it becomes
132 // disconnected.
133 WaitForRoundRobinListChange(
134 {kEndpoint1Addresses[1], kEndpoint2Addresses[0]},
135 {kEndpoint2Addresses[0]});
136 });
137 // Then RR will re-add the endpoint with the new address.
138 WaitForRoundRobinListChange({kEndpoint2Addresses[0]},
139 {kEndpoint1Addresses[0], kEndpoint2Addresses[0]});
140 // No more connection attempts triggered.
141 EXPECT_FALSE(subchannel1_0->ConnectionRequested());
142 EXPECT_FALSE(subchannel1_1->ConnectionRequested());
143 EXPECT_FALSE(subchannel2_0->ConnectionRequested());
144 EXPECT_FALSE(subchannel2_1->ConnectionRequested());
145 }
146
147 // TODO(roth): Add test cases:
148 // - empty address list
149 // - subchannels failing connection attempts
150
151 } // namespace
152 } // namespace testing
153 } // namespace grpc_core
154
main(int argc,char ** argv)155 int main(int argc, char** argv) {
156 ::testing::InitGoogleTest(&argc, argv);
157 grpc::testing::TestEnvironment env(&argc, argv);
158 return RUN_ALL_TESTS();
159 }
160