-
Notifications
You must be signed in to change notification settings - Fork 3.8k
/
WeightedTargetLoadBalancer.java
220 lines (197 loc) · 7.88 KB
/
WeightedTargetLoadBalancer.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
/*
* Copyright 2020 The gRPC Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.grpc.xds;
import static com.google.common.base.Preconditions.checkNotNull;
import static io.grpc.ConnectivityState.CONNECTING;
import static io.grpc.ConnectivityState.IDLE;
import static io.grpc.ConnectivityState.READY;
import static io.grpc.ConnectivityState.TRANSIENT_FAILURE;
import static io.grpc.xds.XdsSubchannelPickers.BUFFER_PICKER;
import com.google.common.collect.ImmutableMap;
import io.grpc.ConnectivityState;
import io.grpc.InternalLogId;
import io.grpc.LoadBalancer;
import io.grpc.Status;
import io.grpc.util.ForwardingLoadBalancerHelper;
import io.grpc.util.GracefulSwitchLoadBalancer;
import io.grpc.xds.WeightedRandomPicker.WeightedChildPicker;
import io.grpc.xds.WeightedTargetLoadBalancerProvider.WeightedPolicySelection;
import io.grpc.xds.WeightedTargetLoadBalancerProvider.WeightedTargetConfig;
import io.grpc.xds.XdsLogger.XdsLogLevel;
import io.grpc.xds.XdsSubchannelPickers.ErrorPicker;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.Nullable;
/** Load balancer for weighted_target policy. */
final class WeightedTargetLoadBalancer extends LoadBalancer {
private final XdsLogger logger;
private final Map<String, GracefulSwitchLoadBalancer> childBalancers = new HashMap<>();
private final Map<String, ChildHelper> childHelpers = new HashMap<>();
private final Helper helper;
private Map<String, WeightedPolicySelection> targets = ImmutableMap.of();
// Set to true if currently in the process of handling resolved addresses.
private boolean resolvingAddresses;
WeightedTargetLoadBalancer(Helper helper) {
this.helper = checkNotNull(helper, "helper");
logger = XdsLogger.withLogId(
InternalLogId.allocate("weighted-target-lb", helper.getAuthority()));
logger.log(XdsLogLevel.INFO, "Created");
}
@Override
public void handleResolvedAddresses(ResolvedAddresses resolvedAddresses) {
try {
resolvingAddresses = true;
handleResolvedAddressesInternal(resolvedAddresses);
} finally {
resolvingAddresses = false;
}
}
public void handleResolvedAddressesInternal(ResolvedAddresses resolvedAddresses) {
logger.log(XdsLogLevel.DEBUG, "Received resolution result: {0}", resolvedAddresses);
Object lbConfig = resolvedAddresses.getLoadBalancingPolicyConfig();
checkNotNull(lbConfig, "missing weighted_target lb config");
WeightedTargetConfig weightedTargetConfig = (WeightedTargetConfig) lbConfig;
Map<String, WeightedPolicySelection> newTargets = weightedTargetConfig.targets;
for (String targetName : newTargets.keySet()) {
WeightedPolicySelection weightedChildLbConfig = newTargets.get(targetName);
if (!targets.containsKey(targetName)) {
ChildHelper childHelper = new ChildHelper(targetName);
GracefulSwitchLoadBalancer childBalancer = new GracefulSwitchLoadBalancer(childHelper);
childBalancer.switchTo(weightedChildLbConfig.policySelection.getProvider());
childHelpers.put(targetName, childHelper);
childBalancers.put(targetName, childBalancer);
} else if (!weightedChildLbConfig.policySelection.getProvider().equals(
targets.get(targetName).policySelection.getProvider())) {
childBalancers.get(targetName)
.switchTo(weightedChildLbConfig.policySelection.getProvider());
}
}
targets = newTargets;
for (String targetName : targets.keySet()) {
childBalancers.get(targetName).handleResolvedAddresses(
resolvedAddresses.toBuilder()
.setAddresses(AddressFilter.filter(resolvedAddresses.getAddresses(), targetName))
.setLoadBalancingPolicyConfig(targets.get(targetName).policySelection.getConfig())
.build());
}
// Cleanup removed targets.
// TODO(zdapeng): cache removed target for 15 minutes.
for (String targetName : childBalancers.keySet()) {
if (!targets.containsKey(targetName)) {
childBalancers.get(targetName).shutdown();
}
}
childBalancers.keySet().retainAll(targets.keySet());
childHelpers.keySet().retainAll(targets.keySet());
updateOverallBalancingState();
}
@Override
public void handleNameResolutionError(Status error) {
logger.log(XdsLogLevel.WARNING, "Received name resolution error: {0}", error);
if (childBalancers.isEmpty()) {
helper.updateBalancingState(TRANSIENT_FAILURE, new ErrorPicker(error));
}
for (LoadBalancer childBalancer : childBalancers.values()) {
childBalancer.handleNameResolutionError(error);
}
}
@Override
public boolean canHandleEmptyAddressListFromNameResolution() {
return true;
}
@Override
public void shutdown() {
logger.log(XdsLogLevel.INFO, "Shutdown");
for (LoadBalancer childBalancer : childBalancers.values()) {
childBalancer.shutdown();
}
childBalancers.clear();
}
private void updateOverallBalancingState() {
List<WeightedChildPicker> childPickers = new ArrayList<>();
ConnectivityState overallState = null;
List<WeightedChildPicker> errorPickers = new ArrayList<>();
for (String name : targets.keySet()) {
ChildHelper childHelper = childHelpers.get(name);
ConnectivityState childState = childHelper.currentState;
overallState = aggregateState(overallState, childState);
int weight = targets.get(name).weight;
if (READY == childState) {
childPickers.add(new WeightedChildPicker(weight, childHelper.currentPicker));
} else if (TRANSIENT_FAILURE == childState) {
errorPickers.add(new WeightedChildPicker(weight, childHelper.currentPicker));
}
}
SubchannelPicker picker;
if (childPickers.isEmpty()) {
if (overallState == TRANSIENT_FAILURE) {
picker = new WeightedRandomPicker(errorPickers);
} else {
picker = XdsSubchannelPickers.BUFFER_PICKER;
}
} else {
picker = new WeightedRandomPicker(childPickers);
}
if (overallState != null) {
helper.updateBalancingState(overallState, picker);
}
}
@Nullable
private static ConnectivityState aggregateState(
@Nullable ConnectivityState overallState, ConnectivityState childState) {
if (overallState == null) {
return childState;
}
if (overallState == READY || childState == READY) {
return READY;
}
if (overallState == CONNECTING || childState == CONNECTING) {
return CONNECTING;
}
if (overallState == IDLE || childState == IDLE) {
return IDLE;
}
return overallState;
}
private final class ChildHelper extends ForwardingLoadBalancerHelper {
String name;
ConnectivityState currentState = CONNECTING;
SubchannelPicker currentPicker = BUFFER_PICKER;
private ChildHelper(String name) {
this.name = name;
}
@Override
public void updateBalancingState(final ConnectivityState newState,
final SubchannelPicker newPicker) {
if (!childBalancers.containsKey(name)) {
return;
}
currentState = newState;
currentPicker = newPicker;
// If we are already in the process of resolving addresses, the overall balancing state
// will be updated at the end of it, and we don't need to trigger that update here.
if (!resolvingAddresses) {
updateOverallBalancingState();
}
}
@Override
protected Helper delegate() {
return helper;
}
}
}