forked from grpc/grpc-java
/
RlsLoadBalancer.java
140 lines (125 loc) · 4.69 KB
/
RlsLoadBalancer.java
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/*
* 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.rls;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.MoreObjects;
import io.grpc.ChannelLogger;
import io.grpc.ChannelLogger.ChannelLogLevel;
import io.grpc.ConnectivityState;
import io.grpc.LoadBalancer;
import io.grpc.Status;
import javax.annotation.Nullable;
/**
* Implementation of {@link LoadBalancer} backed by route lookup service.
*/
final class RlsLoadBalancer extends LoadBalancer {
private final ChannelLogger logger;
private final Helper helper;
@VisibleForTesting
CachingRlsLbClientBuilderProvider cachingRlsLbClientBuilderProvider =
new DefaultCachingRlsLbClientBuilderProvider();
@Nullable
private LbPolicyConfiguration lbPolicyConfiguration;
@Nullable
private CachingRlsLbClient routeLookupClient;
RlsLoadBalancer(Helper helper) {
this.helper = checkNotNull(helper, "helper");
logger = helper.getChannelLogger();
logger.log(ChannelLogLevel.DEBUG, "Rls lb created. Authority: {0}", helper.getAuthority());
}
@Override
public void handleResolvedAddresses(ResolvedAddresses resolvedAddresses) {
logger.log(ChannelLogLevel.DEBUG, "Received resolution result: {0}", resolvedAddresses);
LbPolicyConfiguration lbPolicyConfiguration =
(LbPolicyConfiguration) resolvedAddresses.getLoadBalancingPolicyConfig();
checkNotNull(lbPolicyConfiguration, "Missing rls lb config");
if (!lbPolicyConfiguration.equals(this.lbPolicyConfiguration)) {
boolean needToConnect = this.lbPolicyConfiguration == null
|| !this.lbPolicyConfiguration.getRouteLookupConfig().getLookupService().equals(
lbPolicyConfiguration.getRouteLookupConfig().getLookupService());
if (needToConnect) {
if (routeLookupClient != null) {
routeLookupClient.close();
}
routeLookupClient =
cachingRlsLbClientBuilderProvider
.get()
.setHelper(helper)
.setLbPolicyConfig(lbPolicyConfiguration)
.setResolvedAddressesFactory(
new ChildLbResolvedAddressFactory(
resolvedAddresses.getAddresses(), resolvedAddresses.getAttributes()))
.build();
logger.log(
ChannelLogLevel.DEBUG, "LbPolicyConfiguration updated to {0}", lbPolicyConfiguration);
}
// TODO(creamsoup) allow incremental service config update. for initial use case, it is
// not required.
this.lbPolicyConfiguration = lbPolicyConfiguration;
}
}
@Override
public void requestConnection() {
if (routeLookupClient != null) {
routeLookupClient.requestConnection();
}
}
@Override
public void handleNameResolutionError(final Status error) {
logger.log(ChannelLogLevel.DEBUG, "Received resolution error: {0}", error);
class ErrorPicker extends SubchannelPicker {
@Override
public PickResult pickSubchannel(PickSubchannelArgs args) {
return PickResult.withError(error);
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("error", error)
.toString();
}
}
if (routeLookupClient != null) {
routeLookupClient.close();
routeLookupClient = null;
lbPolicyConfiguration = null;
}
helper.updateBalancingState(ConnectivityState.TRANSIENT_FAILURE, new ErrorPicker());
}
@Override
public void shutdown() {
logger.log(ChannelLogLevel.DEBUG, "Rls lb shutdown");
if (routeLookupClient != null) {
routeLookupClient.close();
routeLookupClient = null;
}
}
/**
* Provides {@link CachingRlsLbClient.Builder} with default settings. This is useful for
* testing.
*/
interface CachingRlsLbClientBuilderProvider {
CachingRlsLbClient.Builder get();
}
static final class DefaultCachingRlsLbClientBuilderProvider
implements CachingRlsLbClientBuilderProvider {
@Override
public CachingRlsLbClient.Builder get() {
return CachingRlsLbClient.newBuilder().setThrottler(AdaptiveThrottler.builder().build());
}
}
}