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LocalityStore.java
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LocalityStore.java
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/*
* Copyright 2019 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 com.google.common.annotations.VisibleForTesting;
import com.google.common.base.MoreObjects;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import io.grpc.ConnectivityState;
import io.grpc.EquivalentAddressGroup;
import io.grpc.LoadBalancer;
import io.grpc.LoadBalancer.Helper;
import io.grpc.LoadBalancer.PickResult;
import io.grpc.LoadBalancer.PickSubchannelArgs;
import io.grpc.LoadBalancer.ResolvedAddresses;
import io.grpc.LoadBalancer.SubchannelPicker;
import io.grpc.LoadBalancerProvider;
import io.grpc.LoadBalancerRegistry;
import io.grpc.Status;
import io.grpc.SynchronizationContext.ScheduledHandle;
import io.grpc.util.ForwardingLoadBalancerHelper;
import io.grpc.xds.ClientLoadCounter.LoadRecordingSubchannelPicker;
import io.grpc.xds.ClientLoadCounter.MetricsObservingSubchannelPicker;
import io.grpc.xds.ClientLoadCounter.MetricsRecordingListener;
import io.grpc.xds.EnvoyProtoData.DropOverload;
import io.grpc.xds.EnvoyProtoData.LbEndpoint;
import io.grpc.xds.EnvoyProtoData.Locality;
import io.grpc.xds.EnvoyProtoData.LocalityLbEndpoints;
import io.grpc.xds.InterLocalityPicker.WeightedChildPicker;
import io.grpc.xds.OrcaOobUtil.OrcaReportingConfig;
import io.grpc.xds.OrcaOobUtil.OrcaReportingHelperWrapper;
import io.grpc.xds.XdsSubchannelPickers.ErrorPicker;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import javax.annotation.Nullable;
/**
* Manages EAG and locality info for a collection of subchannels, not including subchannels
* created by the fallback balancer.
*/
// Must be accessed/run in SynchronizedContext.
interface LocalityStore {
void reset();
void updateLocalityStore(Map<Locality, LocalityLbEndpoints> localityInfoMap);
void updateDropPercentage(List<DropOverload> dropOverloads);
void updateOobMetricsReportInterval(long reportIntervalNano);
@VisibleForTesting
abstract class LocalityStoreFactory {
private static final LocalityStoreFactory DEFAULT_INSTANCE =
new LocalityStoreFactory() {
@Override
LocalityStore newLocalityStore(
Helper helper, LoadBalancerRegistry lbRegistry, LoadStatsStore loadStatsStore) {
return new LocalityStoreImpl(helper, lbRegistry, loadStatsStore);
}
};
static LocalityStoreFactory getInstance() {
return DEFAULT_INSTANCE;
}
abstract LocalityStore newLocalityStore(
Helper helper, LoadBalancerRegistry lbRegistry, LoadStatsStore loadStatsStore);
}
final class LocalityStoreImpl implements LocalityStore {
private static final String ROUND_ROBIN = "round_robin";
private static final long DELAYED_DELETION_TIMEOUT_MINUTES = 15L;
private final Helper helper;
private final PickerFactory pickerFactory;
private final LoadBalancerProvider loadBalancerProvider;
private final ThreadSafeRandom random;
private final LoadStatsStore loadStatsStore;
private final OrcaPerRequestUtil orcaPerRequestUtil;
private final OrcaOobUtil orcaOobUtil;
private final PriorityManager priorityManager = new PriorityManager();
private final Map<Locality, LocalityLbInfo> localityMap = new HashMap<>();
// Most current set of localities instructed by traffic director
private Set<Locality> localities = ImmutableSet.of();
private List<DropOverload> dropOverloads = ImmutableList.of();
private long metricsReportIntervalNano = -1;
LocalityStoreImpl(
Helper helper, LoadBalancerRegistry lbRegistry, LoadStatsStore loadStatsStore) {
this(helper, pickerFactoryImpl, lbRegistry, ThreadSafeRandom.ThreadSafeRandomImpl.instance,
loadStatsStore, OrcaPerRequestUtil.getInstance(), OrcaOobUtil.getInstance());
}
@VisibleForTesting
LocalityStoreImpl(
Helper helper,
PickerFactory pickerFactory,
LoadBalancerRegistry lbRegistry,
ThreadSafeRandom random,
LoadStatsStore loadStatsStore,
OrcaPerRequestUtil orcaPerRequestUtil,
OrcaOobUtil orcaOobUtil) {
this.helper = checkNotNull(helper, "helper");
this.pickerFactory = checkNotNull(pickerFactory, "pickerFactory");
loadBalancerProvider = checkNotNull(
lbRegistry.getProvider(ROUND_ROBIN),
"Unable to find '%s' LoadBalancer", ROUND_ROBIN);
this.random = checkNotNull(random, "random");
this.loadStatsStore = checkNotNull(loadStatsStore, "loadStatsStore");
this.orcaPerRequestUtil = checkNotNull(orcaPerRequestUtil, "orcaPerRequestUtil");
this.orcaOobUtil = checkNotNull(orcaOobUtil, "orcaOobUtil");
}
@VisibleForTesting // Introduced for testing only.
interface PickerFactory {
SubchannelPicker picker(List<WeightedChildPicker> childPickers);
}
private static final class DroppablePicker extends SubchannelPicker {
final List<DropOverload> dropOverloads;
final SubchannelPicker delegate;
final ThreadSafeRandom random;
final LoadStatsStore loadStatsStore;
DroppablePicker(
List<DropOverload> dropOverloads, SubchannelPicker delegate,
ThreadSafeRandom random, LoadStatsStore loadStatsStore) {
this.dropOverloads = dropOverloads;
this.delegate = delegate;
this.random = random;
this.loadStatsStore = loadStatsStore;
}
@Override
public PickResult pickSubchannel(PickSubchannelArgs args) {
for (DropOverload dropOverload : dropOverloads) {
int rand = random.nextInt(1000_000);
if (rand < dropOverload.getDropsPerMillion()) {
loadStatsStore.recordDroppedRequest(dropOverload.getCategory());
return PickResult.withDrop(Status.UNAVAILABLE.withDescription(
"dropped by loadbalancer: " + dropOverload.toString()));
}
}
return delegate.pickSubchannel(args);
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.add("dropOverloads", dropOverloads)
.add("delegate", delegate)
.toString();
}
}
private static final PickerFactory pickerFactoryImpl =
new PickerFactory() {
@Override
public SubchannelPicker picker(List<WeightedChildPicker> childPickers) {
return new InterLocalityPicker(childPickers);
}
};
@Override
public void reset() {
for (Locality locality : localityMap.keySet()) {
localityMap.get(locality).shutdown();
}
localityMap.clear();
for (Locality locality : localities) {
loadStatsStore.removeLocality(locality);
}
localities = ImmutableSet.of();
priorityManager.reset();
}
// This is triggered by EDS response.
@Override
public void updateLocalityStore(
final Map<Locality, LocalityLbEndpoints> localityInfoMap) {
Set<Locality> newLocalities = localityInfoMap.keySet();
// TODO: put endPointWeights into attributes for WRR.
for (Locality locality : newLocalities) {
if (localityMap.containsKey(locality)) {
LocalityLbInfo localityLbInfo = localityMap.get(locality);
LocalityLbEndpoints localityLbEndpoints = localityInfoMap.get(locality);
handleEagsOnChildBalancer(helper, localityLbInfo, localityLbEndpoints, locality);
}
}
for (Locality newLocality : newLocalities) {
if (!localities.contains(newLocality)) {
loadStatsStore.addLocality(newLocality);
}
}
final Set<Locality> toBeRemovedFromStatsStore = new HashSet<>();
// There is a race between picking a subchannel and updating localities, which leads to
// the possibility that RPCs will be sent to a removed locality. As a result, those RPC
// loads will not be recorded. We consider this to be natural. By removing locality counters
// after updating subchannel pickers, we eliminate the race and conservatively record loads
// happening in that period.
for (Locality oldLocality : localities) {
if (!localityInfoMap.containsKey(oldLocality)) {
toBeRemovedFromStatsStore.add(oldLocality);
}
}
helper.getSynchronizationContext().execute(new Runnable() {
@Override
public void run() {
for (Locality locality : toBeRemovedFromStatsStore) {
loadStatsStore.removeLocality(locality);
}
}
});
localities = newLocalities;
priorityManager.updateLocalities(localityInfoMap);
for (Locality oldLocality : localityMap.keySet()) {
if (!newLocalities.contains(oldLocality)) {
deactivate(oldLocality);
}
}
}
@Override
public void updateDropPercentage(List<DropOverload> dropOverloads) {
this.dropOverloads = checkNotNull(dropOverloads, "dropOverloads");
}
private void deactivate(final Locality locality) {
if (!localityMap.containsKey(locality) || localityMap.get(locality).isDeactivated()) {
return;
}
final LocalityLbInfo localityLbInfo = localityMap.get(locality);
class DeletionTask implements Runnable {
@Override
public void run() {
localityLbInfo.shutdown();
localityMap.remove(locality);
}
@Override
public String toString() {
return "DeletionTask: locality=" + locality;
}
}
localityLbInfo.delayedDeletionTimer = helper.getSynchronizationContext().schedule(
new DeletionTask(), DELAYED_DELETION_TIMEOUT_MINUTES,
TimeUnit.MINUTES, helper.getScheduledExecutorService());
}
@Override
public void updateOobMetricsReportInterval(long reportIntervalNano) {
metricsReportIntervalNano = reportIntervalNano;
for (LocalityLbInfo lbInfo : localityMap.values()) {
lbInfo.childHelper.updateMetricsReportInterval(reportIntervalNano);
}
}
@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 void updatePicker(
@Nullable ConnectivityState state, List<WeightedChildPicker> childPickers) {
childPickers = Collections.unmodifiableList(childPickers);
SubchannelPicker picker;
if (childPickers.isEmpty()) {
if (state == TRANSIENT_FAILURE) {
picker = new ErrorPicker(Status.UNAVAILABLE); // TODO: more details in status
} else {
picker = XdsSubchannelPickers.BUFFER_PICKER;
}
} else {
picker = pickerFactory.picker(childPickers);
}
if (!dropOverloads.isEmpty()) {
picker = new DroppablePicker(dropOverloads, picker, random, loadStatsStore);
}
if (state != null) {
helper.updateBalancingState(state, picker);
}
}
/**
* State of a single Locality.
*/
// TODO(zdapeng): rename it to LocalityLbState
static final class LocalityLbInfo {
final LoadBalancer childBalancer;
final ChildHelper childHelper;
@Nullable
private ScheduledHandle delayedDeletionTimer;
LocalityLbInfo(
LoadBalancer childBalancer, ChildHelper childHelper) {
this.childBalancer = checkNotNull(childBalancer, "childBalancer");
this.childHelper = checkNotNull(childHelper, "childHelper");
}
void shutdown() {
if (delayedDeletionTimer != null) {
delayedDeletionTimer.cancel();
delayedDeletionTimer = null;
}
childBalancer.shutdown();
}
void reactivate() {
if (delayedDeletionTimer != null) {
delayedDeletionTimer.cancel();
delayedDeletionTimer = null;
}
}
boolean isDeactivated() {
return delayedDeletionTimer != null;
}
}
class ChildHelper extends ForwardingLoadBalancerHelper {
private final OrcaReportingHelperWrapper orcaReportingHelperWrapper;
private SubchannelPicker currentChildPicker = XdsSubchannelPickers.BUFFER_PICKER;
private ConnectivityState currentChildState = CONNECTING;
ChildHelper(final Locality locality, final ClientLoadCounter counter,
OrcaOobUtil orcaOobUtil) {
checkNotNull(locality, "locality");
checkNotNull(counter, "counter");
checkNotNull(orcaOobUtil, "orcaOobUtil");
Helper delegate = new ForwardingLoadBalancerHelper() {
@Override
protected Helper delegate() {
return helper;
}
@Override
public void updateBalancingState(ConnectivityState newState,
final SubchannelPicker newPicker) {
checkNotNull(newState, "newState");
checkNotNull(newPicker, "newPicker");
currentChildState = newState;
currentChildPicker =
new LoadRecordingSubchannelPicker(counter,
new MetricsObservingSubchannelPicker(new MetricsRecordingListener(counter),
newPicker, orcaPerRequestUtil));
// delegate to parent helper
priorityManager.updatePriorityState(priorityManager.getPriority(locality));
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this).add("locality", locality).toString();
}
@Override
public String getAuthority() {
//FIXME: This should be a new proposed field of Locality, locality_name
return locality.getSubzone();
}
};
orcaReportingHelperWrapper =
checkNotNull(orcaOobUtil, "orcaOobUtil")
.newOrcaReportingHelperWrapper(delegate, new MetricsRecordingListener(counter));
if (metricsReportIntervalNano > 0) {
updateMetricsReportInterval(metricsReportIntervalNano);
}
}
void updateMetricsReportInterval(long intervalNanos) {
orcaReportingHelperWrapper
.setReportingConfig(OrcaReportingConfig.newBuilder()
.setReportInterval(intervalNanos, TimeUnit.NANOSECONDS).build());
}
@Override
protected Helper delegate() {
return orcaReportingHelperWrapper.asHelper();
}
}
private final class PriorityManager {
private final List<List<Locality>> priorityTable = new ArrayList<>();
private Map<Locality, LocalityLbEndpoints> localityInfoMap = ImmutableMap.of();
private int currentPriority = -1;
private ScheduledHandle failOverTimer;
/**
* Updates the priority ordering of localities with the given collection of localities.
* Recomputes the current ready localities to be used.
*/
void updateLocalities(Map<Locality, LocalityLbEndpoints> localityInfoMap) {
this.localityInfoMap = localityInfoMap;
priorityTable.clear();
for (Locality newLocality : localityInfoMap.keySet()) {
int priority = localityInfoMap.get(newLocality).getPriority();
while (priorityTable.size() <= priority) {
priorityTable.add(new ArrayList<Locality>());
}
priorityTable.get(priority).add(newLocality);
}
currentPriority = -1;
failOver();
}
/**
* Refreshes the group of localities with the given priority. Recomputes the current ready
* localities to be used.
*/
void updatePriorityState(int priority) {
if (priority == -1 || priority > currentPriority) {
return;
}
List<WeightedChildPicker> childPickers = new ArrayList<>();
ConnectivityState overallState = null;
for (Locality l : priorityTable.get(priority)) {
if (!localityMap.containsKey(l)) {
initLocality(l);
}
LocalityLbInfo localityLbInfo = localityMap.get(l);
localityLbInfo.reactivate();
ConnectivityState childState = localityLbInfo.childHelper.currentChildState;
SubchannelPicker childPicker = localityLbInfo.childHelper.currentChildPicker;
overallState = aggregateState(overallState, childState);
if (READY == childState) {
childPickers.add(
new WeightedChildPicker(localityInfoMap.get(l).getLocalityWeight(), childPicker));
}
}
if (priority == currentPriority) {
updatePicker(overallState, childPickers);
if (overallState == READY) {
cancelFailOverTimer();
} else if (overallState == TRANSIENT_FAILURE) {
cancelFailOverTimer();
failOver();
} else if (failOverTimer == null) {
failOver();
} // else, still connecting and failOverTimer not expired yet, noop
} else if (overallState == READY) {
updatePicker(overallState, childPickers);
cancelFailOverTimer();
currentPriority = priority;
}
if (overallState == READY) {
for (int p = priority + 1; p < priorityTable.size(); p++) {
for (Locality xdsLocality : priorityTable.get(p)) {
deactivate(xdsLocality);
}
}
}
}
int getPriority(Locality locality) {
if (localityInfoMap.containsKey(locality)) {
return localityInfoMap.get(locality).getPriority();
}
return -1;
}
void reset() {
cancelFailOverTimer();
priorityTable.clear();
localityInfoMap = ImmutableMap.of();
currentPriority = -1;
}
private void cancelFailOverTimer() {
if (failOverTimer != null) {
failOverTimer.cancel();
failOverTimer = null;
}
}
private void failOver() {
if (currentPriority == priorityTable.size() - 1) {
return;
}
currentPriority++;
List<Locality> localities = priorityTable.get(currentPriority);
boolean initializedBefore = false;
for (Locality locality : localities) {
if (localityMap.containsKey(locality)) {
initializedBefore = true;
localityMap.get(locality).reactivate();
} else {
initLocality(locality);
}
}
if (!initializedBefore) {
class FailOverTask implements Runnable {
@Override
public void run() {
failOverTimer = null;
failOver();
}
}
failOverTimer = helper.getSynchronizationContext().schedule(
new FailOverTask(), 10, TimeUnit.SECONDS, helper.getScheduledExecutorService());
}
updatePriorityState(currentPriority);
}
private void initLocality(Locality locality) {
ChildHelper childHelper =
new ChildHelper(locality, loadStatsStore.getLocalityCounter(locality),
orcaOobUtil);
LocalityLbInfo localityLbInfo =
new LocalityLbInfo(
loadBalancerProvider.newLoadBalancer(childHelper),
childHelper);
localityMap.put(locality, localityLbInfo);
LocalityLbEndpoints localityLbEndpoints = localityInfoMap.get(locality);
handleEagsOnChildBalancer(childHelper, localityLbInfo, localityLbEndpoints, locality);
}
}
private static void handleEagsOnChildBalancer(
Helper childHelper, final LocalityLbInfo localityLbInfo,
final LocalityLbEndpoints localityLbEndpoints, final Locality locality) {
final List<EquivalentAddressGroup> eags = new ArrayList<>();
for (LbEndpoint endpoint : localityLbEndpoints.getEndpoints()) {
if (endpoint.isHealthy()) {
eags.add(endpoint.getAddress());
}
}
// In extreme case handleResolvedAddresses() may trigger updateBalancingState()
// immediately, so execute handleResolvedAddresses() after all the setup in the caller is
// complete.
childHelper.getSynchronizationContext().execute(new Runnable() {
@Override
public void run() {
if (eags.isEmpty()
&& !localityLbInfo.childBalancer.canHandleEmptyAddressListFromNameResolution()) {
localityLbInfo.childBalancer.handleNameResolutionError(
Status.UNAVAILABLE.withDescription(
"No healthy address available from EDS update '" + localityLbEndpoints
+ "' for locality '" + locality + "'"));
} else {
localityLbInfo.childBalancer
.handleResolvedAddresses(ResolvedAddresses.newBuilder()
.setAddresses(eags).build());
}
}
});
}
}
}