From f63efbb8d74d8b6dff7df56af8e7e57a867c1413 Mon Sep 17 00:00:00 2001 From: Eric Anderson Date: Mon, 29 Dec 2025 10:02:25 -0800 Subject: [PATCH 1/2] core: Implement oobChannel with resolvingOobChannel The most important part of this change is to ensure that CallCredentials are not propagated to the OOB channel. Because the authority of the OOB channel doesn't match the parent channel, we must ensure that any bearer tokens are not sent to the different server. However, this was not a problem because resolvingOobChannel has the same constraint. (RLS has a different constraint, but we were able to let RLS manage that itself.) This commit does change the behavior of channelz, shutdown, and metrics for the OOB channel. Previously the OOB channel was registered with channelz, but it is only a TODO for resolving channel. Channel shutdown no longer shuts down the OOB channel and it no longer waits for the OOB channel to terminate before becoming terminated itself. That is also a pre-existing TODO. Since ManagedChannelImplBuilder is now being used, global configurators and census are enabled. The proper behavior here is still being determined, but we would want it to be the same for resolving OOB channel and OOB channel. The OOB channel used to refresh the name resolution when the subchannel went IDLE or TF. That is an older behavior from back when regular subchannels would also cause the name resolver to refresh. Now-a-days that goes though the LB tree. gRPC-LB already refreshes name resolution when its RPC closes, so no longer doing it automatically should be fine. balancerRpcExecutorPool no longer has its lifetime managed by the child. It'd be easiest to not use it at all from OOB channel, which wouldn't actually change the regular behavior, as channels already use the same executor by default. However, the tests are making use of the executor being injected, so some propagation needs to be preserved. Lots of OOB channel tests were deleted, but these were either testing OobChannel, which is now gone, or things like channelz, which are known to no longer work like before. --- .../io/grpc/internal/ManagedChannelImpl.java | 153 ++---- .../java/io/grpc/internal/OobChannel.java | 345 -------------- .../internal/OobNameResolverProvider.java | 121 +++++ .../grpc/internal/ManagedChannelImplTest.java | 434 +----------------- .../main/java/io/grpc/grpclb/GrpclbState.java | 5 +- 5 files changed, 173 insertions(+), 885 deletions(-) delete mode 100644 core/src/main/java/io/grpc/internal/OobChannel.java create mode 100644 core/src/main/java/io/grpc/internal/OobNameResolverProvider.java diff --git a/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java b/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java index 849e4b8e45c..a3ad662dcd0 100644 --- a/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java +++ b/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java @@ -95,6 +95,7 @@ import io.grpc.internal.RetriableStream.ChannelBufferMeter; import io.grpc.internal.RetriableStream.Throttle; import java.net.URI; +import java.net.URISyntaxException; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; @@ -167,11 +168,9 @@ public Result selectConfig(PickSubchannelArgs args) { @Nullable private final ChannelCredentials originalChannelCreds; private final ClientTransportFactory transportFactory; - private final ClientTransportFactory oobTransportFactory; private final RestrictedScheduledExecutor scheduledExecutor; private final Executor executor; private final ObjectPool executorPool; - private final ObjectPool balancerRpcExecutorPool; private final ExecutorHolder balancerRpcExecutorHolder; private final ExecutorHolder offloadExecutorHolder; private final TimeProvider timeProvider; @@ -240,9 +239,6 @@ public void uncaughtException(Thread t, Throwable e) { private Collection> pendingCalls; private final Object pendingCallsInUseObject = new Object(); - // Must be mutated from syncContext - private final Set oobChannels = new HashSet<>(1, .75f); - // reprocess() must be run from syncContext private final DelayedClientTransport delayedTransport; private final UncommittedRetriableStreamsRegistry uncommittedRetriableStreamsRegistry @@ -312,9 +308,6 @@ private void maybeShutdownNowSubchannels() { for (InternalSubchannel subchannel : subchannels) { subchannel.shutdownNow(SHUTDOWN_NOW_STATUS); } - for (OobChannel oobChannel : oobChannels) { - oobChannel.getInternalSubchannel().shutdownNow(SHUTDOWN_NOW_STATUS); - } } } @@ -334,7 +327,6 @@ public void run() { builder.setTarget(target).setState(channelStateManager.getState()); List children = new ArrayList<>(); children.addAll(subchannels); - children.addAll(oobChannels); builder.setSubchannels(children); ret.set(builder.build()); } @@ -564,8 +556,6 @@ ClientStream newSubstream( new ExecutorHolder(checkNotNull(builder.offloadExecutorPool, "offloadExecutorPool")); this.transportFactory = new CallCredentialsApplyingTransportFactory( clientTransportFactory, builder.callCredentials, this.offloadExecutorHolder); - this.oobTransportFactory = new CallCredentialsApplyingTransportFactory( - clientTransportFactory, null, this.offloadExecutorHolder); this.scheduledExecutor = new RestrictedScheduledExecutor(transportFactory.getScheduledExecutorService()); maxTraceEvents = builder.maxTraceEvents; @@ -604,8 +594,8 @@ ClientStream newSubstream( this.nameResolverArgs = nameResolverArgsBuilder.build(); this.nameResolver = getNameResolver( targetUri, authorityOverride, nameResolverProvider, nameResolverArgs); - this.balancerRpcExecutorPool = checkNotNull(balancerRpcExecutorPool, "balancerRpcExecutorPool"); - this.balancerRpcExecutorHolder = new ExecutorHolder(balancerRpcExecutorPool); + this.balancerRpcExecutorHolder = new ExecutorHolder( + checkNotNull(balancerRpcExecutorPool, "balancerRpcExecutorPool")); this.delayedTransport = new DelayedClientTransport(this.executor, this.syncContext); this.delayedTransport.start(delayedTransportListener); this.backoffPolicyProvider = backoffPolicyProvider; @@ -1187,7 +1177,7 @@ private void maybeTerminateChannel() { if (terminated) { return; } - if (shutdown.get() && subchannels.isEmpty() && oobChannels.isEmpty()) { + if (shutdown.get() && subchannels.isEmpty()) { channelLogger.log(ChannelLogLevel.INFO, "Terminated"); channelz.removeRootChannel(this); executorPool.returnObject(executor); @@ -1201,13 +1191,6 @@ private void maybeTerminateChannel() { } } - // Must be called from syncContext - private void handleInternalSubchannelState(ConnectivityStateInfo newState) { - if (newState.getState() == TRANSIENT_FAILURE || newState.getState() == IDLE) { - refreshNameResolution(); - } - } - @Override public ConnectivityState getState(boolean requestConnection) { ConnectivityState savedChannelState = channelStateManager.getState(); @@ -1253,9 +1236,6 @@ public void run() { for (InternalSubchannel subchannel : subchannels) { subchannel.resetConnectBackoff(); } - for (OobChannel oobChannel : oobChannels) { - oobChannel.resetConnectBackoff(); - } } } @@ -1413,86 +1393,28 @@ public ManagedChannel createOobChannel(EquivalentAddressGroup addressGroup, Stri @Override public ManagedChannel createOobChannel(List addressGroup, String authority) { - // TODO(ejona): can we be even stricter? Like terminating? - checkState(!terminated, "Channel is terminated"); - long oobChannelCreationTime = timeProvider.currentTimeNanos(); - InternalLogId oobLogId = InternalLogId.allocate("OobChannel", /*details=*/ null); - InternalLogId subchannelLogId = - InternalLogId.allocate("Subchannel-OOB", /*details=*/ authority); - ChannelTracer oobChannelTracer = - new ChannelTracer( - oobLogId, maxTraceEvents, oobChannelCreationTime, - "OobChannel for " + addressGroup); - final OobChannel oobChannel = new OobChannel( - authority, balancerRpcExecutorPool, oobTransportFactory.getScheduledExecutorService(), - syncContext, callTracerFactory.create(), oobChannelTracer, channelz, timeProvider); - channelTracer.reportEvent(new ChannelTrace.Event.Builder() - .setDescription("Child OobChannel created") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(oobChannelCreationTime) - .setChannelRef(oobChannel) - .build()); - ChannelTracer subchannelTracer = - new ChannelTracer(subchannelLogId, maxTraceEvents, oobChannelCreationTime, - "Subchannel for " + addressGroup); - ChannelLogger subchannelLogger = new ChannelLoggerImpl(subchannelTracer, timeProvider); - final class ManagedOobChannelCallback extends InternalSubchannel.Callback { - @Override - void onTerminated(InternalSubchannel is) { - oobChannels.remove(oobChannel); - channelz.removeSubchannel(is); - oobChannel.handleSubchannelTerminated(); - maybeTerminateChannel(); - } - - @Override - void onStateChange(InternalSubchannel is, ConnectivityStateInfo newState) { - // TODO(chengyuanzhang): change to let LB policies explicitly manage OOB channel's - // state and refresh name resolution if necessary. - handleInternalSubchannelState(newState); - oobChannel.handleSubchannelStateChange(newState); - } - } - - final InternalSubchannel internalSubchannel = new InternalSubchannel( - CreateSubchannelArgs.newBuilder().setAddresses(addressGroup).build(), - authority, userAgent, backoffPolicyProvider, oobTransportFactory, - oobTransportFactory.getScheduledExecutorService(), stopwatchSupplier, syncContext, - // All callback methods are run from syncContext - new ManagedOobChannelCallback(), - channelz, - callTracerFactory.create(), - subchannelTracer, - subchannelLogId, - subchannelLogger, - transportFilters, - target, - lbHelper.getMetricRecorder()); - oobChannelTracer.reportEvent(new ChannelTrace.Event.Builder() - .setDescription("Child Subchannel created") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(oobChannelCreationTime) - .setSubchannelRef(internalSubchannel) - .build()); - channelz.addSubchannel(oobChannel); - channelz.addSubchannel(internalSubchannel); - oobChannel.setSubchannel(internalSubchannel); - final class AddOobChannel implements Runnable { - @Override - public void run() { - if (terminating) { - oobChannel.shutdown(); - } - if (!terminated) { - // If channel has not terminated, it will track the subchannel and block termination - // for it. - oobChannels.add(oobChannel); - } - } - } - - syncContext.execute(new AddOobChannel()); - return oobChannel; + NameResolverRegistry nameResolverRegistry = new NameResolverRegistry(); + OobNameResolverProvider resolverProvider = + new OobNameResolverProvider(authority, addressGroup, syncContext); + nameResolverRegistry.register(resolverProvider); + // We could use a hard-coded target, as the name resolver won't actually use this string. + // However, that would make debugging less clear, as we use the target to identify the + // channel. + String target; + try { + target = new URI("oob", "", "/" + authority, null, null).toString(); + } catch (URISyntaxException ex) { + // Any special characters in the path will be percent encoded. So this should be impossible. + throw new AssertionError(ex); + } + ManagedChannel delegate = createResolvingOobChannelBuilder( + target, new DefaultChannelCreds(), nameResolverRegistry) + // TODO(zdapeng): executors should not outlive the parent channel. + .executor(balancerRpcExecutorHolder.getExecutor()) + .idleTimeout(Integer.MAX_VALUE, TimeUnit.SECONDS) + .disableRetry() + .build(); + return new OobChannel(delegate, resolverProvider); } @Deprecated @@ -1504,11 +1426,17 @@ public ManagedChannelBuilder createResolvingOobChannelBuilder(String target) .overrideAuthority(getAuthority()); } - // TODO(creamsoup) prevent main channel to shutdown if oob channel is not terminated - // TODO(zdapeng) register the channel as a subchannel of the parent channel in channelz. @Override public ManagedChannelBuilder createResolvingOobChannelBuilder( final String target, final ChannelCredentials channelCreds) { + return createResolvingOobChannelBuilder(target, channelCreds, nameResolverRegistry); + } + + // TODO(creamsoup) prevent main channel to shutdown if oob channel is not terminated + // TODO(zdapeng) register the channel as a subchannel of the parent channel in channelz. + private ManagedChannelBuilder createResolvingOobChannelBuilder( + final String target, final ChannelCredentials channelCreds, + NameResolverRegistry nameResolverRegistry) { checkNotNull(channelCreds, "channelCreds"); final class ResolvingOobChannelBuilder @@ -1641,6 +1569,19 @@ public ChannelCredentials withoutBearerTokens() { } } + static final class OobChannel extends ForwardingManagedChannel { + private final OobNameResolverProvider resolverProvider; + + public OobChannel(ManagedChannel delegate, OobNameResolverProvider resolverProvider) { + super(delegate); + this.resolverProvider = checkNotNull(resolverProvider, "resolverProvider"); + } + + public void updateAddresses(List eags) { + resolverProvider.updateAddresses(eags); + } + } + final class NameResolverListener extends NameResolver.Listener2 { final LbHelperImpl helper; final NameResolver resolver; diff --git a/core/src/main/java/io/grpc/internal/OobChannel.java b/core/src/main/java/io/grpc/internal/OobChannel.java deleted file mode 100644 index 30c9f55e796..00000000000 --- a/core/src/main/java/io/grpc/internal/OobChannel.java +++ /dev/null @@ -1,345 +0,0 @@ -/* - * Copyright 2016 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.internal; - -import static com.google.common.base.Preconditions.checkNotNull; - -import com.google.common.annotations.VisibleForTesting; -import com.google.common.base.MoreObjects; -import com.google.common.base.Preconditions; -import com.google.common.util.concurrent.ListenableFuture; -import com.google.common.util.concurrent.SettableFuture; -import io.grpc.Attributes; -import io.grpc.CallOptions; -import io.grpc.ClientCall; -import io.grpc.ClientStreamTracer; -import io.grpc.ConnectivityState; -import io.grpc.ConnectivityStateInfo; -import io.grpc.Context; -import io.grpc.EquivalentAddressGroup; -import io.grpc.InternalChannelz; -import io.grpc.InternalChannelz.ChannelStats; -import io.grpc.InternalChannelz.ChannelTrace; -import io.grpc.InternalInstrumented; -import io.grpc.InternalLogId; -import io.grpc.InternalWithLogId; -import io.grpc.LoadBalancer; -import io.grpc.LoadBalancer.PickResult; -import io.grpc.LoadBalancer.PickSubchannelArgs; -import io.grpc.LoadBalancer.Subchannel; -import io.grpc.LoadBalancer.SubchannelPicker; -import io.grpc.ManagedChannel; -import io.grpc.Metadata; -import io.grpc.MethodDescriptor; -import io.grpc.Status; -import io.grpc.SynchronizationContext; -import io.grpc.internal.ClientCallImpl.ClientStreamProvider; -import java.util.Collections; -import java.util.List; -import java.util.concurrent.CountDownLatch; -import java.util.concurrent.Executor; -import java.util.concurrent.ScheduledExecutorService; -import java.util.concurrent.TimeUnit; -import java.util.logging.Level; -import java.util.logging.Logger; -import javax.annotation.concurrent.ThreadSafe; - -/** - * A ManagedChannel backed by a single {@link InternalSubchannel} and used for {@link LoadBalancer} - * to its own RPC needs. - */ -@ThreadSafe -final class OobChannel extends ManagedChannel implements InternalInstrumented { - private static final Logger log = Logger.getLogger(OobChannel.class.getName()); - - private InternalSubchannel subchannel; - private AbstractSubchannel subchannelImpl; - private SubchannelPicker subchannelPicker; - - private final InternalLogId logId; - private final String authority; - private final DelayedClientTransport delayedTransport; - private final InternalChannelz channelz; - private final ObjectPool executorPool; - private final Executor executor; - private final ScheduledExecutorService deadlineCancellationExecutor; - private final CountDownLatch terminatedLatch = new CountDownLatch(1); - private volatile boolean shutdown; - private final CallTracer channelCallsTracer; - private final ChannelTracer channelTracer; - private final TimeProvider timeProvider; - - private final ClientStreamProvider transportProvider = new ClientStreamProvider() { - @Override - public ClientStream newStream(MethodDescriptor method, - CallOptions callOptions, Metadata headers, Context context) { - ClientStreamTracer[] tracers = GrpcUtil.getClientStreamTracers( - callOptions, headers, 0, /* isTransparentRetry= */ false, - /* isHedging= */ false); - Context origContext = context.attach(); - // delayed transport's newStream() always acquires a lock, but concurrent performance doesn't - // matter here because OOB communication should be sparse, and it's not on application RPC's - // critical path. - try { - return delayedTransport.newStream(method, headers, callOptions, tracers); - } finally { - context.detach(origContext); - } - } - }; - - OobChannel( - String authority, ObjectPool executorPool, - ScheduledExecutorService deadlineCancellationExecutor, SynchronizationContext syncContext, - CallTracer callsTracer, ChannelTracer channelTracer, InternalChannelz channelz, - TimeProvider timeProvider) { - this.authority = checkNotNull(authority, "authority"); - this.logId = InternalLogId.allocate(getClass(), authority); - this.executorPool = checkNotNull(executorPool, "executorPool"); - this.executor = checkNotNull(executorPool.getObject(), "executor"); - this.deadlineCancellationExecutor = checkNotNull( - deadlineCancellationExecutor, "deadlineCancellationExecutor"); - this.delayedTransport = new DelayedClientTransport(executor, syncContext); - this.channelz = Preconditions.checkNotNull(channelz); - this.delayedTransport.start(new ManagedClientTransport.Listener() { - @Override - public void transportShutdown(Status s) { - // Don't care - } - - @Override - public void transportTerminated() { - subchannelImpl.shutdown(); - } - - @Override - public void transportReady() { - // Don't care - } - - @Override - public Attributes filterTransport(Attributes attributes) { - return attributes; - } - - @Override - public void transportInUse(boolean inUse) { - // Don't care - } - }); - this.channelCallsTracer = callsTracer; - this.channelTracer = checkNotNull(channelTracer, "channelTracer"); - this.timeProvider = checkNotNull(timeProvider, "timeProvider"); - } - - // Must be called only once, right after the OobChannel is created. - void setSubchannel(final InternalSubchannel subchannel) { - log.log(Level.FINE, "[{0}] Created with [{1}]", new Object[] {this, subchannel}); - this.subchannel = subchannel; - subchannelImpl = new AbstractSubchannel() { - @Override - public void shutdown() { - subchannel.shutdown(Status.UNAVAILABLE.withDescription("OobChannel is shutdown")); - } - - @Override - InternalInstrumented getInstrumentedInternalSubchannel() { - return subchannel; - } - - @Override - public void requestConnection() { - subchannel.obtainActiveTransport(); - } - - @Override - public List getAllAddresses() { - return subchannel.getAddressGroups(); - } - - @Override - public Attributes getAttributes() { - return Attributes.EMPTY; - } - - @Override - public Object getInternalSubchannel() { - return subchannel; - } - }; - - final class OobSubchannelPicker extends SubchannelPicker { - final PickResult result = PickResult.withSubchannel(subchannelImpl); - - @Override - public PickResult pickSubchannel(PickSubchannelArgs args) { - return result; - } - - @Override - public String toString() { - return MoreObjects.toStringHelper(OobSubchannelPicker.class) - .add("result", result) - .toString(); - } - } - - subchannelPicker = new OobSubchannelPicker(); - delayedTransport.reprocess(subchannelPicker); - } - - void updateAddresses(List eag) { - subchannel.updateAddresses(eag); - } - - @Override - public ClientCall newCall( - MethodDescriptor methodDescriptor, CallOptions callOptions) { - return new ClientCallImpl<>(methodDescriptor, - callOptions.getExecutor() == null ? executor : callOptions.getExecutor(), - callOptions, transportProvider, deadlineCancellationExecutor, channelCallsTracer, null); - } - - @Override - public String authority() { - return authority; - } - - @Override - public boolean isTerminated() { - return terminatedLatch.getCount() == 0; - } - - @Override - public boolean awaitTermination(long time, TimeUnit unit) throws InterruptedException { - return terminatedLatch.await(time, unit); - } - - @Override - public ConnectivityState getState(boolean requestConnectionIgnored) { - if (subchannel == null) { - return ConnectivityState.IDLE; - } - return subchannel.getState(); - } - - @Override - public ManagedChannel shutdown() { - shutdown = true; - delayedTransport.shutdown(Status.UNAVAILABLE.withDescription("OobChannel.shutdown() called")); - return this; - } - - @Override - public boolean isShutdown() { - return shutdown; - } - - @Override - public ManagedChannel shutdownNow() { - shutdown = true; - delayedTransport.shutdownNow( - Status.UNAVAILABLE.withDescription("OobChannel.shutdownNow() called")); - return this; - } - - void handleSubchannelStateChange(final ConnectivityStateInfo newState) { - channelTracer.reportEvent( - new ChannelTrace.Event.Builder() - .setDescription("Entering " + newState.getState() + " state") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(timeProvider.currentTimeNanos()) - .build()); - switch (newState.getState()) { - case READY: - case IDLE: - delayedTransport.reprocess(subchannelPicker); - break; - case TRANSIENT_FAILURE: - final class OobErrorPicker extends SubchannelPicker { - final PickResult errorResult = PickResult.withError(newState.getStatus()); - - @Override - public PickResult pickSubchannel(PickSubchannelArgs args) { - return errorResult; - } - - @Override - public String toString() { - return MoreObjects.toStringHelper(OobErrorPicker.class) - .add("errorResult", errorResult) - .toString(); - } - } - - delayedTransport.reprocess(new OobErrorPicker()); - break; - default: - // Do nothing - } - } - - // must be run from channel executor - void handleSubchannelTerminated() { - channelz.removeSubchannel(this); - // When delayedTransport is terminated, it shuts down subchannel. Therefore, at this point - // both delayedTransport and subchannel have terminated. - executorPool.returnObject(executor); - terminatedLatch.countDown(); - } - - @VisibleForTesting - Subchannel getSubchannel() { - return subchannelImpl; - } - - InternalSubchannel getInternalSubchannel() { - return subchannel; - } - - @Override - public ListenableFuture getStats() { - final SettableFuture ret = SettableFuture.create(); - final ChannelStats.Builder builder = new ChannelStats.Builder(); - channelCallsTracer.updateBuilder(builder); - channelTracer.updateBuilder(builder); - builder - .setTarget(authority) - .setState(subchannel.getState()) - .setSubchannels(Collections.singletonList(subchannel)); - ret.set(builder.build()); - return ret; - } - - @Override - public InternalLogId getLogId() { - return logId; - } - - @Override - public String toString() { - return MoreObjects.toStringHelper(this) - .add("logId", logId.getId()) - .add("authority", authority) - .toString(); - } - - @Override - public void resetConnectBackoff() { - subchannel.resetConnectBackoff(); - } -} diff --git a/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java b/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java new file mode 100644 index 00000000000..af94ddad396 --- /dev/null +++ b/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java @@ -0,0 +1,121 @@ +/* + * Copyright 2025 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.internal; + +import static java.util.Objects.requireNonNull; + +import io.grpc.EquivalentAddressGroup; +import io.grpc.NameResolver; +import io.grpc.NameResolverProvider; +import io.grpc.StatusOr; +import io.grpc.SynchronizationContext; +import java.net.URI; +import java.util.Collection; +import java.util.LinkedList; +import java.util.List; + +/** + * A provider that is passed addresses and relays those addresses to its created resolvers. + */ +final class OobNameResolverProvider extends NameResolverProvider { + private final String authority; + private final SynchronizationContext parentSyncContext; + // Only accessed from parentSyncContext + @SuppressWarnings("JdkObsolete") // LinkedList uses O(n) memory, including after deletions + private final Collection resolvers = new LinkedList<>(); + // Only accessed from parentSyncContext + private List lastEags; + + public OobNameResolverProvider( + String authority, List eags, SynchronizationContext syncContext) { + this.authority = requireNonNull(authority, "authority"); + this.lastEags = requireNonNull(eags, "eags"); + this.parentSyncContext = requireNonNull(syncContext, "syncContext"); + } + + @Override + public String getDefaultScheme() { + return "oob"; + } + + @Override + protected boolean isAvailable() { + return true; + } + + @Override + protected int priority() { + return 5; + } + + public void updateAddresses(List eags) { + requireNonNull(eags, "eags"); + parentSyncContext.execute(() -> { + this.lastEags = eags; + for (OobNameResolver resolver : resolvers) { + resolver.updateAddresses(eags); + } + }); + } + + @Override + public NameResolver newNameResolver(URI targetUri, NameResolver.Args args) { + return new OobNameResolver(args.getSynchronizationContext()); + } + + final class OobNameResolver extends NameResolver { + private final SynchronizationContext syncContext; + // Null before started, and after shutdown. Only accessed from syncContext + private Listener2 listener; + + public OobNameResolver(SynchronizationContext syncContext) { + this.syncContext = requireNonNull(syncContext, "syncContext"); + } + + @Override + public String getServiceAuthority() { + return authority; + } + + @Override + public void start(Listener2 listener) { + this.listener = requireNonNull(listener, "listener"); + parentSyncContext.execute(() -> { + resolvers.add(this); + updateAddresses(lastEags); + }); + } + + void updateAddresses(List eags) { + parentSyncContext.throwIfNotInThisSynchronizationContext(); + syncContext.execute(() -> { + if (listener == null) { + return; + } + listener.onResult2(ResolutionResult.newBuilder() + .setAddressesOrError(StatusOr.fromValue(lastEags)) + .build()); + }); + } + + @Override + public void shutdown() { + this.listener = null; + parentSyncContext.execute(() -> resolvers.remove(this)); + } + } +} diff --git a/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java b/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java index 91a9f506bc8..7954620b31a 100644 --- a/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java +++ b/core/src/test/java/io/grpc/internal/ManagedChannelImplTest.java @@ -285,10 +285,6 @@ public String getPolicyName() { @Mock private ClientCall.Listener mockCallListener3; @Mock - private ClientCall.Listener mockCallListener4; - @Mock - private ClientCall.Listener mockCallListener5; - @Mock private ObjectPool executorPool; @Mock private ObjectPool balancerRpcExecutorPool; @@ -816,46 +812,6 @@ public void channelzMembership_subchannel() throws Exception { assertNotNull(channelz.getRootChannel(channel.getLogId().getId())); } - @Test - public void channelzMembership_oob() throws Exception { - createChannel(); - OobChannel oob = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), AUTHORITY); - // oob channels are not root channels - assertNull(channelz.getRootChannel(oob.getLogId().getId())); - assertTrue(channelz.containsSubchannel(oob.getLogId())); - assertThat(getStats(channel).subchannels).containsExactly(oob); - assertTrue(channelz.containsSubchannel(oob.getLogId())); - - AbstractSubchannel subchannel = (AbstractSubchannel) oob.getSubchannel(); - assertTrue( - channelz.containsSubchannel(subchannel.getInstrumentedInternalSubchannel().getLogId())); - assertThat(getStats(oob).subchannels) - .containsExactly(subchannel.getInstrumentedInternalSubchannel()); - assertTrue( - channelz.containsSubchannel(subchannel.getInstrumentedInternalSubchannel().getLogId())); - - oob.getSubchannel().requestConnection(); - MockClientTransportInfo transportInfo = transports.poll(); - assertNotNull(transportInfo); - assertTrue(channelz.containsClientSocket(transportInfo.transport.getLogId())); - - // terminate transport - transportInfo.listener.transportShutdown(Status.INTERNAL); - transportInfo.listener.transportTerminated(); - assertFalse(channelz.containsClientSocket(transportInfo.transport.getLogId())); - - // terminate oobchannel - oob.shutdown(); - assertFalse(channelz.containsSubchannel(oob.getLogId())); - assertThat(getStats(channel).subchannels).isEmpty(); - assertFalse( - channelz.containsSubchannel(subchannel.getInstrumentedInternalSubchannel().getLogId())); - - // channel still appears - assertNotNull(channelz.getRootChannel(channel.getLogId().getId())); - } - @Test public void callsAndShutdown() { subtestCallsAndShutdown(false, false); @@ -1788,7 +1744,7 @@ public void subchannelsNoConnectionShutdownNow() { channel.shutdownNow(); verify(mockLoadBalancer).shutdown(); - // Channel's shutdownNow() will call shutdownNow() on all subchannels and oobchannels. + // Channel's shutdownNow() will call shutdownNow() on all subchannels. // Therefore, channel is terminated without relying on LoadBalancer to shutdown subchannels. assertTrue(channel.isTerminated()); verify(mockTransportFactory, never()) @@ -1796,112 +1752,6 @@ public void subchannelsNoConnectionShutdownNow() { any(SocketAddress.class), any(ClientTransportOptions.class), any(ChannelLogger.class)); } - @Test - public void oobchannels() { - createChannel(); - - ManagedChannel oob1 = helper.createOobChannel( - Collections.singletonList(addressGroup), "oob1authority"); - ManagedChannel oob2 = helper.createOobChannel( - Collections.singletonList(addressGroup), "oob2authority"); - verify(balancerRpcExecutorPool, times(2)).getObject(); - - assertEquals("oob1authority", oob1.authority()); - assertEquals("oob2authority", oob2.authority()); - - // OOB channels create connections lazily. A new call will initiate the connection. - Metadata headers = new Metadata(); - ClientCall call = oob1.newCall(method, CallOptions.DEFAULT); - call.start(mockCallListener, headers); - verify(mockTransportFactory) - .newClientTransport( - eq(socketAddress), - eq(new ClientTransportOptions().setAuthority("oob1authority").setUserAgent(USER_AGENT)), - isA(ChannelLogger.class)); - MockClientTransportInfo transportInfo = transports.poll(); - assertNotNull(transportInfo); - - assertEquals(0, balancerRpcExecutor.numPendingTasks()); - transportInfo.listener.transportReady(); - assertEquals(1, balancerRpcExecutor.runDueTasks()); - verify(transportInfo.transport).newStream( - same(method), same(headers), same(CallOptions.DEFAULT), - ArgumentMatchers.any()); - - // The transport goes away - transportInfo.listener.transportShutdown(Status.UNAVAILABLE); - transportInfo.listener.transportTerminated(); - - // A new call will trigger a new transport - ClientCall call2 = oob1.newCall(method, CallOptions.DEFAULT); - call2.start(mockCallListener2, headers); - ClientCall call3 = - oob1.newCall(method, CallOptions.DEFAULT.withWaitForReady()); - call3.start(mockCallListener3, headers); - verify(mockTransportFactory, times(2)).newClientTransport( - eq(socketAddress), - eq(new ClientTransportOptions().setAuthority("oob1authority").setUserAgent(USER_AGENT)), - isA(ChannelLogger.class)); - transportInfo = transports.poll(); - assertNotNull(transportInfo); - - // This transport fails - Status transportError = Status.UNAVAILABLE.withDescription("Connection refused"); - assertEquals(0, balancerRpcExecutor.numPendingTasks()); - transportInfo.listener.transportShutdown(transportError); - assertTrue(balancerRpcExecutor.runDueTasks() > 0); - - // Fail-fast RPC will fail, while wait-for-ready RPC will still be pending - verify(mockCallListener2).onClose(same(transportError), any(Metadata.class)); - verify(mockCallListener3, never()).onClose(any(Status.class), any(Metadata.class)); - - // Shutdown - assertFalse(oob1.isShutdown()); - assertFalse(oob2.isShutdown()); - oob1.shutdown(); - oob2.shutdownNow(); - assertTrue(oob1.isShutdown()); - assertTrue(oob2.isShutdown()); - assertTrue(oob2.isTerminated()); - verify(balancerRpcExecutorPool).returnObject(balancerRpcExecutor.getScheduledExecutorService()); - - // New RPCs will be rejected. - assertEquals(0, balancerRpcExecutor.numPendingTasks()); - ClientCall call4 = oob1.newCall(method, CallOptions.DEFAULT); - ClientCall call5 = oob2.newCall(method, CallOptions.DEFAULT); - call4.start(mockCallListener4, headers); - call5.start(mockCallListener5, headers); - assertTrue(balancerRpcExecutor.runDueTasks() > 0); - verify(mockCallListener4).onClose(statusCaptor.capture(), any(Metadata.class)); - Status status4 = statusCaptor.getValue(); - assertEquals(Status.Code.UNAVAILABLE, status4.getCode()); - verify(mockCallListener5).onClose(statusCaptor.capture(), any(Metadata.class)); - Status status5 = statusCaptor.getValue(); - assertEquals(Status.Code.UNAVAILABLE, status5.getCode()); - - // The pending RPC will still be pending - verify(mockCallListener3, never()).onClose(any(Status.class), any(Metadata.class)); - - // This will shutdownNow() the delayed transport, terminating the pending RPC - assertEquals(0, balancerRpcExecutor.numPendingTasks()); - oob1.shutdownNow(); - assertTrue(balancerRpcExecutor.runDueTasks() > 0); - verify(mockCallListener3).onClose(any(Status.class), any(Metadata.class)); - - // Shut down the channel, and it will not terminated because OOB channel has not. - channel.shutdown(); - assertFalse(channel.isTerminated()); - // Delayed transport has already terminated. Terminating the transport terminates the - // subchannel, which in turn terimates the OOB channel, which terminates the channel. - assertFalse(oob1.isTerminated()); - verify(balancerRpcExecutorPool).returnObject(balancerRpcExecutor.getScheduledExecutorService()); - transportInfo.listener.transportTerminated(); - assertTrue(oob1.isTerminated()); - assertTrue(channel.isTerminated()); - verify(balancerRpcExecutorPool, times(2)) - .returnObject(balancerRpcExecutor.getScheduledExecutorService()); - } - @Test public void oobChannelHasNoChannelCallCredentials() { Metadata.Key metadataKey = @@ -1953,7 +1803,7 @@ public void oobChannelHasNoChannelCallCredentials() { balancerRpcExecutor.runDueTasks(); verify(transportInfo.transport).newStream( - same(method), same(headers), same(callOptions), + same(method), same(headers), ArgumentMatchers.any(), ArgumentMatchers.any()); assertThat(headers.getAll(metadataKey)).containsExactly(callCredValue); oob.shutdownNow(); @@ -2080,74 +1930,6 @@ public SwapChannelCredentialsResult answer(InvocationOnMock invocation) { oob.shutdownNow(); } - @Test - public void oobChannelsWhenChannelShutdownNow() { - createChannel(); - ManagedChannel oob1 = helper.createOobChannel( - Collections.singletonList(addressGroup), "oob1Authority"); - ManagedChannel oob2 = helper.createOobChannel( - Collections.singletonList(addressGroup), "oob2Authority"); - - oob1.newCall(method, CallOptions.DEFAULT).start(mockCallListener, new Metadata()); - oob2.newCall(method, CallOptions.DEFAULT).start(mockCallListener2, new Metadata()); - - assertThat(transports).hasSize(2); - MockClientTransportInfo ti1 = transports.poll(); - MockClientTransportInfo ti2 = transports.poll(); - - ti1.listener.transportReady(); - ti2.listener.transportReady(); - - channel.shutdownNow(); - verify(ti1.transport).shutdownNow(any(Status.class)); - verify(ti2.transport).shutdownNow(any(Status.class)); - - ti1.listener.transportShutdown(Status.UNAVAILABLE.withDescription("shutdown now")); - ti2.listener.transportShutdown(Status.UNAVAILABLE.withDescription("shutdown now")); - ti1.listener.transportTerminated(); - - assertFalse(channel.isTerminated()); - ti2.listener.transportTerminated(); - assertTrue(channel.isTerminated()); - } - - @Test - public void oobChannelsNoConnectionShutdown() { - createChannel(); - ManagedChannel oob1 = helper.createOobChannel( - Collections.singletonList(addressGroup), "oob1Authority"); - ManagedChannel oob2 = helper.createOobChannel( - Collections.singletonList(addressGroup), "oob2Authority"); - channel.shutdown(); - - verify(mockLoadBalancer).shutdown(); - oob1.shutdown(); - assertTrue(oob1.isTerminated()); - assertFalse(channel.isTerminated()); - oob2.shutdown(); - assertTrue(oob2.isTerminated()); - assertTrue(channel.isTerminated()); - verify(mockTransportFactory, never()) - .newClientTransport( - any(SocketAddress.class), any(ClientTransportOptions.class), any(ChannelLogger.class)); - } - - @Test - public void oobChannelsNoConnectionShutdownNow() { - createChannel(); - helper.createOobChannel(Collections.singletonList(addressGroup), "oob1Authority"); - helper.createOobChannel(Collections.singletonList(addressGroup), "oob2Authority"); - channel.shutdownNow(); - - verify(mockLoadBalancer).shutdown(); - assertTrue(channel.isTerminated()); - // Channel's shutdownNow() will call shutdownNow() on all subchannels and oobchannels. - // Therefore, channel is terminated without relying on LoadBalancer to shutdown oobchannels. - verify(mockTransportFactory, never()) - .newClientTransport( - any(SocketAddress.class), any(ClientTransportOptions.class), any(ChannelLogger.class)); - } - @Test public void subchannelChannel_normalUsage() { createChannel(); @@ -2293,67 +2075,6 @@ public void lbHelper_getNonDefaultNameResolverRegistry() { .isNotSameInstanceAs(NameResolverRegistry.getDefaultRegistry()); } - @Test - public void refreshNameResolution_whenOobChannelConnectionFailed_notIdle() { - subtestNameResolutionRefreshWhenConnectionFailed(false); - } - - @Test - public void notRefreshNameResolution_whenOobChannelConnectionFailed_idle() { - subtestNameResolutionRefreshWhenConnectionFailed(true); - } - - private void subtestNameResolutionRefreshWhenConnectionFailed(boolean isIdle) { - FakeNameResolverFactory nameResolverFactory = - new FakeNameResolverFactory.Builder(expectedUri) - .setServers(Collections.singletonList(new EquivalentAddressGroup(socketAddress))) - .build(); - channelBuilder.nameResolverFactory(nameResolverFactory); - createChannel(); - OobChannel oobChannel = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), "oobAuthority"); - oobChannel.getSubchannel().requestConnection(); - - MockClientTransportInfo transportInfo = transports.poll(); - assertNotNull(transportInfo); - - FakeNameResolverFactory.FakeNameResolver resolver = nameResolverFactory.resolvers.remove(0); - - if (isIdle) { - channel.enterIdle(); - // Entering idle mode will result in a new resolver - resolver = nameResolverFactory.resolvers.remove(0); - } - - assertEquals(0, nameResolverFactory.resolvers.size()); - - int expectedRefreshCount = 0; - - // Transport closed when connecting - assertEquals(expectedRefreshCount, resolver.refreshCalled); - transportInfo.listener.transportShutdown(Status.UNAVAILABLE); - // When channel enters idle, new resolver is created but not started. - if (!isIdle) { - expectedRefreshCount++; - } - assertEquals(expectedRefreshCount, resolver.refreshCalled); - - timer.forwardNanos(RECONNECT_BACKOFF_INTERVAL_NANOS); - transportInfo = transports.poll(); - assertNotNull(transportInfo); - - transportInfo.listener.transportReady(); - - // Transport closed when ready - assertEquals(expectedRefreshCount, resolver.refreshCalled); - transportInfo.listener.transportShutdown(Status.UNAVAILABLE); - // When channel enters idle, new resolver is created but not started. - if (!isIdle) { - expectedRefreshCount++; - } - assertEquals(expectedRefreshCount, resolver.refreshCalled); - } - /** * Test that information such as the Call's context, MethodDescriptor, authority, executor are * propagated to newStream() and applyRequestMetadata(). @@ -3506,48 +3227,6 @@ public void channelTracing_subchannelStateChangeEvent() throws Exception { .build()); } - @Test - public void channelTracing_oobChannelStateChangeEvent() throws Exception { - channelBuilder.maxTraceEvents(10); - createChannel(); - OobChannel oobChannel = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), "authority"); - timer.forwardNanos(1234); - oobChannel.handleSubchannelStateChange( - ConnectivityStateInfo.forNonError(ConnectivityState.CONNECTING)); - assertThat(getStats(oobChannel).channelTrace.events).contains(new ChannelTrace.Event.Builder() - .setDescription("Entering CONNECTING state") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(timer.getTicker().read()) - .build()); - } - - @Test - public void channelTracing_oobChannelCreationEvents() throws Exception { - channelBuilder.maxTraceEvents(10); - createChannel(); - timer.forwardNanos(1234); - OobChannel oobChannel = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), "authority"); - assertThat(getStats(channel).channelTrace.events).contains(new ChannelTrace.Event.Builder() - .setDescription("Child OobChannel created") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(timer.getTicker().read()) - .setChannelRef(oobChannel) - .build()); - assertThat(getStats(oobChannel).channelTrace.events).contains(new ChannelTrace.Event.Builder() - .setDescription("OobChannel for [[[test-addr]/{}]] created") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(timer.getTicker().read()) - .build()); - assertThat(getStats(oobChannel.getInternalSubchannel()).channelTrace.events).contains( - new ChannelTrace.Event.Builder() - .setDescription("Subchannel for [[[test-addr]/{}]] created") - .setSeverity(ChannelTrace.Event.Severity.CT_INFO) - .setTimestampNanos(timer.getTicker().read()) - .build()); - } - @Test public void channelsAndSubchannels_instrumented_state() throws Exception { createChannel(); @@ -3663,115 +3342,6 @@ private void channelsAndSubchannels_instrumented0(boolean success) throws Except } } - @Test - public void channelsAndSubchannels_oob_instrumented_success() throws Exception { - channelsAndSubchannels_oob_instrumented0(true); - } - - @Test - public void channelsAndSubchannels_oob_instrumented_fail() throws Exception { - channelsAndSubchannels_oob_instrumented0(false); - } - - private void channelsAndSubchannels_oob_instrumented0(boolean success) throws Exception { - // set up - ClientStream mockStream = mock(ClientStream.class); - createChannel(); - - OobChannel oobChannel = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), "oobauthority"); - AbstractSubchannel oobSubchannel = (AbstractSubchannel) oobChannel.getSubchannel(); - FakeClock callExecutor = new FakeClock(); - CallOptions options = - CallOptions.DEFAULT.withExecutor(callExecutor.getScheduledExecutorService()); - ClientCall call = oobChannel.newCall(method, options); - Metadata headers = new Metadata(); - - // Channel stat bumped when ClientCall.start() called - assertEquals(0, getStats(oobChannel).callsStarted); - call.start(mockCallListener, headers); - assertEquals(1, getStats(oobChannel).callsStarted); - - MockClientTransportInfo transportInfo = transports.poll(); - ConnectionClientTransport mockTransport = transportInfo.transport; - ManagedClientTransport.Listener transportListener = transportInfo.listener; - when(mockTransport.newStream( - same(method), same(headers), any(CallOptions.class), - ArgumentMatchers.any())) - .thenReturn(mockStream); - - // subchannel stat bumped when call gets assigned to it - assertEquals(0, getStats(oobSubchannel).callsStarted); - transportListener.transportReady(); - callExecutor.runDueTasks(); - verify(mockStream).start(streamListenerCaptor.capture()); - assertEquals(1, getStats(oobSubchannel).callsStarted); - - ClientStreamListener streamListener = streamListenerCaptor.getValue(); - call.halfClose(); - - // closing stream listener affects subchannel stats immediately - assertEquals(0, getStats(oobSubchannel).callsSucceeded); - assertEquals(0, getStats(oobSubchannel).callsFailed); - streamListener.closed(success ? Status.OK : Status.UNKNOWN, PROCESSED, new Metadata()); - if (success) { - assertEquals(1, getStats(oobSubchannel).callsSucceeded); - assertEquals(0, getStats(oobSubchannel).callsFailed); - } else { - assertEquals(0, getStats(oobSubchannel).callsSucceeded); - assertEquals(1, getStats(oobSubchannel).callsFailed); - } - - // channel stats bumped when the ClientCall.Listener is notified - assertEquals(0, getStats(oobChannel).callsSucceeded); - assertEquals(0, getStats(oobChannel).callsFailed); - callExecutor.runDueTasks(); - if (success) { - assertEquals(1, getStats(oobChannel).callsSucceeded); - assertEquals(0, getStats(oobChannel).callsFailed); - } else { - assertEquals(0, getStats(oobChannel).callsSucceeded); - assertEquals(1, getStats(oobChannel).callsFailed); - } - // oob channel is separate from the original channel - assertEquals(0, getStats(channel).callsSucceeded); - assertEquals(0, getStats(channel).callsFailed); - } - - @Test - public void channelsAndSubchannels_oob_instrumented_name() throws Exception { - createChannel(); - - String authority = "oobauthority"; - OobChannel oobChannel = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), authority); - assertEquals(authority, getStats(oobChannel).target); - } - - @Test - public void channelsAndSubchannels_oob_instrumented_state() throws Exception { - createChannel(); - - OobChannel oobChannel = (OobChannel) helper.createOobChannel( - Collections.singletonList(addressGroup), "oobauthority"); - assertEquals(IDLE, getStats(oobChannel).state); - - oobChannel.getSubchannel().requestConnection(); - assertEquals(CONNECTING, getStats(oobChannel).state); - - MockClientTransportInfo transportInfo = transports.poll(); - ManagedClientTransport.Listener transportListener = transportInfo.listener; - - transportListener.transportReady(); - assertEquals(READY, getStats(oobChannel).state); - - // oobchannel state is separate from the ManagedChannel - assertEquals(CONNECTING, getStats(channel).state); - channel.shutdownNow(); - assertEquals(SHUTDOWN, getStats(channel).state); - assertEquals(SHUTDOWN, getStats(oobChannel).state); - } - @Test public void binaryLogInstalled() throws Exception { final SettableFuture intercepted = SettableFuture.create(); diff --git a/grpclb/src/main/java/io/grpc/grpclb/GrpclbState.java b/grpclb/src/main/java/io/grpc/grpclb/GrpclbState.java index 49b74645ec8..124a03fbc01 100644 --- a/grpclb/src/main/java/io/grpc/grpclb/GrpclbState.java +++ b/grpclb/src/main/java/io/grpc/grpclb/GrpclbState.java @@ -355,11 +355,12 @@ private void useFallbackBackends() { } private void shutdownLbComm() { + shutdownLbRpc(); if (lbCommChannel != null) { - lbCommChannel.shutdown(); + // The channel should have no RPCs at this point + lbCommChannel.shutdownNow(); lbCommChannel = null; } - shutdownLbRpc(); } private void shutdownLbRpc() { From 1c80037405604caf61a707f1e95ee4ab3b6b090b Mon Sep 17 00:00:00 2001 From: Eric Anderson Date: Mon, 5 Jan 2026 09:56:50 -0800 Subject: [PATCH 2/2] Comment that the provider's priority doesn't matter --- .../src/main/java/io/grpc/internal/OobNameResolverProvider.java | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java b/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java index af94ddad396..408b92e0c84 100644 --- a/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java +++ b/core/src/main/java/io/grpc/internal/OobNameResolverProvider.java @@ -59,7 +59,7 @@ protected boolean isAvailable() { @Override protected int priority() { - return 5; + return 5; // Doesn't matter, as we expect only one provider in the registry } public void updateAddresses(List eags) {