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/*
 * 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.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static io.grpc.ClientStreamTracer.NAME_RESOLUTION_DELAYED;
import static io.grpc.ConnectivityState.CONNECTING;
import static io.grpc.ConnectivityState.IDLE;
import static io.grpc.ConnectivityState.SHUTDOWN;
import static io.grpc.ConnectivityState.TRANSIENT_FAILURE;
import static io.grpc.EquivalentAddressGroup.ATTR_AUTHORITY_OVERRIDE;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.MoreObjects;
import com.google.common.base.Stopwatch;
import com.google.common.base.Supplier;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.SettableFuture;
import io.grpc.Attributes;
import io.grpc.CallCredentials;
import io.grpc.CallOptions;
import io.grpc.Channel;
import io.grpc.ChannelCredentials;
import io.grpc.ChannelLogger;
import io.grpc.ChannelLogger.ChannelLogLevel;
import io.grpc.ClientCall;
import io.grpc.ClientInterceptor;
import io.grpc.ClientInterceptors;
import io.grpc.ClientStreamTracer;
import io.grpc.ClientTransportFilter;
import io.grpc.CompressorRegistry;
import io.grpc.ConnectivityState;
import io.grpc.ConnectivityStateInfo;
import io.grpc.Context;
import io.grpc.Deadline;
import io.grpc.DecompressorRegistry;
import io.grpc.EquivalentAddressGroup;
import io.grpc.ForwardingChannelBuilder2;
import io.grpc.ForwardingClientCall;
import io.grpc.Grpc;
import io.grpc.InternalChannelz;
import io.grpc.InternalChannelz.ChannelStats;
import io.grpc.InternalChannelz.ChannelTrace;
import io.grpc.InternalConfigSelector;
import io.grpc.InternalInstrumented;
import io.grpc.InternalLogId;
import io.grpc.InternalWithLogId;
import io.grpc.LoadBalancer;
import io.grpc.LoadBalancer.CreateSubchannelArgs;
import io.grpc.LoadBalancer.PickResult;
import io.grpc.LoadBalancer.PickSubchannelArgs;
import io.grpc.LoadBalancer.ResolvedAddresses;
import io.grpc.LoadBalancer.SubchannelPicker;
import io.grpc.LoadBalancer.SubchannelStateListener;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.Metadata;
import io.grpc.MethodDescriptor;
import io.grpc.MetricInstrumentRegistry;
import io.grpc.MetricRecorder;
import io.grpc.NameResolver;
import io.grpc.NameResolver.ConfigOrError;
import io.grpc.NameResolver.ResolutionResult;
import io.grpc.NameResolverProvider;
import io.grpc.NameResolverRegistry;
import io.grpc.ProxyDetector;
import io.grpc.Status;
import io.grpc.SynchronizationContext;
import io.grpc.SynchronizationContext.ScheduledHandle;
import io.grpc.internal.AutoConfiguredLoadBalancerFactory.AutoConfiguredLoadBalancer;
import io.grpc.internal.ClientCallImpl.ClientStreamProvider;
import io.grpc.internal.ClientTransportFactory.SwapChannelCredentialsResult;
import io.grpc.internal.ManagedChannelImplBuilder.ClientTransportFactoryBuilder;
import io.grpc.internal.ManagedChannelImplBuilder.FixedPortProvider;
import io.grpc.internal.ManagedChannelServiceConfig.MethodInfo;
import io.grpc.internal.ManagedChannelServiceConfig.ServiceConfigConvertedSelector;
import io.grpc.internal.RetriableStream.ChannelBufferMeter;
import io.grpc.internal.RetriableStream.Throttle;
import io.grpc.internal.RetryingNameResolver.ResolutionResultListener;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.Nullable;
import javax.annotation.concurrent.GuardedBy;
import javax.annotation.concurrent.ThreadSafe;

/** A communication channel for making outgoing RPCs. */
@ThreadSafe
final class ManagedChannelImpl extends ManagedChannel implements
    InternalInstrumented {
  @VisibleForTesting
  static final Logger logger = Logger.getLogger(ManagedChannelImpl.class.getName());

  static final long IDLE_TIMEOUT_MILLIS_DISABLE = -1;

  static final long SUBCHANNEL_SHUTDOWN_DELAY_SECONDS = 5;

  @VisibleForTesting
  static final Status SHUTDOWN_NOW_STATUS =
      Status.UNAVAILABLE.withDescription("Channel shutdownNow invoked");

  @VisibleForTesting
  static final Status SHUTDOWN_STATUS =
      Status.UNAVAILABLE.withDescription("Channel shutdown invoked");

  @VisibleForTesting
  static final Status SUBCHANNEL_SHUTDOWN_STATUS =
      Status.UNAVAILABLE.withDescription("Subchannel shutdown invoked");

  private static final ManagedChannelServiceConfig EMPTY_SERVICE_CONFIG =
      ManagedChannelServiceConfig.empty();
  private static final InternalConfigSelector INITIAL_PENDING_SELECTOR =
      new InternalConfigSelector() {
        @Override
        public Result selectConfig(PickSubchannelArgs args) {
          throw new IllegalStateException("Resolution is pending");
        }
      };
  private static final LoadBalancer.PickDetailsConsumer NOOP_PICK_DETAILS_CONSUMER =
      new LoadBalancer.PickDetailsConsumer() {};

  private final InternalLogId logId;
  private final String target;
  @Nullable
  private final String authorityOverride;
  private final NameResolverRegistry nameResolverRegistry;
  private final URI targetUri;
  private final NameResolverProvider nameResolverProvider;
  private final NameResolver.Args nameResolverArgs;
  private final AutoConfiguredLoadBalancerFactory loadBalancerFactory;
  private final ClientTransportFactory originalTransportFactory;
  @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;
  private final int maxTraceEvents;

  @VisibleForTesting
  final SynchronizationContext syncContext = new SynchronizationContext(
      new Thread.UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread t, Throwable e) {
          logger.log(
              Level.SEVERE,
              "[" + getLogId() + "] Uncaught exception in the SynchronizationContext. Panic!",
              e);
          panic(e);
        }
      });

  private boolean fullStreamDecompression;

  private final DecompressorRegistry decompressorRegistry;
  private final CompressorRegistry compressorRegistry;

  private final Supplier stopwatchSupplier;
  /** The timeout before entering idle mode. */
  private final long idleTimeoutMillis;

  private final ConnectivityStateManager channelStateManager = new ConnectivityStateManager();
  private final BackoffPolicy.Provider backoffPolicyProvider;

  /**
   * We delegate to this channel, so that we can have interceptors as necessary. If there aren't
   * any interceptors and the {@link io.grpc.BinaryLog} is {@code null} then this will just be a
   * {@link RealChannel}.
   */
  private final Channel interceptorChannel;

  private final List transportFilters;
  @Nullable private final String userAgent;

  // Only null after channel is terminated. Must be assigned from the syncContext.
  private NameResolver nameResolver;

  // Must be accessed from the syncContext.
  private boolean nameResolverStarted;

  // null when channel is in idle mode.  Must be assigned from syncContext.
  @Nullable
  private LbHelperImpl lbHelper;

  // Must ONLY be assigned from updateSubchannelPicker(), which is called from syncContext.
  // null if channel is in idle mode.
  @Nullable
  private volatile SubchannelPicker subchannelPicker;

  // Must be accessed from the syncContext
  private boolean panicMode;

  // Must be mutated from syncContext
  // If any monitoring hook to be added later needs to get a snapshot of this Set, we could
  // switch to a ConcurrentHashMap.
  private final Set subchannels = new HashSet<>(16, .75f);

  // Must be accessed from syncContext
  @Nullable
  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
      = new UncommittedRetriableStreamsRegistry();

  // Shutdown states.
  //
  // Channel's shutdown process:
  // 1. shutdown(): stop accepting new calls from applications
  //   1a shutdown <- true
  //   1b subchannelPicker <- null
  //   1c delayedTransport.shutdown()
  // 2. delayedTransport terminated: stop stream-creation functionality
  //   2a terminating <- true
  //   2b loadBalancer.shutdown()
  //     * LoadBalancer will shutdown subchannels and OOB channels
  //   2c loadBalancer <- null
  //   2d nameResolver.shutdown()
  //   2e nameResolver <- null
  // 3. All subchannels and OOB channels terminated: Channel considered terminated

  private final AtomicBoolean shutdown = new AtomicBoolean(false);
  // Must only be mutated and read from syncContext
  private boolean shutdownNowed;
  // Must only be mutated from syncContext
  private boolean terminating;
  // Must be mutated from syncContext
  private volatile boolean terminated;
  private final CountDownLatch terminatedLatch = new CountDownLatch(1);

  private final CallTracer.Factory callTracerFactory;
  private final CallTracer channelCallTracer;
  private final ChannelTracer channelTracer;
  private final ChannelLogger channelLogger;
  private final InternalChannelz channelz;
  private final RealChannel realChannel;
  // Must be mutated and read from syncContext
  // a flag for doing channel tracing when flipped
  private ResolutionState lastResolutionState = ResolutionState.NO_RESOLUTION;
  // Must be mutated and read from constructor or syncContext
  // used for channel tracing when value changed
  private ManagedChannelServiceConfig lastServiceConfig = EMPTY_SERVICE_CONFIG;

  @Nullable
  private final ManagedChannelServiceConfig defaultServiceConfig;
  // Must be mutated and read from constructor or syncContext
  private boolean serviceConfigUpdated = false;
  private final boolean lookUpServiceConfig;

  // One instance per channel.
  private final ChannelBufferMeter channelBufferUsed = new ChannelBufferMeter();

  private final long perRpcBufferLimit;
  private final long channelBufferLimit;

  // Temporary false flag that can skip the retry code path.
  private final boolean retryEnabled;

  private final Deadline.Ticker ticker = Deadline.getSystemTicker();

  // Called from syncContext
  private final ManagedClientTransport.Listener delayedTransportListener =
      new DelayedTransportListener();

  // Must be called from syncContext
  private void maybeShutdownNowSubchannels() {
    if (shutdownNowed) {
      for (InternalSubchannel subchannel : subchannels) {
        subchannel.shutdownNow(SHUTDOWN_NOW_STATUS);
      }
      for (OobChannel oobChannel : oobChannels) {
        oobChannel.getInternalSubchannel().shutdownNow(SHUTDOWN_NOW_STATUS);
      }
    }
  }

  // Must be accessed from syncContext
  @VisibleForTesting
  final InUseStateAggregator inUseStateAggregator = new IdleModeStateAggregator();

  @Override
  public ListenableFuture getStats() {
    final SettableFuture ret = SettableFuture.create();
    final class StatsFetcher implements Runnable {
      @Override
      public void run() {
        ChannelStats.Builder builder = new InternalChannelz.ChannelStats.Builder();
        channelCallTracer.updateBuilder(builder);
        channelTracer.updateBuilder(builder);
        builder.setTarget(target).setState(channelStateManager.getState());
        List children = new ArrayList<>();
        children.addAll(subchannels);
        children.addAll(oobChannels);
        builder.setSubchannels(children);
        ret.set(builder.build());
      }
    }

    // subchannels and oobchannels can only be accessed from syncContext
    syncContext.execute(new StatsFetcher());
    return ret;
  }

  @Override
  public InternalLogId getLogId() {
    return logId;
  }

  // Run from syncContext
  private class IdleModeTimer implements Runnable {

    @Override
    public void run() {
      // Workaround timer scheduled while in idle mode. This can happen from handleNotInUse() after
      // an explicit enterIdleMode() by the user. Protecting here as other locations are a bit too
      // subtle to change rapidly to resolve the channel panic. See #8714
      if (lbHelper == null) {
        return;
      }
      enterIdleMode();
    }
  }

  // Must be called from syncContext
  private void shutdownNameResolverAndLoadBalancer(boolean channelIsActive) {
    syncContext.throwIfNotInThisSynchronizationContext();
    if (channelIsActive) {
      checkState(nameResolverStarted, "nameResolver is not started");
      checkState(lbHelper != null, "lbHelper is null");
    }
    if (nameResolver != null) {
      nameResolver.shutdown();
      nameResolverStarted = false;
      if (channelIsActive) {
        nameResolver = getNameResolver(
            targetUri, authorityOverride, nameResolverProvider, nameResolverArgs);
      } else {
        nameResolver = null;
      }
    }
    if (lbHelper != null) {
      lbHelper.lb.shutdown();
      lbHelper = null;
    }
    subchannelPicker = null;
  }

  /**
   * Make the channel exit idle mode, if it's in it.
   *
   * 

Must be called from syncContext */ @VisibleForTesting void exitIdleMode() { syncContext.throwIfNotInThisSynchronizationContext(); if (shutdown.get() || panicMode) { return; } if (inUseStateAggregator.isInUse()) { // Cancel the timer now, so that a racing due timer will not put Channel on idleness // when the caller of exitIdleMode() is about to use the returned loadBalancer. cancelIdleTimer(false); } else { // exitIdleMode() may be called outside of inUseStateAggregator.handleNotInUse() while // isInUse() == false, in which case we still need to schedule the timer. rescheduleIdleTimer(); } if (lbHelper != null) { return; } channelLogger.log(ChannelLogLevel.INFO, "Exiting idle mode"); LbHelperImpl lbHelper = new LbHelperImpl(); lbHelper.lb = loadBalancerFactory.newLoadBalancer(lbHelper); // Delay setting lbHelper until fully initialized, since loadBalancerFactory is user code and // may throw. We don't want to confuse our state, even if we will enter panic mode. this.lbHelper = lbHelper; channelStateManager.gotoState(CONNECTING); NameResolverListener listener = new NameResolverListener(lbHelper, nameResolver); nameResolver.start(listener); nameResolverStarted = true; } // Must be run from syncContext private void enterIdleMode() { // nameResolver and loadBalancer are guaranteed to be non-null. If any of them were null, // either the idleModeTimer ran twice without exiting the idle mode, or the task in shutdown() // did not cancel idleModeTimer, or enterIdle() ran while shutdown or in idle, all of // which are bugs. shutdownNameResolverAndLoadBalancer(true); delayedTransport.reprocess(null); channelLogger.log(ChannelLogLevel.INFO, "Entering IDLE state"); channelStateManager.gotoState(IDLE); // If the inUseStateAggregator still considers pending calls to be queued up or the delayed // transport to be holding some we need to exit idle mode to give these calls a chance to // be processed. if (inUseStateAggregator.anyObjectInUse(pendingCallsInUseObject, delayedTransport)) { exitIdleMode(); } } // Must be run from syncContext private void cancelIdleTimer(boolean permanent) { idleTimer.cancel(permanent); } // Always run from syncContext private void rescheduleIdleTimer() { if (idleTimeoutMillis == IDLE_TIMEOUT_MILLIS_DISABLE) { return; } idleTimer.reschedule(idleTimeoutMillis, TimeUnit.MILLISECONDS); } /** * Force name resolution refresh to happen immediately. Must be run * from syncContext. */ private void refreshNameResolution() { syncContext.throwIfNotInThisSynchronizationContext(); if (nameResolverStarted) { nameResolver.refresh(); } } private final class ChannelStreamProvider implements ClientStreamProvider { volatile Throttle throttle; @Override public ClientStream newStream( final MethodDescriptor method, final CallOptions callOptions, final Metadata headers, final Context context) { // There is no need to reschedule the idle timer here. If the channel isn't shut down, either // the delayed transport or a real transport will go in-use and cancel the idle timer. if (!retryEnabled) { ClientStreamTracer[] tracers = GrpcUtil.getClientStreamTracers( callOptions, headers, 0, /* isTransparentRetry= */ false); Context origContext = context.attach(); try { return delayedTransport.newStream(method, headers, callOptions, tracers); } finally { context.detach(origContext); } } else { MethodInfo methodInfo = callOptions.getOption(MethodInfo.KEY); final RetryPolicy retryPolicy = methodInfo == null ? null : methodInfo.retryPolicy; final HedgingPolicy hedgingPolicy = methodInfo == null ? null : methodInfo.hedgingPolicy; final class RetryStream extends RetriableStream { @SuppressWarnings("unchecked") RetryStream() { super( (MethodDescriptor) method, headers, channelBufferUsed, perRpcBufferLimit, channelBufferLimit, getCallExecutor(callOptions), transportFactory.getScheduledExecutorService(), retryPolicy, hedgingPolicy, throttle); } @Override Status prestart() { return uncommittedRetriableStreamsRegistry.add(this); } @Override void postCommit() { uncommittedRetriableStreamsRegistry.remove(this); } @Override ClientStream newSubstream( Metadata newHeaders, ClientStreamTracer.Factory factory, int previousAttempts, boolean isTransparentRetry) { CallOptions newOptions = callOptions.withStreamTracerFactory(factory); ClientStreamTracer[] tracers = GrpcUtil.getClientStreamTracers( newOptions, newHeaders, previousAttempts, isTransparentRetry); Context origContext = context.attach(); try { return delayedTransport.newStream(method, newHeaders, newOptions, tracers); } finally { context.detach(origContext); } } } return new RetryStream<>(); } } } private final ChannelStreamProvider transportProvider = new ChannelStreamProvider(); private final Rescheduler idleTimer; private final MetricRecorder metricRecorder; ManagedChannelImpl( ManagedChannelImplBuilder builder, ClientTransportFactory clientTransportFactory, URI targetUri, NameResolverProvider nameResolverProvider, BackoffPolicy.Provider backoffPolicyProvider, ObjectPool balancerRpcExecutorPool, Supplier stopwatchSupplier, List interceptors, final TimeProvider timeProvider) { this.target = checkNotNull(builder.target, "target"); this.logId = InternalLogId.allocate("Channel", target); this.timeProvider = checkNotNull(timeProvider, "timeProvider"); this.executorPool = checkNotNull(builder.executorPool, "executorPool"); this.executor = checkNotNull(executorPool.getObject(), "executor"); this.originalChannelCreds = builder.channelCredentials; this.originalTransportFactory = clientTransportFactory; this.offloadExecutorHolder = 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; channelTracer = new ChannelTracer( logId, builder.maxTraceEvents, timeProvider.currentTimeNanos(), "Channel for '" + target + "'"); channelLogger = new ChannelLoggerImpl(channelTracer, timeProvider); ProxyDetector proxyDetector = builder.proxyDetector != null ? builder.proxyDetector : GrpcUtil.DEFAULT_PROXY_DETECTOR; this.retryEnabled = builder.retryEnabled; this.loadBalancerFactory = new AutoConfiguredLoadBalancerFactory(builder.defaultLbPolicy); this.nameResolverRegistry = builder.nameResolverRegistry; this.targetUri = checkNotNull(targetUri, "targetUri"); this.nameResolverProvider = checkNotNull(nameResolverProvider, "nameResolverProvider"); ScParser serviceConfigParser = new ScParser( retryEnabled, builder.maxRetryAttempts, builder.maxHedgedAttempts, loadBalancerFactory); this.authorityOverride = builder.authorityOverride; this.nameResolverArgs = NameResolver.Args.newBuilder() .setDefaultPort(builder.getDefaultPort()) .setProxyDetector(proxyDetector) .setSynchronizationContext(syncContext) .setScheduledExecutorService(scheduledExecutor) .setServiceConfigParser(serviceConfigParser) .setChannelLogger(channelLogger) .setOffloadExecutor(this.offloadExecutorHolder) .setOverrideAuthority(this.authorityOverride) .build(); this.nameResolver = getNameResolver( targetUri, authorityOverride, nameResolverProvider, nameResolverArgs); this.balancerRpcExecutorPool = checkNotNull(balancerRpcExecutorPool, "balancerRpcExecutorPool"); this.balancerRpcExecutorHolder = new ExecutorHolder(balancerRpcExecutorPool); this.delayedTransport = new DelayedClientTransport(this.executor, this.syncContext); this.delayedTransport.start(delayedTransportListener); this.backoffPolicyProvider = backoffPolicyProvider; if (builder.defaultServiceConfig != null) { ConfigOrError parsedDefaultServiceConfig = serviceConfigParser.parseServiceConfig(builder.defaultServiceConfig); checkState( parsedDefaultServiceConfig.getError() == null, "Default config is invalid: %s", parsedDefaultServiceConfig.getError()); this.defaultServiceConfig = (ManagedChannelServiceConfig) parsedDefaultServiceConfig.getConfig(); this.transportProvider.throttle = this.defaultServiceConfig.getRetryThrottling(); } else { this.defaultServiceConfig = null; } this.lookUpServiceConfig = builder.lookUpServiceConfig; realChannel = new RealChannel(nameResolver.getServiceAuthority()); Channel channel = realChannel; if (builder.binlog != null) { channel = builder.binlog.wrapChannel(channel); } this.interceptorChannel = ClientInterceptors.intercept(channel, interceptors); this.transportFilters = new ArrayList<>(builder.transportFilters); this.stopwatchSupplier = checkNotNull(stopwatchSupplier, "stopwatchSupplier"); if (builder.idleTimeoutMillis == IDLE_TIMEOUT_MILLIS_DISABLE) { this.idleTimeoutMillis = builder.idleTimeoutMillis; } else { checkArgument( builder.idleTimeoutMillis >= ManagedChannelImplBuilder.IDLE_MODE_MIN_TIMEOUT_MILLIS, "invalid idleTimeoutMillis %s", builder.idleTimeoutMillis); this.idleTimeoutMillis = builder.idleTimeoutMillis; } idleTimer = new Rescheduler( new IdleModeTimer(), syncContext, transportFactory.getScheduledExecutorService(), stopwatchSupplier.get()); this.fullStreamDecompression = builder.fullStreamDecompression; this.decompressorRegistry = checkNotNull(builder.decompressorRegistry, "decompressorRegistry"); this.compressorRegistry = checkNotNull(builder.compressorRegistry, "compressorRegistry"); this.userAgent = builder.userAgent; this.channelBufferLimit = builder.retryBufferSize; this.perRpcBufferLimit = builder.perRpcBufferLimit; final class ChannelCallTracerFactory implements CallTracer.Factory { @Override public CallTracer create() { return new CallTracer(timeProvider); } } this.callTracerFactory = new ChannelCallTracerFactory(); channelCallTracer = callTracerFactory.create(); this.channelz = checkNotNull(builder.channelz); channelz.addRootChannel(this); if (!lookUpServiceConfig) { if (defaultServiceConfig != null) { channelLogger.log( ChannelLogLevel.INFO, "Service config look-up disabled, using default service config"); } serviceConfigUpdated = true; } this.metricRecorder = new MetricRecorderImpl(builder.metricSinks, MetricInstrumentRegistry.getDefaultRegistry()); } @VisibleForTesting static NameResolver getNameResolver( URI targetUri, @Nullable final String overrideAuthority, NameResolverProvider provider, NameResolver.Args nameResolverArgs) { NameResolver resolver = provider.newNameResolver(targetUri, nameResolverArgs); if (resolver == null) { throw new IllegalArgumentException("cannot create a NameResolver for " + targetUri); } // We wrap the name resolver in a RetryingNameResolver to give it the ability to retry failures. // TODO: After a transition period, all NameResolver implementations that need retry should use // RetryingNameResolver directly and this step can be removed. NameResolver usedNameResolver = new RetryingNameResolver(resolver, new BackoffPolicyRetryScheduler(new ExponentialBackoffPolicy.Provider(), nameResolverArgs.getScheduledExecutorService(), nameResolverArgs.getSynchronizationContext()), nameResolverArgs.getSynchronizationContext()); if (overrideAuthority == null) { return usedNameResolver; } return new ForwardingNameResolver(usedNameResolver) { @Override public String getServiceAuthority() { return overrideAuthority; } }; } @VisibleForTesting InternalConfigSelector getConfigSelector() { return realChannel.configSelector.get(); } @VisibleForTesting boolean hasThrottle() { return this.transportProvider.throttle != null; } /** * Initiates an orderly shutdown in which preexisting calls continue but new calls are immediately * cancelled. */ @Override public ManagedChannelImpl shutdown() { channelLogger.log(ChannelLogLevel.DEBUG, "shutdown() called"); if (!shutdown.compareAndSet(false, true)) { return this; } final class Shutdown implements Runnable { @Override public void run() { channelLogger.log(ChannelLogLevel.INFO, "Entering SHUTDOWN state"); channelStateManager.gotoState(SHUTDOWN); } } syncContext.execute(new Shutdown()); realChannel.shutdown(); final class CancelIdleTimer implements Runnable { @Override public void run() { cancelIdleTimer(/* permanent= */ true); } } syncContext.execute(new CancelIdleTimer()); return this; } /** * Initiates a forceful shutdown in which preexisting and new calls are cancelled. Although * forceful, the shutdown process is still not instantaneous; {@link #isTerminated()} will likely * return {@code false} immediately after this method returns. */ @Override public ManagedChannelImpl shutdownNow() { channelLogger.log(ChannelLogLevel.DEBUG, "shutdownNow() called"); shutdown(); realChannel.shutdownNow(); final class ShutdownNow implements Runnable { @Override public void run() { if (shutdownNowed) { return; } shutdownNowed = true; maybeShutdownNowSubchannels(); } } syncContext.execute(new ShutdownNow()); return this; } // Called from syncContext @VisibleForTesting void panic(final Throwable t) { if (panicMode) { // Preserve the first panic information return; } panicMode = true; cancelIdleTimer(/* permanent= */ true); shutdownNameResolverAndLoadBalancer(false); final class PanicSubchannelPicker extends SubchannelPicker { private final PickResult panicPickResult = PickResult.withDrop( Status.INTERNAL.withDescription("Panic! This is a bug!").withCause(t)); @Override public PickResult pickSubchannel(PickSubchannelArgs args) { return panicPickResult; } @Override public String toString() { return MoreObjects.toStringHelper(PanicSubchannelPicker.class) .add("panicPickResult", panicPickResult) .toString(); } } updateSubchannelPicker(new PanicSubchannelPicker()); realChannel.updateConfigSelector(null); channelLogger.log(ChannelLogLevel.ERROR, "PANIC! Entering TRANSIENT_FAILURE"); channelStateManager.gotoState(TRANSIENT_FAILURE); } @VisibleForTesting boolean isInPanicMode() { return panicMode; } // Called from syncContext private void updateSubchannelPicker(SubchannelPicker newPicker) { subchannelPicker = newPicker; delayedTransport.reprocess(newPicker); } @Override public boolean isShutdown() { return shutdown.get(); } @Override public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException { return terminatedLatch.await(timeout, unit); } @Override public boolean isTerminated() { return terminated; } /* * Creates a new outgoing call on the channel. */ @Override public ClientCall newCall(MethodDescriptor method, CallOptions callOptions) { return interceptorChannel.newCall(method, callOptions); } @Override public String authority() { return interceptorChannel.authority(); } private Executor getCallExecutor(CallOptions callOptions) { Executor executor = callOptions.getExecutor(); if (executor == null) { executor = this.executor; } return executor; } private class RealChannel extends Channel { // Reference to null if no config selector is available from resolution result // Reference must be set() from syncContext private final AtomicReference configSelector = new AtomicReference<>(INITIAL_PENDING_SELECTOR); // Set when the NameResolver is initially created. When we create a new NameResolver for the // same target, the new instance must have the same value. private final String authority; private final Channel clientCallImplChannel = new Channel() { @Override public ClientCall newCall( MethodDescriptor method, CallOptions callOptions) { return new ClientCallImpl<>( method, getCallExecutor(callOptions), callOptions, transportProvider, terminated ? null : transportFactory.getScheduledExecutorService(), channelCallTracer, null) .setFullStreamDecompression(fullStreamDecompression) .setDecompressorRegistry(decompressorRegistry) .setCompressorRegistry(compressorRegistry); } @Override public String authority() { return authority; } }; private RealChannel(String authority) { this.authority = checkNotNull(authority, "authority"); } @Override public ClientCall newCall( MethodDescriptor method, CallOptions callOptions) { if (configSelector.get() != INITIAL_PENDING_SELECTOR) { return newClientCall(method, callOptions); } syncContext.execute(new Runnable() { @Override public void run() { exitIdleMode(); } }); if (configSelector.get() != INITIAL_PENDING_SELECTOR) { // This is an optimization for the case (typically with InProcessTransport) when name // resolution result is immediately available at this point. Otherwise, some users' // tests might observe slight behavior difference from earlier grpc versions. return newClientCall(method, callOptions); } if (shutdown.get()) { // Return a failing ClientCall. return new ClientCall() { @Override public void start(Listener responseListener, Metadata headers) { responseListener.onClose(SHUTDOWN_STATUS, new Metadata()); } @Override public void request(int numMessages) {} @Override public void cancel(@Nullable String message, @Nullable Throwable cause) {} @Override public void halfClose() {} @Override public void sendMessage(ReqT message) {} }; } Context context = Context.current(); final PendingCall pendingCall = new PendingCall<>(context, method, callOptions); syncContext.execute(new Runnable() { @Override public void run() { if (configSelector.get() == INITIAL_PENDING_SELECTOR) { if (pendingCalls == null) { pendingCalls = new LinkedHashSet<>(); inUseStateAggregator.updateObjectInUse(pendingCallsInUseObject, true); } pendingCalls.add(pendingCall); } else { pendingCall.reprocess(); } } }); return pendingCall; } // Must run in SynchronizationContext. void updateConfigSelector(@Nullable InternalConfigSelector config) { InternalConfigSelector prevConfig = configSelector.get(); configSelector.set(config); if (prevConfig == INITIAL_PENDING_SELECTOR && pendingCalls != null) { for (RealChannel.PendingCall pendingCall : pendingCalls) { pendingCall.reprocess(); } } } // Must run in SynchronizationContext. void onConfigError() { if (configSelector.get() == INITIAL_PENDING_SELECTOR) { updateConfigSelector(null); } } void shutdown() { final class RealChannelShutdown implements Runnable { @Override public void run() { if (pendingCalls == null) { if (configSelector.get() == INITIAL_PENDING_SELECTOR) { configSelector.set(null); } uncommittedRetriableStreamsRegistry.onShutdown(SHUTDOWN_STATUS); } } } syncContext.execute(new RealChannelShutdown()); } void shutdownNow() { final class RealChannelShutdownNow implements Runnable { @Override public void run() { if (configSelector.get() == INITIAL_PENDING_SELECTOR) { configSelector.set(null); } if (pendingCalls != null) { for (RealChannel.PendingCall pendingCall : pendingCalls) { pendingCall.cancel("Channel is forcefully shutdown", null); } } uncommittedRetriableStreamsRegistry.onShutdownNow(SHUTDOWN_NOW_STATUS); } } syncContext.execute(new RealChannelShutdownNow()); } @Override public String authority() { return authority; } private final class PendingCall extends DelayedClientCall { final Context context; final MethodDescriptor method; final CallOptions callOptions; private final long callCreationTime; PendingCall( Context context, MethodDescriptor method, CallOptions callOptions) { super(getCallExecutor(callOptions), scheduledExecutor, callOptions.getDeadline()); this.context = context; this.method = method; this.callOptions = callOptions; this.callCreationTime = ticker.nanoTime(); } /** Called when it's ready to create a real call and reprocess the pending call. */ void reprocess() { ClientCall realCall; Context previous = context.attach(); try { CallOptions delayResolutionOption = callOptions.withOption(NAME_RESOLUTION_DELAYED, ticker.nanoTime() - callCreationTime); realCall = newClientCall(method, delayResolutionOption); } finally { context.detach(previous); } Runnable toRun = setCall(realCall); if (toRun == null) { syncContext.execute(new PendingCallRemoval()); } else { getCallExecutor(callOptions).execute(new Runnable() { @Override public void run() { toRun.run(); syncContext.execute(new PendingCallRemoval()); } }); } } @Override protected void callCancelled() { super.callCancelled(); syncContext.execute(new PendingCallRemoval()); } final class PendingCallRemoval implements Runnable { @Override public void run() { if (pendingCalls != null) { pendingCalls.remove(PendingCall.this); if (pendingCalls.isEmpty()) { inUseStateAggregator.updateObjectInUse(pendingCallsInUseObject, false); pendingCalls = null; if (shutdown.get()) { uncommittedRetriableStreamsRegistry.onShutdown(SHUTDOWN_STATUS); } } } } } } private ClientCall newClientCall( MethodDescriptor method, CallOptions callOptions) { InternalConfigSelector selector = configSelector.get(); if (selector == null) { return clientCallImplChannel.newCall(method, callOptions); } if (selector instanceof ServiceConfigConvertedSelector) { MethodInfo methodInfo = ((ServiceConfigConvertedSelector) selector).config.getMethodConfig(method); if (methodInfo != null) { callOptions = callOptions.withOption(MethodInfo.KEY, methodInfo); } return clientCallImplChannel.newCall(method, callOptions); } return new ConfigSelectingClientCall<>( selector, clientCallImplChannel, executor, method, callOptions); } } /** * A client call for a given channel that applies a given config selector when it starts. */ static final class ConfigSelectingClientCall extends ForwardingClientCall { private final InternalConfigSelector configSelector; private final Channel channel; private final Executor callExecutor; private final MethodDescriptor method; private final Context context; private CallOptions callOptions; private ClientCall delegate; ConfigSelectingClientCall( InternalConfigSelector configSelector, Channel channel, Executor channelExecutor, MethodDescriptor method, CallOptions callOptions) { this.configSelector = configSelector; this.channel = channel; this.method = method; this.callExecutor = callOptions.getExecutor() == null ? channelExecutor : callOptions.getExecutor(); this.callOptions = callOptions.withExecutor(callExecutor); this.context = Context.current(); } @Override protected ClientCall delegate() { return delegate; } @SuppressWarnings("unchecked") @Override public void start(Listener observer, Metadata headers) { PickSubchannelArgs args = new PickSubchannelArgsImpl(method, headers, callOptions, NOOP_PICK_DETAILS_CONSUMER); InternalConfigSelector.Result result = configSelector.selectConfig(args); Status status = result.getStatus(); if (!status.isOk()) { executeCloseObserverInContext(observer, GrpcUtil.replaceInappropriateControlPlaneStatus(status)); delegate = (ClientCall) NOOP_CALL; return; } ClientInterceptor interceptor = result.getInterceptor(); ManagedChannelServiceConfig config = (ManagedChannelServiceConfig) result.getConfig(); MethodInfo methodInfo = config.getMethodConfig(method); if (methodInfo != null) { callOptions = callOptions.withOption(MethodInfo.KEY, methodInfo); } if (interceptor != null) { delegate = interceptor.interceptCall(method, callOptions, channel); } else { delegate = channel.newCall(method, callOptions); } delegate.start(observer, headers); } private void executeCloseObserverInContext( final Listener observer, final Status status) { class CloseInContext extends ContextRunnable { CloseInContext() { super(context); } @Override public void runInContext() { observer.onClose(status, new Metadata()); } } callExecutor.execute(new CloseInContext()); } @Override public void cancel(@Nullable String message, @Nullable Throwable cause) { if (delegate != null) { delegate.cancel(message, cause); } } } private static final ClientCall NOOP_CALL = new ClientCall() { @Override public void start(Listener responseListener, Metadata headers) {} @Override public void request(int numMessages) {} @Override public void cancel(String message, Throwable cause) {} @Override public void halfClose() {} @Override public void sendMessage(Object message) {} // Always returns {@code false}, since this is only used when the startup of the call fails. @Override public boolean isReady() { return false; } }; /** * Terminate the channel if termination conditions are met. */ // Must be run from syncContext private void maybeTerminateChannel() { if (terminated) { return; } if (shutdown.get() && subchannels.isEmpty() && oobChannels.isEmpty()) { channelLogger.log(ChannelLogLevel.INFO, "Terminated"); channelz.removeRootChannel(this); executorPool.returnObject(executor); balancerRpcExecutorHolder.release(); offloadExecutorHolder.release(); // Release the transport factory so that it can deallocate any resources. transportFactory.close(); terminated = true; terminatedLatch.countDown(); } } // Must be called from syncContext private void handleInternalSubchannelState(ConnectivityStateInfo newState) { if (newState.getState() == TRANSIENT_FAILURE || newState.getState() == IDLE) { refreshNameResolution(); } } @Override @SuppressWarnings("deprecation") public ConnectivityState getState(boolean requestConnection) { ConnectivityState savedChannelState = channelStateManager.getState(); if (requestConnection && savedChannelState == IDLE) { final class RequestConnection implements Runnable { @Override public void run() { exitIdleMode(); if (subchannelPicker != null) { subchannelPicker.requestConnection(); } if (lbHelper != null) { lbHelper.lb.requestConnection(); } } } syncContext.execute(new RequestConnection()); } return savedChannelState; } @Override public void notifyWhenStateChanged(final ConnectivityState source, final Runnable callback) { final class NotifyStateChanged implements Runnable { @Override public void run() { channelStateManager.notifyWhenStateChanged(callback, executor, source); } } syncContext.execute(new NotifyStateChanged()); } @Override public void resetConnectBackoff() { final class ResetConnectBackoff implements Runnable { @Override public void run() { if (shutdown.get()) { return; } if (nameResolverStarted) { refreshNameResolution(); } for (InternalSubchannel subchannel : subchannels) { subchannel.resetConnectBackoff(); } for (OobChannel oobChannel : oobChannels) { oobChannel.resetConnectBackoff(); } } } syncContext.execute(new ResetConnectBackoff()); } @Override public void enterIdle() { final class PrepareToLoseNetworkRunnable implements Runnable { @Override public void run() { if (shutdown.get() || lbHelper == null) { return; } cancelIdleTimer(/* permanent= */ false); enterIdleMode(); } } syncContext.execute(new PrepareToLoseNetworkRunnable()); } /** * A registry that prevents channel shutdown from killing existing retry attempts that are in * backoff. */ private final class UncommittedRetriableStreamsRegistry { // TODO(zdapeng): This means we would acquire a lock for each new retry-able stream, // it's worthwhile to look for a lock-free approach. final Object lock = new Object(); @GuardedBy("lock") Collection uncommittedRetriableStreams = new HashSet<>(); @GuardedBy("lock") Status shutdownStatus; void onShutdown(Status reason) { boolean shouldShutdownDelayedTransport = false; synchronized (lock) { if (shutdownStatus != null) { return; } shutdownStatus = reason; // Keep the delayedTransport open until there is no more uncommitted streams, b/c those // retriable streams, which may be in backoff and not using any transport, are already // started RPCs. if (uncommittedRetriableStreams.isEmpty()) { shouldShutdownDelayedTransport = true; } } if (shouldShutdownDelayedTransport) { delayedTransport.shutdown(reason); } } void onShutdownNow(Status reason) { onShutdown(reason); Collection streams; synchronized (lock) { streams = new ArrayList<>(uncommittedRetriableStreams); } for (ClientStream stream : streams) { stream.cancel(reason); } delayedTransport.shutdownNow(reason); } /** * Registers a RetriableStream and return null if not shutdown, otherwise just returns the * shutdown Status. */ @Nullable Status add(RetriableStream retriableStream) { synchronized (lock) { if (shutdownStatus != null) { return shutdownStatus; } uncommittedRetriableStreams.add(retriableStream); return null; } } void remove(RetriableStream retriableStream) { Status shutdownStatusCopy = null; synchronized (lock) { uncommittedRetriableStreams.remove(retriableStream); if (uncommittedRetriableStreams.isEmpty()) { shutdownStatusCopy = shutdownStatus; // Because retriable transport is long-lived, we take this opportunity to down-size the // hashmap. uncommittedRetriableStreams = new HashSet<>(); } } if (shutdownStatusCopy != null) { delayedTransport.shutdown(shutdownStatusCopy); } } } private final class LbHelperImpl extends LoadBalancer.Helper { AutoConfiguredLoadBalancer lb; @Override public AbstractSubchannel createSubchannel(CreateSubchannelArgs args) { syncContext.throwIfNotInThisSynchronizationContext(); // No new subchannel should be created after load balancer has been shutdown. checkState(!terminating, "Channel is being terminated"); return new SubchannelImpl(args); } @Override public void updateBalancingState( final ConnectivityState newState, final SubchannelPicker newPicker) { syncContext.throwIfNotInThisSynchronizationContext(); checkNotNull(newState, "newState"); checkNotNull(newPicker, "newPicker"); final class UpdateBalancingState implements Runnable { @Override public void run() { if (LbHelperImpl.this != lbHelper) { return; } updateSubchannelPicker(newPicker); // It's not appropriate to report SHUTDOWN state from lb. // Ignore the case of newState == SHUTDOWN for now. if (newState != SHUTDOWN) { channelLogger.log( ChannelLogLevel.INFO, "Entering {0} state with picker: {1}", newState, newPicker); channelStateManager.gotoState(newState); } } } syncContext.execute(new UpdateBalancingState()); } @Override public void refreshNameResolution() { syncContext.throwIfNotInThisSynchronizationContext(); final class LoadBalancerRefreshNameResolution implements Runnable { @Override public void run() { ManagedChannelImpl.this.refreshNameResolution(); } } syncContext.execute(new LoadBalancerRefreshNameResolution()); } @Override public ManagedChannel createOobChannel(EquivalentAddressGroup addressGroup, String authority) { return createOobChannel(Collections.singletonList(addressGroup), authority); } @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( addressGroup, authority, userAgent, backoffPolicyProvider, oobTransportFactory, oobTransportFactory.getScheduledExecutorService(), stopwatchSupplier, syncContext, // All callback methods are run from syncContext new ManagedOobChannelCallback(), channelz, callTracerFactory.create(), subchannelTracer, subchannelLogId, subchannelLogger, transportFilters); 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; } @Deprecated @Override public ManagedChannelBuilder createResolvingOobChannelBuilder(String target) { return createResolvingOobChannelBuilder(target, new DefaultChannelCreds()) // Override authority to keep the old behavior. // createResolvingOobChannelBuilder(String target) will be deleted soon. .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) { checkNotNull(channelCreds, "channelCreds"); final class ResolvingOobChannelBuilder extends ForwardingChannelBuilder2 { final ManagedChannelBuilder delegate; ResolvingOobChannelBuilder() { final ClientTransportFactory transportFactory; CallCredentials callCredentials; if (channelCreds instanceof DefaultChannelCreds) { transportFactory = originalTransportFactory; callCredentials = null; } else { SwapChannelCredentialsResult swapResult = originalTransportFactory.swapChannelCredentials(channelCreds); if (swapResult == null) { delegate = Grpc.newChannelBuilder(target, channelCreds); return; } else { transportFactory = swapResult.transportFactory; callCredentials = swapResult.callCredentials; } } ClientTransportFactoryBuilder transportFactoryBuilder = new ClientTransportFactoryBuilder() { @Override public ClientTransportFactory buildClientTransportFactory() { return transportFactory; } }; delegate = new ManagedChannelImplBuilder( target, channelCreds, callCredentials, transportFactoryBuilder, new FixedPortProvider(nameResolverArgs.getDefaultPort())) .nameResolverRegistry(nameResolverRegistry); } @Override protected ManagedChannelBuilder delegate() { return delegate; } } checkState(!terminated, "Channel is terminated"); @SuppressWarnings("deprecation") ResolvingOobChannelBuilder builder = new ResolvingOobChannelBuilder(); return builder // TODO(zdapeng): executors should not outlive the parent channel. .executor(executor) .offloadExecutor(offloadExecutorHolder.getExecutor()) .maxTraceEvents(maxTraceEvents) .proxyDetector(nameResolverArgs.getProxyDetector()) .userAgent(userAgent); } @Override public ChannelCredentials getUnsafeChannelCredentials() { if (originalChannelCreds == null) { return new DefaultChannelCreds(); } return originalChannelCreds; } @Override public void updateOobChannelAddresses(ManagedChannel channel, EquivalentAddressGroup eag) { updateOobChannelAddresses(channel, Collections.singletonList(eag)); } @Override public void updateOobChannelAddresses(ManagedChannel channel, List eag) { checkArgument(channel instanceof OobChannel, "channel must have been returned from createOobChannel"); ((OobChannel) channel).updateAddresses(eag); } @Override public String getAuthority() { return ManagedChannelImpl.this.authority(); } @Override public String getChannelTarget() { return targetUri.toString(); } @Override public SynchronizationContext getSynchronizationContext() { return syncContext; } @Override public ScheduledExecutorService getScheduledExecutorService() { return scheduledExecutor; } @Override public ChannelLogger getChannelLogger() { return channelLogger; } @Override public NameResolver.Args getNameResolverArgs() { return nameResolverArgs; } @Override public NameResolverRegistry getNameResolverRegistry() { return nameResolverRegistry; } @Override public MetricRecorder getMetricRecorder() { return metricRecorder; } /** * A placeholder for channel creds if user did not specify channel creds for the channel. */ // TODO(zdapeng): get rid of this class and let all ChannelBuilders always provide a non-null // channel creds. final class DefaultChannelCreds extends ChannelCredentials { @Override public ChannelCredentials withoutBearerTokens() { return this; } } } final class NameResolverListener extends NameResolver.Listener2 { final LbHelperImpl helper; final NameResolver resolver; NameResolverListener(LbHelperImpl helperImpl, NameResolver resolver) { this.helper = checkNotNull(helperImpl, "helperImpl"); this.resolver = checkNotNull(resolver, "resolver"); } @Override public void onResult(final ResolutionResult resolutionResult) { final class NamesResolved implements Runnable { @Override public void run() { Status status = onResult2(resolutionResult); ResolutionResultListener resolutionResultListener = resolutionResult.getAttributes() .get(RetryingNameResolver.RESOLUTION_RESULT_LISTENER_KEY); resolutionResultListener.resolutionAttempted(status); } } syncContext.execute(new NamesResolved()); } @SuppressWarnings("ReferenceEquality") @Override public Status onResult2(final ResolutionResult resolutionResult) { syncContext.throwIfNotInThisSynchronizationContext(); if (ManagedChannelImpl.this.nameResolver != resolver) { return Status.OK; } List servers = resolutionResult.getAddresses(); channelLogger.log( ChannelLogLevel.DEBUG, "Resolved address: {0}, config={1}", servers, resolutionResult.getAttributes()); if (lastResolutionState != ResolutionState.SUCCESS) { channelLogger.log(ChannelLogLevel.INFO, "Address resolved: {0}", servers); lastResolutionState = ResolutionState.SUCCESS; } ConfigOrError configOrError = resolutionResult.getServiceConfig(); InternalConfigSelector resolvedConfigSelector = resolutionResult.getAttributes().get(InternalConfigSelector.KEY); ManagedChannelServiceConfig validServiceConfig = configOrError != null && configOrError.getConfig() != null ? (ManagedChannelServiceConfig) configOrError.getConfig() : null; Status serviceConfigError = configOrError != null ? configOrError.getError() : null; ManagedChannelServiceConfig effectiveServiceConfig; if (!lookUpServiceConfig) { if (validServiceConfig != null) { channelLogger.log( ChannelLogLevel.INFO, "Service config from name resolver discarded by channel settings"); } effectiveServiceConfig = defaultServiceConfig == null ? EMPTY_SERVICE_CONFIG : defaultServiceConfig; if (resolvedConfigSelector != null) { channelLogger.log( ChannelLogLevel.INFO, "Config selector from name resolver discarded by channel settings"); } realChannel.updateConfigSelector(effectiveServiceConfig.getDefaultConfigSelector()); } else { // Try to use config if returned from name resolver // Otherwise, try to use the default config if available if (validServiceConfig != null) { effectiveServiceConfig = validServiceConfig; if (resolvedConfigSelector != null) { realChannel.updateConfigSelector(resolvedConfigSelector); if (effectiveServiceConfig.getDefaultConfigSelector() != null) { channelLogger.log( ChannelLogLevel.DEBUG, "Method configs in service config will be discarded due to presence of" + "config-selector"); } } else { realChannel.updateConfigSelector(effectiveServiceConfig.getDefaultConfigSelector()); } } else if (defaultServiceConfig != null) { effectiveServiceConfig = defaultServiceConfig; realChannel.updateConfigSelector(effectiveServiceConfig.getDefaultConfigSelector()); channelLogger.log( ChannelLogLevel.INFO, "Received no service config, using default service config"); } else if (serviceConfigError != null) { if (!serviceConfigUpdated) { // First DNS lookup has invalid service config, and cannot fall back to default channelLogger.log( ChannelLogLevel.INFO, "Fallback to error due to invalid first service config without default config"); // This error could be an "inappropriate" control plane error that should not bleed // through to client code using gRPC. We let them flow through here to the LB as // we later check for these error codes when investigating pick results in // GrpcUtil.getTransportFromPickResult(). onError(configOrError.getError()); return configOrError.getError(); } else { effectiveServiceConfig = lastServiceConfig; } } else { effectiveServiceConfig = EMPTY_SERVICE_CONFIG; realChannel.updateConfigSelector(null); } if (!effectiveServiceConfig.equals(lastServiceConfig)) { channelLogger.log( ChannelLogLevel.INFO, "Service config changed{0}", effectiveServiceConfig == EMPTY_SERVICE_CONFIG ? " to empty" : ""); lastServiceConfig = effectiveServiceConfig; transportProvider.throttle = effectiveServiceConfig.getRetryThrottling(); } try { // TODO(creamsoup): when `servers` is empty and lastResolutionStateCopy == SUCCESS // and lbNeedAddress, it shouldn't call the handleServiceConfigUpdate. But, // lbNeedAddress is not deterministic serviceConfigUpdated = true; } catch (RuntimeException re) { logger.log( Level.WARNING, "[" + getLogId() + "] Unexpected exception from parsing service config", re); } } Attributes effectiveAttrs = resolutionResult.getAttributes(); // Call LB only if it's not shutdown. If LB is shutdown, lbHelper won't match. if (NameResolverListener.this.helper == ManagedChannelImpl.this.lbHelper) { Attributes.Builder attrBuilder = effectiveAttrs.toBuilder().discard(InternalConfigSelector.KEY); Map healthCheckingConfig = effectiveServiceConfig.getHealthCheckingConfig(); if (healthCheckingConfig != null) { attrBuilder .set(LoadBalancer.ATTR_HEALTH_CHECKING_CONFIG, healthCheckingConfig) .build(); } Attributes attributes = attrBuilder.build(); return helper.lb.tryAcceptResolvedAddresses( ResolvedAddresses.newBuilder() .setAddresses(servers) .setAttributes(attributes) .setLoadBalancingPolicyConfig(effectiveServiceConfig.getLoadBalancingConfig()) .build()); } return Status.OK; } @Override public void onError(final Status error) { checkArgument(!error.isOk(), "the error status must not be OK"); final class NameResolverErrorHandler implements Runnable { @Override public void run() { handleErrorInSyncContext(error); } } syncContext.execute(new NameResolverErrorHandler()); } private void handleErrorInSyncContext(Status error) { logger.log(Level.WARNING, "[{0}] Failed to resolve name. status={1}", new Object[] {getLogId(), error}); realChannel.onConfigError(); if (lastResolutionState != ResolutionState.ERROR) { channelLogger.log(ChannelLogLevel.WARNING, "Failed to resolve name: {0}", error); lastResolutionState = ResolutionState.ERROR; } // Call LB only if it's not shutdown. If LB is shutdown, lbHelper won't match. if (NameResolverListener.this.helper != ManagedChannelImpl.this.lbHelper) { return; } helper.lb.handleNameResolutionError(error); } } private final class SubchannelImpl extends AbstractSubchannel { final CreateSubchannelArgs args; final InternalLogId subchannelLogId; final ChannelLoggerImpl subchannelLogger; final ChannelTracer subchannelTracer; List addressGroups; InternalSubchannel subchannel; boolean started; boolean shutdown; ScheduledHandle delayedShutdownTask; SubchannelImpl(CreateSubchannelArgs args) { checkNotNull(args, "args"); addressGroups = args.getAddresses(); if (authorityOverride != null) { List eagsWithoutOverrideAttr = stripOverrideAuthorityAttributes(args.getAddresses()); args = args.toBuilder().setAddresses(eagsWithoutOverrideAttr).build(); } this.args = args; subchannelLogId = InternalLogId.allocate("Subchannel", /*details=*/ authority()); subchannelTracer = new ChannelTracer( subchannelLogId, maxTraceEvents, timeProvider.currentTimeNanos(), "Subchannel for " + args.getAddresses()); subchannelLogger = new ChannelLoggerImpl(subchannelTracer, timeProvider); } @Override public void start(final SubchannelStateListener listener) { syncContext.throwIfNotInThisSynchronizationContext(); checkState(!started, "already started"); checkState(!shutdown, "already shutdown"); checkState(!terminating, "Channel is being terminated"); started = true; final class ManagedInternalSubchannelCallback extends InternalSubchannel.Callback { // All callbacks are run in syncContext @Override void onTerminated(InternalSubchannel is) { subchannels.remove(is); channelz.removeSubchannel(is); maybeTerminateChannel(); } @Override void onStateChange(InternalSubchannel is, ConnectivityStateInfo newState) { checkState(listener != null, "listener is null"); listener.onSubchannelState(newState); } @Override void onInUse(InternalSubchannel is) { inUseStateAggregator.updateObjectInUse(is, true); } @Override void onNotInUse(InternalSubchannel is) { inUseStateAggregator.updateObjectInUse(is, false); } } final InternalSubchannel internalSubchannel = new InternalSubchannel( args.getAddresses(), authority(), userAgent, backoffPolicyProvider, transportFactory, transportFactory.getScheduledExecutorService(), stopwatchSupplier, syncContext, new ManagedInternalSubchannelCallback(), channelz, callTracerFactory.create(), subchannelTracer, subchannelLogId, subchannelLogger, transportFilters); channelTracer.reportEvent(new ChannelTrace.Event.Builder() .setDescription("Child Subchannel started") .setSeverity(ChannelTrace.Event.Severity.CT_INFO) .setTimestampNanos(timeProvider.currentTimeNanos()) .setSubchannelRef(internalSubchannel) .build()); this.subchannel = internalSubchannel; channelz.addSubchannel(internalSubchannel); subchannels.add(internalSubchannel); } @Override InternalInstrumented getInstrumentedInternalSubchannel() { checkState(started, "not started"); return subchannel; } @Override public void shutdown() { syncContext.throwIfNotInThisSynchronizationContext(); if (subchannel == null) { // start() was not successful shutdown = true; return; } if (shutdown) { if (terminating && delayedShutdownTask != null) { // shutdown() was previously called when terminating == false, thus a delayed shutdown() // was scheduled. Now since terminating == true, We should expedite the shutdown. delayedShutdownTask.cancel(); delayedShutdownTask = null; // Will fall through to the subchannel.shutdown() at the end. } else { return; } } else { shutdown = true; } // Add a delay to shutdown to deal with the race between 1) a transport being picked and // newStream() being called on it, and 2) its Subchannel is shut down by LoadBalancer (e.g., // because of address change, or because LoadBalancer is shutdown by Channel entering idle // mode). If (2) wins, the app will see a spurious error. We work around this by delaying // shutdown of Subchannel for a few seconds here. // // TODO(zhangkun83): consider a better approach // (https://github.com/grpc/grpc-java/issues/2562). if (!terminating) { final class ShutdownSubchannel implements Runnable { @Override public void run() { subchannel.shutdown(SUBCHANNEL_SHUTDOWN_STATUS); } } delayedShutdownTask = syncContext.schedule( new LogExceptionRunnable(new ShutdownSubchannel()), SUBCHANNEL_SHUTDOWN_DELAY_SECONDS, TimeUnit.SECONDS, transportFactory.getScheduledExecutorService()); return; } // When terminating == true, no more real streams will be created. It's safe and also // desirable to shutdown timely. subchannel.shutdown(SHUTDOWN_STATUS); } @Override public void requestConnection() { syncContext.throwIfNotInThisSynchronizationContext(); checkState(started, "not started"); subchannel.obtainActiveTransport(); } @Override public List getAllAddresses() { syncContext.throwIfNotInThisSynchronizationContext(); checkState(started, "not started"); return addressGroups; } @Override public Attributes getAttributes() { return args.getAttributes(); } @Override public String toString() { return subchannelLogId.toString(); } @Override public Channel asChannel() { checkState(started, "not started"); return new SubchannelChannel( subchannel, balancerRpcExecutorHolder.getExecutor(), transportFactory.getScheduledExecutorService(), callTracerFactory.create(), new AtomicReference(null)); } @Override public Object getInternalSubchannel() { checkState(started, "Subchannel is not started"); return subchannel; } @Override public ChannelLogger getChannelLogger() { return subchannelLogger; } @Override public void updateAddresses(List addrs) { syncContext.throwIfNotInThisSynchronizationContext(); addressGroups = addrs; if (authorityOverride != null) { addrs = stripOverrideAuthorityAttributes(addrs); } subchannel.updateAddresses(addrs); } @Override public Attributes getConnectedAddressAttributes() { return subchannel.getConnectedAddressAttributes(); } private List stripOverrideAuthorityAttributes( List eags) { List eagsWithoutOverrideAttr = new ArrayList<>(); for (EquivalentAddressGroup eag : eags) { EquivalentAddressGroup eagWithoutOverrideAttr = new EquivalentAddressGroup( eag.getAddresses(), eag.getAttributes().toBuilder().discard(ATTR_AUTHORITY_OVERRIDE).build()); eagsWithoutOverrideAttr.add(eagWithoutOverrideAttr); } return Collections.unmodifiableList(eagsWithoutOverrideAttr); } } @Override public String toString() { return MoreObjects.toStringHelper(this) .add("logId", logId.getId()) .add("target", target) .toString(); } /** * Called from syncContext. */ private final class DelayedTransportListener implements ManagedClientTransport.Listener { @Override public void transportShutdown(Status s) { checkState(shutdown.get(), "Channel must have been shut down"); } @Override public void transportReady() { // Don't care } @Override public Attributes filterTransport(Attributes attributes) { return attributes; } @Override public void transportInUse(final boolean inUse) { inUseStateAggregator.updateObjectInUse(delayedTransport, inUse); if (inUse) { // It's possible to be in idle mode while inUseStateAggregator is in-use, if one of the // subchannels is in use. But we should never be in idle mode when delayed transport is in // use. exitIdleMode(); } } @Override public void transportTerminated() { checkState(shutdown.get(), "Channel must have been shut down"); terminating = true; shutdownNameResolverAndLoadBalancer(false); // No need to call channelStateManager since we are already in SHUTDOWN state. // Until LoadBalancer is shutdown, it may still create new subchannels. We catch them // here. maybeShutdownNowSubchannels(); maybeTerminateChannel(); } } /** * Must be accessed from syncContext. */ private final class IdleModeStateAggregator extends InUseStateAggregator { @Override protected void handleInUse() { exitIdleMode(); } @Override protected void handleNotInUse() { if (shutdown.get()) { return; } rescheduleIdleTimer(); } } /** * Lazily request for Executor from an executor pool. * Also act as an Executor directly to simply run a cmd */ @VisibleForTesting static final class ExecutorHolder implements Executor { private final ObjectPool pool; private Executor executor; ExecutorHolder(ObjectPool executorPool) { this.pool = checkNotNull(executorPool, "executorPool"); } synchronized Executor getExecutor() { if (executor == null) { executor = checkNotNull(pool.getObject(), "%s.getObject()", executor); } return executor; } synchronized void release() { if (executor != null) { executor = pool.returnObject(executor); } } @Override public void execute(Runnable command) { getExecutor().execute(command); } } private static final class RestrictedScheduledExecutor implements ScheduledExecutorService { final ScheduledExecutorService delegate; private RestrictedScheduledExecutor(ScheduledExecutorService delegate) { this.delegate = checkNotNull(delegate, "delegate"); } @Override public ScheduledFuture schedule(Callable callable, long delay, TimeUnit unit) { return delegate.schedule(callable, delay, unit); } @Override public ScheduledFuture schedule(Runnable cmd, long delay, TimeUnit unit) { return delegate.schedule(cmd, delay, unit); } @Override public ScheduledFuture scheduleAtFixedRate( Runnable command, long initialDelay, long period, TimeUnit unit) { return delegate.scheduleAtFixedRate(command, initialDelay, period, unit); } @Override public ScheduledFuture scheduleWithFixedDelay( Runnable command, long initialDelay, long delay, TimeUnit unit) { return delegate.scheduleWithFixedDelay(command, initialDelay, delay, unit); } @Override public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException { return delegate.awaitTermination(timeout, unit); } @Override public List> invokeAll(Collection> tasks) throws InterruptedException { return delegate.invokeAll(tasks); } @Override public List> invokeAll( Collection> tasks, long timeout, TimeUnit unit) throws InterruptedException { return delegate.invokeAll(tasks, timeout, unit); } @Override public T invokeAny(Collection> tasks) throws InterruptedException, ExecutionException { return delegate.invokeAny(tasks); } @Override public T invokeAny(Collection> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException { return delegate.invokeAny(tasks, timeout, unit); } @Override public boolean isShutdown() { return delegate.isShutdown(); } @Override public boolean isTerminated() { return delegate.isTerminated(); } @Override public void shutdown() { throw new UnsupportedOperationException("Restricted: shutdown() is not allowed"); } @Override public List shutdownNow() { throw new UnsupportedOperationException("Restricted: shutdownNow() is not allowed"); } @Override public Future submit(Callable task) { return delegate.submit(task); } @Override public Future submit(Runnable task) { return delegate.submit(task); } @Override public Future submit(Runnable task, T result) { return delegate.submit(task, result); } @Override public void execute(Runnable command) { delegate.execute(command); } } /** * A ResolutionState indicates the status of last name resolution. */ enum ResolutionState { NO_RESOLUTION, SUCCESS, ERROR } }