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io.grpc.internal.ManagedChannelImpl Maven / Gradle / Ivy
/*
* Copyright 2016, gRPC Authors All rights reserved.
*
* 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.ConnectivityState.IDLE;
import static io.grpc.ConnectivityState.SHUTDOWN;
import static io.grpc.ConnectivityState.TRANSIENT_FAILURE;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Stopwatch;
import com.google.common.base.Supplier;
import io.grpc.Attributes;
import io.grpc.CallOptions;
import io.grpc.Channel;
import io.grpc.ClientCall;
import io.grpc.ClientInterceptor;
import io.grpc.ClientInterceptors;
import io.grpc.CompressorRegistry;
import io.grpc.ConnectivityState;
import io.grpc.ConnectivityStateInfo;
import io.grpc.DecompressorRegistry;
import io.grpc.EquivalentAddressGroup;
import io.grpc.LoadBalancer;
import io.grpc.LoadBalancer.PickResult;
import io.grpc.LoadBalancer.PickSubchannelArgs;
import io.grpc.LoadBalancer.SubchannelPicker;
import io.grpc.ManagedChannel;
import io.grpc.MethodDescriptor;
import io.grpc.NameResolver;
import io.grpc.Status;
import io.grpc.internal.ClientCallImpl.ClientTransportProvider;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.Logger;
import java.util.regex.Pattern;
import javax.annotation.Nullable;
import javax.annotation.concurrent.GuardedBy;
import javax.annotation.concurrent.ThreadSafe;
/** A communication channel for making outgoing RPCs. */
@ThreadSafe
public final class ManagedChannelImpl extends ManagedChannel implements WithLogId {
static final Logger logger = Logger.getLogger(ManagedChannelImpl.class.getName());
// Matching this pattern means the target string is a URI target or at least intended to be one.
// A URI target must be an absolute hierarchical URI.
// From RFC 2396: scheme = alpha *( alpha | digit | "+" | "-" | "." )
@VisibleForTesting
static final Pattern URI_PATTERN = Pattern.compile("[a-zA-Z][a-zA-Z0-9+.-]*:/.*");
static final long IDLE_TIMEOUT_MILLIS_DISABLE = -1;
@VisibleForTesting
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 final String target;
private final NameResolver.Factory nameResolverFactory;
private final Attributes nameResolverParams;
private final LoadBalancer.Factory loadBalancerFactory;
private final ClientTransportFactory transportFactory;
private final Executor executor;
private final ObjectPool executorPool;
private final ObjectPool oobExecutorPool;
private final LogId logId = LogId.allocate(getClass().getName());
private final ChannelExecutor channelExecutor = new ChannelExecutor();
private boolean fullStreamDecompression;
private final DecompressorRegistry decompressorRegistry;
private final CompressorRegistry compressorRegistry;
private final Supplier stopwatchSupplier;
/** The timout 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 this will just be {@link RealChannel}.
*/
private final Channel interceptorChannel;
@Nullable private final String userAgent;
// Only null after channel is terminated. Must be assigned from the channelExecutor.
private NameResolver nameResolver;
private final ProxyDetector proxyDetector;
// Must be accessed from the channelExecutor.
private boolean nameResolverStarted;
// null when channel is in idle mode. Must be assigned from channelExecutor.
@Nullable
private LbHelperImpl lbHelper;
// Must be assigned from channelExecutor. null if channel is in idle mode.
@Nullable
private volatile SubchannelPicker subchannelPicker;
// Must be mutated from channelExecutor
// 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 mutated from channelExecutor
private final Set oobChannels = new HashSet(1, .75f);
// reprocess() must be run from channelExecutor
private final DelayedClientTransport delayedTransport;
// 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 channelExecutor
private boolean shutdownNowed;
// Must be mutated from channelExecutor
private volatile boolean terminating;
// Must be mutated from channelExecutor
private volatile boolean terminated;
private final CountDownLatch terminatedLatch = new CountDownLatch(1);
private final ManagedChannelReference phantom;
// Called from channelExecutor
private final ManagedClientTransport.Listener delayedTransportListener =
new 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 void transportInUse(final boolean inUse) {
inUseStateAggregator.updateObjectInUse(delayedTransport, inUse);
}
@Override
public void transportTerminated() {
checkState(shutdown.get(), "Channel must have been shut down");
terminating = true;
if (lbHelper != null) {
lbHelper.lb.shutdown();
lbHelper = null;
}
if (nameResolver != null) {
nameResolver.shutdown();
nameResolver = null;
nameResolverStarted = false;
}
// Until LoadBalancer is shutdown, it may still create new subchannels. We catch them
// here.
maybeShutdownNowSubchannels();
maybeTerminateChannel();
}
};
// Must be called from channelExecutor
private void maybeShutdownNowSubchannels() {
if (shutdownNowed) {
for (InternalSubchannel subchannel : subchannels) {
subchannel.shutdownNow(SHUTDOWN_NOW_STATUS);
}
for (InternalSubchannel oobChannel : oobChannels) {
oobChannel.shutdownNow(SHUTDOWN_NOW_STATUS);
}
}
}
// Must be accessed from channelExecutor
@VisibleForTesting
final InUseStateAggregator inUseStateAggregator =
new InUseStateAggregator() {
@Override
void handleInUse() {
exitIdleMode();
}
@Override
void handleNotInUse() {
if (shutdown.get()) {
return;
}
rescheduleIdleTimer();
}
};
// Run from channelExecutor
private class IdleModeTimer implements Runnable {
// Only mutated from channelExecutor
boolean cancelled;
@Override
public void run() {
if (cancelled) {
// Race detected: this task was scheduled on channelExecutor before cancelIdleTimer()
// could cancel the timer.
return;
}
logger.log(Level.FINE, "[{0}] Entering idle mode", getLogId());
// 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, both of which are bugs.
nameResolver.shutdown();
nameResolverStarted = false;
nameResolver = getNameResolver(target, nameResolverFactory, nameResolverParams);
lbHelper.lb.shutdown();
lbHelper = null;
subchannelPicker = null;
if (!channelStateManager.isDisabled()) {
channelStateManager.gotoState(IDLE);
}
}
}
// Must be used from channelExecutor
@Nullable
private ScheduledFuture idleModeTimerFuture;
// Must be used from channelExecutor
@Nullable
private IdleModeTimer idleModeTimer;
/**
* Make the channel exit idle mode, if it's in it.
*
* Must be called from channelExecutor
*/
@VisibleForTesting
void exitIdleMode() {
if (shutdown.get()) {
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();
} 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;
}
logger.log(Level.FINE, "[{0}] Exiting idle mode", getLogId());
lbHelper = new LbHelperImpl(nameResolver);
lbHelper.lb = loadBalancerFactory.newLoadBalancer(lbHelper);
NameResolverListenerImpl listener = new NameResolverListenerImpl(lbHelper);
try {
nameResolver.start(listener);
nameResolverStarted = true;
} catch (Throwable t) {
listener.onError(Status.fromThrowable(t));
}
}
// Must be run from channelExecutor
private void cancelIdleTimer() {
if (idleModeTimerFuture != null) {
idleModeTimerFuture.cancel(false);
idleModeTimer.cancelled = true;
idleModeTimerFuture = null;
idleModeTimer = null;
}
}
// Always run from channelExecutor
private void rescheduleIdleTimer() {
if (idleTimeoutMillis == IDLE_TIMEOUT_MILLIS_DISABLE) {
return;
}
cancelIdleTimer();
idleModeTimer = new IdleModeTimer();
idleModeTimerFuture = transportFactory.getScheduledExecutorService().schedule(
new LogExceptionRunnable(new Runnable() {
@Override
public void run() {
channelExecutor.executeLater(idleModeTimer).drain();
}
}),
idleTimeoutMillis, TimeUnit.MILLISECONDS);
}
private final ClientTransportProvider transportProvider = new ClientTransportProvider() {
@Override
public ClientTransport get(PickSubchannelArgs args) {
SubchannelPicker pickerCopy = subchannelPicker;
if (shutdown.get()) {
// If channel is shut down, delayedTransport is also shut down which will fail the stream
// properly.
return delayedTransport;
}
if (pickerCopy == null) {
channelExecutor.executeLater(new Runnable() {
@Override
public void run() {
exitIdleMode();
}
}).drain();
return delayedTransport;
}
// There is no need to reschedule the idle timer here.
//
// pickerCopy != null, which means idle timer has not expired when this method starts.
// Even if idle timer expires right after we grab pickerCopy, and it shuts down LoadBalancer
// which calls Subchannel.shutdown(), the InternalSubchannel will be actually shutdown after
// SUBCHANNEL_SHUTDOWN_DELAY_SECONDS, which gives the caller time to start RPC on it.
//
// In most cases the idle timer is scheduled to fire after the transport has created the
// stream, which would have reported in-use state to the channel that would have cancelled
// the idle timer.
PickResult pickResult = pickerCopy.pickSubchannel(args);
ClientTransport transport = GrpcUtil.getTransportFromPickResult(
pickResult, args.getCallOptions().isWaitForReady());
if (transport != null) {
return transport;
}
return delayedTransport;
}
};
ManagedChannelImpl(
AbstractManagedChannelImplBuilder builder,
ClientTransportFactory clientTransportFactory,
BackoffPolicy.Provider backoffPolicyProvider,
ObjectPool oobExecutorPool,
Supplier stopwatchSupplier,
List interceptors,
ProxyDetector proxyDetector) {
this.target = checkNotNull(builder.target, "target");
this.nameResolverFactory = builder.getNameResolverFactory();
this.nameResolverParams = checkNotNull(builder.getNameResolverParams(), "nameResolverParams");
this.nameResolver = getNameResolver(target, nameResolverFactory, nameResolverParams);
this.loadBalancerFactory =
checkNotNull(builder.loadBalancerFactory, "loadBalancerFactory");
this.executorPool = checkNotNull(builder.executorPool, "executorPool");
this.oobExecutorPool = checkNotNull(oobExecutorPool, "oobExecutorPool");
this.executor = checkNotNull(executorPool.getObject(), "executor");
this.delayedTransport = new DelayedClientTransport(this.executor, this.channelExecutor);
this.delayedTransport.start(delayedTransportListener);
this.backoffPolicyProvider = backoffPolicyProvider;
this.transportFactory =
new CallCredentialsApplyingTransportFactory(clientTransportFactory, this.executor);
this.interceptorChannel = ClientInterceptors.intercept(new RealChannel(), interceptors);
this.stopwatchSupplier = checkNotNull(stopwatchSupplier, "stopwatchSupplier");
if (builder.idleTimeoutMillis == IDLE_TIMEOUT_MILLIS_DISABLE) {
this.idleTimeoutMillis = builder.idleTimeoutMillis;
} else {
checkArgument(
builder.idleTimeoutMillis
>= AbstractManagedChannelImplBuilder.IDLE_MODE_MIN_TIMEOUT_MILLIS,
"invalid idleTimeoutMillis %s", builder.idleTimeoutMillis);
this.idleTimeoutMillis = builder.idleTimeoutMillis;
}
this.fullStreamDecompression = builder.fullStreamDecompression;
this.decompressorRegistry = checkNotNull(builder.decompressorRegistry, "decompressorRegistry");
this.compressorRegistry = checkNotNull(builder.compressorRegistry, "compressorRegistry");
this.userAgent = builder.userAgent;
this.proxyDetector = proxyDetector;
phantom = new ManagedChannelReference(this);
logger.log(Level.FINE, "[{0}] Created with target {1}", new Object[] {getLogId(), target});
}
@VisibleForTesting
static NameResolver getNameResolver(String target, NameResolver.Factory nameResolverFactory,
Attributes nameResolverParams) {
// Finding a NameResolver. Try using the target string as the URI. If that fails, try prepending
// "dns:///".
URI targetUri = null;
StringBuilder uriSyntaxErrors = new StringBuilder();
try {
targetUri = new URI(target);
// For "localhost:8080" this would likely cause newNameResolver to return null, because
// "localhost" is parsed as the scheme. Will fall into the next branch and try
// "dns:///localhost:8080".
} catch (URISyntaxException e) {
// Can happen with ip addresses like "[::1]:1234" or 127.0.0.1:1234.
uriSyntaxErrors.append(e.getMessage());
}
if (targetUri != null) {
NameResolver resolver = nameResolverFactory.newNameResolver(targetUri, nameResolverParams);
if (resolver != null) {
return resolver;
}
// "foo.googleapis.com:8080" cause resolver to be null, because "foo.googleapis.com" is an
// unmapped scheme. Just fall through and will try "dns:///foo.googleapis.com:8080"
}
// If we reached here, the targetUri couldn't be used.
if (!URI_PATTERN.matcher(target).matches()) {
// It doesn't look like a URI target. Maybe it's an authority string. Try with the default
// scheme from the factory.
try {
targetUri = new URI(nameResolverFactory.getDefaultScheme(), "", "/" + target, null);
} catch (URISyntaxException e) {
// Should not be possible.
throw new IllegalArgumentException(e);
}
NameResolver resolver = nameResolverFactory.newNameResolver(targetUri, nameResolverParams);
if (resolver != null) {
return resolver;
}
}
throw new IllegalArgumentException(String.format(
"cannot find a NameResolver for %s%s",
target, uriSyntaxErrors.length() > 0 ? " (" + uriSyntaxErrors + ")" : ""));
}
/**
* Initiates an orderly shutdown in which preexisting calls continue but new calls are immediately
* cancelled.
*/
@Override
public ManagedChannelImpl shutdown() {
logger.log(Level.FINE, "[{0}] shutdown() called", getLogId());
if (!shutdown.compareAndSet(false, true)) {
return this;
}
phantom.shutdown = true;
// Put gotoState(SHUTDOWN) as early into the channelExecutor's queue as possible.
// delayedTransport.shutdown() may also add some tasks into the queue. But some things inside
// delayedTransport.shutdown() like setting delayedTransport.shutdown = true are not run in the
// channelExecutor's queue and should not be blocked, so we do not drain() immediately here.
channelExecutor.executeLater(new Runnable() {
@Override
public void run() {
if (!channelStateManager.isDisabled()) {
channelStateManager.gotoState(SHUTDOWN);
}
}
});
delayedTransport.shutdown(SHUTDOWN_STATUS);
channelExecutor.executeLater(new Runnable() {
@Override
public void run() {
cancelIdleTimer();
}
}).drain();
logger.log(Level.FINE, "[{0}] Shutting down", getLogId());
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() {
logger.log(Level.FINE, "[{0}] shutdownNow() called", getLogId());
shutdown();
phantom.shutdownNow = true;
delayedTransport.shutdownNow(SHUTDOWN_NOW_STATUS);
channelExecutor.executeLater(new Runnable() {
@Override
public void run() {
if (shutdownNowed) {
return;
}
shutdownNowed = true;
maybeShutdownNowSubchannels();
}
}).drain();
return this;
}
@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 class RealChannel extends Channel {
@Override
public ClientCall newCall(MethodDescriptor method,
CallOptions callOptions) {
Executor executor = callOptions.getExecutor();
if (executor == null) {
executor = ManagedChannelImpl.this.executor;
}
return new ClientCallImpl(
method,
executor,
callOptions,
transportProvider,
terminated ? null : transportFactory.getScheduledExecutorService())
.setFullStreamDecompression(fullStreamDecompression)
.setDecompressorRegistry(decompressorRegistry)
.setCompressorRegistry(compressorRegistry);
}
@Override
public String authority() {
String authority = nameResolver.getServiceAuthority();
return checkNotNull(authority, "authority");
}
}
/**
* Terminate the channel if termination conditions are met.
*/
// Must be run from channelExecutor
private void maybeTerminateChannel() {
if (terminated) {
return;
}
if (shutdown.get() && subchannels.isEmpty() && oobChannels.isEmpty()) {
logger.log(Level.FINE, "[{0}] Terminated", getLogId());
terminated = true;
phantom.terminated = true;
phantom.clear();
terminatedLatch.countDown();
executorPool.returnObject(executor);
// Release the transport factory so that it can deallocate any resources.
transportFactory.close();
}
}
@Override
public ConnectivityState getState(boolean requestConnection) {
ConnectivityState savedChannelState = channelStateManager.getState();
if (requestConnection && savedChannelState == IDLE) {
channelExecutor.executeLater(
new Runnable() {
@Override
public void run() {
exitIdleMode();
}
}).drain();
}
return savedChannelState;
}
@Override
public void notifyWhenStateChanged(final ConnectivityState source, final Runnable callback) {
channelExecutor.executeLater(
new Runnable() {
@Override
public void run() {
channelStateManager.notifyWhenStateChanged(callback, executor, source);
}
}).drain();
}
@Override
public void resetConnectBackoff() {
channelExecutor.executeLater(
new Runnable() {
@Override
public void run() {
if (shutdown.get()) {
return;
}
if (nameResolverStarted) {
nameResolver.refresh();
}
for (InternalSubchannel subchannel : subchannels) {
subchannel.resetConnectBackoff();
}
for (InternalSubchannel oobChannel : oobChannels) {
oobChannel.resetConnectBackoff();
}
}
}).drain();
}
private class LbHelperImpl extends LoadBalancer.Helper {
LoadBalancer lb;
final NameResolver nr;
LbHelperImpl(NameResolver nr) {
this.nr = checkNotNull(nr, "NameResolver");
}
// Must be called from channelExecutor
private void handleInternalSubchannelState(ConnectivityStateInfo newState) {
if (newState.getState() == TRANSIENT_FAILURE || newState.getState() == IDLE) {
nr.refresh();
}
}
@Override
public AbstractSubchannel createSubchannel(
EquivalentAddressGroup addressGroup, Attributes attrs) {
checkNotNull(addressGroup, "addressGroup");
checkNotNull(attrs, "attrs");
// TODO(ejona): can we be even stricter? Like loadBalancer == null?
checkState(!terminated, "Channel is terminated");
final SubchannelImpl subchannel = new SubchannelImpl(attrs);
final InternalSubchannel internalSubchannel = new InternalSubchannel(
addressGroup, authority(), userAgent, backoffPolicyProvider, transportFactory,
transportFactory.getScheduledExecutorService(), stopwatchSupplier, channelExecutor,
new InternalSubchannel.Callback() {
// All callbacks are run in channelExecutor
@Override
void onTerminated(InternalSubchannel is) {
subchannels.remove(is);
maybeTerminateChannel();
}
@Override
void onStateChange(InternalSubchannel is, ConnectivityStateInfo newState) {
handleInternalSubchannelState(newState);
// Call LB only if it's not shutdown. If LB is shutdown, lbHelper won't match.
if (LbHelperImpl.this == ManagedChannelImpl.this.lbHelper) {
lb.handleSubchannelState(subchannel, newState);
}
}
@Override
void onInUse(InternalSubchannel is) {
inUseStateAggregator.updateObjectInUse(is, true);
}
@Override
void onNotInUse(InternalSubchannel is) {
inUseStateAggregator.updateObjectInUse(is, false);
}
},
proxyDetector);
subchannel.subchannel = internalSubchannel;
logger.log(Level.FINE, "[{0}] {1} created for {2}",
new Object[] {getLogId(), internalSubchannel.getLogId(), addressGroup});
runSerialized(new Runnable() {
@Override
public void run() {
if (terminating) {
// Because runSerialized() doesn't guarantee the runnable has been executed upon when
// returning, the subchannel may still be returned to the balancer without being
// shutdown even if "terminating" is already true. The subchannel will not be used in
// this case, because delayed transport has terminated when "terminating" becomes
// true, and no more requests will be sent to balancer beyond this point.
internalSubchannel.shutdown(SHUTDOWN_STATUS);
}
if (!terminated) {
// If channel has not terminated, it will track the subchannel and block termination
// for it.
subchannels.add(internalSubchannel);
}
}
});
return subchannel;
}
@Override
public void updateBalancingState(
final ConnectivityState newState, final SubchannelPicker newPicker) {
checkNotNull(newState, "newState");
checkNotNull(newPicker, "newPicker");
runSerialized(
new Runnable() {
@Override
public void run() {
if (LbHelperImpl.this != lbHelper) {
return;
}
subchannelPicker = newPicker;
delayedTransport.reprocess(newPicker);
// It's not appropriate to report SHUTDOWN state from lb.
// Ignore the case of newState == SHUTDOWN for now.
if (newState != SHUTDOWN) {
channelStateManager.gotoState(newState);
}
}
});
}
@Override
public void updateSubchannelAddresses(
LoadBalancer.Subchannel subchannel, EquivalentAddressGroup addrs) {
checkArgument(subchannel instanceof SubchannelImpl,
"subchannel must have been returned from createSubchannel");
((SubchannelImpl) subchannel).subchannel.updateAddresses(addrs);
}
@Override
public ManagedChannel createOobChannel(EquivalentAddressGroup addressGroup, String authority) {
// TODO(ejona): can we be even stricter? Like terminating?
checkState(!terminated, "Channel is terminated");
final OobChannel oobChannel = new OobChannel(
authority, oobExecutorPool, transportFactory.getScheduledExecutorService(),
channelExecutor);
final InternalSubchannel internalSubchannel = new InternalSubchannel(
addressGroup, authority, userAgent, backoffPolicyProvider, transportFactory,
transportFactory.getScheduledExecutorService(), stopwatchSupplier, channelExecutor,
// All callback methods are run from channelExecutor
new InternalSubchannel.Callback() {
@Override
void onTerminated(InternalSubchannel is) {
oobChannels.remove(is);
oobChannel.handleSubchannelTerminated();
maybeTerminateChannel();
}
@Override
void onStateChange(InternalSubchannel is, ConnectivityStateInfo newState) {
handleInternalSubchannelState(newState);
oobChannel.handleSubchannelStateChange(newState);
}
},
proxyDetector);
oobChannel.setSubchannel(internalSubchannel);
runSerialized(new 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(internalSubchannel);
}
}
});
return oobChannel;
}
@Override
public void updateOobChannelAddresses(ManagedChannel channel, EquivalentAddressGroup 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 NameResolver.Factory getNameResolverFactory() {
return nameResolverFactory;
}
@Override
public void runSerialized(Runnable task) {
channelExecutor.executeLater(task).drain();
}
}
@Override
public LogId getLogId() {
return logId;
}
private class NameResolverListenerImpl implements NameResolver.Listener {
final LoadBalancer balancer;
final LoadBalancer.Helper helper;
NameResolverListenerImpl(LbHelperImpl helperImpl) {
this.balancer = helperImpl.lb;
this.helper = helperImpl;
}
@Override
public void onAddresses(final List servers, final Attributes config) {
if (servers.isEmpty()) {
onError(Status.UNAVAILABLE.withDescription("NameResolver returned an empty list"));
return;
}
logger.log(Level.FINE, "[{0}] resolved address: {1}, config={2}",
new Object[] {getLogId(), servers, config});
helper.runSerialized(new Runnable() {
@Override
public void run() {
// Call LB only if it's not shutdown. If LB is shutdown, lbHelper won't match.
if (NameResolverListenerImpl.this.helper != ManagedChannelImpl.this.lbHelper) {
return;
}
try {
balancer.handleResolvedAddressGroups(servers, config);
} catch (Throwable e) {
logger.log(
Level.WARNING, "[" + getLogId() + "] Unexpected exception from LoadBalancer", e);
// It must be a bug! Push the exception back to LoadBalancer in the hope that it may
// be propagated to the application.
balancer.handleNameResolutionError(Status.INTERNAL.withCause(e)
.withDescription("Thrown from handleResolvedAddresses(): " + e));
}
}
});
}
@Override
public void onError(final Status error) {
checkArgument(!error.isOk(), "the error status must not be OK");
logger.log(Level.WARNING, "[{0}] Failed to resolve name. status={1}",
new Object[] {getLogId(), error});
channelExecutor.executeLater(new Runnable() {
@Override
public void run() {
// Call LB only if it's not shutdown. If LB is shutdown, lbHelper won't match.
if (NameResolverListenerImpl.this.helper != ManagedChannelImpl.this.lbHelper) {
return;
}
balancer.handleNameResolutionError(error);
}
}).drain();
}
}
private final class SubchannelImpl extends AbstractSubchannel {
// Set right after SubchannelImpl is created.
InternalSubchannel subchannel;
final Object shutdownLock = new Object();
final Attributes attrs;
@GuardedBy("shutdownLock")
boolean shutdownRequested;
@GuardedBy("shutdownLock")
ScheduledFuture delayedShutdownTask;
SubchannelImpl(Attributes attrs) {
this.attrs = checkNotNull(attrs, "attrs");
}
@Override
ClientTransport obtainActiveTransport() {
return subchannel.obtainActiveTransport();
}
@Override
public void shutdown() {
synchronized (shutdownLock) {
if (shutdownRequested) {
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(false);
delayedShutdownTask = null;
// Will fall through to the subchannel.shutdown() at the end.
} else {
return;
}
} else {
shutdownRequested = 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) {
delayedShutdownTask = transportFactory.getScheduledExecutorService().schedule(
new LogExceptionRunnable(
new Runnable() {
@Override
public void run() {
subchannel.shutdown(SUBCHANNEL_SHUTDOWN_STATUS);
}
}), SUBCHANNEL_SHUTDOWN_DELAY_SECONDS, TimeUnit.SECONDS);
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() {
subchannel.obtainActiveTransport();
}
@Override
public EquivalentAddressGroup getAddresses() {
return subchannel.getAddressGroup();
}
@Override
public Attributes getAttributes() {
return attrs;
}
@Override
public String toString() {
return subchannel.getLogId().toString();
}
}
@VisibleForTesting
static final class ManagedChannelReference extends WeakReference {
private static final ReferenceQueue refQueue =
new ReferenceQueue();
// Retain the References so they don't get GC'd
private static final ConcurrentMap refs =
new ConcurrentHashMap();
private static final String ALLOCATION_SITE_PROPERTY_NAME =
"io.grpc.ManagedChannel.enableAllocationTracking";
private static final boolean ENABLE_ALLOCATION_TRACKING =
Boolean.parseBoolean(System.getProperty(ALLOCATION_SITE_PROPERTY_NAME, "true"));
private static final RuntimeException missingCallSite = missingCallSite();
private final LogId logId;
private final String target;
private final Reference allocationSite;
private volatile boolean shutdown;
private volatile boolean shutdownNow;
private volatile boolean terminated;
ManagedChannelReference(ManagedChannelImpl chan) {
super(chan, refQueue);
allocationSite = new SoftReference(
ENABLE_ALLOCATION_TRACKING
? new RuntimeException("ManagedChannel allocation site")
: missingCallSite);
logId = chan.logId;
target = chan.target;
refs.put(this, this);
cleanQueue();
}
/**
* This clear() is *not* called automatically by the JVM. As this is a weak ref, the reference
* will be cleared automatically by the JVM, but will not be removed from {@link #refs}.
* We do it here to avoid this ending up on the reference queue.
*/
@Override
public void clear() {
clearInternal();
// We run this here to periodically clean up the queue if at least some of the channels are
// being shutdown properly.
cleanQueue();
}
// avoid reentrancy
private void clearInternal() {
super.clear();
refs.remove(this);
allocationSite.clear();
}
@VisibleForTesting
static int cleanQueue() {
ManagedChannelReference ref;
int orphanedChannels = 0;
while ((ref = (ManagedChannelReference) refQueue.poll()) != null) {
RuntimeException maybeAllocationSite = ref.allocationSite.get();
ref.clearInternal(); // technically the reference is gone already.
if (!(ref.shutdown && ref.terminated)) {
orphanedChannels++;
Level level = ref.shutdownNow ? Level.FINE : Level.SEVERE;
if (logger.isLoggable(level)) {
String fmt = new StringBuilder()
.append("*~*~*~ Channel {0} for target {1} was not ")
// Prefer to complain about shutdown if neither has been called.
.append(!ref.shutdown ? "shutdown" : "terminated")
.append(" properly!!! ~*~*~*")
.append(System.getProperty("line.separator"))
.append(" Make sure to call shutdown()/shutdownNow() and awaitTermination().")
.toString();
LogRecord lr = new LogRecord(level, fmt);
lr.setLoggerName(logger.getName());
lr.setParameters(new Object[]{ref.logId, ref.target});
lr.setThrown(maybeAllocationSite);
logger.log(lr);
}
}
}
return orphanedChannels;
}
private static RuntimeException missingCallSite() {
RuntimeException e = new RuntimeException(
"ManagedChannel allocation site not recorded. Set -D"
+ ALLOCATION_SITE_PROPERTY_NAME + "=true to enable it");
e.setStackTrace(new StackTraceElement[0]);
return e;
}
}
}