Class ManagedChannelImpl

java.lang.Object

io.grpc.Channel

io.grpc.ManagedChannel

io.grpc.internal.ManagedChannelImpl

All Implemented Interfaces:

InternalInstrumented<InternalChannelz.ChannelStats>, InternalWithLogId

@ThreadSafe
final class ManagedChannelImpl
extends ManagedChannel
implements InternalInstrumented<InternalChannelz.ChannelStats>

A communication channel for making outgoing RPCs.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private final class	ManagedChannelImpl.ChannelStreamProvider
(package private) static final class	ManagedChannelImpl.ConfigSelectingClientCall<ReqT,RespT>	A client call for a given channel that applies a given config selector when it starts.
private final class	ManagedChannelImpl.DelayedTransportListener	Called from syncContext.
(package private) static final class	ManagedChannelImpl.ExecutorHolder	Lazily request for Executor from an executor pool.
private final class	ManagedChannelImpl.IdleModeStateAggregator	Must be accessed from syncContext.
private class	ManagedChannelImpl.IdleModeTimer
private final class	ManagedChannelImpl.LbHelperImpl
(package private) final class	ManagedChannelImpl.NameResolverListener
private class	ManagedChannelImpl.RealChannel
(package private) static enum	ManagedChannelImpl.ResolutionState	A ResolutionState indicates the status of last name resolution.
private static final class	ManagedChannelImpl.RestrictedScheduledExecutor
private final class	ManagedChannelImpl.SubchannelImpl
private final class	ManagedChannelImpl.UncommittedRetriableStreamsRegistry	A registry that prevents channel shutdown from killing existing retry attempts that are in backoff.

Field Summary

Fields

Modifier and Type	Field	Description
private final String	authorityOverride
private final BackoffPolicy.Provider	backoffPolicyProvider
private final ManagedChannelImpl.ExecutorHolder	balancerRpcExecutorHolder
private final ObjectPool<? extends Executor>	balancerRpcExecutorPool
private final CallTracer.Factory	callTracerFactory
private final long	channelBufferLimit
private final RetriableStream.ChannelBufferMeter	channelBufferUsed
private final CallTracer	channelCallTracer
private final ChannelLogger	channelLogger
private final ConnectivityStateManager	channelStateManager
private final ChannelTracer	channelTracer
private final InternalChannelz	channelz
private final CompressorRegistry	compressorRegistry
private final DecompressorRegistry	decompressorRegistry
private final ManagedChannelServiceConfig	defaultServiceConfig
private final DelayedClientTransport	delayedTransport
private final ManagedClientTransport.Listener	delayedTransportListener
private static final ManagedChannelServiceConfig	EMPTY_SERVICE_CONFIG
private final Executor	executor
private final ObjectPool<? extends Executor>	executorPool
private boolean	fullStreamDecompression
(package private) static final long	IDLE_TIMEOUT_MILLIS_DISABLE
private final long	idleTimeoutMillis	The timeout before entering idle mode.
private final Rescheduler	idleTimer
private static final InternalConfigSelector	INITIAL_PENDING_SELECTOR
private final Channel	interceptorChannel	We delegate to this channel, so that we can have interceptors as necessary.
(package private) final InUseStateAggregator<Object>	inUseStateAggregator
private ManagedChannelImpl.ResolutionState	lastResolutionState
private ManagedChannelServiceConfig	lastServiceConfig
private ManagedChannelImpl.LbHelperImpl	lbHelper
private final AutoConfiguredLoadBalancerFactory	loadBalancerFactory
(package private) static final Logger	logger
private final InternalLogId	logId
private final boolean	lookUpServiceConfig
private final int	maxTraceEvents
private final MetricRecorder	metricRecorder
private NameResolver	nameResolver
private final NameResolver.Args	nameResolverArgs
private final NameResolverProvider	nameResolverProvider
private final NameResolverRegistry	nameResolverRegistry
private boolean	nameResolverStarted
private static final ClientCall<Object,Object>	NOOP_CALL
private static final LoadBalancer.PickDetailsConsumer	NOOP_PICK_DETAILS_CONSUMER
private final ManagedChannelImpl.ExecutorHolder	offloadExecutorHolder
private final Set<OobChannel>	oobChannels
private final ClientTransportFactory	oobTransportFactory
private final ChannelCredentials	originalChannelCreds
private final ClientTransportFactory	originalTransportFactory
private boolean	panicMode
private Collection<ManagedChannelImpl.RealChannel.PendingCall<?,?>>	pendingCalls
private final Object	pendingCallsInUseObject
private final long	perRpcBufferLimit
private final ManagedChannelImpl.RealChannel	realChannel
private final boolean	retryEnabled
private final ManagedChannelImpl.RestrictedScheduledExecutor	scheduledExecutor
private boolean	serviceConfigUpdated
private final AtomicBoolean	shutdown
(package private) static final Status	SHUTDOWN_NOW_STATUS
(package private) static final Status	SHUTDOWN_STATUS
private boolean	shutdownNowed
private final com.google.common.base.Supplier<com.google.common.base.Stopwatch>	stopwatchSupplier
(package private) static final long	SUBCHANNEL_SHUTDOWN_DELAY_SECONDS
(package private) static final Status	SUBCHANNEL_SHUTDOWN_STATUS
private LoadBalancer.SubchannelPicker	subchannelPicker
private final Set<InternalSubchannel>	subchannels
(package private) final SynchronizationContext	syncContext
private final String	target
private final URI	targetUri
private boolean	terminated
private final CountDownLatch	terminatedLatch
private boolean	terminating
private final Deadline.Ticker	ticker
private final TimeProvider	timeProvider
private final ClientTransportFactory	transportFactory
private final List<ClientTransportFilter>	transportFilters
private final ManagedChannelImpl.ChannelStreamProvider	transportProvider
private final ManagedChannelImpl.UncommittedRetriableStreamsRegistry	uncommittedRetriableStreamsRegistry
private final String	userAgent

Constructor Summary

Constructors

Constructor

Description

ManagedChannelImpl(ManagedChannelImplBuilder builder, ClientTransportFactory clientTransportFactory, URI targetUri, NameResolverProvider nameResolverProvider, BackoffPolicy.Provider backoffPolicyProvider, ObjectPool<? extends Executor> balancerRpcExecutorPool, com.google.common.base.Supplier<com.google.common.base.Stopwatch> stopwatchSupplier, List<ClientInterceptor> interceptors, TimeProvider timeProvider)

Method Summary

Modifier and Type	Method	Description
String	authority()	The authority of the destination this channel connects to.
boolean	awaitTermination(long timeout, TimeUnit unit)	Waits for the channel to become terminated, giving up if the timeout is reached.
private void	cancelIdleTimer(boolean permanent)
void	enterIdle()	Invoking this method moves the channel into the IDLE state and triggers tear-down of the channel's name resolver and load balancer, while still allowing on-going RPCs on the channel to continue.
private void	enterIdleMode()
(package private) void	exitIdleMode()	Make the channel exit idle mode, if it's in it.
private Executor	getCallExecutor(CallOptions callOptions)
(package private) InternalConfigSelector	getConfigSelector()
InternalLogId	getLogId()	Returns an ID that is primarily used in debug logs.
(package private) static NameResolver	getNameResolver(URI targetUri, String overrideAuthority, NameResolverProvider provider, NameResolver.Args nameResolverArgs)
ConnectivityState	getState(boolean requestConnection)	Gets the current connectivity state.
com.google.common.util.concurrent.ListenableFuture<InternalChannelz.ChannelStats>	getStats()	Returns the stats object.
private void	handleInternalSubchannelState(ConnectivityStateInfo newState)
(package private) boolean	hasThrottle()
(package private) boolean	isInPanicMode()
boolean	isShutdown()	Returns whether the channel is shutdown.
boolean	isTerminated()	Returns whether the channel is terminated.
private void	maybeShutdownNowSubchannels()
private void	maybeTerminateChannel()	Terminate the channel if termination conditions are met.
<ReqT,RespT> ClientCall<ReqT,RespT>	newCall(MethodDescriptor<ReqT,RespT> method, CallOptions callOptions)	Create a ClientCall to the remote operation specified by the given MethodDescriptor.
void	notifyWhenStateChanged(ConnectivityState source, Runnable callback)	Registers a one-off callback that will be run if the connectivity state of the channel diverges from the given source, which is typically what has just been returned by ManagedChannel.getState(boolean).
(package private) void	panic(Throwable t)
private void	refreshNameResolution()	Force name resolution refresh to happen immediately.
private void	rescheduleIdleTimer()
void	resetConnectBackoff()	For subchannels that are in TRANSIENT_FAILURE state, short-circuit the backoff timer and make them reconnect immediately.
ManagedChannelImpl	shutdown()	Initiates an orderly shutdown in which preexisting calls continue but new calls are immediately cancelled.
private void	shutdownNameResolverAndLoadBalancer(boolean channelIsActive)
ManagedChannelImpl	shutdownNow()	Initiates a forceful shutdown in which preexisting and new calls are cancelled.
String	toString()
private void	updateSubchannelPicker(LoadBalancer.SubchannelPicker newPicker)

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

logger

static final Logger logger

IDLE_TIMEOUT_MILLIS_DISABLE

static final long IDLE_TIMEOUT_MILLIS_DISABLE

See Also:

• Constant Field Values

SUBCHANNEL_SHUTDOWN_DELAY_SECONDS

static final long SUBCHANNEL_SHUTDOWN_DELAY_SECONDS

See Also:

• Constant Field Values

SHUTDOWN_NOW_STATUS

static final Status SHUTDOWN_NOW_STATUS

SHUTDOWN_STATUS

static final Status SHUTDOWN_STATUS

SUBCHANNEL_SHUTDOWN_STATUS

static final Status SUBCHANNEL_SHUTDOWN_STATUS

EMPTY_SERVICE_CONFIG

private static final ManagedChannelServiceConfig EMPTY_SERVICE_CONFIG

INITIAL_PENDING_SELECTOR

private static final InternalConfigSelector INITIAL_PENDING_SELECTOR

NOOP_PICK_DETAILS_CONSUMER

private static final LoadBalancer.PickDetailsConsumer NOOP_PICK_DETAILS_CONSUMER

logId

private final InternalLogId logId

target

private final String target

authorityOverride

@Nullable
private final String authorityOverride

nameResolverRegistry

private final NameResolverRegistry nameResolverRegistry

targetUri

private final URI targetUri

nameResolverProvider

private final NameResolverProvider nameResolverProvider

nameResolverArgs

private final NameResolver.Args nameResolverArgs

loadBalancerFactory

private final AutoConfiguredLoadBalancerFactory loadBalancerFactory

originalTransportFactory

private final ClientTransportFactory originalTransportFactory

originalChannelCreds

@Nullable
private final ChannelCredentials originalChannelCreds

transportFactory

private final ClientTransportFactory transportFactory

oobTransportFactory

private final ClientTransportFactory oobTransportFactory

scheduledExecutor

private final ManagedChannelImpl.RestrictedScheduledExecutor scheduledExecutor

executor

private final Executor executor

executorPool

private final ObjectPool<? extends Executor> executorPool

balancerRpcExecutorPool

private final ObjectPool<? extends Executor> balancerRpcExecutorPool

balancerRpcExecutorHolder

private final ManagedChannelImpl.ExecutorHolder balancerRpcExecutorHolder

offloadExecutorHolder

private final ManagedChannelImpl.ExecutorHolder offloadExecutorHolder

timeProvider

private final TimeProvider timeProvider

maxTraceEvents

private final int maxTraceEvents

syncContext

final SynchronizationContext syncContext

fullStreamDecompression

private boolean fullStreamDecompression

decompressorRegistry

private final DecompressorRegistry decompressorRegistry

compressorRegistry

private final CompressorRegistry compressorRegistry

stopwatchSupplier

private final com.google.common.base.Supplier<com.google.common.base.Stopwatch> stopwatchSupplier

idleTimeoutMillis

private final long idleTimeoutMillis

The timeout before entering idle mode.

channelStateManager

private final ConnectivityStateManager channelStateManager

backoffPolicyProvider

private final BackoffPolicy.Provider backoffPolicyProvider

interceptorChannel

private final Channel interceptorChannel

We delegate to this channel, so that we can have interceptors as necessary. If there aren't any interceptors and the BinaryLog is null then this will just be a ManagedChannelImpl.RealChannel.

transportFilters

private final List<ClientTransportFilter> transportFilters

userAgent

@Nullable
private final String userAgent

nameResolver

private NameResolver nameResolver

nameResolverStarted

private boolean nameResolverStarted

lbHelper

@Nullable
private ManagedChannelImpl.LbHelperImpl lbHelper

subchannelPicker

@Nullable
private volatile LoadBalancer.SubchannelPicker subchannelPicker

panicMode

private boolean panicMode

subchannels

private final Set<InternalSubchannel> subchannels

pendingCalls

@Nullable
private Collection<ManagedChannelImpl.RealChannel.PendingCall<?,?>> pendingCalls

pendingCallsInUseObject

private final Object pendingCallsInUseObject

oobChannels

private final Set<OobChannel> oobChannels

delayedTransport

private final DelayedClientTransport delayedTransport

uncommittedRetriableStreamsRegistry

private final ManagedChannelImpl.UncommittedRetriableStreamsRegistry uncommittedRetriableStreamsRegistry

shutdown

private final AtomicBoolean shutdown

shutdownNowed

private boolean shutdownNowed

terminating

private boolean terminating

terminated

private volatile boolean terminated

terminatedLatch

private final CountDownLatch terminatedLatch

callTracerFactory

private final CallTracer.Factory callTracerFactory

channelCallTracer

private final CallTracer channelCallTracer

channelTracer

private final ChannelTracer channelTracer

channelLogger

private final ChannelLogger channelLogger

channelz

private final InternalChannelz channelz

realChannel

private final ManagedChannelImpl.RealChannel realChannel

lastResolutionState

private ManagedChannelImpl.ResolutionState lastResolutionState

lastServiceConfig

private ManagedChannelServiceConfig lastServiceConfig

defaultServiceConfig

@Nullable
private final ManagedChannelServiceConfig defaultServiceConfig

serviceConfigUpdated

private boolean serviceConfigUpdated

lookUpServiceConfig

private final boolean lookUpServiceConfig

channelBufferUsed

private final RetriableStream.ChannelBufferMeter channelBufferUsed

perRpcBufferLimit

private final long perRpcBufferLimit

channelBufferLimit

private final long channelBufferLimit

retryEnabled

private final boolean retryEnabled

ticker

private final Deadline.Ticker ticker

delayedTransportListener

private final ManagedClientTransport.Listener delayedTransportListener

inUseStateAggregator

final InUseStateAggregator<Object> inUseStateAggregator

transportProvider

private final ManagedChannelImpl.ChannelStreamProvider transportProvider

idleTimer

private final Rescheduler idleTimer

metricRecorder

private final MetricRecorder metricRecorder

NOOP_CALL

private static final ClientCall<Object,Object> NOOP_CALL

Constructor Details

ManagedChannelImpl

ManagedChannelImpl(ManagedChannelImplBuilder builder,
 ClientTransportFactory clientTransportFactory,
 URI targetUri,
 NameResolverProvider nameResolverProvider,
 BackoffPolicy.Provider backoffPolicyProvider,
 ObjectPool<? extends Executor> balancerRpcExecutorPool,
 com.google.common.base.Supplier<com.google.common.base.Stopwatch> stopwatchSupplier,
 List<ClientInterceptor> interceptors,
 TimeProvider timeProvider)

Method Details

maybeShutdownNowSubchannels

private void maybeShutdownNowSubchannels()

getStats

public com.google.common.util.concurrent.ListenableFuture<InternalChannelz.ChannelStats> getStats()

Description copied from interface: InternalInstrumented

Returns the stats object.

Specified by:

getStats in interface InternalInstrumented<InternalChannelz.ChannelStats>

getLogId

public InternalLogId getLogId()

Description copied from interface: InternalWithLogId

Returns an ID that is primarily used in debug logs. It usually contains the class name and a numeric ID that is unique among the instances.

The subclasses of this interface usually want to include the log ID in their Object.toString() results.

Specified by:

getLogId in interface InternalWithLogId

shutdownNameResolverAndLoadBalancer

private void shutdownNameResolverAndLoadBalancer(boolean channelIsActive)

exitIdleMode

void exitIdleMode()

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

Must be called from syncContext

enterIdleMode

private void enterIdleMode()

cancelIdleTimer

private void cancelIdleTimer(boolean permanent)

rescheduleIdleTimer

private void rescheduleIdleTimer()

refreshNameResolution

private void refreshNameResolution()

Force name resolution refresh to happen immediately. Must be run from syncContext.

getNameResolver

static NameResolver getNameResolver(URI targetUri,
 @Nullable
 String overrideAuthority,
 NameResolverProvider provider,
 NameResolver.Args nameResolverArgs)

getConfigSelector

InternalConfigSelector getConfigSelector()

hasThrottle

boolean hasThrottle()

shutdown

public ManagedChannelImpl shutdown()

Initiates an orderly shutdown in which preexisting calls continue but new calls are immediately cancelled.

Specified by:

shutdown in class ManagedChannel

Returns:

this

shutdownNow

public ManagedChannelImpl shutdownNow()

Initiates a forceful shutdown in which preexisting and new calls are cancelled. Although forceful, the shutdown process is still not instantaneous; isTerminated() will likely return false immediately after this method returns.

Specified by:

shutdownNow in class ManagedChannel

Returns:

this

panic

void panic(Throwable t)

isInPanicMode

boolean isInPanicMode()

updateSubchannelPicker

private void updateSubchannelPicker(LoadBalancer.SubchannelPicker newPicker)

isShutdown

public boolean isShutdown()

Description copied from class: ManagedChannel

Returns whether the channel is shutdown. Shutdown channels immediately cancel any new calls, but may still have some calls being processed.

Specified by:

isShutdown in class ManagedChannel

See Also:

• ManagedChannel.shutdown()
• ManagedChannel.isTerminated()

awaitTermination

public boolean awaitTermination(long timeout,
 TimeUnit unit)
                         throws InterruptedException

Description copied from class: ManagedChannel

Waits for the channel to become terminated, giving up if the timeout is reached.

Specified by:

awaitTermination in class ManagedChannel

Returns:

whether the channel is terminated, as would be done by ManagedChannel.isTerminated().

Throws:

InterruptedException

isTerminated

public boolean isTerminated()

Description copied from class: ManagedChannel

Returns whether the channel is terminated. Terminated channels have no running calls and relevant resources released (like TCP connections).

Specified by:

isTerminated in class ManagedChannel

See Also:

• ManagedChannel.isShutdown()

newCall

public <ReqT,RespT> ClientCall<ReqT,RespT> newCall(MethodDescriptor<ReqT,RespT> method,
 CallOptions callOptions)

Description copied from class: Channel

Create a ClientCall to the remote operation specified by the given MethodDescriptor. The returned ClientCall does not trigger any remote behavior until ClientCall.start(ClientCall.Listener, Metadata) is invoked.

Specified by:

newCall in class Channel

Parameters:

method - describes the name and parameter types of the operation to call.

callOptions - runtime options to be applied to this call.

Returns:

a ClientCall bound to the specified method.

authority

public String authority()

Description copied from class: Channel

The authority of the destination this channel connects to. Typically this is in the format host:port.

Specified by:

authority in class Channel

getCallExecutor

private Executor getCallExecutor(CallOptions callOptions)

maybeTerminateChannel

private void maybeTerminateChannel()

Terminate the channel if termination conditions are met.

handleInternalSubchannelState

private void handleInternalSubchannelState(ConnectivityStateInfo newState)

getState

public ConnectivityState getState(boolean requestConnection)

Description copied from class: ManagedChannel

Gets the current connectivity state. Note the result may soon become outdated.

Note that the core library did not provide an implementation of this method until v1.6.1.

Overrides:

getState in class ManagedChannel

Parameters:

requestConnection - if true, the channel will try to make a connection if it is currently IDLE

notifyWhenStateChanged

public void notifyWhenStateChanged(ConnectivityState source,
 Runnable callback)

Description copied from class: ManagedChannel

Registers a one-off callback that will be run if the connectivity state of the channel diverges from the given source, which is typically what has just been returned by ManagedChannel.getState(boolean). If the states are already different, the callback will be called immediately. The callback is run in the same executor that runs Call listeners.

There is an inherent race between the notification to callback and any call to getState(). There is a similar race between getState() and a call to notifyWhenStateChanged(). The state can change during those races, so there is not a way to see every state transition. "Transitions" to the same state are possible, because intermediate states may not have been observed. The API is only reliable in tracking the current state.

Note that the core library did not provide an implementation of this method until v1.6.1.

Overrides:

notifyWhenStateChanged in class ManagedChannel

Parameters:

source - the assumed current state, typically just returned by ManagedChannel.getState(boolean)

callback - the one-off callback

resetConnectBackoff

public void resetConnectBackoff()

Description copied from class: ManagedChannel

For subchannels that are in TRANSIENT_FAILURE state, short-circuit the backoff timer and make them reconnect immediately. May also attempt to invoke NameResolver.refresh().

This is primarily intended for Android users, where the network may experience frequent temporary drops. Rather than waiting for gRPC's name resolution and reconnect timers to elapse before reconnecting, the app may use this method as a mechanism to notify gRPC that the network is now available and a reconnection attempt may occur immediately.

No-op if not supported by the implementation.

Overrides:

resetConnectBackoff in class ManagedChannel

enterIdle

public void enterIdle()

Description copied from class: ManagedChannel

Invoking this method moves the channel into the IDLE state and triggers tear-down of the channel's name resolver and load balancer, while still allowing on-going RPCs on the channel to continue. New RPCs on the channel will trigger creation of a new connection.

This is primarily intended for Android users when a device is transitioning from a cellular to a wifi connection. The OS will issue a notification that a new network (wifi) has been made the default, but for approximately 30 seconds the device will maintain both the cellular and wifi connections. Apps may invoke this method to ensure that new RPCs are created using the new default wifi network, rather than the soon-to-be-disconnected cellular network.

No-op if not supported by implementation.

Overrides:

enterIdle in class ManagedChannel

toString

public String toString()

Overrides:

toString in class Object