Class InternalSubchannel

java.lang.Object

io.grpc.internal.InternalSubchannel

All Implemented Interfaces:

TransportProvider, InternalInstrumented<InternalChannelz.ChannelStats>, InternalWithLogId

@ThreadSafe
final class InternalSubchannel
extends Object
implements InternalInstrumented<InternalChannelz.ChannelStats>, TransportProvider

Transports for a single SocketAddress.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	InternalSubchannel.Callback
(package private) static final class	InternalSubchannel.CallTracingTransport
(package private) static final class	InternalSubchannel.Index	Index as in 'i', the pointer to an entry.
private class	InternalSubchannel.TransportListener	Listener for real transports.
(package private) static final class	InternalSubchannel.TransportLogger

Field Summary

Fields

Modifier and Type	Field	Description
private ManagedClientTransport	activeTransport	The transport for new outgoing requests.
private List<EquivalentAddressGroup>	addressGroups	A volatile accessor to invalid reference Index#getAddressGroups() .
private final InternalSubchannel.Index	addressIndex	The index of the address corresponding to pendingTransport/activeTransport, or at beginning if both are null.
private final String	authority
private final BackoffPolicy.Provider	backoffPolicyProvider
private final InternalSubchannel.Callback	callback
private final CallTracer	callsTracer
private final ChannelLogger	channelLogger
private final ChannelTracer	channelTracer
private final InternalChannelz	channelz
private Attributes	connectedAddressAttributes
private final com.google.common.base.Stopwatch	connectingTimer	Timer monitoring duration since entering CONNECTING state.
private final InUseStateAggregator<ConnectionClientTransport>	inUseStateAggregator
private final InternalLogId	logId
private ConnectionClientTransport	pendingTransport	The to-be active transport, which is not ready yet.
private final boolean	reconnectDisabled
private BackoffPolicy	reconnectPolicy	The policy to control back off between reconnects.
private SynchronizationContext.ScheduledHandle	reconnectTask
private final ScheduledExecutorService	scheduledExecutor
private SynchronizationContext.ScheduledHandle	shutdownDueToUpdateTask
private ManagedClientTransport	shutdownDueToUpdateTransport
private Status	shutdownReason
private ConnectivityStateInfo	state
private final SynchronizationContext	syncContext	All field must be mutated in the syncContext.
private final ClientTransportFactory	transportFactory
private final List<ClientTransportFilter>	transportFilters
private final Collection<ConnectionClientTransport>	transports	All transports that are not terminated.
private final String	userAgent

Constructor Summary

Constructors

Constructor

Description

InternalSubchannel(LoadBalancer.CreateSubchannelArgs args, String authority, String userAgent, BackoffPolicy.Provider backoffPolicyProvider, ClientTransportFactory transportFactory, ScheduledExecutorService scheduledExecutor, com.google.common.base.Supplier<com.google.common.base.Stopwatch> stopwatchSupplier, SynchronizationContext syncContext, InternalSubchannel.Callback callback, InternalChannelz channelz, CallTracer callsTracer, ChannelTracer channelTracer, InternalLogId logId, ChannelLogger channelLogger, List<ClientTransportFilter> transportFilters)

Method Summary

Modifier and Type	Method	Description
private void	cancelReconnectTask()
private static void	checkListHasNoNulls(List<?> list, String msg)
(package private) List<EquivalentAddressGroup>	getAddressGroups()
(package private) String	getAuthority()	Returns the authority string associated with this Subchannel.
(package private) ChannelLogger	getChannelLogger()
Attributes	getConnectedAddressAttributes()	Return attributes for server address connected by sub channel.
InternalLogId	getLogId()	Returns an ID that is primarily used in debug logs.
(package private) ConnectivityState	getState()
com.google.common.util.concurrent.ListenableFuture<InternalChannelz.ChannelStats>	getStats()	Returns the stats object.
(package private) ClientTransport	getTransport()	Returns a READY transport if there is any, without trying to connect.
private void	gotoNonErrorState(ConnectivityState newState)
private void	gotoState(ConnectivityStateInfo newState)
private void	handleTermination()
private void	handleTransportInUseState(ConnectionClientTransport transport, boolean inUse)
ClientTransport	obtainActiveTransport()	Returns a READY transport that will be used to create new streams.
private String	printShortStatus(Status status)
(package private) void	resetConnectBackoff()	Immediately attempt to reconnect if the current state is TRANSIENT_FAILURE.
private void	scheduleBackoff(Status status)	Only called after all addresses attempted and failed (TRANSIENT_FAILURE).
void	shutdown(Status reason)
(package private) void	shutdownNow(Status reason)
private void	startNewTransport()
String	toString()
void	updateAddresses(List<EquivalentAddressGroup> newAddressGroups)	Replaces the existing addresses, avoiding unnecessary reconnects.

Methods inherited from class Object

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

Field Details

logId

private final InternalLogId logId

authority

private final String authority

userAgent

private final String userAgent

backoffPolicyProvider

private final BackoffPolicy.Provider backoffPolicyProvider

callback

private final InternalSubchannel.Callback callback

transportFactory

private final ClientTransportFactory transportFactory

scheduledExecutor

private final ScheduledExecutorService scheduledExecutor

channelz

private final InternalChannelz channelz

callsTracer

private final CallTracer callsTracer

channelTracer

private final ChannelTracer channelTracer

channelLogger

private final ChannelLogger channelLogger

reconnectDisabled

private final boolean reconnectDisabled

transportFilters

private final List<ClientTransportFilter> transportFilters

syncContext

private final SynchronizationContext syncContext

All field must be mutated in the syncContext.

addressIndex

private final InternalSubchannel.Index addressIndex

The index of the address corresponding to pendingTransport/activeTransport, or at beginning if both are null.

Note: any

invalid reference

Index#updateAddresses(List)

should also update addressGroups.

addressGroups

private volatile List<EquivalentAddressGroup> addressGroups

A volatile accessor to

invalid reference

Index#getAddressGroups()

. There are few methods (getAddressGroups() and toString() access this value where they supposed to access in the syncContext. Ideally

invalid reference

Index#getAddressGroups()

can be volatile, so we don't need to maintain this volatile accessor. Although, having this accessor can reduce unnecessary volatile reads while it delivers clearer intention of why .

reconnectPolicy

private BackoffPolicy reconnectPolicy

The policy to control back off between reconnects. Non-null when a reconnect task is scheduled.

connectingTimer

private final com.google.common.base.Stopwatch connectingTimer

Timer monitoring duration since entering CONNECTING state.

reconnectTask

@Nullable
private SynchronizationContext.ScheduledHandle reconnectTask

shutdownDueToUpdateTask

@Nullable
private SynchronizationContext.ScheduledHandle shutdownDueToUpdateTask

shutdownDueToUpdateTransport

@Nullable
private ManagedClientTransport shutdownDueToUpdateTransport

transports

private final Collection<ConnectionClientTransport> transports

All transports that are not terminated. At the very least the value of activeTransport will be present, but previously used transports that still have streams or are stopping may also be present.

inUseStateAggregator

private final InUseStateAggregator<ConnectionClientTransport> inUseStateAggregator

pendingTransport

@Nullable
private ConnectionClientTransport pendingTransport

The to-be active transport, which is not ready yet.

activeTransport

@Nullable
private volatile ManagedClientTransport activeTransport

The transport for new outgoing requests. Non-null only in READY state.

state

private volatile ConnectivityStateInfo state

shutdownReason

private Status shutdownReason

connectedAddressAttributes

private volatile Attributes connectedAddressAttributes

Constructor Details

InternalSubchannel

InternalSubchannel(LoadBalancer.CreateSubchannelArgs args,
 String authority,
 String userAgent,
 BackoffPolicy.Provider backoffPolicyProvider,
 ClientTransportFactory transportFactory,
 ScheduledExecutorService scheduledExecutor,
 com.google.common.base.Supplier<com.google.common.base.Stopwatch> stopwatchSupplier,
 SynchronizationContext syncContext,
 InternalSubchannel.Callback callback,
 InternalChannelz channelz,
 CallTracer callsTracer,
 ChannelTracer channelTracer,
 InternalLogId logId,
 ChannelLogger channelLogger,
 List<ClientTransportFilter> transportFilters)

Method Details

getChannelLogger

ChannelLogger getChannelLogger()

obtainActiveTransport

public ClientTransport obtainActiveTransport()

Description copied from interface: TransportProvider

Returns a READY transport that will be used to create new streams.

Returns null if the state is not READY. Will try to connect if state is IDLE.

Specified by:

obtainActiveTransport in interface TransportProvider

getTransport

@Nullable
ClientTransport getTransport()

Returns a READY transport if there is any, without trying to connect.

getAuthority

String getAuthority()

Returns the authority string associated with this Subchannel.

startNewTransport

private void startNewTransport()

scheduleBackoff

private void scheduleBackoff(Status status)

Only called after all addresses attempted and failed (TRANSIENT_FAILURE).

Parameters:

status - the causal status when the channel begins transition to TRANSIENT_FAILURE.

resetConnectBackoff

void resetConnectBackoff()

Immediately attempt to reconnect if the current state is TRANSIENT_FAILURE. Otherwise this method has no effect.

gotoNonErrorState

private void gotoNonErrorState(ConnectivityState newState)

gotoState

private void gotoState(ConnectivityStateInfo newState)

updateAddresses

public void updateAddresses(List<EquivalentAddressGroup> newAddressGroups)

Replaces the existing addresses, avoiding unnecessary reconnects.

shutdown

public void shutdown(Status reason)

toString

public String toString()

Overrides:

toString in class Object

handleTermination

private void handleTermination()

handleTransportInUseState

private void handleTransportInUseState(ConnectionClientTransport transport,
 boolean inUse)

shutdownNow

void shutdownNow(Status reason)

getAddressGroups

List<EquivalentAddressGroup> getAddressGroups()

cancelReconnectTask

private void cancelReconnectTask()

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

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>

getConnectedAddressAttributes

public Attributes getConnectedAddressAttributes()

Return attributes for server address connected by sub channel.

getState

ConnectivityState getState()

checkListHasNoNulls

private static void checkListHasNoNulls(List<?> list,
 String msg)

printShortStatus

private String printShortStatus(Status status)