Class ForwardingLoadBalancerHelper
- java.lang.Object
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- io.grpc.LoadBalancer.Helper
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- io.grpc.util.ForwardingLoadBalancerHelper
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- Direct Known Subclasses:
HealthProducerHelper
@ExperimentalApi("https://github.com/grpc/grpc-java/issues/1771") public abstract class ForwardingLoadBalancerHelper extends LoadBalancer.Helper
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Constructor Summary
Constructors Constructor Description ForwardingLoadBalancerHelper()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods Modifier and Type Method Description ManagedChannel
createOobChannel(EquivalentAddressGroup eag, String authority)
Create an out-of-band channel for the LoadBalancer’s own RPC needs, e.g., talking to an external load-balancer service.ManagedChannel
createOobChannel(List<EquivalentAddressGroup> eag, String authority)
Create an out-of-band channel for the LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service.ManagedChannel
createResolvingOobChannel(String target)
Creates an out-of-band channel for LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service, that is specified by a target string.ManagedChannelBuilder<?>
createResolvingOobChannelBuilder(String target)
Deprecated.ManagedChannelBuilder<?>
createResolvingOobChannelBuilder(String target, ChannelCredentials creds)
Creates an out-of-band channel builder for LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service, that is specified by a target string and credentials.LoadBalancer.Subchannel
createSubchannel(LoadBalancer.CreateSubchannelArgs args)
Creates a Subchannel, which is a logical connection to the given group of addresses which are considered equivalent.protected abstract LoadBalancer.Helper
delegate()
Returns the underlying helper.String
getAuthority()
Returns the authority string of the channel, which is derived from the DNS-style target name.ChannelCredentials
getChannelCredentials()
Returns the ChannelCredentials used to construct the channel, without bearer tokens.ChannelLogger
getChannelLogger()
Returns theChannelLogger
for the Channel served by this LoadBalancer.String
getChannelTarget()
Returns the target string of the channel, guaranteed to include its scheme.io.grpc.MetricRecorder
getMetricRecorder()
Returns theMetricRecorder
that the channel uses to record metrics.NameResolver.Args
getNameResolverArgs()
Returns theNameResolver.Args
that the Channel uses to createNameResolver
s.NameResolverRegistry
getNameResolverRegistry()
Returns theNameResolverRegistry
that the Channel uses to look forNameResolver
s.ScheduledExecutorService
getScheduledExecutorService()
Returns aScheduledExecutorService
for scheduling delayed tasks.SynchronizationContext
getSynchronizationContext()
Returns aSynchronizationContext
that runs tasks in the same Synchronization Context as that the callback methods on theLoadBalancer
interface are run in.ChannelCredentials
getUnsafeChannelCredentials()
Returns the UNSAFE ChannelCredentials used to construct the channel, including bearer tokens.void
ignoreRefreshNameResolutionCheck()
Deprecated.void
refreshNameResolution()
CallNameResolver.refresh()
on the channel's resolver.String
toString()
void
updateBalancingState(ConnectivityState newState, LoadBalancer.SubchannelPicker newPicker)
Set a new state with a new picker to the channel.void
updateOobChannelAddresses(ManagedChannel channel, EquivalentAddressGroup eag)
Updates the addresses used for connections in theChannel
that was created byLoadBalancer.Helper.createOobChannel(EquivalentAddressGroup, String)
.void
updateOobChannelAddresses(ManagedChannel channel, List<EquivalentAddressGroup> eag)
Updates the addresses with a new EAG list.
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Method Detail
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delegate
protected abstract LoadBalancer.Helper delegate()
Returns the underlying helper.
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createSubchannel
public LoadBalancer.Subchannel createSubchannel(LoadBalancer.CreateSubchannelArgs args)
Description copied from class:LoadBalancer.Helper
Creates a Subchannel, which is a logical connection to the given group of addresses which are considered equivalent. Theattrs
are custom attributes associated with this Subchannel, and can be accessed later throughSubchannel.getAttributes()
.The LoadBalancer is responsible for closing unused Subchannels, and closing all Subchannels within
LoadBalancer.shutdown()
.It must be called from
the Synchronization Context
- Overrides:
createSubchannel
in classLoadBalancer.Helper
- Returns:
- Must return a valid Subchannel object, may not return null.
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createOobChannel
public ManagedChannel createOobChannel(EquivalentAddressGroup eag, String authority)
Description copied from class:LoadBalancer.Helper
Create an out-of-band channel for the LoadBalancer’s own RPC needs, e.g., talking to an external load-balancer service.The LoadBalancer is responsible for closing unused OOB channels, and closing all OOB channels within
LoadBalancer.shutdown()
.- Specified by:
createOobChannel
in classLoadBalancer.Helper
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createOobChannel
public ManagedChannel createOobChannel(List<EquivalentAddressGroup> eag, String authority)
Description copied from class:LoadBalancer.Helper
Create an out-of-band channel for the LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service. This version of the method allows multiple EAGs, so different addresses can have different authorities.The LoadBalancer is responsible for closing unused OOB channels, and closing all OOB channels within
LoadBalancer.shutdown()
.- Overrides:
createOobChannel
in classLoadBalancer.Helper
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updateOobChannelAddresses
public void updateOobChannelAddresses(ManagedChannel channel, EquivalentAddressGroup eag)
Description copied from class:LoadBalancer.Helper
Updates the addresses used for connections in theChannel
that was created byLoadBalancer.Helper.createOobChannel(EquivalentAddressGroup, String)
. This is superior toLoadBalancer.Helper.createOobChannel(EquivalentAddressGroup, String)
when the old and new addresses overlap, since the channel can continue using an existing connection.- Overrides:
updateOobChannelAddresses
in classLoadBalancer.Helper
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updateOobChannelAddresses
public void updateOobChannelAddresses(ManagedChannel channel, List<EquivalentAddressGroup> eag)
Description copied from class:LoadBalancer.Helper
Updates the addresses with a new EAG list. Connection is continued when old and new addresses overlap.- Overrides:
updateOobChannelAddresses
in classLoadBalancer.Helper
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createResolvingOobChannelBuilder
@Deprecated public ManagedChannelBuilder<?> createResolvingOobChannelBuilder(String target)
Deprecated.Description copied from class:LoadBalancer.Helper
Creates an out-of-band channel builder for LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service, that is specified by a target string. See the documentation onManagedChannelBuilder.forTarget(java.lang.String)
for the format of a target string.The target string will be resolved by a
NameResolver
created according to the target string.The returned oob-channel builder defaults to use the same authority and ChannelCredentials (without bearer tokens) as the parent channel's for authentication. This is different from
LoadBalancer.Helper.createResolvingOobChannelBuilder(String, ChannelCredentials)
.The LoadBalancer is responsible for closing unused OOB channels, and closing all OOB channels within
LoadBalancer.shutdown()
.- Overrides:
createResolvingOobChannelBuilder
in classLoadBalancer.Helper
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createResolvingOobChannelBuilder
public ManagedChannelBuilder<?> createResolvingOobChannelBuilder(String target, ChannelCredentials creds)
Description copied from class:LoadBalancer.Helper
Creates an out-of-band channel builder for LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service, that is specified by a target string and credentials. See the documentation onGrpc.newChannelBuilder(java.lang.String, io.grpc.ChannelCredentials)
for the format of a target string.The target string will be resolved by a
NameResolver
created according to the target string.The LoadBalancer is responsible for closing unused OOB channels, and closing all OOB channels within
LoadBalancer.shutdown()
.- Overrides:
createResolvingOobChannelBuilder
in classLoadBalancer.Helper
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createResolvingOobChannel
public ManagedChannel createResolvingOobChannel(String target)
Description copied from class:LoadBalancer.Helper
Creates an out-of-band channel for LoadBalancer's own RPC needs, e.g., talking to an external load-balancer service, that is specified by a target string. See the documentation onManagedChannelBuilder.forTarget(java.lang.String)
for the format of a target string.The target string will be resolved by a
NameResolver
created according to the target string.The LoadBalancer is responsible for closing unused OOB channels, and closing all OOB channels within
LoadBalancer.shutdown()
.- Overrides:
createResolvingOobChannel
in classLoadBalancer.Helper
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updateBalancingState
public void updateBalancingState(ConnectivityState newState, LoadBalancer.SubchannelPicker newPicker)
Description copied from class:LoadBalancer.Helper
Set a new state with a new picker to the channel.When a new picker is provided via
updateBalancingState()
, the channel will apply the picker on all buffered RPCs, by callingLoadBalancer.SubchannelPicker.pickSubchannel( LoadBalancer.PickSubchannelArgs)
.The channel will hold the picker and use it for all RPCs, until
updateBalancingState()
is called again and a new picker replaces the old one. IfupdateBalancingState()
has never been called, the channel will buffer all RPCs until a picker is provided.It should be called from the Synchronization Context. Currently will log a warning if violated. It will become an exception eventually. See #5015 for the background.
The passed state will be the channel's new state. The SHUTDOWN state should not be passed and its behavior is undefined.
- Specified by:
updateBalancingState
in classLoadBalancer.Helper
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refreshNameResolution
public void refreshNameResolution()
Description copied from class:LoadBalancer.Helper
CallNameResolver.refresh()
on the channel's resolver.It should be called from the Synchronization Context. Currently will log a warning if violated. It will become an exception eventually. See #5015 for the background.
- Overrides:
refreshNameResolution
in classLoadBalancer.Helper
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ignoreRefreshNameResolutionCheck
@Deprecated public void ignoreRefreshNameResolutionCheck()
Deprecated.Description copied from class:LoadBalancer.Helper
Historically the channel automatically refreshes name resolution if any subchannel connection is broken. It's transitioning to let load balancers make the decision. To avoid silent breakages, the channel checks ifLoadBalancer.Helper.refreshNameResolution()
is called by the load balancer. If not, it will do it and log a warning. This will be removed in the future and load balancers are completely responsible for triggering the refresh. See #8088 for the background.This should rarely be used, but sometimes the address for the subchannel wasn't provided by the name resolver and a refresh needs to be directed somewhere else instead. Then you can call this method to disable the short-tem check for detecting LoadBalancers that need to be updated for the new expected behavior.
- Overrides:
ignoreRefreshNameResolutionCheck
in classLoadBalancer.Helper
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getAuthority
public String getAuthority()
Description copied from class:LoadBalancer.Helper
Returns the authority string of the channel, which is derived from the DNS-style target name. If overridden by a load balancer,LoadBalancer.Helper.getUnsafeChannelCredentials()
must also be overridden to callLoadBalancer.Helper.getChannelCredentials()
or provide appropriate credentials.- Specified by:
getAuthority
in classLoadBalancer.Helper
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getChannelTarget
public String getChannelTarget()
Description copied from class:LoadBalancer.Helper
Returns the target string of the channel, guaranteed to include its scheme.- Overrides:
getChannelTarget
in classLoadBalancer.Helper
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getChannelCredentials
public ChannelCredentials getChannelCredentials()
Description copied from class:LoadBalancer.Helper
Returns the ChannelCredentials used to construct the channel, without bearer tokens.- Overrides:
getChannelCredentials
in classLoadBalancer.Helper
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getUnsafeChannelCredentials
public ChannelCredentials getUnsafeChannelCredentials()
Description copied from class:LoadBalancer.Helper
Returns the UNSAFE ChannelCredentials used to construct the channel, including bearer tokens. Load balancers should generally have no use for these credentials and use of them is heavily discouraged. These must be used very carefully to avoid sending bearer tokens to untrusted servers as the server could then impersonate the client. Generally it is only safe to use these credentials when communicating with the backend.- Overrides:
getUnsafeChannelCredentials
in classLoadBalancer.Helper
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getSynchronizationContext
public SynchronizationContext getSynchronizationContext()
Description copied from class:LoadBalancer.Helper
Returns aSynchronizationContext
that runs tasks in the same Synchronization Context as that the callback methods on theLoadBalancer
interface are run in.Pro-tip: in order to call
SynchronizationContext.schedule(java.lang.Runnable, long, java.util.concurrent.TimeUnit, java.util.concurrent.ScheduledExecutorService)
, you need to provide aScheduledExecutorService
.LoadBalancer.Helper.getScheduledExecutorService()
is provided for your convenience.- Overrides:
getSynchronizationContext
in classLoadBalancer.Helper
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getScheduledExecutorService
public ScheduledExecutorService getScheduledExecutorService()
Description copied from class:LoadBalancer.Helper
Returns aScheduledExecutorService
for scheduling delayed tasks.This service is a shared resource and is only meant for quick tasks. DO NOT block or run time-consuming tasks.
The returned service doesn't support
shutdown()
andshutdownNow()
. They will throw if called.- Overrides:
getScheduledExecutorService
in classLoadBalancer.Helper
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getChannelLogger
public ChannelLogger getChannelLogger()
Description copied from class:LoadBalancer.Helper
Returns theChannelLogger
for the Channel served by this LoadBalancer.- Overrides:
getChannelLogger
in classLoadBalancer.Helper
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getNameResolverArgs
public NameResolver.Args getNameResolverArgs()
Description copied from class:LoadBalancer.Helper
Returns theNameResolver.Args
that the Channel uses to createNameResolver
s.- Overrides:
getNameResolverArgs
in classLoadBalancer.Helper
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getNameResolverRegistry
public NameResolverRegistry getNameResolverRegistry()
Description copied from class:LoadBalancer.Helper
Returns theNameResolverRegistry
that the Channel uses to look forNameResolver
s.- Overrides:
getNameResolverRegistry
in classLoadBalancer.Helper
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getMetricRecorder
public io.grpc.MetricRecorder getMetricRecorder()
Description copied from class:LoadBalancer.Helper
Returns theMetricRecorder
that the channel uses to record metrics.- Overrides:
getMetricRecorder
in classLoadBalancer.Helper
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