Package io.grpc.grpclb
Class GrpclbLoadBalancer
java.lang.Object
io.grpc.LoadBalancer
io.grpc.grpclb.GrpclbLoadBalancer
A
LoadBalancer
that uses the GRPCLB protocol.
Optionally, when requested by the naming system, will delegate the work to a local pick-first or round-robin balancer.
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Nested Class Summary
Nested classes/interfaces inherited from class io.grpc.LoadBalancer
LoadBalancer.CreateSubchannelArgs, LoadBalancer.ErrorPicker, LoadBalancer.Factory, LoadBalancer.FixedResultPicker, LoadBalancer.Helper, LoadBalancer.PickDetailsConsumer, LoadBalancer.PickResult, LoadBalancer.PickSubchannelArgs, LoadBalancer.ResolvedAddresses, LoadBalancer.Subchannel, LoadBalancer.SubchannelPicker, LoadBalancer.SubchannelStateListener
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final BackoffPolicy.Provider
private GrpclbConfig
private final Context
private static final GrpclbConfig
private GrpclbState
private final LoadBalancer.Helper
private final com.google.common.base.Stopwatch
private final SubchannelPool
private final TimeProvider
Fields inherited from class io.grpc.LoadBalancer
ATTR_HEALTH_CHECKING_CONFIG, DISABLE_SUBCHANNEL_RECONNECT_KEY, EMPTY_PICKER, HAS_HEALTH_PRODUCER_LISTENER_KEY, HEALTH_CONSUMER_LISTENER_ARG_KEY, IS_PETIOLE_POLICY
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Constructor Summary
ConstructorsConstructorDescriptionGrpclbLoadBalancer
(LoadBalancer.Helper helper, Context context, SubchannelPool subchannelPool, TimeProvider time, com.google.common.base.Stopwatch stopwatch, BackoffPolicy.Provider backoffPolicyProvider) -
Method Summary
Modifier and TypeMethodDescriptionacceptResolvedAddresses
(LoadBalancer.ResolvedAddresses resolvedAddresses) Accepts newly resolved addresses from the name resolution system.boolean
Whether this LoadBalancer can handle empty address group list to be passed toLoadBalancer.handleResolvedAddresses(ResolvedAddresses)
.(package private) GrpclbState
void
handleNameResolutionError
(Status error) Handles an error from the name resolution system.private void
void
The channel asks the LoadBalancer to establish connections now (if applicable) so that the upcoming RPC may then just pick a ready connection without waiting for connections.private void
void
shutdown()
The channel asks the load-balancer to shutdown.Methods inherited from class io.grpc.LoadBalancer
handleResolvedAddresses, handleSubchannelState
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Field Details
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DEFAULT_CONFIG
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helper
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context
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time
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stopwatch
private final com.google.common.base.Stopwatch stopwatch -
subchannelPool
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backoffPolicyProvider
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config
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grpclbState
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Constructor Details
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GrpclbLoadBalancer
GrpclbLoadBalancer(LoadBalancer.Helper helper, Context context, SubchannelPool subchannelPool, TimeProvider time, com.google.common.base.Stopwatch stopwatch, BackoffPolicy.Provider backoffPolicyProvider)
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Method Details
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acceptResolvedAddresses
Description copied from class:LoadBalancer
Accepts newly resolved addresses from the name resolution system. TheEquivalentAddressGroup
addresses should be considered equivalent but may be flattened into a single list if needed.Implementations can choose to reject the given addresses by returning
false
.Implementations should not modify the given
addresses
.- Overrides:
acceptResolvedAddresses
in classLoadBalancer
- Parameters:
resolvedAddresses
- the resolved server addresses, attributes, and config.- Returns:
true
if the resolved addresses were accepted.false
if rejected.
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requestConnection
public void requestConnection()Description copied from class:LoadBalancer
The channel asks the LoadBalancer to establish connections now (if applicable) so that the upcoming RPC may then just pick a ready connection without waiting for connections. This is triggered byManagedChannel.getState(true)
.If LoadBalancer doesn't override it, this is no-op. If it infeasible to create connections given the current state, e.g. no Subchannel has been created yet, LoadBalancer can ignore this request.
- Overrides:
requestConnection
in classLoadBalancer
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resetStates
private void resetStates() -
recreateStates
private void recreateStates() -
shutdown
public void shutdown()Description copied from class:LoadBalancer
The channel asks the load-balancer to shutdown. No more methods on this class will be called after this method. The implementation should shutdown all Subchannels and OOB channels, and do any other cleanup as necessary.- Specified by:
shutdown
in classLoadBalancer
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handleNameResolutionError
Description copied from class:LoadBalancer
Handles an error from the name resolution system.- Specified by:
handleNameResolutionError
in classLoadBalancer
- Parameters:
error
- a non-OK status
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canHandleEmptyAddressListFromNameResolution
public boolean canHandleEmptyAddressListFromNameResolution()Description copied from class:LoadBalancer
Whether this LoadBalancer can handle empty address group list to be passed toLoadBalancer.handleResolvedAddresses(ResolvedAddresses)
. The default implementation returnsfalse
, meaning that if the NameResolver returns an empty list, the Channel will turn that into an error and callLoadBalancer.handleNameResolutionError(io.grpc.Status)
. LoadBalancers that want to accept empty lists should override this method and returntrue
.This method should always return a constant value. It's not specified when this will be called.
- Overrides:
canHandleEmptyAddressListFromNameResolution
in classLoadBalancer
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getGrpclbState
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