Package io.grpc.grpclb
Class GrpclbLoadBalancer
- java.lang.Object
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- io.grpc.LoadBalancer
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- io.grpc.grpclb.GrpclbLoadBalancer
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class GrpclbLoadBalancer extends LoadBalancer
ALoadBalancer
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
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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
Fields Modifier and Type Field Description private BackoffPolicy.Provider
backoffPolicyProvider
private GrpclbConfig
config
private Context
context
private static GrpclbConfig
DEFAULT_CONFIG
private GrpclbState
grpclbState
private LoadBalancer.Helper
helper
private com.google.common.base.Stopwatch
stopwatch
private SubchannelPool
subchannelPool
private TimeProvider
time
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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
Constructors Constructor Description GrpclbLoadBalancer(LoadBalancer.Helper helper, Context context, SubchannelPool subchannelPool, TimeProvider time, com.google.common.base.Stopwatch stopwatch, BackoffPolicy.Provider backoffPolicyProvider)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Status
acceptResolvedAddresses(LoadBalancer.ResolvedAddresses resolvedAddresses)
Accepts newly resolved addresses from the name resolution system.boolean
canHandleEmptyAddressListFromNameResolution()
Whether this LoadBalancer can handle empty address group list to be passed toLoadBalancer.handleResolvedAddresses(ResolvedAddresses)
.(package private) GrpclbState
getGrpclbState()
void
handleNameResolutionError(Status error)
Handles an error from the name resolution system.private void
recreateStates()
void
requestConnection()
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
resetStates()
void
shutdown()
The channel asks the load-balancer to shutdown.-
Methods inherited from class io.grpc.LoadBalancer
handleResolvedAddresses, handleSubchannelState
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Field Detail
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DEFAULT_CONFIG
private static final GrpclbConfig DEFAULT_CONFIG
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helper
private final LoadBalancer.Helper helper
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context
private final Context context
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time
private final TimeProvider time
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stopwatch
private final com.google.common.base.Stopwatch stopwatch
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subchannelPool
private final SubchannelPool subchannelPool
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backoffPolicyProvider
private final BackoffPolicy.Provider backoffPolicyProvider
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config
private GrpclbConfig config
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grpclbState
@Nullable private GrpclbState grpclbState
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Constructor Detail
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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 Detail
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acceptResolvedAddresses
public Status acceptResolvedAddresses(LoadBalancer.ResolvedAddresses resolvedAddresses)
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()
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recreateStates
private void recreateStates()
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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
public void handleNameResolutionError(Status error)
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
@Nullable GrpclbState getGrpclbState()
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