Package io.servicetalk.loadbalancer

Class DelegatingLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

java.lang.Object

io.servicetalk.loadbalancer.DelegatingLoadBalancerBuilder<ResolvedAddress,C>

Type Parameters:

ResolvedAddress - The resolved address type.

C - The type of connection.

All Implemented Interfaces:

LoadBalancerBuilder<ResolvedAddress,C>

public class DelegatingLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>
extends Object
implements LoadBalancerBuilder<ResolvedAddress,C>

A LoadBalancerBuilder that delegates all methods to another LoadBalancerBuilder.

Constructor Summary

Constructors

Constructor	Description
DelegatingLoadBalancerBuilder(LoadBalancerBuilder<ResolvedAddress,C> delegate)	Creates a new builder which delegates to the provided LoadBalancerBuilder.

Method Summary

Modifier and Type	Method	Description
LoadBalancerBuilder<ResolvedAddress,C>	backgroundExecutor(Executor backgroundExecutor)	Set the background Executor to use for determining time and scheduling background tasks such as those associated with outlier detection.
LoadBalancerFactory<ResolvedAddress,C>	build()	Builds the LoadBalancerFactory configured by this builder.
LoadBalancerBuilder<ResolvedAddress,C>	connectionSelectorPolicy(ConnectionSelectorPolicy<C> connectionSelectorPolicy)	Set the ConnectionSelectorPolicy to use with this load balancer.
protected final LoadBalancerBuilder<ResolvedAddress,C>	delegate()	Returns the DelegatingLoadBalancerBuilder delegate.
LoadBalancerBuilder<ResolvedAddress,C>	loadBalancerObserver(LoadBalancerObserverFactory loadBalancerObserverFactory)	Set the LoadBalancerObserverFactory to use with this load balancer.
LoadBalancerBuilder<ResolvedAddress,C>	loadBalancingPolicy(LoadBalancingPolicy<ResolvedAddress,C> loadBalancingPolicy)	Set the loadBalancingPolicy to use with this load balancer.
LoadBalancerBuilder<ResolvedAddress,C>	maxRandomSubsetSize(int maxUsed)	Set the maximum number of healthy backends to load balance against using a random-subsetting strategy.
LoadBalancerBuilder<ResolvedAddress,C>	minConnectionsPerHost(int minConnectionsPerHost)	Set the minimum number of connections an active host should maintain in its pool.
LoadBalancerBuilder<ResolvedAddress,C>	outlierDetectorConfig(OutlierDetectorConfig outlierDetectorConfig)	Set the OutlierDetectorConfig to use with this load balancer.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

DelegatingLoadBalancerBuilder

public DelegatingLoadBalancerBuilder(LoadBalancerBuilder<ResolvedAddress,C> delegate)

Creates a new builder which delegates to the provided LoadBalancerBuilder.

Parameters:

delegate - the delegate builder.

Method Details

delegate

protected final LoadBalancerBuilder<ResolvedAddress,C> delegate()

Returns the DelegatingLoadBalancerBuilder delegate.

Returns:

Delegate DelegatingLoadBalancerBuilder.

loadBalancingPolicy

public LoadBalancerBuilder<ResolvedAddress,C> loadBalancingPolicy(LoadBalancingPolicy<ResolvedAddress,C> loadBalancingPolicy)

Description copied from interface: LoadBalancerBuilder

Set the loadBalancingPolicy to use with this load balancer.

Specified by:

loadBalancingPolicy in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

loadBalancingPolicy - the loadBalancingPolicy to use

Returns:

this

loadBalancerObserver

public LoadBalancerBuilder<ResolvedAddress,C> loadBalancerObserver(@Nullable
 LoadBalancerObserverFactory loadBalancerObserverFactory)

Description copied from interface: LoadBalancerBuilder

Set the LoadBalancerObserverFactory to use with this load balancer.

Specified by:

loadBalancerObserver in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

loadBalancerObserverFactory - the LoadBalancerObserverFactory to use, or null to not use an observer.

Returns:

{code this}

outlierDetectorConfig

public LoadBalancerBuilder<ResolvedAddress,C> outlierDetectorConfig(OutlierDetectorConfig outlierDetectorConfig)

Description copied from interface: LoadBalancerBuilder

Set the OutlierDetectorConfig to use with this load balancer.

The outlier detection system works in conjunction with the load balancing policy to attempt to avoid hosts that have been determined to be unhealthy or slow. The details of the selection process are determined by the LoadBalancingPolicy while the health status is determined by the outlier detection configuration.

Specified by:

outlierDetectorConfig in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

outlierDetectorConfig - the OutlierDetectorConfig to use, or null to use the default outlier detection.

Returns:

{code this}

See Also:

• LoadBalancerBuilder.loadBalancingPolicy(LoadBalancingPolicy)
• for common preconfigured policies

maxRandomSubsetSize

public LoadBalancerBuilder<ResolvedAddress,C> maxRandomSubsetSize(int maxUsed)

Description copied from interface: LoadBalancerBuilder

Set the maximum number of healthy backends to load balance against using a random-subsetting strategy. Note: If a backend within the subset is found to be unhealthy, another endpoint will be added until the unhealthy backend recovers, after which the subset will return to its original state.

Specified by:

maxRandomSubsetSize in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

maxUsed - the maximum number of healthy backends to use.

Returns:

this

backgroundExecutor

public LoadBalancerBuilder<ResolvedAddress,C> backgroundExecutor(Executor backgroundExecutor)

Description copied from interface: LoadBalancerBuilder

Set the background Executor to use for determining time and scheduling background tasks such as those associated with outlier detection.

Specified by:

backgroundExecutor in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

backgroundExecutor - Executor to use as a time source and for scheduling background tasks.

Returns:

this.

connectionSelectorPolicy

public LoadBalancerBuilder<ResolvedAddress,C> connectionSelectorPolicy(ConnectionSelectorPolicy<C> connectionSelectorPolicy)

Description copied from interface: LoadBalancerBuilder

Set the ConnectionSelectorPolicy to use with this load balancer.

Specified by:

connectionSelectorPolicy in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

connectionSelectorPolicy - the factory of connection selection strategies to use.

Returns:

this

minConnectionsPerHost

public LoadBalancerBuilder<ResolvedAddress,C> minConnectionsPerHost(int minConnectionsPerHost)

Description copied from interface: LoadBalancerBuilder

Set the minimum number of connections an active host should maintain in its pool.

Setting a minimum number of connections can help reduce the occurrences where connection establishment happens on the request path, thereby reducing tail latencies, particularly for links which are prone idle-connection closure. The tradeoff is that it may require tuning and will create more connection overhead overall.

Note: this is a best-effort setting. There are inherent uncertainties, race conditions, and assumptions that will cause the number of connections to transiently fall below the specified minimum. Currently, these include:

• At startup: implementations do not try to warm never-used pools to prevent unexpected resource usage.
• When warming fails: implementations do not attempt to recover from connection establishment failures to prevent infinite retry loops.

Specified by:

minConnectionsPerHost in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

minConnectionsPerHost - the minimum number of connections a host should maintain.

Returns:

this

build

public LoadBalancerFactory<ResolvedAddress,C> build()

Description copied from interface: LoadBalancerBuilder

Builds the LoadBalancerFactory configured by this builder.

Specified by:

build in interface LoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Returns:

a new instance of LoadBalancerFactory with settings from this builder.

toString

public String toString()

Overrides:

toString in class Object