Package io.servicetalk.loadbalancer

Class DelegatingRoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

java.lang.Object

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

Type Parameters:

ResolvedAddress - The resolved address type.

C - The type of connection.

All Implemented Interfaces:

RoundRobinLoadBalancerBuilder<ResolvedAddress,C>

public class DelegatingRoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>
extends Object
implements RoundRobinLoadBalancerBuilder<ResolvedAddress,C>

A RoundRobinLoadBalancerBuilder that delegates all methods to another RoundRobinLoadBalancerBuilder.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
RoundRobinLoadBalancerBuilder<ResolvedAddress,C>	backgroundExecutor(Executor backgroundExecutor)	This LoadBalancer may monitor hosts to which connection establishment has failed using health checks that run in the background.
LoadBalancerFactory<ResolvedAddress,C>	build()	Builds the LoadBalancerFactory configured by this builder.
protected final RoundRobinLoadBalancerBuilder<ResolvedAddress,C>	delegate()	Returns the DelegatingRoundRobinLoadBalancerBuilder delegate.
RoundRobinLoadBalancerBuilder<ResolvedAddress,C>	healthCheckFailedConnectionsThreshold(int threshold)	Configure a threshold for consecutive connection failures to a host.
RoundRobinLoadBalancerBuilder<ResolvedAddress,C>	healthCheckInterval(Duration interval, Duration jitter)	Configure an interval for health checking a host that failed to open connections.
RoundRobinLoadBalancerBuilder<ResolvedAddress,C>	healthCheckResubscribeInterval(Duration interval, Duration jitter)	Configure an interval for re-subscribing to the original events stream in case all existing hosts become unhealthy.
RoundRobinLoadBalancerBuilder<ResolvedAddress,C>	linearSearchSpace(int linearSearchSpace)	Sets the linear search space to find an available connection for the next host.

Methods inherited from class java.lang.Object

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

Constructor Details

DelegatingRoundRobinLoadBalancerBuilder

public DelegatingRoundRobinLoadBalancerBuilder(RoundRobinLoadBalancerBuilder<ResolvedAddress,C> delegate)

Creates a new builder which delegates to the provided RoundRobinLoadBalancerBuilder.

Parameters:

delegate - the delegate builder.

Method Details

delegate

protected final RoundRobinLoadBalancerBuilder<ResolvedAddress,C> delegate()

Returns the DelegatingRoundRobinLoadBalancerBuilder delegate.

Returns:

Delegate DelegatingRoundRobinLoadBalancerBuilder.

linearSearchSpace

public RoundRobinLoadBalancerBuilder<ResolvedAddress,C> linearSearchSpace(int linearSearchSpace)

Description copied from interface: RoundRobinLoadBalancerBuilder

Sets the linear search space to find an available connection for the next host.

When the next host has already opened connections, this LoadBalancer will perform a linear search for a connection that can serve the next request up to a specified number of attempts. If there are more open connections, selection of remaining connections will be attempted randomly.

Higher linear search space may help to better identify excess connections in highly concurrent environments, but may result in slightly increased selection time.

Specified by:

linearSearchSpace in interface RoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

linearSearchSpace - the number of attempts for a linear search space, 0 enforces random selection all the time.

Returns:

this.

backgroundExecutor

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

Description copied from interface: RoundRobinLoadBalancerBuilder

This LoadBalancer may monitor hosts to which connection establishment has failed using health checks that run in the background. The health check tries to establish a new connection and if it succeeds, the host is returned to the load balancing pool. As long as the connection establishment fails, the host is not considered for opening new connections for processed requests. If an Executor is not provided using this method, a default shared instance is used for all LoadBalancers created by this factory.

RoundRobinLoadBalancerBuilder.healthCheckFailedConnectionsThreshold(int) can be used to disable this mechanism and always consider all hosts for establishing new connections.

Specified by:

backgroundExecutor in interface RoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

backgroundExecutor - Executor on which to schedule health checking.

Returns:

this.

See Also:

• RoundRobinLoadBalancerBuilder.healthCheckFailedConnectionsThreshold(int)

healthCheckInterval

public RoundRobinLoadBalancerBuilder<ResolvedAddress,C> healthCheckInterval(Duration interval,
 Duration jitter)

Description copied from interface: RoundRobinLoadBalancerBuilder

Configure an interval for health checking a host that failed to open connections. If no interval is provided using this method, a default value will be used.

RoundRobinLoadBalancerBuilder.healthCheckFailedConnectionsThreshold(int) can be used to disable the health checking mechanism and always consider all hosts for establishing new connections.

Specified by:

healthCheckInterval in interface RoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

interval - interval at which a background health check will be scheduled.

jitter - the amount of jitter to apply to each retry interval.

Returns:

this.

See Also:

• RoundRobinLoadBalancerBuilder.healthCheckFailedConnectionsThreshold(int)

healthCheckResubscribeInterval

public RoundRobinLoadBalancerBuilder<ResolvedAddress,C> healthCheckResubscribeInterval(Duration interval,
 Duration jitter)

Description copied from interface: RoundRobinLoadBalancerBuilder

Configure an interval for re-subscribing to the original events stream in case all existing hosts become unhealthy.

In situations when there is a latency between ServiceDiscoverer propagating the updated state and all known hosts become unhealthy, which could happen due to intermediate caching layers, re-subscribe to the events stream can help to exit from a dead state.

RoundRobinLoadBalancerBuilder.healthCheckFailedConnectionsThreshold(int) can be used to disable the health checking mechanism and always consider all hosts for establishing new connections.

Specified by:

healthCheckResubscribeInterval in interface RoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

interval - interval at which re-subscribes will be scheduled.

jitter - the amount of jitter to apply to each re-subscribe interval.

Returns:

this.

See Also:

• RoundRobinLoadBalancerBuilder.healthCheckFailedConnectionsThreshold(int)

healthCheckFailedConnectionsThreshold

public RoundRobinLoadBalancerBuilder<ResolvedAddress,C> healthCheckFailedConnectionsThreshold(int threshold)

Description copied from interface: RoundRobinLoadBalancerBuilder

Configure a threshold for consecutive connection failures to a host. When the LoadBalancer consecutively fails to open connections in the amount greater or equal to the specified value, the host will be marked as unhealthy and connection establishment will take place in the background repeatedly until a connection is established. During that time, the host will not take part in load balancing selection.

Use a negative value of the argument to disable health checking.

Specified by:

healthCheckFailedConnectionsThreshold in interface RoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Parameters:

threshold - number of consecutive connection failures to consider a host unhealthy and eligible for background health checking. Use negative value to disable the health checking mechanism.

Returns:

this.

See Also:

• RoundRobinLoadBalancerBuilder.backgroundExecutor(Executor)

build

public LoadBalancerFactory<ResolvedAddress,C> build()

Description copied from interface: RoundRobinLoadBalancerBuilder

Builds the LoadBalancerFactory configured by this builder.

Specified by:

build in interface RoundRobinLoadBalancerBuilder<ResolvedAddress,C extends LoadBalancedConnection>

Returns:

a new instance of LoadBalancerFactory with settings from this builder.