Module io.inverno.mod.discovery.http

Package io.inverno.mod.discovery.http

Class MinLoadFactorTrafficLoadBalancer

java.lang.Object

io.inverno.mod.discovery.http.MinLoadFactorTrafficLoadBalancer

All Implemented Interfaces:

TrafficLoadBalancer<HttpServiceInstance,UnboundExchange<?>>

public class MinLoadFactorTrafficLoadBalancer
extends Object
implements TrafficLoadBalancer<HttpServiceInstance,UnboundExchange<?>>

An HTTP traffic load balancer that selects the service instance with the minimum load factor from a random subset of instances.

In order to select a service instance, the load balancer first selects getChoiceCount() instances and calculates a score for each of them based on the following formula:

 score = instance_weight * (1 - instance_load_factor) ^ bias
 

The getBias() is used to increase the importance of the load factor: the greater it is, the more instances with lower load factor are selected.

The instance with the highest score is eventually then selected.

Since:

1.12

Author:

Jeremy Kuhn

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	MinLoadFactorTrafficLoadBalancer.Factory	A minimum load factor traffic load balancer factory.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_BIAS	The default bias on load factor.
static final int	DEFAULT_CHOICE_COUNT	The default choice count.

Constructor Summary

Constructors

Constructor	Description
MinLoadFactorTrafficLoadBalancer(Collection<HttpServiceInstance> instances)	Creates a minimum load factor traffic load balancer.
MinLoadFactorTrafficLoadBalancer(Collection<HttpServiceInstance> instances, int choiceCount, int bias)	Creates a minimum load factor traffic load balancer.

Method Summary

Modifier and Type	Method	Description
int	getBias()	Returns the load factor bias used to increase the importance of load factor when selecting an instance.
int	getChoiceCount()	Returns the number of service instances to consider when selecting an instance.
Mono<HttpServiceInstance>	next(UnboundExchange<?> serviceRequest)	Returns the next service instance to use to process the specified service request.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_CHOICE_COUNT

public static final int DEFAULT_CHOICE_COUNT

The default choice count.

See Also:

• Constant Field Values

DEFAULT_BIAS

public static final int DEFAULT_BIAS

The default bias on load factor.

See Also:

• Constant Field Values

Constructor Details

MinLoadFactorTrafficLoadBalancer

public MinLoadFactorTrafficLoadBalancer(Collection<HttpServiceInstance> instances)

Creates a minimum load factor traffic load balancer.

Parameters:

instances - a collection of HTTP service instances

MinLoadFactorTrafficLoadBalancer

public MinLoadFactorTrafficLoadBalancer(Collection<HttpServiceInstance> instances,
 int choiceCount,
 int bias)

Creates a minimum load factor traffic load balancer.

Parameters:

instances - a collection of HTTP service instances

choiceCount - the choice count

bias - the bias on load factor

Method Details

getChoiceCount

public int getChoiceCount()

Returns the number of service instances to consider when selecting an instance.

Returns:

the choice count

getBias

public int getBias()

Returns the load factor bias used to increase the importance of load factor when selecting an instance.

The greater it is, the more instances with lower load factor are selected.

Returns:

the load factor bias

next

public Mono<HttpServiceInstance> next(UnboundExchange<?> serviceRequest)

Description copied from interface: TrafficLoadBalancer

Returns the next service instance to use to process the specified service request.

Specified by:

next in interface TrafficLoadBalancer<HttpServiceInstance,UnboundExchange<?>>

Parameters:

serviceRequest - a service request

Returns:

a Mono emitting the next service instance