LoadBalance Extension

Summary

Pick one from service providers and fire the invocation.

Extension Interface

org.apache.dubbo.rpc.cluster.LoadBalance

Extension Configuration

<dubbo:protocol loadbalance="xxx" />
<!-- default configuration, will take effect when loadbalance is not configured in <dubbo:protocol> -->
<dubbo:provider loadbalance="xxx" />

Existing Extension

  • org.apache.dubbo.rpc.cluster.loadbalance.RandomLoadBalance
  • org.apache.dubbo.rpc.cluster.loadbalance.RoundRobinLoadBalance
  • org.apache.dubbo.rpc.cluster.loadbalance.LeastActiveLoadBalance

Extension Guide

Directory layout:

src
 |-main
    |-java
        |-com
            |-xxx
                |-XxxLoadBalance.java (LoadBalance implementation)
    |-resources
        |-META-INF
            |-dubbo
                |-org.apache.dubbo.rpc.cluster.LoadBalance (plain text file with the content: xxx=com.xxx.XxxLoadBalance)

XxxLoadBalance.java:

package com.xxx;
 
import org.apache.dubbo.rpc.cluster.LoadBalance;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Invocation;
import org.apache.dubbo.rpc.RpcException; 
 
public class XxxLoadBalance implements LoadBalance {
    public <T> Invoker<T> select(List<Invoker<T>> invokers, Invocation invocation) throws RpcException {
        // ...
    }
}

META-INF/dubbo/org.apache.dubbo.rpc.cluster.LoadBalance:

xxx=com.xxx.XxxLoadBalance