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