Cluster Extension

Summary

Group service providers in a cluster, and treat them as one single provider.

Extension Interface

org.apache.dubbo.rpc.cluster.Cluster

Extension Configuration

<dubbo:protocol cluster="xxx" />
<!-- default configuration, will take affect if cluster attribute is not configured in <dubbo:protocol>  -->
<dubbo:provider cluster="xxx" />

Existing Extensions

  • org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterWrapper
  • org.apache.dubbo.rpc.cluster.support.FailoverCluster
  • org.apache.dubbo.rpc.cluster.support.FailfastCluster
  • org.apache.dubbo.rpc.cluster.support.FailsafeCluster
  • org.apache.dubbo.rpc.cluster.support.FailbackCluster
  • org.apache.dubbo.rpc.cluster.support.ForkingCluster
  • org.apache.dubbo.rpc.cluster.support.AvailableCluster
  • org.apache.dubbo.rpc.cluster.support.MergeableCluster
  • org.apache.dubbo.rpc.cluster.support.BroadcastCluster
  • org.apache.dubbo.rpc.cluster.support.registry.ZoneAwareCluster

Extension Guide

Directory layout:

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

XxxCluster.java:

package com.xxx;
 
import org.apache.dubbo.rpc.cluster.Cluster;
import org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker;
import org.apache.dubbo.rpc.cluster.Directory;
import org.apache.dubbo.rpc.cluster.LoadBalance;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Invocation;
import org.apache.dubbo.rpc.Result;
import org.apache.dubbo.rpc.RpcException;
 
public class XxxCluster implements Cluster {
    public <T> Invoker<T> merge(Directory<T> directory) throws RpcException {
        return new AbstractClusterInvoker<T>(directory) {
            public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
                // ...
            }
        };
    }
}

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

xxx=com.xxx.XxxCluster